JP2009276140A - Impact testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To observe or analyze the impact exerted on the internal structure of an inspection target equal to an actual product by applying the impact to the inspection target. <P>SOLUTION: The impact is applied to the inspection target 4 in the X-ray beam 9 emitted from an X-ray generator 1 and the X-ray transmitted image being the X-ray intensity distribution transmitted through the inspection target 4 is continuously photographed at a speed of ≥100 frames/sec by an X-ray detector 3 with a high-speed camera 11 and converted to a digital transmitted image to be recorded. The recorded digital transmitted image is animatedly displayed at a slow motion speed reduced from the speed of ≥100 frames/sec in a predetermined ratio by display means 8 and 13 to observe the state of the internal structure of the inspection target. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an impact test apparatus for analyzing the effects of applying an impact to various structures.

  In recent years, mobile devices such as cellular phones and portable information terminals, which are structural bodies, have become widespread. Since these devices are used in a state where they can be carried, there are many opportunities to receive impacts such as dropping or collision. Therefore, in order to make a product with improved impact resistance, an impact test is performed using an actual product such as a mobile phone.

  Conventionally, the technology related to the impact test is to drop the subject with the vibrometer, measure the impact applied to the subject with the vibrometer, investigate the effect on the subject from its appearance, and display the measurement data of the vibrometer A device for observing the strength and direction of impact has been proposed (Patent Document 1).

  Another technique related to impact testing is to capture a subject subject to impact with a high-speed camera, obtain impact characteristics (time-deformation amount characteristics, etc.) from the image, and obtain the subject's impact from the obtained impact characteristics. What has obtained the material characteristic (stress-strain characteristic) at the time of an impact is proposed (patent document 2).

In addition, as another technology related to impact testing, the subject's drop / collision is photographed with a high-speed camera, the instantaneous distortion and acceleration of the subject are analyzed from the camera image, and the behavior of the subject with respect to impact is analyzed. Attempts have been made to improve impact resistance performance by investigating and reflecting it in the design of members constituting the subject. This impact test is performed by, for example, determining several points that are target points of the outer shape of the subject, measuring the positions of the marks and the like in time series, and measuring the acceleration at the mark positions and the distance between the marks. There is one that calculates the magnitude of distortion from changes and the like.
JP 2007-024507 A JP 2006-258588 A

  Therefore, the impact test using the high-speed camera as described above measures only the external form of the subject in order to improve the impact resistance performance of the subject. It is unclear whether it is being received, and it is not sufficient as a test.

  As an impact test, it is difficult to make a subject with high impact resistance unless the change in the mounting state of components inside the subject and the acceleration applied to each component are grasped. Specifically, when the subject is a mobile phone, it is not possible to inspect the junction between the internal substrate of the mobile phone that is easily damaged and the IC component, the battery, and the like. In order to improve the impact resistance performance of the mobile phone, it is desirable to analyze the distortion and acceleration of the substrate, the substrate mounting component, the battery, and the like.

  When analyzing the impact of the internal structure of the subject, for example, it may be possible to perform a test instead of a transparent outer frame only during the test, but the impact received by the internal structure depends greatly on the material and shape of the outer frame structure. Therefore, there is a problem that it is no longer an actual test.

  Furthermore, the impact test itself is often aimed at how to design the outer frame in order to protect the internal components, and testing in place of another outer frame is a fall.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an impact test apparatus that applies an impact to a subject equivalent to an actual product and observes or analyzes the impact on the internal structure of the subject. And

  In order to solve the above-described problem, an impact test apparatus corresponding to claim 1 is provided with impact applying means for impacting a subject, which is a structure having an internal structure, and at least while the subject is impacted. A first X-ray generator that irradiates the specimen with X-rays, and X-rays emitted from the first X-ray generator and transmitted through the subject are detected, converted into a visible light transmission image, and output. First X-ray visible light converting means and a visible light transmission image output from the first X-ray visible light converting means are continuously photographed at a speed of 100 frames or more per second, converted into a digital transmission image and stored. A first high-speed camera, and display means for displaying a moving image stored in the first high-speed camera in slow motion from a speed of 100 frames or more per second at a predetermined reduced speed. It is the structure provided with.

  By taking such measures, the X-ray transmission image transmitted through the subject is displayed as a moving image in slow motion at an appropriate reduction speed, so that the impact on the internal structure of the subject is reduced. Easy to observe.

  An impact test apparatus corresponding to claim 2 is newly added to the configuration of the impact test apparatus corresponding to claim 1, and at least during the impact of the subject, the appearance image of the subject is at a speed of 100 frames or more per second. A second high-speed camera that continuously shoots, converts it into a digital appearance image and stores it, and trigger signal generating means for generating a common trigger signal for synchronizing the first and second high-speed cameras The first and second high-speed cameras that are provided and receive synchronous images in response to a trigger signal are configured to continuously capture and store a transmission image and an appearance image of the subject.

  By taking such a means, a transmission image and an appearance image by X-rays transmitted through the subject are displayed as a moving image in slow motion at an appropriate reduction speed, so that the internal structure of the subject and The impact on the appearance can be easily observed.

  The impact test apparatus corresponding to claim 3 is a test object newly appearing on either one or both of the transmitted images and the external appearance images in addition to the configuration of the impact test apparatus corresponding to claim 1 or claim 2. This is a configuration in which a data processing unit is provided for tracking feature points on the inner structure and outer surface of the device in time or retroactively and calculating a trajectory of the feature points in a two-dimensional space.

  By taking such means, the trajectory on the image as the time change of the position of the feature point can be obtained by tracking the internal structure of the subject. Here, if the trajectory in the real space is in a plane orthogonal to the transmission direction of the transmission image or in a range that does not greatly deviate from this plane, the trajectory in the real space is multiplied by a constant on the trajectory on the image. It can be calculated.

  Furthermore, the acceleration can be obtained by differentiating the trajectory in the real space once with respect to time and differentiating with speed twice. Further, by obtaining the trajectories of a plurality of feature points, it is possible to obtain the time change of the distortion. As a result, the movement, deformation, deviation, etc. of the internal structure of the subject can be analyzed.

  In addition, the impact test apparatus corresponding to claim 4 is a configuration of the impact test apparatus corresponding to claim 1, and the irradiation is different from that of the first X-ray generator at least while the subject is impacted. A second X-ray generator that irradiates the subject with X-rays from the direction, and X-rays that are irradiated from the second X-ray generator and transmitted through the subject are detected and converted into a visible light transmission image. The second X-ray visible light converting means that outputs the image and the visible light transmission image output from the second X-ray visible light converting means are continuously photographed at a speed of 100 frames or more per second and converted into a digital transmission image. And a second high-speed camera for storing and a trigger signal generating means for generating a common trigger signal for synchronizing the first and second high-speed cameras, and receiving the trigger signal for synchronous shooting The first and second high-speed cameras It is configured to continuous shooting and stored transmission image coming transmitted from the direction.

  By taking such measures, transmission images of X-rays transmitted from different directions of the subject can be displayed individually or side by side and displayed in slow motion with an appropriate reduction ratio. The impact applied to the can be easily observed. That is, the movement, deformation, displacement, etc. of the internal structure when the subject receives an impact can be observed from two directions in slow motion.

  Further, an impact test apparatus corresponding to claim 5 is an object which appears on each transmission image respectively stored in the first and second high-speed cameras in the configuration of the impact test apparatus corresponding to claim 4. This is a configuration in which a data processing unit is provided that tracks feature points of the internal structure in time or retrospectively and calculates a trajectory of each feature point in a three-dimensional space.

  By taking such means, the impact applied to the internal structure of the subject can be analyzed three-dimensionally, and the same analysis result as the impact test apparatus corresponding to claim 3 can be obtained.

  According to the present invention, it is possible to give an impact to a subject equivalent to an actual product and appropriately observe or analyze the state of the impact applied to the internal structure of the subject.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a first embodiment of an impact test apparatus according to the present invention.
The impact test apparatus is disposed immediately below the X-ray generator 1, the X-ray controller 2, the X-ray detector 3, the emitter 5 that emits the subject 4, and the subject 4 that is emitted from the emitter 5. The collision member 6 includes a trigger signal generator 7 attached to the collision member 6, a data processing unit 8, and the like.

  The subject 4 is a structure having an internal structure and corresponds to various portable devices. Here, for example, description will be made assuming a mobile phone. The discharger 5 and the collision member 6 correspond to the impact applying means described in the claims.

  The X-ray generator 1 includes an X-ray tube and a high voltage generator. For example, an X-ray beam 9 having a required intensity based on a tube voltage and a tube current set and operated from the panel of the X-ray controller 2. Irradiate. In addition, the X-ray controller 2 may be configured to set a tube voltage and a tube current in the X-ray generator 1 in accordance with a setting instruction from the data processing unit 8 in cooperation with the data processing unit 8.

  The X-ray detector 3 is disposed at a position facing the X-ray generator 1, and has a function of detecting and photographing a part of the X-ray beam 9 emitted from the X-ray focal point F of the X-ray generator 1. have.

  The X-ray detector 3 detects X-rays with a two-dimensional spatial resolution, and includes an X-ray II (image intensifier) 10 as an X-ray visible light converting means and a high-speed camera 11. The X-ray II10 converts an X-ray transmission image, which is an X-ray intensity distribution detected on the X-ray detection surface 10a, into a visible light transmission image, and outputs it from the output surface 10b. Note that the X-ray II 10 is used with little afterglow.

  The high-speed camera 11 includes a lens, an image sensor such as a CCD sensor or a CMOS image sensor, an AD converter, a memory unit 11a, and the like. The high-speed camera 11 forms a visible light transmission image on the output surface 10b of the X-ray II 10 on the image pickup device through a lens, converts the electric signal into an electric signal by the image pickup device, and converts the electric signal to an AD converter. Then, it is converted into digital data (digital image) and stored in the memory unit 11a.

  As the high-speed camera 11, a camera that continuously shoots at a speed of 100 frames per second or more is used. A normal video camera shoots and stores continuously at 30 frames per second, and plays back and displays a video at the same speed of 30 frames per second. However, the high-speed camera 11 continuously shoots and stores at 100 frames per second or more. Slow motion display is possible by playing back and displaying at a frame rate of 2 seconds.

  Accordingly, the high-speed camera 11 sequentially stores a series of transmission images continuously captured at 100 frames per second or more in the memory unit 11a. For example, when the effective capacity is 10 Gbytes, the memory unit 11a can store a transmission image of 1 Mbytes for about 10,000 frames.

  The emitter 5 has a structure in which the subject 4 is always dropped by supporting the subject 4 with, for example, an appropriate arm (not shown) and removing the support at a predetermined timing.

  The emitter 5 is provided with a guide portion 5a such as a guide plate or a guide cylinder having a required shape in the direction in which the subject 4 falls. The guide portion 5a is made of a material having a low friction surface, and the subject 4 slides and falls with a small frictional resistance, passes through the X-ray beam 9, and collides with the collision member 6 directly below the emitter 5. The reason why the subject 4 is slid along the guide portion 5a is to prevent the subject 4 from rotating while falling and cause the subject 4 to collide with the collision member 6 in a stable posture.

  The space between the lower end of the guide portion 5a and the collision member 6 has a spatial distance that is at least the length of the subject 4, more preferably the length of the subject 4, and the subject 4 is a collision member. It is desirable to have a spatial distance that does not hit the lower end portion of the guide portion 5a when it collides with 6 and bounces back. Thereby, the high-speed camera 11 can image a collision and a bounce in a state where the subject 4 does not collide with the guide portion 5a.

  A plurality of collision members 6 are prepared so that they can be exchanged with ones made of various materials (for example, plastic material, concrete material, etc.) because it is necessary to test by changing the impact of the collision.

  A trigger signal generator 7 is attached to the collision member 6. The trigger signal generator 7 includes, for example, a strain sensor (strain gauge) and an electric circuit, and detects the vibration of the collision member 6 when the subject 4 collides with the change of the electric resistance of the strain sensor. The electric circuit extracts the strain sensor output as a vibration signal, generates an electric trigger signal when the vibration signal level exceeds a predetermined value, and transmits the trigger signal to the high-speed camera 11.

  The high-speed camera 11 starts imaging immediately before the subject 4 falls or immediately before the subject 4 collides, and sequentially stores the transmitted images in the memory unit 11a. Although it is repeatedly stored, the memory portion 11a of the transmission image being photographed according to the ratio arbitrarily set in the high-speed camera 11 in advance when the trigger signal sent from the trigger signal generator 7 is received is set as the trigger point. Implement memory control. Therefore, the high-speed camera 11 also stores a transmission image before the trigger point in the memory unit 11a.

  For example, assuming that the ratio set for the high-speed camera 11 is 10% before the trigger point and 90% after the trigger point, the transmission image taken by the high-speed camera 11 from the trigger point as shown in FIG. Overwriting is continued until 90% of the capacity is reached, and shooting is completed 10% before the trigger point. As a result, if 90% after the trigger point is added to 10% before the trigger point, the effective capacity of the memory unit 11a can be used effectively, and the state of impact after the collision can be imaged before the subject 4 collides. Become.

  The data processing unit 8 has a processing function equivalent to that of a normal personal computer, and is connected to an input unit 12 such as a keyboard and a mouse and a display unit 13 and internally includes a CPU, an internal memory unit, a memory An interface with the unit 11a is provided, and an external storage device such as a disk is connected as necessary.

  The data processing unit 8 is connected to the high-speed camera 11, reads a transmission image stored in the memory unit 11 a, executes a necessary process, and displays the transmission image data and the like on the display unit 13 as a moving image.

  Further, although not shown, the impact test apparatus is provided with an X-ray shielding portion that covers the X-ray generator 1, the X-ray detector 3, the emitter 5, the collision member 6, the trigger signal generator 7, and the like. Yes.

Next, the operation of the impact test apparatus as described above will be described.
First, the operator fixes the subject 4 so as to enter the X-ray beam 9 irradiated from the X-ray generator 1, performs provisional imaging, and sets necessary conditions. Specifically, a tube voltage and a tube current are temporarily set from the panel of the X-ray controller 2 to the X-ray generator 1, and the X-ray beam 9 is irradiated from the X-ray generator 1. An X-ray transmission image passing through the subject 4 is captured by the X-ray II 10 and the high-speed camera 11, stored in the memory unit 11 a, read by the data processing unit 8, and displayed on the display unit 13. While observing the displayed transmission image, the tube voltage, tube current, imaging speed, and gain of the high-speed camera 11 are repeatedly adjusted to set optimum X-ray conditions and imaging conditions.

When the above condition setting is completed, the subject 4 is held by the emitter 5.
The operator operates the X-ray controller 2 to activate the X-ray generator 1 and irradiates the X-ray beam 9 from the X-ray focal point F of the X-ray generator 1. Here, the high-speed camera 11 starts shooting, and saves while repeating high-speed shooting and overwriting to the memory unit 11a.

  As a result, the X-ray beam 9 transmitted through the subject 4 is detected as an X-ray transmission image on the detection surface 10a of the X-ray II 10, converted into a visible light transmission image, and output from the output surface 10b. The high-speed camera 11 takes a visible light transmission image output from the output surface 10b at high speed, converts it into electrical digital data (digital image), and repeatedly overwrites the oldest image in the memory unit 11a. Continue to store sequentially as the latest image.

  At this time, the subject 4 is dropped from the emitter 5. The subject 4 falls through the guide portion 5 a and the X-ray beam 9 and collides with the collision member 6. The trigger signal generator 7 transmits a trigger signal to the high-speed camera 11 when the subject 4 collides. The high-speed camera 11 uses the trigger point when the trigger signal is received from the trigger signal generator 7 as the trigger point. As described above, the high-speed camera 11 finishes shooting when 90% of the memory portion effective capacity is shot and stored from the trigger point. . As a result, the memory unit 11a of the high-speed camera 11 stores a time-series transmission image of 10% before the trigger point (collision point) and 90% after the trigger point.

The operator stops the X-ray irradiation of the X-ray generator 1 through the X-ray controller 2.
When the high-speed camera 11 finishes shooting, the high-speed camera 11 transmits the transmission image stored in the memory unit 11 a to the data processing unit 8. Alternatively, the data processing unit 8 transmits a transmission command to the high speed camera 11 to transmit a transmission image from the high speed camera 11. The data processing unit 8 stores the transmitted transmission image in, for example, an internal memory unit or an external storage device (not shown).

The data processing unit 8 performs display and analysis processing of a transmission image obtained from the memory unit 11a of the high-speed camera 11.
That is, the data processing unit 8 can also display the transmission images stored in the internal memory unit one by one as still images. For example, the data processing unit 8 sequentially reads the transmission images in time series at 30 frames per second, and displays the display unit 13. It is also possible to display a moving image. For example, if a transmission image is taken at 3000 frames per second, slow motion display can be performed with a reduction of 100 times.

  FIG. 3 is a schematic diagram illustrating an example of a transmission image 17 at the moment when the subject 4 (for example, a mobile phone) collides with the collision member 6.

  In the figure, a subject 4 includes an outer frame 4a, a substrate 4b, a battery 4c (for example, a lithium ion polymer battery), and the like. ICs 4d and 4e, a capacitor 4f, a resistor 4g, and the like are attached on the substrate 4b, and a power supply terminal 4h is provided on the battery 4c. Reference numerals 4i and 4j denote BGAs (ball grid arrays). The transmitted image 17 represents a state taken at a moment of collision from a direction substantially perpendicular to the surface of the substrate 4b.

  Therefore, if the transmitted image 17 of the subject 4 at the moment of collision with the collision member 6 is displayed in slow motion while being visible, distortion and displacement of the internal structure of the subject 4 at the time of the collision can be observed as a whole. For example, it is possible to observe the contact state and the shift state of the power terminal 4h. Incidentally, the power supply terminal 4h is a place where a problem such as erasure of the contents stored in the IC of the subject 4 occurs when the connection place is disconnected even for a moment.

Next, a transmission image analysis processing example by the data processing unit 8 will be described with reference to FIG.
First, distortion correction processing is executed. From the viewpoint of ensuring the accuracy of the analysis result, distortion correction processing of the transmission image 17 is performed as preprocessing. Here, the distortion correction is correction for erasing image distortion caused by the X-ray II 10 or the lens of the high-speed camera 11. There are various known correction methods for distortion correction. Here, for example, correction processing using a polynomial is performed.

In the correction process, assuming that the transmission image (image) before correction is P (x, y) and the transmission image (image) after correction is P ′ (n, m), for all pixels (n, m), The corrected transmission image P ′ (n, m) is obtained by a polynomial arithmetic expression shown below.
x = Σ _{l = 0 to 5} Σ _{k = 0 to 5} { _{al, k} · n ^l _· m ^k } (1)
y = Σ _{l = 0 to 5} Σ _{k = 0 to 5} {b _{l, k} · n ^l _· m ^k } (2)
P ′ (n, m) = P (x, y) (3)
Here, a _{l, k} , b _{l, k} are constants obtained in advance by calibration.

  That is, x and y are obtained by a quintic equation of n and m as shown in equations (1) and (2). Usually, since x and y are not integers, the right side of Equation (3) is calculated by, for example, linear interpolation (linear interpolation). Here, the distortion correction process is sequentially performed on all the transmission images P to be analyzed, and the corrected transmission image P ′ is acquired and stored in, for example, the internal memory unit. The following processes are all performed using the transmission image P ′ (= transmission image 17) after distortion correction.

  Next, feature point setting processing is executed. The operator sets the feature points to be tracking points on the single transmission image 17 shown in FIG. 3 by specifying the ROI. The feature points are, for example, a point having a large image density or a point having a large change in image density. For example, when a small square ROI (feeling area) is set, the feature point is uniquely determined in image processing within this ROI. It is done. For example, the center of gravity of the capacitor 4f, the resistor 4g, the corner point of the battery 4c, the substrate 4b, the IC 4e, the center of gravity of one ball of the BGA 4j that joins the IC 4e, and the like can be cited as characteristic points. Here, for example, points A, B, C, and D at the four corners of the substrate 4b are feature points and also tracking points.

  Subsequently, feature point trajectory determination processing is executed. This feature point trajectory determination process tracks all the transmission images 17 to be analyzed by finding the positions of the feature points according to the time series order or the reverse order of the time series. The points A, B, C, and D at the four corners are determined. Note that image processing for tracking feature points is a well-known technique and will not be described in detail here. Tracking of feature points is performed by identifying feature points that are close to each other between adjacent images as the same point (for example, point A).

  By this feature point trajectory determination process, the points A, B, C, and D at the four corners of each transmission image 17 are tracked in time series, and the trajectory can be determined by grasping the position of each point. That is, the horizontal / vertical position, n (t), m (t) of each point on the image in time series can be obtained.

  By the way, when analyzing only the short-time trajectory at the time of the collision, the posture of the substrate 4b does not change so much, and a transmission image from a direction substantially orthogonal to the surface of the substrate 4b is obtained for this short time. Under this condition, the size of one pixel at each point of the substrate 4d is constant. If the pixel size is ps (mm / pixel), the trajectory of each point in the real space is obtained in mm based on the following equation.

g (t) = ps · n (t) (4)
h (t) = ps · m (t) (5)
Next, required differentiation processing is executed. In this differentiation process, first, g (t) and h (t) obtained by the equations (4) and (5) are differentiated by t, respectively, and the horizontal / vertical components u (t) and v (t ) Is obtained, and the obtained u (t) and v (t) are further differentiated by t to obtain accelerations α (t) and β (t) at each point.

  Through the above processing, the acceleration received at each point on the substrate 4b is obtained, so that the force received by the substrate 4b can be known. Further, it is possible to know the time change of strain in the substrate 4b from the positions g (t) and h (t) of the respective points on the substrate 4b.

  Therefore, according to the first embodiment described above, a transmission image of X-rays transmitted through the subject 4 is displayed as a moving image in slow motion on the display unit 13, so that an impact applied to the internal structure of the subject 4 is reduced. Can be observed. That is, the movement, deformation, displacement, etc. of the internal structure of the subject 4 when subjected to an impact can be observed in slow motion. Further, the impact on the internal structure of the subject 4 can be analyzed.

  Specifically, the trajectories n (t) and m (t) on the transmission image of the feature points inside the subject can be obtained. Also, if the trajectory in real space is in the plane orthogonal to the transmission direction of the transmission image, or in a range that does not deviate significantly from this plane, the trajectory on the transmission image is multiplied by the pixel size and The trajectories g (t) and h (t) can be obtained. Furthermore, the trajectory in the real space can be differentiated once by time t, and the velocity can be differentiated twice to obtain the acceleration. In addition, by obtaining trajectories of a plurality of feature points, it is possible to acquire a time change of distortion. As a result, the movement, deformation, displacement, etc. of the internal structure of the subject 4 can be easily analyzed.

(Modification of the first embodiment)
(1) In the impact test in the first embodiment, the subject 4 is caused to collide with the collision member 6 in a state where the subject 4 is naturally dropped. You may make it discharge | release in the state given and to make it collide with the collision member 6. FIG. In this case, it is possible to apply a large impact without increasing the distance between the discharger 5 and the collision member 6, thereby reducing the size of the apparatus. In the first embodiment, the guide 5a is used to collide while the rotation of the subject 4 is suppressed, but conversely, the subject 4 is caused to collide while rotating, and the type of impact is changed in various ways. You can also test. Further, instead of moving the subject 4, the collision member 6 may be moved to collide with the subject 4 to give an impact. Moreover, the structure which gives an impact so that the subject 4 may be pinched | interposed with two collision members may be sufficient.

(2) In the first embodiment, the transmission image taken by the high-speed camera 11 is temporarily stored in the memory unit 11a, but may be directly stored in the internal memory unit or the external storage device of the data processing unit 8. . Alternatively, an analog transmission image may be output from the high-speed camera 11, the analog transmission image may be converted into a digital transmission image by the data processing unit 8, and stored in an internal memory unit or the like.

(3) In the first embodiment, the trigger signal generator 7 extracts the trigger signal from the output signal level of the strain sensor, but is not a strain sensor, for example, a photoelectric switch that captures the timing at which the subject 4 crosses, The trigger signal may be taken out using a laser displacement meter or a microphone or accelerometer that is attached to the collision member 6 and detects vibration sound.

(4) In the first embodiment, the X-ray II 10 is used as the X-ray visible light converting means, but a microchannel plate or the like may be used.

(5) In the first embodiment, a process is described in which a mobile phone is assumed as the subject 4 and the impact analysis of, for example, the substrate 4b, which is one of the internal structures of the mobile phone, is performed. Not only that, but an impact test can be performed on all structures from which a transmission image can be obtained, and an impact analysis can be performed if there are traceable feature points in the transmission image of the internal structure.

(6) Moreover, the structure of an impact test apparatus as shown in FIG. 4 may be used. This impact test apparatus is newly provided with a clock signal for synchronizing the high-speed camera 21 for capturing an appearance image of the subject 4 and the plurality of high-speed cameras 11 and 21 in all the configurations shown in FIG. In this configuration, a generated clock generation unit 22 and a mirror 23 are added. The high-speed camera 21 having the same configuration and function as the high-speed camera 11 is used.

  The high-speed camera 21 captures an image reflected from the mirror 23 inserted at 45 ° with respect to the X-ray beam 9, thereby obtaining an external image of the subject 4 by visible light from the same direction as the transmitted image. Set to shoot. However, when the external image of the subject 4 from a different direction is taken, the mirror 23 is not necessary, and it may be set so that the image is taken directly toward the subject 4.

  If the high-speed camera 21 is arranged so that the object space principal point H of the lens and the camera optical axis coincide with the mirror images of the X-ray focal point F and the X-ray optical axis, respectively, the appearance image and the X-ray transmission image of the subject 4. Since the images can be accurately superimposed as images of the same perspective (perspective) viewed from the same viewpoint, they can be appropriately displayed on the display unit 13 in a superimposed manner or in parallel.

  When a transmission image is taken at a high magnification, the collision position of the subject 4 is brought close to the X-ray focal point F, and the mirror 23 and the high-speed camera 21 are arranged between the collision position and the X-ray detector 3. To do. In this case, the viewpoints of the appearance image and the X-ray transmission image are different, but the magnification of the X-ray transmission image can be increased without the mirror 23 being in the way.

  In this impact test apparatus, the clock generation unit 22 transmits a common clock signal to the high-speed cameras 11 and 21 and performs shooting in synchronization with the cameras 11 and 21. In parallel with this, the trigger signal generator 7 detects vibration, and when the vibration signal level exceeds a threshold value, a common trigger signal is sent to the high-speed cameras 11 and 21, and the two cameras The shooting of 11 and 21 is synchronized. Here, the trigger signal generator 7 and the clock generator 22 are means for synchronizing the two cameras 11 and 21. The trigger signal generator 7 has a role of roughly synchronizing the photographing period unit, and the clock generator 22 has a role of accurately synchronizing within the photographing period.

  According to such a configuration, an X-ray transmission image due to the movement of the subject 4 at the time of collision and an external appearance image by visible light can be simultaneously photographed at high speed at the same time, and each of the X-ray transmission image and the external appearance image can be used. Video display and impact analysis. In addition, the X-ray transmission image and the appearance image can be displayed side by side or superimposed, and a moving image can be displayed, or the impact analysis can be performed by combining the outer surface and the inside using the X-ray transmission image and the appearance image.

  In the sixth modification, the clock generator 22 can be omitted. In this case, since each high-speed camera 11 and 21 performs shooting with the respective internal clock, a phase shift occurs in the shooting timing. However, since synchronization is performed with a common trigger signal, the synchronization error is less than the shooting cycle. It can be used depending on the application.

(Second Embodiment)
In the first embodiment, the example in which the impact analysis is performed from the transmission image in one direction has been described. However, for example, when the feature point moves in the depth direction of the transmission image, the image magnification changes. May not be obtained. Also, it is good if multiple feature points exist in a plane perpendicular to the perspective direction, but if the points shifted in the depth direction are moving relative to each other, the perspective (perspective method) There is a certain positional relationship, and the analysis error increases.

  Therefore, in the second embodiment, two sets of the X-ray generator 1 and the X-ray detector 3 are used, and transmission images from two directions having different transmission directions are simultaneously and continuously photographed, and the subject is examined. In this configuration, the four changes are analyzed three-dimensionally. This can be achieved by obtaining the three-dimensional movement of the feature point (tracking point) of interest from the transmitted images in two directions.

  FIG. 5 is a block diagram showing a second embodiment of the impact test apparatus according to the present invention. In this figure, the same or equivalent components as in FIG. This impact test apparatus represents a state viewed from the direction in which the subject 4 collides with the collision member 6, and the subject 4 and the emitter 5 are not shown for convenience of explanation.

  This impact test apparatus has a configuration in which an X-ray generator 31, an X-ray controller 32, an X-ray detector 33, and a clock generator 34 are newly added to the entire configuration shown in FIG. The X-ray generator 31 and the X-ray controller 32 have the same configuration and function as the X-ray generator 1 and the X-ray controller 2, respectively. The X-ray detector 33 has the same configuration and function as the X-ray detector 3 and includes an X-ray II 35 and a high-speed camera 36.

In this impact test apparatus, the transmission direction of the transmission image can be set in various ways. Here, the simplest example will be described.
First, positions in two sets of photographing systems are set. Here, as the coordinate system, an orthogonal coordinate system xyz is set with the point O as the origin and the impact direction (vertical direction) as the z axis. The first imaging system comprising the X-ray generator 1 and the X-ray detector 3 is positioned so that the X-ray optical axis (the line connecting the X-ray focal point F1 and the center of the X-ray detection surface 10a) matches the x-axis, The second imaging system composed of the X-ray generator 31 and the X-ray detector 33 is positioned so that the X-ray optical axis (line connecting the X-ray focal point F2 and the center of the X-ray detection surface 35a) matches the y-axis.

  The clock generator 34 is connected to the two high-speed cameras 11 and 36, transmits a common clock signal to the high-speed cameras 11 and 36, and continuously shoots while synchronizing these cameras 11 and 36. The trigger signal generator 7 generates a trigger signal when the vibration signal level detected by the strain sensor exceeds a threshold value, and sends the trigger signal to the two high-speed cameras 11, 36 to send the two high-speed cameras 11, 36. The 36 shootings are synchronized. Here, the trigger signal generator 7 and the clock generator 34 are means for synchronizing the two cameras 11 and 36. The trigger signal generator 7 has a role of roughly synchronizing the photographing period, and the clock generator 34 has a role of accurately synchronizing within the photographing period.

  The high-speed cameras 11 and 36 perform shooting based on the common clock signal as described above, and use the trigger point when the common trigger signal is received as described in the first embodiment. The transmission image of 10% before the point and 90% after the trigger point is stored in the memory units 11a and 36a, and the photographing is finished. Accordingly, transmission images in two directions can be sequentially stored at the same time and in time series.

  The data processing unit 8 performs the same analysis process as in the first embodiment, but the content of the collision analysis is different.

Next, the operation of the impact test apparatus in this embodiment will be described.
Similar to the first embodiment, the two high-speed cameras 11 and 36 take a transmission image of the subject 4 in synchronization and store them in the corresponding memory units 11a and 36a in time series. Then, after X-ray irradiation from the X-ray generators 1 and 31 is stopped, the transmission images stored in the memory units 11 a and 36 a are transmitted to the data processing unit 8. Alternatively, the data processing unit 8 transmits a transmission command to the high-speed cameras 11 and 36 and causes the high-speed cameras 11 and 36 to transmit a transmission image. The data processing unit 8 sequentially stores transmitted transmission images in, for example, an internal memory unit.

  The data processing unit 8 performs display and analysis processing of transmission images collected from the memory units 11a and 36a of the high-speed cameras 11 and 36. Here, one of the transmission images collected from the high-speed cameras 11 and 36 is a transmission image as shown in FIG. 3, for example. The transmission image can be displayed as a still image one by one on the display unit 13 of the data processing unit 8 as in the first embodiment. However, the transmission image is sequentially switched in time series at 30 frames per second. It can also be displayed. For example, if a picture is taken at 3000 frames per second, the slow motion display is 100 times. For moving image display, either one of the transmission images taken by the high-speed camera 11 or 36 can be selected and displayed, or both images can be displayed side by side while being synchronized.

Next, an example of transmission image analysis processing by the data processing unit 8 will be described with reference to FIGS.
First, distortion correction processing is executed as in the first embodiment. From the viewpoint of ensuring the accuracy of the analysis result, the distortion correction processing of each transmission image is performed on all transmission images to be subjected to collision analysis in the same manner as in the first embodiment. The following processes are all performed using the transmission image after distortion correction.

  Next, feature point setting processing is executed. In the feature point setting process, feature points are set on one transmission image of each of the two imaging systems.

  FIG. 6 is a schematic diagram illustrating an example of feature points. Note that the transmission image is displayed in the left-right direction as viewed from the X-ray focal point side. On the left side of the display unit 13, one transmission image 41 taken by the first imaging system is displayed side by side, and on the right side of the display unit 13, one transmission image 42 taken by the second imaging system is displayed side by side.

  The operator sets feature points on the displayed transmission images 41 and 42. For example, points A, B, C, and D at the four corners of the substrate 4b are feature points and simultaneously tracking points.

  Subsequently, feature point trajectory determination processing is executed. In this feature point trajectory determination process, all the transmission images 41 and 42 to be analyzed are obtained and tracked according to the time series order or the reverse order of the time series, so that the four corners of each transmission image 41 are sequentially detected. The positions of points A, B, C and D are determined. Note that the image processing for obtaining the feature points is already a known technique, so details are not described here. Tracking of feature points is performed by identifying feature points that are close to each other between adjacent images as the same point (for example, point A).

  By determining the positions of the four corner points A, B, C, and D of the transmission images 41 and 42 by this feature point trajectory determination process, the trajectory can be determined on the images in the two directions. That is, for each point on each transmission image 41, 42, the trajectory on the transmission image 41 by the first imaging system, n1 (t), m1 (t) and the trajectory on the transmission image 42 by the second imaging system, n2 ( t) and m2 (t) can be obtained.

  Next, the trajectories x (t), y (t), and z (t) in the three-dimensional space are obtained from the trajectories n1 (t), m1 (t), n2 (t), and m2 (t) on the transmission image. As an example, the following procedure is used.

  First, the positions g and h of the points projected along the X-ray onto the center plane (plane passing through the origin O and orthogonal to the optical axis) are obtained from the following formulas (see FIG. 6).

g1 (t) = ps1 · {n1 (t) −n0} (6)
h1 (t) = − ps1 · {m1 (t) −m0} (7)
g2 (t) = ps2 · {n2 (t) −n0} (8)
h2 (t) = − ps2 · {m2 (t) −m0} (9)
Here, n0 and m0 are positions of the origin O on the transmission image, that is, the center of the image. Further, ps1 and ps2 are pixel sizes (mm / pixel) at the position of the origin O, and are predetermined constants.

Furthermore, “(t)” is omitted, and g1, h1, g2, and h2 in the above formula are used.
x = r1 · g2 · (r2−g1) / (r1 · r2 + g1 · g2) (10)
y = −r2 · g1 · (r1 + g2) / (r1 · r2 + g1 · g2) (11)
z1 = h1 · (r1 + x) / r1 (12)
z2 = h2 · (r2 + y) / r2 (13)
z = (z1 + z2) · 2 (14)
Are sequentially calculated, and trajectories x (t), y (t), and z (t) in the real space are calculated. Here, r1 is the distance between the X-ray focal point F1 and the origin O, and r2 is the distance between the X-ray focal point F2 and the origin O.

  In addition, although Formula (10)-Formula (14) can be derived | led-out from the geometric diagram which calculates the position in the three-dimensional space of the tracking point shown in FIG. 7, it abbreviate | omits for details.

  In short, to obtain the trajectories x (t), y (t), z (t) in the real space, as shown in FIG. 7, the projection lines Lp1 in two directions along the X-ray with respect to the tracking point are This is a problem of obtaining the xyz coordinates of the intersection with Lp2. Here, it should be noted that, since g and h generally include measurement errors, Lp1 and Lp2 are close to each other but do not strictly intersect.

  Therefore, as shown in the lower part of FIG. 7, a midpoint between two points P1 (height z1) and P2 (height z2) that intersect each other when viewed from the z-axis direction is calculated as the intersection point P. This is equivalent to obtaining the average of the measurement values because the unknown number 3 (xyz) is the known number 4 (g1, g2, h1, h2) and the measurement value includes redundancy. Statistical accuracy can be increased. Furthermore, in Formula (14), z1 and z2 are averaged by multiplying them by a one-to-one weight, but the ratio of these weights may be changed. For example, the measurement value h1 seen through the substrate 4b from the front direction may be emphasized, and z1 may be weighted and averaged.

  Next, differential processing is executed. This differentiation process is performed by differentiating x (t), y (t), and z (t) in a three-dimensional space by t, respectively, thereby obtaining vx (t), vy (t), Find vz (t). Further, vx (t), vy (t), and vz (t) are differentiated by t, and αx (t), αy (t), and αz (t), which are three-dimensional components of acceleration α at each point, are obtained. Ask. Thereby, the force received by the substrate 4b can be determined by obtaining the acceleration at each point of the substrate 4b. Further, it is possible to know the time change of the strain of the substrate 4b from the positions x (t), y (t), z (t) of each point of the substrate 4b.

Therefore, according to the second embodiment described above, the X-ray transmission images transmitted through the subject 4 in different directions are individually or side by side and displayed in slow motion as a moving image, thereby affecting the internal structure of the subject 4. You can observe the impact. That is, the movement, deformation, displacement, etc. of the internal structure of the subject 4 when subjected to an impact can be observed from two directions in slow motion.
Further, according to this embodiment, the impact applied to the internal structure of the subject 4 can be analyzed three-dimensionally.

  Specifically, after tracing a feature point of the internal structure of the subject 4 to obtain a trajectory on the image as a temporal change in the position of the feature point, a trajectory in real space from a trajectory on a transmission image in two different directions. Can be requested.

  Furthermore, the trajectory in the real space can be differentiated once by time t, and the velocity can be differentiated twice to obtain the acceleration. In addition, by obtaining the trajectories of a plurality of feature points, it is possible to obtain a change in distortion over time. Thereby, the movement, deformation, deviation, etc. of the internal structure of the subject 4 can be analyzed.

(Modification of the second embodiment)
(1) Also in the second embodiment, the modification of the first embodiment can be applied as it is.
(2) In the second embodiment, the X-ray optical axes of the first imaging system and the second imaging system are set to intersect at 90 °. However, the X-ray optical axes are always set to intersect at 90 °. Not limited.

(3) In the second embodiment, the X-ray optical axes of the first imaging system and the second imaging system are set to intersect at a narrow angle, and the captured transmission image can be displayed in stereo. In this case, for example, viewing the right-eye image with only the right eye and viewing the left-eye image with only the left eye results in a stereoscopic display. This technique is already known. For example, there is a method in which a right-eye image and a left-eye image are switched and displayed in a time-sharing manner, and in accordance with this, the left side and the right side are observed with glasses that alternately repeat shading / transmission.

(4) In the second embodiment, two imaging systems are used. However, simultaneous imaging can be performed with three or more imaging systems. In the case of the two imaging systems, if one of the images happens to have a long transmission direction, the transmission image becomes too dark and the feature points cannot be tracked, and the trajectory in the three-dimensional space is obtained. However, it can be prevented by using three or more photographing systems. That is, the trajectory can be obtained from other images excluding images that are too dark. In addition, since the number of photographing systems increases, the measurement values are averaged to obtain a result, which has the effect of increasing the statistical accuracy.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

The block diagram which shows 1st Embodiment of the impact test apparatus which concerns on this invention. The figure explaining the example which memorize | stores the transmission image continuously image | photographed at high speed in the memory part shown in FIG. The schematic diagram which shows an example of the permeation | transmission image of a subject. The block diagram of the impact test apparatus explaining one modification in 1st Embodiment of the impact test apparatus which concerns on this invention. The block diagram which shows 2nd Embodiment of the impact test apparatus which concerns on this invention. The schematic diagram explaining an example of the tracking of the feature point in 2nd Embodiment. The geometric diagram which calculates the position in three-dimensional space by the tracking of the feature point in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... X-ray generator, 3 ... X-ray detector, 4 ... Subject, 4a ... Outer frame, 4b ... Substrate, 4c ... Battery, 5 ... Ejector, 6 ... Colliding member, 7 ... Trigger signal generator, 8 Data processing unit, 10 X-ray II, 11 High-speed camera, 11a Memory unit, 13 Display unit, 21 High-speed camera, 22 Clock generation unit, 23 Mirror, 31 X-ray generator 33 ... X-ray detector, 34 ... Clock generation unit, 35 ... X-ray II, 36 ... High-speed camera, 36a ... Memory unit.

Claims (5)

  An impact applying means for impacting a subject, which is a structure having an internal structure, a first X-ray generator for irradiating the subject with X-rays at least while the subject is impacted; First X-ray visible light converting means for detecting X-rays irradiated from the first X-ray generator and transmitted through the subject, converting the detected X-rays into a visible light transmission image, and the first X-ray visible light converting means; A first high-speed camera that continuously shoots a visible light transmission image output from the line-visible light conversion means at a speed of 100 frames or more per second, converts it into a digital transmission image, and stores it in the first high-speed camera. An impact test apparatus comprising: display means for displaying a stored transmission image as a moving image in slow motion at a speed of a predetermined reduction from the speed of 100 frames or more per second. The impact test apparatus according to claim 1,
A second high-speed camera that continuously captures an external appearance image of the subject at a speed of 100 frames or more per second, converts it into a digital external appearance image, and stores it at least while the subject is impacted; And trigger signal generating means for generating a common trigger signal for synchronizing the second high-speed camera,
An impact test apparatus, wherein the first and second high-speed cameras that receive the trigger signal and perform synchronous imaging continuously capture and store the transmission image and the appearance image of the subject. In the impact test apparatus according to claim 1 or 2,
The feature points on the internal structure and the outer surface of the subject appearing on either one or both of the stored transmission image and the appearance image are tracked in time or retrospectively, and the feature points are two-dimensionally recorded. An impact test apparatus comprising a data processing unit for calculating a trajectory in space. The impact test apparatus according to claim 1,
A second X-ray generator that irradiates the subject with X-rays from an irradiation direction different from that of the first X-ray generator at least while the subject is impacted, and the second X-ray generation From the second X-ray visible light converting means for detecting X-rays irradiated from the instrument and transmitted through the subject, converting the X-rays into a visible light transmission image, and outputting them, and the second X-ray visible light converting means The second high-speed camera that continuously captures the output visible light transmission image at a speed of 100 frames per second or more, converts it into a digital transmission image and stores it, and the first and second high-speed cameras are synchronized. Trigger signal generating means for generating a common trigger signal for,
An impact test apparatus, wherein the first and second high-speed cameras that receive the trigger signal and perform synchronous imaging continuously capture and store transmission images transmitted from different directions of the subject. The impact test apparatus according to claim 4,
The feature points of the internal structure of the subject appearing on the transmission images respectively stored in the first and second high-speed cameras are tracked in time or retrospectively, and the feature points in the three-dimensional space are tracked. An impact test apparatus comprising a data processing unit for calculating a trajectory.

Images