DE102013108367A1 - Apparatus and method for recording radiographic images in a computer tomography - Google Patents

Abstract

The invention relates to a method for recording a plurality of radiographic images of a measurement object for performing a computed tomography, wherein radiographic images are recorded in a plurality of rotational positions. In this case, a computed tomography sensor is used, which consists of at least one radiation source, at least one scintillator running flat and at least one planar, optical detector. The radiation emitted by the scintillator is at least partially detected by the detector. In this case, the area of the scintillator detected by the optical detector and emitting the optical radiation is adjusted in size and / or position.

Description

The invention relates to a method and to a device for recording a plurality of radiographic images of a measurement object for performing a computed tomography.

The computed tomography preferably relates to the determination of dimensional features on a measurement object, wherein from the plurality of recorded radiographic images in different rotational positions between the measurement object and computed tomography sensor, at least and consists of a radiation source such as X-ray tube, at least one area scintillator and at least one planar running, optical Detector, a so-called voxel volume is reconstructed and from which surface measurement points are generated, but is not limited thereto.

Likewise, evaluations on the voxel volume can be carried out, for example the known methods of material inspection, for example the analysis of material inhomogeneities, inclusions or voids or the like.

The invention relates in particular to a device and the use of this device for the method according to the invention, wherein no already assembled unit comprising a scintillator and an optical detector is used as the detector for the measuring radiation, as is usually done according to the prior art, but Scintillator and optical detector are constructed separately from each other. The scintillator is used to convert the received measurement radiation into optical radiation, which can be received by an optical detector with a plurality of photosensitive elements such as a CCD or CMOS camera. In order to achieve the highest possible resolution scintillators are often provided with ancillary equipment, such as many tubular, the resulting optical radiation-conducting elements. In addition, the achievable resolution is also influenced by the resolution of the optical detector used.

Devices with an optical detector separated from the scintillator have the advantage that an optical system can be used to increase the resolution between the scintillator and the optical detector, as described, for example, in US Pat US 7,400,704 is described. In the US 7,400,704 However, it is disadvantageous that different optical magnifications can be used only by means of a revolver. This is complex, it takes a lot of space and the position of the optics used in each case can only be adjusted inaccurate. In addition, it is not possible to measure at different locations with respect to the scintillator. The in the US 7,400,704 described displacement of the optical detector in the direction of its optical axis serves only either the fine adjustment of the scintillator in the focal plane of the optics or, when moving together with the scintillator, the adaptation of computed tomographic magnification. However, the detected area of the scintillator can not be changed in its size or position. A shift perpendicular to the optical axis is in the US 7,400,704 merely intended to align the optical detector centered to the object to be measured.

Due to the local separation of scintillator and optical detector, it is also possible to arrange a flipping mirror between the two in order to limit the installation space in the direction of the measuring radiation and to protect the optical detector from the measuring radiation. The US 6,353,657 describes a multiple deflection of the radiation emitted by the scintillator optical radiation, which is recorded by two fixedly arranged optical detectors, which may also contain a permanently installed optics. The two optical detectors thereby capture overlapping areas of the scintillator, which, however, can only be assembled inaccurately into an overall image. A similar invention using multiple optical detectors is in the US 6,483,893 described. A deflection mirror, which serves as a beam splitter for two different energy ranges, is in the US 7,286,640 described.

A disadvantage of the prior art is that the detected by the optical detector portion of the scintillator, which emits the optical radiation, in its size and position is not freely adjustable. It is also unsolved to detect several areas of the scintillator, preferably also in different resolutions. For example, it is not possible to capture large areas of a scintillator completely in high resolution.

It is likewise disadvantageous in the prior art that, when deflecting mirrors are used, they usually have to have a correspondingly large extent in order to reflect the entire optical radiation emitted by the scintillator.

The invention relates to a device and a method for recording a plurality of radiographic images of a measurement object for performing a computed tomography, wherein radiographic images in a plurality of rotational positions, set by a rotating device such as mechanical axis of rotation in which the measurement object and a computed tomography sensor are arranged rotated relative to each other , preferably the measurement object is rotated, recorded, wherein the computed tomography sensor at least consists of a radiation source such as an X-ray tube, at least one scintillator and at least one areal exported, optical detector, wherein the radiographic images are taken by at least one optical detector and reconstructed into a voxel volume from which preferably surface points are determined at material transitions wherein the optical radiation emitted by the scintillator is at least partially detected by the at least one optical detector.

The object of the present invention is to avoid the disadvantages of the prior art. In particular, it should be achieved that the size, the position and the resolution for the area of the scintillator detected by the optical detector are freely selectable and can be set as quickly as possible and also several areas, possibly with high resolution, can be detected.

It is likewise an object of the invention to provide a compact structure for detecting the optical radiation emitted by the scintillator. Preferably, the optical detector should be constructed protected by the measuring radiation of the radiation source.

This object is achieved by the present invention essentially in that the first area and / or further areas of the scintillator detected by the optical detector are set in size and / or position, preferably by the optical detector and the scintillator being displaced relative to one another as well as through an appropriate device that provides the means to the appropriate settings.

For setting the area of the scintillator respectively detected by the optical detector, several alternatives are provided according to the invention.

On the one hand, the optical detector and the scintillator are displaced relative to one another in the direction of the normal direction of the optical detector. This makes it possible to adapt the size of the detected area of the scintillator. In this case, the use of an optical system is initially not necessary, but inasmuch as an optic is used, the working distance of the optics must be adjusted accordingly, so that a sharp image of the scintillator takes place. In addition, according to the invention, the displacement of the optical detector and the scintillator relative to each other is perpendicular to the direction of the normal direction of the optical detector. This adjusts the position of the detected area within the entire optical radiation emitting area of the scintillator. In order to realize this relative displacement, precise linear axes, such as are used, for example, in coordinate measuring machines, are provided according to the invention, which are equipped with position measuring systems for determining the respectively assumed positions. Corresponding axes or positioning systems are also used to move the lens groups to adjust the working distance and the optical magnification of the optics. As a result, it is also possible in advance to measure in each case the range detected in each case, for example by measuring a calibrated standard.

Preferably, the displacement of the optical detector, and not of the scintillator, since the optical detector can usually have a smaller size.

In a first alternative embodiment, a deflection mirror is arranged between the scintillator and the optical detector. Deflection mirror and scintillator are arranged displaceable relative to one another, preferably in the direction of the normal direction of the deflection mirror, whereby, depending on the position of the deflection mirror, another region of the scintillator is imaged onto the optical detector. The deflecting mirror makes it possible to arrange the optical detector outside the direct or deflected radiation of the radiation source, for example in a housing made of a material absorbing the measuring radiation, for example lead in the case of the preferably used X-ray radiation. Only the area to enter the optical radiation must remain open. This radiation protection panel can be fixed, or preferably, moved with the optical detector with. It is also achieved by the deflecting mirror that the space in the direction of propagation direction of the radiation of the radiation source can be advantageously kept small.

In a second alternative embodiment, the rotation of the deflection mirror is also provided. This also makes it possible to select the area of the scintillator which is imaged onto the optical detector. This is possible by the deflection mirror is rotated by a direction different from its normal direction.

The third alternative embodiment provides that an optical system is arranged between the scintillator and the optical detector. For maximum flexibility, the working distance or the optical reproduction scale can be set for this optic. By optics, it is possible to achieve a much higher resolution for the radiographic images than with an optical detector fixed behind the scintillator.

The optical magnification of the optics is to be distinguished from the computer tomographic magnification, which is defined by the ratio of the two variables "distance radiation source to scintillator" and "distance radiation source to object to be measured". Depending on the computer tomographic magnification, the measuring range is obtained in computed tomography. This is defined by the area recorded by the detector, ie the combination of scintillator and optical detector, in the respective relative position of the components radiation source, measurement object and detector. This can therefore, in the case that the optical detector does not detect the entire scintillator, be smaller than limited by the scintillator. By using optics, it becomes possible to change the size and resolution of the detected area of the scintillator even without moving the optical detector or optics to the scintillator. For maximum flexibility, there are optics for which, for example, optical magnification and working distance can be set separately.

The four explained embodiments can also be combined. Thus, for example, the adjustment of the size of the detected area by means of the movement of the optical detector in the direction of the scintillator and changing the working distance of the optics moved together with the optical detector, while the position of the detected area by the lateral movement of the unit of optical detector and Optics done.

This combination is also useful and provided when a deflection mirror is used. If, for example, this only has a size which is approximately sufficient to image the area detected by the optics or the optical detector, which is only a partial area of the scintillator, this is moved together with the optical detector and optionally the optics. In this case, the optics can be arranged between the deflecting mirror and the detector, but also between the scintillator and the deflecting mirror. In other words, the deflection mirror is arranged between the scintillator and the optical detector or between the optics and the optical detector.

It makes sense for the optics to have only an appropriate size in order to image the area of the scintillator that can be detected by the optical detector, without, however, leading to a limitation of the invention. Optics of the size to map the entire scintillator are correspondingly more expensive and take up more space. However, the deflection mirror can also have a corresponding size in order to reflect the entire optical radiation emitted by the scintillator necessary for the measurement. Then it is preferably fixed to the scintillator.

• – der optische Detektor und der Szintillator relativ zueinander in Richtung und/oder senkrecht zur Normalenrichtung der Detektorfläche des optischen Detektors verschoben werden und/oder
• – ein zwischen dem Szintillator und dem optischen Detektor angeordneter Umlenkspiegel und der Szintillator relativ zueinander zumindest in Richtung der Normalenrichtung des Umlenkspiegels verschoben werden und/oder
• – ein zwischen dem Szintillator und dem optischen Detektor angeordneter Umlenkspiegel, vorzugsweise gemeinsam mit dem optischen Detektor, relativ zum Szintillator um zumindest eine von der Normalenrichtung des Umlenkspiegels abweichende Richtung gedreht wird und/oder
• – für eine zwischen dem Szintillator und dem optischen Detektor angeordnete Optik der Arbeitsabstand und/oder der optische Abbildungsmaßstab eingestellt wird,

wobei vorzugsweise der erste Bereich und/oder zumindest ein weiterer Bereich lediglich ein Teil der gesamten, die optische Strahlung abgebbaren Region des Szintillators abdeckt.Particularly noteworthy is that for adjusting the area of the scintillator detected by the optical detector

• - The optical detector and the scintillator are shifted relative to each other in the direction and / or perpendicular to the normal direction of the detector surface of the optical detector and / or
• A deflecting mirror arranged between the scintillator and the optical detector and the scintillator are displaced relative to each other at least in the direction of the normal direction of the deflection mirror and / or
• A deflecting mirror arranged between the scintillator and the optical detector, preferably together with the optical detector, is rotated relative to the scintillator by at least one direction deviating from the normal direction of the deflecting mirror and / or
• For an optic arranged between the scintillator and the optical detector, the working distance and / or the optical magnification is set,

wherein preferably the first region and / or at least one further region covers only a part of the entire, the optical radiation deliverable region of the scintillator.

Furthermore, the invention is characterized in that the position of the individual detected areas of the scintillator to each other is determined by the displacement or rotation for setting the respective area is determined and / or by the optics in the respective setting for working distance and optical measurement scale or the optical detector directly detected area is measured and / or by the position of the plurality of optical detectors used is determined to each other.

A particular advantage of the invention is that the measured data, ie the radiographic images, voxel volumes calculated therefrom or the surface points which were determined in different settings for the detected area of the scintillator, can be evaluated jointly, ie in a coordinate system. For this purpose, the position determined by means of the measuring systems of the positioning systems is required in order to be able to assign the different measurement data in space to one another.

It is preferably provided that radiographic images are recorded when several, different regions of the scintillator are detected by the at least one optical detector and the radiographic images, preferably per rotational position, and / or the voxel volumes reconstructed per region and / or surface points determined per region continue to be common be processed or evaluated, the is taken into account in the detection of the respective areas relative to each other position of the areas.

In particular, the invention is characterized in that between the scintillator and the optical detector, an optic is arranged, for which the working distance and the optical magnification is set independently and / or which is displaced together with the optical detector.

Preferably, the invention provides that a deflection mirror arranged between the scintillator and the optical detector or between the optical system and the optical detector is used to change the direction of propagation of at least part of the optical radiation emitted by the scintillator to a correspondingly arranged optical detector or the correspondingly arranged optical system wherein, preferably, at least the optical detector is arranged outside the region covered by the direct and / or reflected and / or scattered radiation of the radiation source, preferably by at least the optical detector being surrounded by a radiation protection lining outside the region in which the optical radiation is incident is, wherein the radiation protection panel is preferably moved together with the optical detector.

It should also be emphasized that optical radiation from the entire region of the scintillator which can be emitted from the optical radiation is reflected by the deflecting mirror in the direction of the optical detector and the deflecting mirror is fixed relative to the scintillator, or that only a part of the total of the deflecting mirror, the optical Radiation detectable region of the scintillator is reflected in the direction of the optical detector and the deflection mirror is moved separately or together with the optical detector or together with the optics or together with the optics and the optical detector relative to the scintillator.

The device according to the invention can also be used for a so-called raster tomography, for example for expanding the measuring range of the computed tomography sensor. In this case, several sections of the measured object are sequentially detected. The sections are perpendicular to the mean beam direction of the radiation source, ie in the same computer tomographic magnification, offset and the measurement object is moved according to the individual measurements in translation with respect to the computed tomography sensor. If the displacement takes place along the direction in which the rotation takes place, the section in its entirety, during the complete rotation of the measurement object, does not leave the area detected by the detector, ie the area covered by the transmission images. In a shift perpendicular to it, from the radiographic images of the multiple measurements for each rotational position, a resulting radiographic image is composed. As a result, corresponding measured values are available for each subarea of the section in all rotational positions and the reconstruction for determining volume data is possible.

Preferably, it is provided that, to expand the measuring range of the computed tomography sensors in the respectively set computer tomographic magnification, the measurement object and the computed tomography sensors are displaced into a plurality of relative positions relative to one another, translationally, and preferably perpendicular to the mean beam direction of the radiation source, and in each of the plurality of relative positions transmissive images in a multiplicity be taken by turning positions.

However, according to the invention, the scanning tomography can also be carried out by displacing the optical detector and the scintillator relative to one another for the detection of the different sections. This is at least possible if the optical detector detects only a part of the scintillator surface, the measurement object is to be measured in the highest possible computer tomographic magnification, for example to obtain a high resolution, and thereby covers a larger part of the scintillator.

The invention is also characterized in that, in order to widen the measuring range of the computed tomography sensors in the respectively set computer tomographic magnification, different areas of the scintillator are detected by the optical detector, the distance between scintillator and optical detector being constant along the optical axis for the several areas, and wherein preferably the optical detector and the scintillator are displaced relative to each other, perpendicular to the normal direction of the detector surface of the optical detector.

It is also provided in each rotational position successively adjust the multiple relative positions between the optical detector and scintillator to detect the multiple sections. Alternatively, however, the multiple rotational positions can be set only in a first and then in other relative positions.

The classical idea of scanning tomography and the extension of the relative movement between the scintillator and the optical detector can also be combined to capture, for example, measuring objects of the size or in a computer tomographic magnification that lead to an image in the scintillator level that exceeds the boundaries of the scintillator.

However, the measurement object is preferably only so large or is arranged only in a computer tomographic magnification such that it is completely imaged on the scintillator in the multiplicity of rotational positions. The adjustment of the area of the scintillator detected by the optical detector takes place while the scintillator remains fixed relative to the object to be measured, for example by displacement of the optical detector and, if appropriate, of the optics and optionally of the deflection mirror. Thus, it is possible to perform the entire measurement object without a translational movement between the measurement object and the radiation source and the scintillator.

In particular, the invention is characterized in that, at least for adjusting the area of the scintillator detected by the optical detector, the scintillator remains fixed relative to the measurement object and preferably the measurement object in the plurality of rotational positions is completely imaged on the scintillator.

According to a particular suggestion, it is provided that the size of the area of the scintillator detected by the optical detector, and preferably the achievable resolution in the detection of the area with the optical detector, is adjusted by adjusting the optical magnification of the optics used.

In particular, the invention also relates to the use of one or more so-called local tomographies, which are also referred to as "region of interest tomography" (ROI-CT). In the case of ROI-CT, only a section of the measurement object, called ROI, is tomographed, ie, metrologically determined. This section is to be distinguished from a section of the measuring object, as already explained. The ROI-CT is characterized in that in one or more rotational positions at least a portion of the measurement object is not detected by the respective radiographic image, which is detected in at least one other rotational positions of the corresponding radiographic image, or in other words, during rotation at least a subregion of the measurement object leaves the region (measurement region) detected by the respective radiographic image, in particular in the direction perpendicular to the axis about which the rotation takes place, preferably the measurement object is rotated. Insofar as the measurement object or the detail of the measurement object is arranged in a plurality of rotational positions relative to the radiation of a radiation source, the rotation of the measurement object itself is thus preferably affected, but without restricting the invention thereto. Alternatively, the application of the inventive method is provided, wherein the measurement object remains stationary and at least the radiation source, preferably also the detector such as 2D X-ray detector, particularly preferably both together, are rotated about the measurement object. So there are subregions of the measurement object, which are detected due to the selected computer tomographic magnification and / or due to the dimensions of the measurement object in some, but not in all rotational positions. The reconstruction of the recorded radiographic images to a voxel volume is either initially not possible or at least leads to measurement errors.

When performing the measurement of a section in the context of an ROI-CT, however, it must first be ensured that the section is completely imaged on the scintillator in all rotational positions used for the evaluation and detected by the optical detector.

Two alternatives are provided for the complete illustration of the cutout in all rotational positions on the scintillator. In the first, the measurement object is arranged on the mechanical axis of rotation such that the cutout lies approximately in the middle of it. The second alternative provides that the cutout is arranged eccentrically to the mechanical axis of rotation, but the rotation axis during its rotation is additionally moved in a circular path such that the cutout is moved about a virtual axis of rotation different from the mathematical axis of rotation of the mechanical axis of rotation. This virtual axis of rotation preferably runs centrally to the cutout, as a result of which it is imaged in approximately the same area of the scintillator in all rotational positions. This has the advantage that any cutouts can be made on a measurement object without changing the arrangement on the mechanical axis of rotation.

For the complete imaging of the detail in all rotational positions on the optical detector, it is provided according to the invention that the optical detector is adjusted accordingly during the rotation relative to the scintillator. Insofar as the area detectable by the optical detector is smaller than the image of the cutout on the scintillator, it is provided to set several relative positions between the optical detector and the scintillator successively in each rotational position in order to detect the complete section. Alternatively, however, the multiple rotational positions can be set only in a first and then in other relative positions. In all cases, there is the advantage that the cutout does not have to be imaged exactly at the same point of the scintillator in all rotational positions, since the optical Detector of the picture of the clipping is practically tracked.

It is particularly noteworthy that, for recording radiographic images of a section of a measurement object, the detail in all rotational positions used for the evaluation is completely imaged on the scintillator by the cut arranged on the mechanical axis of rotation and / or the mechanical axis of rotation during rotation on a corresponding path, preferably circular path, is moved so that the section rotates about a different from the mathematical axis of rotation of the mechanical axis of rotation, so-called virtual axis of rotation, for at least one, preferably several rotational positions of the measurement object at least a portion of the measurement object not from each recorded radiographic image is detected, wherein this portion is preferably in the direction perpendicular to the axis about which the measurement object is rotated, away from the detected area, and wherein during the rotation of the optical detector relative to the scintillator is adjusted so that the optical radiation resulting from the image of the section on the scintillator is completely detected by the optical detector in all rotational positions used for the evaluation.

However, in order to obtain the missing information in the some rotational positions of the subareas of the measurement object, which are recorded in some, but not in all rotational positions due to the chosen computer tomographic magnification and / or due to the dimensions of the test object, three alternatives are provided.

The first alternative provides that an additional computed tomography measurement is performed with reduced computed tomography magnification, whereby a larger area of the measurement object is imaged on the scintillator. In this so-called overview scan, the sub-areas in all rotational positions are also imaged on the scintillator, which in ROI-CT leave it in some rotational positions.

The second alternative is that additional radiation images are recorded at a reduced optical magnification. This is useful if, during the ROI-CT but also during the measurement in the reduced computerized tomographic magnification, not only the detail, but also the missing portions were imaged on the scintillator, but not detected by the optical detector in the selected original optical magnification , Due to the now set reduced optical magnification, the detected area increases in such a way that the missing areas are detected and measured.

The third alternative provides that the optical detector and the scintillator are adjusted relative to each other, preferably perpendicular to the normal direction of the detector surface of the optical detector. As a result, a correspondingly enlarged area is also detected, so that the missing areas are detected and measured.

The second as well as the third alternative thus provides an adjustment of the optics or the position of the optical detector. This adjustment can in turn be performed in each rotational position sequentially or alternatively after a plurality of rotational positions.

A combination of alternatives is also possible. As already explained, the reduction of the optical magnification can be used for the measurement with the reduced computer tomographic magnification. But the relative displacement between optical detector and scintillator is also useful for the measurement with the reduced computer tomographic magnification in order to detect a larger area of the scintillator. The combination of reduced optical magnification and relative displacement further increases this range.

• – Durchstrahlungsbilder bei verringertem optischen Abbildungsmaßstab aufgenommen werden und/oder
• – Durchstrahlungsbilder bei verringerter computertomografischen Vergrößerung aufgenommen werden und/oder
• – der optische Detektor und der Szintillator relativ zueinander verstellt werden, vorzugsweise senkrecht zur Normalenrichtung der Detektorfläche des optischen Detektors.

Furthermore, the invention is characterized in that the subareas of the measurement object which were detected only in some of the radiographic images are detected at least in the missing rotational positions by

• - Radiation images are recorded at reduced optical magnification and / or
• - Transmitted radiographs are taken at reduced computer tomographic magnification and / or
• - The optical detector and the scintillator are adjusted relative to each other, preferably perpendicular to the normal direction of the detector surface of the optical detector.

According to the invention, a so-called helix tomography is also provided. In this case, the measurement object is moved during a combination of rotational movement and translational movement along the mathematical axis of rotation of the mechanical axis of rotation or the computed tomography sensor with respect to the measurement object, as usual in medical computed tomography. The measurement object is thus displaced during the rotation relative to the computed tomography sensor in the direction of the axis about which the rotation takes place, in which case essentially the displacement Variety of rotational positions is set, in which the radiographic images are recorded.

Preferably, it is provided that a helical computed tomography is carried out, wherein the measurement object is displaced relative to the computed tomography sensor in the direction of the axis about which the rotation is substantially accompanied by the adjustment of the plurality of rotational positions in which the transmission images are recorded ,

A similar procedure takes place in the so-called inline CT. In this case, the computed tomography or the computed tomography sensor is integrated into a manufacturing or measuring line or the like, and the measurement object or a plurality of measured objects are continuously moved to the computed tomography sensor, for example by means of a conveyor belt or robot. Preferably, the rotational movement takes place by the rotation of the computed tomography sensor.

In particular, the invention is characterized in that the computed tomography sensor is integrated into a manufacturing or measurement line or the like and the measurement object or a plurality of measurement objects are continuously moved to the computed tomography sensor.

As a development for the classical helical or inline CT is also provided according to the invention that the optical detector detects only a certain area of the scintillator, namely the area resulting from the imaging of an adjustable limited portion of the measuring object on the scintillator, wherein the portion is substantially confined to a narrow area extending around the plane which is perpendicular to the direction of the axis about which rotation occurs and includes the mean beam direction of the radiation source. This limited range is characterized by reduced measurement errors due to so-called cone beam artifacts.

Preferably, the invention provides that the optical detector detects only the area of the scintillator which emits the optical radiation resulting from the imaging of an adjustable limited section of the measurement object on the scintillator, the section being essentially limited to a narrow area, which extends around the plane which is perpendicular to the direction of the axis about which the rotation takes place and which includes the central beam direction of the radiation source.

In particular in the case of a helix CT, the translational displacement of the measurement object in the direction of the axis about which the rotation occurs can also be simulated, ie replaced by the corresponding displacement of the optical detector. Although cone beam artifacts initially affect the measurement, other solutions exist to avoid or reduce it, such as the use of slit-shaped beam diaphragms, which in this case would have to be displaced together with the optical detector.

It should also be emphasized that a helix computed tomography is performed, wherein the displacement of the measurement object relative to the computed tomography sensor in the direction of the rotation axis is replaced by the optical detector is displaced such that successively radiographic images of portions of the measurement object are added, which are offset in the direction of the axis about which the rotation takes place, wherein substantially the displacement of the optical detector is accompanied by the plurality of rotational positions in which the transmission images are recorded.

As already explained, it is fundamentally possible to adjust the respectively detected area of the scintillator during the change of the rotational position or in each case after one complete revolution.

Preferably, it is provided that the displacement for detecting different areas of the scintillator, during the change of the rotational position and / or between the recording of two successively recorded and used for computed tomography radiographic images, preferably repeatedly between the multiple settings is shifted back and forth, for example alternately to record radiographic images in at least two different optical magnifications or to record radiographic images at the same optical magnification and different detected, preferably in each case adjacent areas of the scintillator.

Further increase in measurement speed or resolution can be achieved by using multiple optical detectors to simultaneously detect different areas of the scintillator. Accurate measurements are in turn only possible if the position of the different areas is known to each other, so the position of the plurality of optical detectors is determined to each other. This is done in turn by means of the already mentioned path measuring systems with which the optical detectors are moved. The movement can take place for the plurality of optical detectors together or by means of a plurality of positioning systems separated from each other. If the optical detectors are fixed to one another, their distance is preferably calibrated Normal measured, as usual in coordinate metrology.

The invention is also characterized in that a plurality of optical detectors are used for the simultaneous detection of different areas of the scintillator, wherein the optical detectors are fixed to each other or movable to each other.

In particular, the invention is characterized in that the computed tomography sensor is operated integrated in a coordinate measuring machine.

The invention also relates to a device which is suitable for applying the method according to the invention, that is to say a device for recording a plurality of radiographic images of a measurement object for performing a computed tomography, wherein radiographic images in a plurality of rotational positions, adjustable by a rotary device such as a mechanical axis of rotation wherein the measurement object and a computed tomography sensor are arranged rotated relative to each other, preferably the measurement object is rotated, are receivable, wherein the computed tomography sensor at least consists of a radiation source such as X-ray tube, at least one scintillator and at least one areal exported, optical detector, wherein the radiographic images of at least one optical detector can be received and are reconstructable to a voxel volume from which preferably surface points can be determined at material transitions, wherein the scintillating Lator emitted optical radiation is at least partially detectable by the at least one optical detector. To achieve the object of the invention, the device is characterized in that means for adjusting the size and / or position of the detectable by the optical detector, the optical radiation emitting first region and / or other areas of the scintillator are present, preferably means with which the optical detector and the scintillator are displaceable relative to each other.

• – Mittel zur Verschiebung des optischen Detektors und des Szintillator relativ zueinander in Richtung und/oder senkrecht zur Normalenrichtung der Detektorfläche des optischen Detektors vorhanden sind und/oder
• – zwischen dem Szintillator und dem optischen Detektor ein Umlenkspiegel angeordnet ist und Mittel zur Verschiebung des Umlenkspiegels und des Szintillators relativ zueinander zumindest in Richtung der Normalenrichtung des Umlenkspiegels vorhanden sind und/oder
• – zwischen dem Szintillator und dem optischen Detektor ein Umlenkspiegel angeordnet ist und Mittel zur Drehung des Umlenkspiegels, vorzugsweise gemeinsam mit dem optischen Detektor, und des Szintillators relativ zueinander um zumindest eine von der Normalenrichtung des Umlenkspiegels abweichende Richtung vorhanden sind und/oder
• – zwischen dem Szintillator und dem optischen Detektor eine Optik angeordnet ist, für die der Arbeitsabstand und/oder der optische Abbildungsmaßstab einstellbar sind.

A device according to the invention is characterized in that the area of the scintillator detected by the optical detector can be adjusted by

• - means for displacing the optical detector and the scintillator relative to each other in the direction and / or perpendicular to the normal direction of the detector surface of the optical detector are present and / or
• A deflection mirror is arranged between the scintillator and the optical detector, and means for displacing the deflection mirror and the scintillator relative to each other are present at least in the direction of the normal direction of the deflection mirror and / or
• A deflecting mirror is arranged between the scintillator and the optical detector, and means for rotating the deflecting mirror, preferably together with the optical detector, and the scintillator relative to each other, are present at least one direction deviating from the normal direction of the deflecting mirror and / or
• - Between the scintillator and the optical detector, an optic is arranged, for which the working distance and / or the optical magnification are adjustable.

It should be emphasized in particular that measuring systems such as path measuring systems are present, which detect the displacements or rotation, triggered by the means for displacement, which are carried out for setting the respective area and / or which detect the position of the plurality of inserted optical detectors to each other.

The invention is also distinguished in particular by the fact that an evaluation device is provided which is suitable for jointly processing or evaluating radiographic images of a plurality of regions, preferably for each rotational position, and / or the surface points reconstructed per region and / or area points determined per region; is taken into account in the detection of the respective areas relative to each other position of the areas.

Preferably, it is provided that an optic is arranged between the scintillator and the optical detector, for which the working distance and the optical magnification can be set independently of one another and / or which is displaceable together with the optical detector.

It should also be emphasized that between the scintillator and the optical detector or between the optics and the optical detector, a deflection mirror for changing the propagation direction of at least a portion of the emitted from the scintillator optical radiation on a correspondingly arranged optical detector or the correspondingly arranged optics is arranged , wherein preferably at least the optical detector is arranged outside of the area covered by the direct and / or reflected and / or scattered radiation of the radiation source, preferably in that at least the optical detector is surrounded by a radiation protection lining outside the area in which the optical radiation is incident , wherein the radiation protection panel is preferably displaced together with the optical detector.

Preferably, the invention provides that the deflection mirror is arranged and has a size such that optical radiation is reflected from the entire, the optical radiation radiationable region of the scintillator in the direction of the optical detector and the deflection mirror is fixed relative to the scintillator, or that the deflecting mirror, preferably together with the optical detector or together with the optics or together with the optics and the optical detector, is displaceable relative to the scintillator and has such a size that only a part of the total, the optical radiation deliverable region of Scintillator is reflected in the direction of the optical detector.

In particular, the invention provides that means for displacement are provided in order to shift the measurement object and the computed tomography sensor system into a plurality of relative positions relative to one another, translationally, and preferably perpendicularly to the mean beam direction of the radiation source.

The invention is characterized in that a plurality of relative positions are adjustable between scintillator and optical detector, wherein the distance between scintillator and optical detector along the optical axis is constant, preferably the optical detector and the scintillator relative to each other, perpendicular to the normal direction of the detector surface of the optical detector are displaceable.

Preferably, it is provided that the scintillator is fixedly arranged relative to the measurement object and preferably the scintillator has a size in order to image the measurement object in the plurality of rotational positions completely on the scintillator.

In particular, it is provided that the optical magnification of the optics used is adjustable.

The invention is also characterized in that means are provided for displacing a section of a measuring object on the mechanical axis of rotation and / or for displacing the mechanical axis of rotation, during rotation, on a path, preferably a circular path.

In particular, the invention is also characterized in that the optical magnification is variable and / or means for changing the computed tomography magnification are present, preferably the mechanical axis of rotation in the direction of the central beam direction of the radiation source is displaceable, and / or means for adjusting the optical detector and of the scintillator relative to each other, preferably perpendicular to the normal direction of the detector surface of the optical detector, are present.

Furthermore, the invention is characterized in that means for displacement are provided in order to displace the measurement object and the computed tomography sensor relative to one another in the direction of the axis about which the rotation takes place.

It should be emphasized in particular that the means for shifting linear axes or multiple linear axes in positioning units, for example, multi-axis positioning units, and are preferably operated by a motor.

The invention is also characterized in particular by the fact that the computed tomography sensor is integrated into a manufacturing or measurement line or the like and the measurement object or several measurement objects are continuously displaceable to the computed tomography sensor, for example by means of a conveyor belt or robot or the like.

Preferably, it is provided that the means for displacement for adjusting the detected area of the scintillator during the change of the rotational position and / or between the recording of two successively recorded and used for computed tomography radiographic images are controlled.

It should also be emphasized that a plurality of optical detectors are provided for the simultaneous detection of different regions of the scintillator, wherein the optical detectors are arranged fixed to one another or movable relative to one another.

Preferably, the invention provides that the computed tomography sensor is integrated in a coordinate measuring machine.

Further details, advantages and features of the invention will become apparent not only from the claims, the features to be taken from them - alone and / or in combination - but also from the following description of the figures.

Show it:

1 an embodiment of the inventive device without deflecting mirror,

2 a first embodiment of the inventive device with deflecting mirror and

3 a second embodiment of the inventive device with deflecting mirror and

4 a third embodiment of the inventive device with deflecting mirror.

Based on 1 a first basic arrangement for implementing the method according to the invention is shown. For the computer tomographic measurement is the measurement object 2 on the mechanical axis of rotation 13 attached between the radiation source 1 and the scintillator 3 arranged. In several, typically several hundred, rotational positions of the measurement object 2 around the mathematical axis of rotation 14 around which the mechanical axis of rotation 13 turns, the measuring object of the measuring radiation 8th and the radiation attenuated by the measurement object 8th meets the scintillator 3 on. This converts the measuring radiation 8th at least partially in optical radiation 4 around, the scintillator 3 on the opposite side of the entrance of the measuring radiation 8th leaves. The optical radiation is at least partially through an optical detector 5 , such as a CCD or CMOS camera detects and determines radiographic images for each detected area. The voxel volume is either calculated directly from these 2D transmission images by means of reconstruction, or a resulting transmission image is determined for each rotational position, for example by combining the transmission images from a plurality of detected regions of the scintillator in order to reconstruct a larger part of the measurement object. At the voxel volume already first evaluations regarding the material or inclusions, blowholes or the like are possible. Furthermore, surface points are determined from the voxel volume by means of the known methods for surface extraction, which are used for the determination of features and dimensions, ie dimensional measured variables on these features, such as distances, angles, diameters and the like.

In 1 is based on the four subareas 2a . 2 B . 2c and 2d of the measurement object 2 the inventive method for adjusting the each detected by the optical detector portion of the scintillator 3 to which the subareas 2a to 2d be mapped, namely the areas 3a to 3d of the scintillator 3 represented. From the entire beam cone of the measuring radiation 8th form the subarea 8a the subarea 2a of the measurement object 2 on the area 3a of the scintillator, the subarea 8b the subarea 2 B of the measurement object 2 on the area 3b of the scintillator and the subarea 8c the subareas 2c and 2d on the areas 3c and 3d of the scintillator. To adjust the size and location of each of the optical detector 5 covered area 3a to 3d of the scintillator 3 is shown the preferred solution in which the optical detector 5 relative to the scintillator 3 or, additionally, the working distance and the optical magnification of one between the optical detector 5 and the scintillator 3 arranged optics 6 is set. The optics 6 is doing together with the optical detector 5 medium of the positioning unit 12-2 postponed. The positioning unit 12-2 contains funds 12a to 12c for displacement in the two axes perpendicular to the optical axis 15 of the optical detector 5 or the optics 6 (Medium 12a and 12b ) and in the direction of the optical axis 15 (Medium 12c ), such as linear axes, which preferably contain position measuring systems, that is, path measuring systems, in order to detect the set position or displacement as accurately as possible. The shift can also be limited to fewer directions. For example, the positioning in the direction of the optical axis 15 be waived if the working distance of the optics used 6 is constant.

To capture the area 3a are the optical detector 5 and the optics 6 in the position 7a arranged. To capture the area 3b the shift occurs through the means 12b perpendicular to the optical axis 15 in the position 7b , Exemplary for the section 8c the measuring radiation imaged areas 2c and 2d the measured object becomes a higher resolution for the detection of the corresponding areas 3c and 3d of the scintillator. For this purpose, there is additionally a shift in the direction of the optical axis 15 with the help of means 12c in the position 7c , where at the same time the working distance of the optics 6 was reduced and the optical magnification was increased, whereby the detectable range of the optics is smaller, but there is a higher resolution, with the now the range 3c is detected. The second position 7d is set to the missing area 3d capture. Alternative may be an optic 6 be used, in which the adjustment of the optical magnification takes place without changing the working distance, whereby the adjustment in the direction of the optical axis is not necessarily required.

However, the entire measurement object can also be divided into several subregions and recorded with the same resolution. In the case of measuring objects with a small diameter, there is only a displacement of the optical detector by the means 12b necessary. For thicker parts are positions adjusted by the means 12a , So in addition to the direction perpendicular to the plane extending necessary to capture the entire measurement object sequentially in sub-areas and, for example, to determine each rotation position a resulting radiographic image.

The inventive method is also used for so-called raster CT. The measurement object 3 becomes relative to the radiation source 1 and the scintillator 3 perpendicular to the mean beam direction of the measuring radiation 8th shifted into several relative positions and in these in the multiplicity of Rotary positions around the axis of rotation 14 Transmitted radiographs. The shift takes place, for example, by the positioning unit 12-1 representing the mechanical axis of rotation 13 together with the measuring object attached to it 3 moved to the relative positions. Here are both perpendicular directions to the axis of rotation 14 , also combined, possible. The direction perpendicular to the plane of the drawing is necessary for targets that are larger in diameter than the selected tomographic magnification on the scintillator 3 is shown. The setting of different relative positions of the DUT 2 also allows the adjustment of the optical detector 5 perpendicular to the optical axis 15 to replace. The opposite is the relative movement of the measurement object 3 by the adjustment of the optical detector 5 replaceable, at least for the areas of the test object imaged on the scintillator 5 , Both movements can be combined according to the invention. Alternatively, the positioning unit 12-1 also on the mechanical axis of rotation 13 be arranged and the measurement object 3 on the positioning unit 12-1 attached and relative to the mechanical axis of rotation 13 be movable. The detection of each imaged on the scintillator areas of the measurement object 2 in turn, by setting appropriate positions of at least the optical detector 5 relative to the scintillator 3 , The resulting radiographic images then result from the multiple positions of the optical detector 6 in the several relative positions of the measurement object 3 , which increases the measuring range of the computer tomograph.

2 shows a first alternative of the device according to the invention using a deflecting mirror 9 for deflecting the scintillator 3 emitted radiation 4 in the direction of in the angled position 10 arranged unit of optical detector 5 , Optics 6 and positioning unit 12-2 , This results in the possibility, on the one hand the required space in the direction of the average measuring radiation 8th to shorten and on the other hand, a radiation protection panel 16 of lead, for example, around the optical detector 5 and optionally the optics 6 to arrange for damage from the measuring radiation 8th , so for example X-rays, to avoid. The radiation protection panel is preferred by the positioning unit 12-2 with the optical detector 5 and the optics 6 moved because it can be built to save space. Likewise, the deflection mirror 9 by a positioning unit separated in this example 12-3 movable. Shown is the position of the two positioning units 12-2 and 12-3 to capture the area 3b of the scintillator 3 , causing the subarea 2 B of the measurement object 2 is measured, ie radiographic images of this area or section or section of the measurement object 2 be recorded. The mechanical axis of rotation 13 is in the 2 not shown, but in turn to the rotation of the measurement object 2 around the axis of rotation 14 used. By shifting the deflecting mirror 9 by means of the positioning unit 12-3 becomes the respectively to be detected portion of the scintillator 3 adjusted by positioning in the direction of the optical axis 15 or perpendicular thereto in the direction in the drawing plane in or out. Here, the unit becomes an optical detector 5 , Optics 6 and radiation protection panel 16 moved accordingly, so that it offers this together with the deflection mirror 9 to move, as in the 3 , but here without representation of the radiation protection panel 16 represented. Alternatively, however, can also be to a positioning of optical detector 5 and optics 6 along the optical axis 15 be waived by the working distance of the optics 6 is adjusted accordingly. Preferably, the optical magnification of the optics is also adjustable, whereby the resolution is set with which the respectively detected area of the scintillator is resolved, as in 1 in the positions 7c and 7d already explained. Be the two positioning units 12-2 and 12-3 moved to an adjustment in the direction of the scintillator to or from this, ie the linear axis 12b the positioning unit 12-2 and the linear axis 12c the linear axis 12-3 used, so can also in this way the according to the working distance of the optics 6 necessary distance between scintillator 3 and optics 6 be adjusted so that each detected area of the scintillator 3 sharp on the optical detector 5 is shown.

In a further embodiment, shown in FIG 4 , the optics 6 between the scintillator 3 and the deflecting mirror 9 arranged and with the deflection mirror 9 moved together by a positioning unit, not shown, or, as shown, also together with the optical detector 5 , Unlike in 2 or 3 illustrated embodiment, this arrangement is selected when an optic 6 is used with a short working distance, as is the case for example with large optical imaging scales. Alternatively, another separate positioning unit only for shifting the optics 6 be used.

In the case of the measured objects shown in the figures 2 can be one or more of the subareas 2a to 2d so-called sections of the measuring object, or so-called cutouts. Several sections are, as mentioned, measured by raster CT. If these are cutouts, these are measured by the already mentioned ROI-CT, with areas around the cutout existing, in some rotational positions in and in others outside of the on the scintillator pictured area. This case is, for example, when the subarea 2 B of the measurement object 2 should be measured in higher computer tomographic magnification and this closer to the radiation source 1 is arranged. For this purpose, for example, the linear axis 12b the positioning unit 12-1 used. Alternatively, the radiation source 1 and the scintillator 3 displaceable in the corresponding direction. In the higher computer tomographic magnification which now exists, the regions lying perpendicular to the plane of the drawing become around the section 2 B possibly only in some of the multitude of rotational positions on the scintillator 3 displayed. For the missing radiographic images of these regions, for example, computer tomographic measurements are taken at a lower magnification or nominal data such as CAD data.

However, an ROI-CT is also present if the regions mentioned on the scintillator 3 imaged but not from the optical detector 5 be recorded. For this case, the computer tomographic measurement can be replaced in the reduced magnification by the missing portions of the transmission images by displacement of the optical detector 5 be detected or by the detected area by changing the optical magnification of the optics 6 is increased accordingly. This can be done according to the invention in succession for all rotational positions, or each rotational position.

For example, if the section to be measured is not exactly centered on the mechanical axis of rotation, it wobbles about the mathematical axis of rotation 14 and is imaged during rotation on different areas of the scintillator. According to the invention, the optical detector 5 or optionally the optics 6 and a deflecting mirror 9 tracked by this tumbling motion to detect each of the corresponding area of the scintillator. This is especially useful if several sections on the same measurement object without a modified arrangement on the mechanical axis of rotation 13 make the measurement object so intentionally staggers. The measurement results of several sections, which are individually measured by a ROI-CT, can also be evaluated jointly according to the invention, since the position of the results of the individual measurements in space can be assigned to one another by using the positioning units used 12-1 to 12-3 Position measuring systems for the detection of the set displacement or position are present and the respectively set position is taken into account in the evaluation.

Alternatively, with a ROI-CT, the linear axes become 12b and 12c the positioning unit 12-1 used to the mechanical axis of rotation 13 so move on a circular path that is off center on the mechanical axis of rotation 13 arranged section of the measurement object in all rotational positions on the scintillator or center is displayed on the scintillator. The cutout rotates about a so-called virtual axis of rotation, preferably the axis of rotation 14 the centerless stationary mechanical axis of rotation 13 corresponds, with this axis of rotation 14 runs through the middle of the neckline. This leaves the image of the cutout at a fixed area on the scintillator, which passes through the optical detector 5 by appropriate shifting or adjustment of the optics 5 is detected.

Alternatively, arrangements are possible in which the deflection mirror is large enough to the complete optical radiation 4 redirect. In this case, the deflection mirror can also be fixed and only the optical detector 5 and the optics 6 are shifted to adjust the area of the scintillator to be detected.

It is also provided according to the invention, a plurality of optical detectors 5 to use for simultaneous detection of different areas of the scintillator. For example, those in the 1 represented areas 3a and 3b of the scintillator 3 also with two in the positions 7a and 7b arranged optical detectors 5 be recorded at the same time. For the two optical detectors can also be a common displacement by means of a positioning unit 12-2 respectively. To those of the two optical detectors 5 Evaluate recorded radiographic images together, is the position of the optical detectors 5 measured to each other or the set positions of the positioning units are again set and taken into account by means of the displacement measuring systems.

By integrating the computer tomographic arrangement according to the invention into a coordinate measuring machine, corresponding positioning systems such as linear axes and the required components for evaluating the position information and further processing for determining dimensions of features or between features as well as the software programs required therefor are already at least partially present, so that appropriate Measurements can be easily done. Likewise, controls are needed that regulate the corresponding movements of the positioning systems. These too are mostly present in coordinate measuring machines.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7400704 [0005, 0005, 0005, 0005]
• US 6353657 [0006]
• US 6483893 [0006]
• US 7286640 [0006]

Claims (39)

A method for recording a plurality of radiographic images of a measurement object for performing a computed tomography, wherein radiographic images in a plurality of rotational positions, set by a rotating device such as mechanical rotation axis in which the measurement object and a computed tomography sensor are arranged rotated relative to each other, preferably the measurement object is rotated, are recorded wherein the computed tomography sensor at least consists of a radiation source such as an X-ray tube, at least one scintillator and at least one areal exported, optical detector, wherein the radiographic images are taken by at least one optical detector and reconstructed into a voxel volume from which preferably determines surface points at material transitions be, wherein the optical radiation emitted by the scintillator is at least partially detected by the at least one optical detector, ge indicates that the optically radiation-emitting first region and / or further regions of the scintillator detected by the optical detector are adjusted in size and / or position, preferably by the optical detector and the scintillator being displaced relative to one another. A method according to claim 1, characterized in that for adjusting the respectively detected by the optical detector portion of the scintillator - the optical detector and the scintillator relative to each other in the direction and / or perpendicular to the normal direction of the detector surface of the optical detector are shifted and / or - an between the deflection mirror and the scintillator arranged relative to each other are displaced relative to one another at least in the direction of the normal direction of the deflection mirror and / or a deflection mirror arranged between the scintillator and the optical detector, preferably together with the optical detector, relative to the scintillator by at least one is rotated from the normal direction of the deflecting mirror deviating direction and / or - is set for an arranged between the scintillator and the optical detector optics of the working distance and / or the optical magnification, preferably e, the first region and / or at least one further region covers only a part of the entire region of the scintillator that can be emitted by the optical radiation. A method according to claim 1 or 2, characterized in that the position of the individual detected areas of the scintillator to each other is determined by the displacement or rotation is determined for setting the respective area and / or by that of the optics in the respective setting for working distance and optical magnification or the optical detector directly detected area is measured and / or by the position of the plurality of optical detectors used is determined to each other. Method according to at least one of the preceding claims, characterized in that radiographic images are recorded during the detection of a plurality of different regions of the scintillator by the at least one optical detector and the radiographic images, preferably per rotational position, and / or the voxel volumes reconstructed per region and / or or surface points determined per area are further processed or evaluated together, taking into account the location of the areas which is present when the respective areas are detected. Method according to at least one of the preceding claims, characterized in that an optic is arranged between the scintillator and the optical detector, for which the working distance and the optical magnification are set independently of one another and / or which is displaced together with the optical detector. Method according to at least one of the preceding claims, characterized in that a deflecting mirror arranged between the scintillator and the optical detector or between the optics and the optical detector for changing the propagation direction of at least part of the optical radiation emitted by the scintillator to a correspondingly arranged optical detector or the correspondingly arranged optics is used, wherein preferably at least the optical detector is arranged outside the area covered by the direct and / or reflected and / or scattered radiation of the radiation source, preferably by at least the optical detector being outside the area in which the optical radiation is incident is surrounded by a radiation protection panel, wherein the radiation protection panel is preferably moved together with the optical detector. Method according to at least one of the preceding claims, characterized in that optical radiation of the whole, the emitting optical radiation region of the scintillator is reflected by the deflection mirror in the direction of the optical detector and the deflection mirror is fixed relative to the scintillator, or that only a part of the total, the optical radiation detectable region of the scintillator is reflected by the deflection mirror in the direction of the optical detector and the deflection mirror is moved separately or together with the optical detector or together with the optics or together with the optics and the optical detector relative to the scintillator. Method according to at least one of the preceding claims, characterized in that in order to expand the measuring range of the computed tomography sensors in the respectively set computer tomographic magnification, the measurement object and the computed tomography sensors are displaced into a plurality of relative positions relative to one another, translationally and preferably perpendicular to the mean beam direction of the radiation source several relative positions each radiographic images are recorded in a variety of rotational positions. Method according to at least one of the preceding claims, characterized in that to expand the measuring range of the computed tomography sensor in the respectively set computer tomographic magnification different areas of the scintillator are detected by the optical detector, wherein the distance between the scintillator and optical detector along the optical axis for the plurality of areas is constant, and preferably wherein the optical detector and the scintillator are displaced relative to each other, perpendicular to the normal direction of the detector surface of the optical detector. Method according to at least one of the preceding claims, characterized in that, at least for adjusting the area of the scintillator detected by the optical detector, the scintillator remains fixed relative to the measurement object and preferably the measurement object in the plurality of rotational positions is completely imaged on the scintillator. Method according to at least one of the preceding claims, characterized in that the size of the area of the scintillator detected by the optical detector, and preferably the achievable resolution in the detection of the area with the optical detector, is adjusted by adjusting the optical magnification of the optics used , Method according to at least one of the preceding claims, characterized in that for receiving radiographic images of a section of a measurement object, the detail is completely displayed on the scintillator in all rotational positions used for the evaluation by the cutout arranged on the mechanical axis of rotation and / or the mechanical axis of rotation during rotation on a corresponding path, preferably circular path, is moved so that the section rotates about a different from the mathematical axis of rotation of the mechanical axis of rotation, so-called virtual axis of rotation, wherein for at least one, preferably several rotational positions of the measurement object at least a portion of the measurement object is not detected by the respective recorded radiation image, wherein this partial region is preferably away from the detected region in the direction perpendicular to the axis about which the measurement object is rotated, and wherein during the D The optical detector is adjusted relative to the scintillator in such a way that the optical radiation resulting from the imaging of the section on the scintillator is completely detected by the optical detector in all rotational positions used for the evaluation. A method according to claim 12, characterized in that the portions of the measurement object that have been detected only in some of the transmission images are detected at least in the missing rotational positions by - Transmitted radiation images at reduced optical magnification and / or - Transmitted radiation images with reduced computer tomographic magnification and / or - the optical detector and the scintillator are adjusted relative to each other, preferably perpendicular to the normal direction of the detector surface of the optical detector. Method according to at least one of the preceding claims, characterized in that a helical computed tomography is performed, wherein the measurement object is displaced relative to the computed tomography sensor in the direction of the axis about which the rotation takes place, wherein substantially the shift is accompanied by the plurality of rotational positions in which the radiographic images are recorded. A method according to claim 14, characterized in that the computed tomography sensor is integrated into a production or measurement line or the like and the measurement object or multiple measurement objects are continuously moved to the computed tomography sensor. A method according to claim 14 or 15, characterized in that the optical detector detects only the portion of the scintillator emitting the optical radiation resulting from the imaging of an adjustable limited portion of the measuring object on the scintillator, the portion being substantially narrow Area is limited, which extends around the plane, the is perpendicular to the direction of the axis about which the rotation takes place and the mean beam direction of the radiation source includes. Method according to at least one of the preceding claims, characterized in that a helical computed tomography is performed, wherein the displacement of the measurement object relative to the computed tomography sensor in the direction of the axis about which the rotation is replaced by the optical detector is shifted such that consecutively taking radiation images of portions of the measuring object which are offset in the direction of the axis about which the rotation takes place, wherein substantially the displacement of the optical detector is adjusted in accordance with the multiplicity of rotational positions in which the transmission images are recorded. Method according to at least one of the preceding claims, characterized in that the displacement for detecting different regions of the scintillator, during the change of the rotational position and / or between the recording of two successively recorded and used for computed tomography radiographic images, preferably multiple times between the multiple settings out and is moved, for example, alternately to receive radiographic images in at least two different optical magnifications or to record radiographic images at the same optical magnification and different detected, preferably adjacent each areas of the scintillator. Method according to at least one of the preceding claims, characterized in that a plurality of optical detectors are used for the simultaneous detection of different areas of the scintillator, wherein the optical detectors are fixed to each other or movable to each other. Method according to at least one of the preceding claims, characterized in that the computed tomography sensor is operated integrated in a coordinate measuring machine. Apparatus for recording a plurality of radiographic images of a measurement object for performing a computed tomography, wherein radiographic images in a plurality of rotational positions, adjustable by a rotating device such as mechanical axis of rotation in which the measurement object and a computed tomography sensor are arranged rotated relative to each other, preferably the measurement object is rotated, are receivable wherein the computed tomography sensor at least consists of a radiation source such as an X-ray tube, at least one scintillator and at least one areal exported, optical detector, the radiographic images of at least one optical detector can be received and are reconstructed to a voxel volume from the surface points of material transitions can be determined are, wherein the optical radiation emitted by the scintillator is at least partially detectable by the at least one optical detector, thereby geken nzeichnet that means for adjusting the size of and / or position of the detectable by the optical detector, the optical radiation emitting first region and / or other areas of the scintillator are present, preferably means by which the optical detector and the scintillator are relatively displaceable. Apparatus according to claim 21, characterized in that the area of the scintillator each detected by the optical detector is adjustable by - means for displacement of the optical detector and the scintillator relative to each other in the direction and / or perpendicular to the normal direction of the detector surface of the optical detector are present and / or - a deflecting mirror is arranged between the scintillator and the optical detector and means for displacing the deflecting mirror and the scintillator relative to each other are provided at least in the direction of the normal direction of the deflecting mirror and / or - a deflecting mirror is arranged between the scintillator and the optical detector and Means for rotating the deflecting mirror, preferably together with the optical detector, and the scintillator relative to each other by at least one of the normal direction of the deflecting mirror deviating direction are present and / or - between the scintillator and the an optical system is arranged for optical detector, for which the working distance and / or the optical magnification are adjustable. Apparatus according to claim 21 or 22, characterized in that measuring systems such as displacement measuring systems are present, which detect the shifts or rotation triggered by the means for displacement, which are carried out for setting the respective area and / or the location of the plurality of inserted detect optical detectors to each other. Device according to at least one of the preceding claims 21 to 23, characterized in that there is an evaluation device which is suitable, transmission images of several areas, preferably per rotational position, and / or the voxel volume reconstructed per area and / or surface points determined per area together be further processed or evaluated, taking into account the location of the areas to each other in the detection of the respective areas. Device according to at least one of the preceding claims 21 to 24, characterized in that between the scintillator and the optical detector, an optic is arranged, for which the working distance and the optical magnification is independently adjustable and / or which is displaceable together with the optical detector , Device according to at least one of the preceding claims 21 to 25, characterized in that between the scintillator and the optical detector or between the optics and the optical detector, a deflection mirror for changing the propagation direction of at least a portion of the emitted from the scintillator optical radiation to a correspondingly arranged optical Preferably, at least the optical detector is arranged outside of the area covered by the direct and / or reflected and / or scattered radiation of the radiation source, preferably by at least the optical detector outside the area in which the optical Radiation incident, is surrounded by a radiation protection panel, wherein the radiation protection panel is preferably displaced together with the optical detector. Device according to at least one of the preceding claims 21 to 26, characterized in that the deflection mirror is arranged and has a corresponding size, that optical radiation from the entire, the optical radiation-releasable region of the scintillator is reflected in the direction of the optical detector and the deflection mirror is arranged fixedly relative to the scintillator, or that the deflection mirror, preferably together with the optical detector or together with the optics or together with the optics and the optical detector, is arranged relative to the scintillator displaceable and has a size such that only a part of Whole, the optical radiation releasable region of the scintillator is reflected in the direction of the optical detector. Device according to at least one of the preceding claims 21 to 27, characterized in that means for displacement are provided in order to shift the measurement object and the computed tomography sensor relative to each other, translationally, and preferably perpendicular to the mean beam direction of the radiation source in a plurality of relative positions. Device according to at least one of the preceding claims 21 to 28, characterized in that a plurality of relative positions are adjustable between the scintillator and the optical detector, the distance between the scintillator and the optical detector being constant along the optical axis, preferably the optical detector and the scintillator relative to one another, are displaceable perpendicular to the normal direction of the detector surface of the optical detector. Device according to at least one of the preceding claims 21 to 29, characterized in that the scintillator is fixedly arranged relative to the measurement object and preferably the scintillator has a size to image the measurement object in the plurality of rotational positions completely on the scintillator. Device according to at least one of the preceding claims, characterized in that the optical magnification of the optics used is adjustable. Device according to at least one of the preceding claims 21 to 31, characterized in that means for displacing a section of a measuring object on the mechanical axis of rotation and / or for displacement of the mechanical axis of rotation during rotation, on a path, preferably circular path, are present. Apparatus according to claim 32, characterized in that the optical magnification is variable and / or means for changing the computed tomography magnification are present, preferably the mechanical axis of rotation in the direction of the central beam direction of the radiation source is displaceable, and / or means for adjusting the optical detector and of the scintillator relative to each other, preferably perpendicular to the normal direction of the detector surface of the optical detector, are present. Device according to at least one of the preceding claims 21 to 33, characterized in that means for displacement are provided in order to displace the measurement object and the computed tomography sensor relative to one another in the direction of the axis about which the rotation takes place. Device according to at least one of the preceding claims 21 to 33, characterized in that the means for shifting linear axes or multiple linear axes in positioning units, for example, multi-axis positioning units, and are preferably operated by a motor. Apparatus according to claim 35, characterized in that the Computed tomography sensor is integrated into a manufacturing or measurement line or the like and the measurement object or multiple measurement objects are continuously displaced to the computed tomography sensor, for example by means of a conveyor belt or robot or the like. Device according to at least one of the preceding claims 21 to 36, characterized in that the means for displacement for adjusting the detected area of the scintillator during the change of the rotational position and / or between the recording of two successively recorded and used for computed tomography radiographic images are controllable. Device according to at least one of the preceding claims 21 to 37, characterized in that a plurality of optical detectors for the simultaneous detection of different areas of the scintillator are provided, wherein the optical detectors are fixed to each other or movable to each other. Device according to at least one of the preceding claims 21 to 38, characterized in that the computed tomography sensor is integrated in a coordinate measuring machine.

Images