JP2015132577A - Image pickup structure, image pickup head which employs the same, and three-dimensional shape measurement apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup structure configured to accurately synthesize images captured at two viewpoints without using special image processing means, in a configuration of three-dimensional shape measurement which captures light reflected from an object at two viewpoints by means of an optical cutting method, while facilitating construction of an optical system, and to provide an image pickup head and a three-dimensional shape measurement apparatus.SOLUTION: An image pickup structure includes: a reflection surface 4 which makes reflected light captured at one viewpoint incident on a half mirror 8 for image superimposition; and a reflection surface 6 which makes reflected light captured at an opposite viewpoint incident on the mirror. Air-conversion lengths of two optical axes LU, LD are made equal to each other so that the optical axes LU, LD reaching the half mirror from a slit light irradiation position via the reflection surfaces 4, 6 may form a parallelogram having diagonals not orthogonal to each other.

Description

  The present invention relates to an image pickup structure used in an optical cutting method, an image pickup head to which the structure is applied, and a three-dimensional shape measuring apparatus. In particular, the present invention is applied to measure the surface shape (three-dimensional shape) of pharmaceuticals such as tablets and capsules, foods, electronic parts, machine parts, steel materials, building materials and other articles (hereinafter referred to as “objects”). Therefore, it is suitable.

  Conventionally, a light cutting method is known as a method for measuring the three-dimensional shape of an object. The light cutting method irradiates the surface of the object with slit light, captures the reflected light of the slit light that appears on the surface with a camera such as an area sensor, and triangulates the shape of the slit light seen on the acquired image This is a technique for measuring the three-dimensional shape of an object by analyzing based on the principle of the above. Then, the measured three-dimensional shape recognizes the feature, and determines the suitability of the three-dimensional shape from the recognized feature (for example, the presence or absence of a defect or the quality when a stamp is added). Served to determine. In measurement of a three-dimensional shape using such a light cutting method, if the reflected light from the object is acquired from only one direction, a part that becomes a blind spot in the imaging direction is generated depending on the object, and the reflection of the part is performed. Since light cannot be acquired, accurate measurement may not be performed. That is, since the light cutting method is a method of measuring a three-dimensional shape based on the height, it is better that there is no blind spot for creating a shadow in order to accurately specify the shape.

Therefore, there is a case where a technique of reducing the blind spot of measurement by capturing the reflected light of the slit light that appears on the surface of the object from two or more viewpoints is sometimes employed. For example, Patent Document 1 discloses an appearance inspection apparatus that employs such a technique. In FIG. 4, a slit light irradiation unit that irradiates the surface of an object with a band-shaped slit light, and a downstream side and an upstream side in the transport direction. First and second optical mechanisms for guiding the reflected light (L ₂ , L ₃ ) of the slit light from each of these to the area sensor camera, an area sensor camera for capturing an image of the reflected light of the slit light, and an area sensor camera A shape determination unit that individually performs image processing on the two images picked up by combining the two images obtained as individual image processing results, and determines the suitability of the surface of the object based on the combined image; The structure provided with the surface shape test | inspection means containing is described. In Patent Document 1, the first and second light are reflected so that the reflected light of the slit light received by the first and second optical mechanisms forms an image side by side on the imaging surface of the area sensor camera (FIG. 9 of the same document). By configuring the optical mechanism, data of two images included in the same raster can be read and output to the shape determination unit by one raster scan, so that the output time is shortened and the shutter speed of the camera is increased. And, in turn, that high-accuracy appearance inspection can be realized.

  As described above, capturing the reflected light of the slit light that appears on the surface of the object from two or more viewpoints enables the measurement of the three-dimensional shape by reducing the blind spot of the measurement. Effective above.

  However, Patent Document 1 discloses only a configuration in which image synthesis is performed by image processing. Therefore, the configuration as in Patent Document 1 requires special means for performing image processing (an image composition processing unit included in the shape determination unit), and requires hardware and software for that purpose. In addition, the first and second optical mechanisms are complicated to form two images side by side on the imaging surface of the camera (aligned in the raster direction). In addition to these mechanisms, the slit light irradiation unit and the area sensor camera There is also a problem that the construction of the entire optical system including the above and the adjustment of each part become complicated. Furthermore, since the reflected light of the slit light acquired from two or more viewpoints is imaged side by side on the imaging surface of the area sensor camera, the camera imaging is performed as compared with the case where one image is imaged on the imaging surface. The use efficiency of the surface is inferior, and the resolution in the raster direction of the image is lowered.

JP 2011-242319 A

  Therefore, the present invention uses a light cutting method and measures the three-dimensional shape of the object by capturing reflected light of the slit light of the object from two or more viewpoints, without requiring special image processing means. The object is to be able to synthesize images captured from two or more viewpoints, to easily construct an optical system and to adjust each part of the optical system, and to make effective use of the imaging surface of the camera. To do.

Therefore, the present invention appears on the object by the irradiation with a light source unit that irradiates slit light having a longitudinal axis in a direction intersecting the direction of the conveyance with respect to the object to be relatively conveyed. An image pickup structure that is applied to a light cutting method using a half mirror that superimposes an image obtained by reflecting reflected light of slit light on the upstream side and the downstream side in the conveyance direction,
A first reflecting surface for directing the reflected light from the upstream side to the half mirror;
A second reflecting surface for directing the reflected light from the downstream side to the half mirror;
The surface that the slit light occupies in space, the first reflection surface, the second reflection surface, and the incident surface of the half mirror of the reflected light are set to be parallel to each other It is characterized by that.

In addition, the present invention provides a light source unit that irradiates slit light having a longitudinal axis in a direction intersecting the transport direction with respect to a relatively transported object, and a slit that appears on the object by the irradiation. An image pickup structure that is applied to a light cutting method using a half mirror that superimposes images obtained by reflecting reflected light of light on the upstream side and the downstream side in the transport direction,
A first reflecting surface for directing the reflected light from the upstream side to the half mirror;
A second reflecting surface for directing the reflected light from the downstream side to the half mirror;
Air-converted length of two optical axes: an optical axis that reaches the half mirror via the first reflecting surface and an optical axis that reaches the half mirror via the second reflecting surface from the position where the slit light is irradiated The first reflecting surface and the second reflecting surface are set so that the two are equal to each other.

  Furthermore, the present invention is an image pickup head to which any one of the image pickup structures described above is applied, wherein the half mirror, the first reflecting surface, and the second reflecting surface are integrally provided.

In addition, the three-dimensional shape measuring apparatus of the present invention is a light source unit that irradiates a relatively conveyed object with slit light having a longitudinal axis in a direction intersecting the conveyance direction;
The above image pickup structure or image pickup head;
A camera unit that images the reflected light superimposed by the half mirror;
It is provided with.

  According to the present invention, no special image processing means is required, accurate image composition can be optically performed, and the light source unit can be disposed without causing positional interference with the half mirror. The construction of the optical system is simplified, the construction of the optical system and the adjustment of each part constituting the optical system are easy, and the imaging surface of the camera can be used effectively.

1 is a schematic front view showing an image pickup structure that is a basis of a first embodiment of the present invention. 1 is a schematic front view showing an image pickup structure according to a first embodiment of the present invention. (A) is a typical front view which shows one Embodiment of the image pick-up head comprised applying the image pick-up structure of FIG. 2, (b) is a typical front view which shows the modification. (A) is a typical front view which shows other embodiment of the image pick-up head comprised applying the image pick-up structure of FIG. 2, (b) is a typical front view which shows the modification. (A) And (b) is a typical front view which shows the structure of the slit light irradiation system which implement | achieves multi-light-source appearance apparently applicable to the image pick-up structure which concerns on the 2nd Embodiment of this invention, respectively. It is a schematic side view. (A) And (b) is the typical front view and typical side view which respectively show the image pick-up structure concerning the 2nd Embodiment of this invention. (A) And (b) is the typical front view and typical side view which respectively show one Embodiment of the image pick-up head comprised by applying the image pick-up structure of FIG. (A) And (b) is the typical front view and typical side view which respectively show the modification of the image pick-up head shown in FIG. (A) And (b) is the typical front view and typical side view which show other embodiment of the image pick-up head comprised by applying the image pick-up structure of FIG. 6, respectively. (A) And (b) is the typical front view and typical side view which respectively show the modification of the image pick-up head shown in FIG. FIGS. 3A and 3B correspond to the image pickup head according to the embodiment of FIGS. 3A and 4A, respectively, and are schematic front views for explaining a configuration for further improving the image pickup head. FIG. (A) is a schematic front view showing an embodiment of the image pickup head of the present invention that is further improved, and (b) is a schematic front view showing a modification thereof. (A) And (b) is the typical front view and typical side view which show other embodiment of the image pick-up head of this invention further improved, respectively. (A) And (b) is the typical front view and typical side view which respectively show the modification of the image pick-up head shown in FIG. It is a mimetic diagram for explaining an embodiment of a three-dimensional shape measuring device concerning the present invention. It is a schematic diagram for demonstrating the image composition performed with the three-dimensional shape measuring apparatus of FIG.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
Regarding the present specification and the accompanying drawings, for convenience, X is an axis orthogonal to the transport direction in the transport surface (horizontal plane) including the transport direction of the object whose three-dimensional shape is measured, and Y is an axis corresponding to the transport direction. , Z is defined as indicating an axis in a direction (vertical direction) perpendicular to the X axis and the Y axis. And the figure at the time of seeing this invention three-dimensional shape measuring device or its component along an X-axis and a Y-axis is respectively called a front view and a side view.

  As used herein, the term “light cutting line” is an intersection line between the slit light and the object, which is a line formed by the reflected light of the slit light that appears on the object at the irradiation position of the slit light. Shall mean. In addition, the term “optical axis” used in this specification refers to a virtual light beam that is representative of a light beam that passes through an optical system, that is, slit light emitted from a light source unit to an object and imaging of the camera from the object. Let us say a representative ray of reflected light directed to a surface and its axis.

(First embodiment)
FIG. 1 is a schematic diagram showing the main part of a three-dimensional shape measuring apparatus including an image pickup structure that is the basis of the first embodiment of the present invention. The main parts of the three-dimensional shape measuring apparatus of the present embodiment generally include the image pickup structure 1, a transport unit 20 that transports an object P to be measured, for example, in the form of a tablet, a light source unit 30, and a camera unit. 40.

  The transport unit 20 is connected to, for example, a pair of timing pulleys arranged on the upstream side and the downstream side in the transport direction T, a timing belt in the form of an endless belt conveyor stretched on the timing pulley, and at least one timing pulley And a motor that is provided with a motor. Then, the timing belt is driven according to the driving of the motor, so that the object P carried thereon is conveyed.

  The light source unit 30 emits slit light, and the emitted slit light is irradiated onto the object P from directly above in the Z-axis direction by the mirror 2 of the image pickup structure 1. The mirrors 4 and 6 forming the first and second reflecting surfaces in the image pickup structure 1 reflect the reflected light of the slit light that appears on the surface of the object P on the upstream side and the downstream side in the transport direction T, respectively. Turn to half mirror 8. Accordingly, the reflected light of the slit light respectively guided from the mirrors 4 and 6 of the image pickup structure 1, that is, the two images of the light cutting line are superimposed and synthesized by the half mirror 8, and further guided to the camera unit 40 and imaged. The The surface shape data of the object P can be calculated by subjecting the captured composite image to image processing by an appropriate image processing unit.

  The condition for simultaneously superimposing two images of the light cutting line appearing on the object P in the optical system and simultaneously forming the image on the camera unit is from the irradiation position of the slit light, that is, the formation position of the light cutting line to the half mirror 8. The air equivalent length taken by the two optical axes between them, that is, the air in the optical axis LU (hereinafter referred to as the upstream optical axis) LU from the formation position of the optical cutting line to the half mirror 8 through the upstream mirror 4 The conversion length is equal to the air conversion length of the optical axis (hereinafter referred to as the downstream optical axis) LD that reaches the half mirror 8 through the downstream mirror 6. In the configuration of FIG. 1, the mirrors 4 and 6 and the half mirror 8 are arranged at positions where the upstream optical axis LU and the downstream optical axis LD form a rhombus.

  As described above, in the configuration shown in FIG. 1, the optical system 1 does not require any special image processing means by simultaneously superimposing the images of the optical cutting lines captured by the up and down flow in the transport direction T in the optical system 1, so that the optical system is not necessary. This makes it possible to perform accurate image composition. Also, this configuration has better utilization efficiency of the imaging surface of the camera unit 40 than the configuration disclosed in Patent Document 1. For example, when the light cutting method is performed with the same resolution (optical magnification), the area of the imaging surface required for this configuration is half of the area of the imaging surface required for the configuration of Patent Document 1.

  And in 1st Embodiment of this invention, in addition to those effects, the structure which simplifies an optical system is provided.

  FIG. 2 is a schematic diagram showing the main part of the three-dimensional shape measuring apparatus including the image pickup structure according to the first embodiment of the present invention, and the same parts as those in FIG. . This configuration is different from the configuration of FIG. 1 in order to make the air conversion length of the upstream optical axis LU equal to the air conversion length of the downstream optical axis LD. However, the image pickup structure 10 having a parallelogram shape whose diagonal lines are not orthogonal is employed. According to such a configuration, the light source unit 30 can be disposed immediately above the irradiation position of the slit light without causing positional interference with the half mirror 8, so that the mirror 2 is not required for the configuration of FIG. That is, according to the first embodiment, in addition to the above effects, the configuration of the optical system is further simplified by adopting the image pickup structure 10 having a small number of parts, and includes the light source unit 30 and the camera unit 40. Position adjustment of each part which comprises the principal part of a three-dimensional shape measuring apparatus becomes easy. Furthermore, by arranging the light source unit 30 directly above the irradiation position of the slit light, it is possible to reduce the dimension of the entire optical system and thus the three-dimensional shape measuring apparatus in the Y axis direction.

  From another viewpoint, the optical system 10 is configured so that the upstream optical axis LU and the downstream optical axis LD form a parallelogram whose diagonals are not orthogonal to each other. This means that the respective parts of the optical system are arranged so that the surface (light beam surface) occupied by the facing slit light, the reflecting surface of the mirror 4, the reflecting surface of the mirror 6, and the incident surface of the half mirror 8 are parallel. However, the surfaces may not be strictly parallel to each other (that is, may be substantially parallel) as long as they are within an allowable range for image synthesis intended in the present invention. Further, as the half mirror 8, it is preferable to use a half mirror 8 in which the ratio of the intensity of the transmitted light and the reflected light is 1: 1, but a range that does not hinder the superposition of the two images of the light section line. It is also possible to use those in which the above ratio is appropriately determined. The same applies to each configuration described below.

  Next, a configuration that applies the image pickup structure according to the first embodiment and realizes a further simplified optical system will be described.

  FIG. 3A is a schematic front view showing an embodiment of an image pickup head configured by applying the image pickup structure of FIG. This embodiment provides an image pickup structure embodied in an integrated image pickup head 100.

  The image pickup head 100 has a substantially rectangular parallelepiped external shape, and is arranged such that three opposing two surfaces of the rectangular parallelepiped are orthogonal to the X axis, the Y axis, and the Z axis, respectively. The image pickup head 100 is configured by joining prisms 104 and 106 having different dimensions in the Y-axis direction with a half mirror 8 made of a member such as a metal thin film interposed therebetween. The image pickup head 100 is arranged so that slit light from the light source unit 30 passes through the prism 106 having a relatively large dimension in the Y-axis direction. The mirror 4 and the mirror 6 are disposed on the side surface 104a of the prism 104 and the side surface 106a of the prism 106, respectively.

  Since the refractive indexes of the prisms 104 and 106 are different from the refractive index of the surrounding air, in the image pickup head 100 configured and arranged as described above, the optical axis of the slit light from the light source unit 30 passes through the prism 106 in the Z-axis direction. The reflected light traveling from the object P toward the mirrors 4 and 6 is refracted at the bottom surface, and the upstream optical axis LU and the downstream optical axis LD do not form a parallelogram. . However, in order to simultaneously superimpose two images of the light section line in the optical system, the condition that the air equivalent length of the upstream optical axis LU and the air equivalent length of the downstream optical axis LD must be equal must be satisfied. . Therefore, in this embodiment, the distance d1 along the optical axis from the irradiation position of the slit light, that is, the position where the optical cutting line is formed, to the bottom surface of the prism 104, and the optical axis to the bottom surface of the prism 106. The image pickup head 100 is configured and arranged so that the distance d2 is equal.

  In addition, since the total reflection occurs when the incident angle of the light beam on the side surface 104a of the prism 104 and / or the side surface 106a of the prism 106 exceeds the critical angle of refraction, the arrangement of the mirror on the side surface is not necessary. FIG. 3B shows a configuration in which the side surface 104a of the prism 104 and the side surface 106a of the prism 106 form first and second reflecting surfaces, and neither of them has a mirror.

  The image pickup head 100 is disposed without causing positional interference with the light source unit 30, and satisfies the condition that the air conversion length of the upstream optical axis LU and the air conversion length of the downstream optical axis LD are equal. As long as it does, various shapes as described below can be adopted.

  FIG. 4A is a schematic front view showing another embodiment of an image pickup head configured by applying the image pickup structure of FIG. The prisms 104 ′ and 106 ′ in this embodiment are configured and arranged so that the optical axes of reflected light from the object P toward each mirror are orthogonal to each other and the distances d1 and d2 from the irradiation position are equal. Is provided. The prism 104 ′ is provided with a surface in which the optical axes from the half mirror 8 toward the camera unit 40 are orthogonal. Therefore, in this embodiment, the upstream optical axis LU and the downstream optical axis LD that form a “parallelogram whose diagonals are not orthogonal” equivalent to the case of FIG. 2 are formed by the prisms 104 ′ and 106 ′.

  Here, when the prism 106 ′ has a shape along the optical axis from the mirror 6 toward the half mirror 8 as shown in the drawing, the optical axis from the light source unit 30 toward the object P is that of the prism 106 ′ where it intersects. Refracts because it is not orthogonal to the surface. However, by making the pair of surfaces where the optical axes intersect parallel to each other and appropriately determining the distance between the surfaces, the object is not greatly shifted from the light source unit 30 toward the object P as shown in the figure. The light source unit 30 can be disposed substantially immediately above P.

  When the incident angle of the light beam on the side surface 104a ′ of the prism 104 ′ and / or the side surface 106a ′ of the prism 106 ′ exceeds the critical angle of refraction, a mirror is arranged as shown in FIG. It can be set as the structure which is not provided.

  According to the embodiment shown in FIG. 3 (a) or FIG. 3 (b), FIG. 4 (a) or FIG. 4 (b), in addition to obtaining the same effect as the embodiment shown in FIG. Since the image pickup structure is configured as an integrated image pickup head, it is possible to obtain an effect that the construction and adjustment of the entire optical system is further facilitated. Here, the material of the prism constituting the image pickup head is not particularly limited, but in the case of an image pickup head having a structure (composite prism structure) in which a plurality of (two) prisms are joined, refraction is caused at the joint surface of the prism. From the viewpoint of transmitting light without being generated, it is strongly desirable to use the same material for the prism or the material with the same refractive index. The same applies to an image pickup head having a composite prism structure as will be described later.

(Second Embodiment)
By using a multi-viewpoint technique, the blind spot of measurement can be reduced. However, even if optical mechanisms are arranged on both the upper and lower sides in the direction of object conveyance, depending on the shape of the object, blind spots (disconnected areas where slit light is not irradiated) and areas where the amount of irradiation light is insufficient may occur. It is conceivable that an accurate shape measurement of the object cannot be performed because a preferable reflected light cannot be obtained from the part. The second embodiment of the present invention can synthesize images without the need for special image processing means, and it is easy to construct an optical system and adjust each component constituting the optical system. In addition to obtaining the same effect as that of the first embodiment in that the imaging surface can be used effectively, the shape of the object can be measured more accurately, and the structure therefor can be made simple and inexpensive. It is intended to be provided.

  FIGS. 5A and 5B are a schematic front view and a schematic side view for explaining the structure of the slit light irradiation system applicable to the image pickup structure according to the second embodiment of the present invention, respectively. It is. In this structure, the mirrors 12 and 14 are arranged in the longitudinal direction of the slit light, that is, the portions on the X-axis facing each other with the conveyance unit 20 interposed therebetween, so that the mirrors 14 and 16 are used in addition to the direct light DL from the light source unit 30. The reflected light RL that is reflected is also irradiated onto the object. In other words, this structure suppresses the generation of blind spot portions and insufficient light amount portions of the irradiation of the slit light on the object P by using a single light source unit 30 and so-called multiple light sources. is there. Although it is possible to arrange a plurality of light source sections that allow slit light to directly enter the object P from a plurality of positions, it is not necessary to arrange a plurality of light source sections, and the slits from the respective light sources are not necessary. From the viewpoint of making it unnecessary to align the light, it is preferable to adopt an irradiation system structure that realizes an apparent multi-light source as shown in FIGS. 5 (a) and 5 (b).

  The irradiation system shown in FIGS. 5A and 5B can be preferably applied to the image pickup structure and the image pickup head according to the first embodiment and the respective modifications thereof.

  For example, FIGS. 6A and 6B are a schematic front view and a schematic side view showing an image pickup structure according to the second embodiment of the present invention, respectively, and the image pickup structure shown in FIG. An irradiation system (hereinafter simply referred to as “irradiation system”) that realizes an apparent multi-light source is applied.

  7A and 7B are a schematic front view and a schematic side view showing an embodiment in which the irradiation system is applied to the image pickup head of FIG. The mirrors 12 and 14 are disposed on the opposite side surface 106b in the X-axis direction. When the incident angle of the light beam with respect to the side surface 104a of the prism 104 and / or the side surfaces 106a and 106b of the prism 106 exceeds the critical angle of refraction, the mirror arrangement is unnecessary as described with reference to FIG. It becomes. FIGS. 8A and 8B are a front view and a side view of a configuration in which no mirror is disposed on the side surface 104a of the prism 104 and the side surfaces 106a and 106b of the prism 106. FIG.

  FIGS. 9A and 9B are a schematic front view and a schematic side view showing an embodiment in which the irradiation system is applied to the image pickup head of FIG. The mirrors 12 and 14 are disposed on the opposite side surface 106b 'in the X-axis direction. When the incident angle of the light beam with respect to the side surface 104a ′ of the prism 104 ′ and / or the side surfaces 106a ′ and 106b ′ of the prism 106 ′ exceeds the critical angle of refraction, as described with reference to FIG. No mirror arrangement is required. FIGS. 10A and 10B show a front view and a side view of a configuration in which no mirror is disposed on the side surface 104a 'of the prism 104' and the side surfaces 106a 'and 106b' of the prism 106 '.

  In each of the above configurations, the same effect as that of the corresponding first embodiment or its modification can be obtained, and the optical cutting line is hard to break, so that the shape of the object can be measured more accurately. At the same time, a structure for that purpose can be provided easily and inexpensively. In particular, when the prisms as shown in FIGS. 7 to 10 are used, it is not necessary or easy to adjust the reflecting surface in order to increase the apparent number of light sources.

(Third embodiment)
Next, in an image pickup head integrated with a prism as shown in FIGS. 3A and 4A, an embodiment for making it possible to measure the shape of an object even more accurately. Will be described.

In the image pickup heads of FIGS. 3 (a) and 4 (a), as shown in FIGS. 11 (a) and 11 (b), the atmosphere, the prism, and the prism on the optical path from the light source unit 30 to the object P, respectively. , And has a boundary surface I3 and a boundary surface I4 on the optical path from the object P to the camera unit 40.
The orientation of these boundary surfaces and the positional relationship in space affect astigmatism. For example, the astigmatism on the camera unit 40 side is such that both the boundary surfaces I3 and I4 are not perpendicular to the optical axis (that is, the structure in FIG. 11A). The case where it is orthogonal to the optical axis (that is, the structure of FIG. 11B) is smaller. On the other hand, the astigmatism on the side of the object P is such that both the boundary surfaces of the boundary surface I1 and the boundary surface I2 are less than when the boundary surfaces are not orthogonal to the optical axis (that is, the structure of FIG. The case where it is orthogonal to the optical axis (that is, the structure of FIG. 11A) is smaller.

  Based on the above, the structure of the image pickup head that can reduce astigmatism on both the camera unit 40 side and the object P side is that the boundary surfaces of the boundary surface I3 and the boundary surface I4 are orthogonal to the optical axis. Having a three-dimensional shape in which prisms are combined so as to satisfy a condition (first condition) to be satisfied and a condition (second condition) in which both boundary surfaces of the boundary surface I1 and the boundary surface I2 are orthogonal to the optical axis It can be said.

  FIG. 12A shows the structure of an image pickup head according to the third embodiment of the present invention, which is configured to satisfy these conditions. That is, the image pickup head 130 according to the present embodiment is positioned on the upstream side and the downstream side in the transport direction T, and the first and second prisms 134 and 136 configured and arranged to satisfy the first condition, The third prism 135 that is configured and arranged to satisfy the condition 2 and allows the slit light from the light source unit 30 to pass therethrough is joined. The half mirror 8 is disposed on the joint surface between the prisms 134 and 136, while the prisms 134 and 136 are respectively provided with mirrors 4 and 6 for directing reflected light of the slit light toward the half mirror 8 and thus the camera unit 40. It is installed. Furthermore, the surfaces of the prisms 134 and 136 where the optical axes of the reflected light from the object P toward each mirror are orthogonal are further set at positions where the distances d1 and d2 from the irradiation position are equal to each other. In this case, an upstream optical axis and a downstream optical axis forming a “parallelogram whose diagonals are not orthogonal to each other” are formed.

  According to such a configuration, in addition to the effects described in the first embodiment, it is possible to perform more accurate image composition by suppressing the generation of astigmatism.

  In addition, when the incident angle of the light ray with respect to the side surface 134a of the prism 134 and / or the side surface 136a of the prism 136 exceeds the critical angle of refraction, the arrangement of the mirror on the side surface is not necessary. FIG. 12B shows a configuration in which there are no mirrors on both the side surface 134 a and the side surface 136 a of the prism 136.

  13 (a) and 13 (b) show an implementation in which the irradiation system as described in FIGS. 6 (a) and 6 (b) is applied to the image pickup head shown in FIG. 12 (a). It is the typical front view and typical side view which show a form. As shown in these drawings, by arranging the mirrors 12 and 14 on the opposite side surface 135b in the X-axis direction of the prism 135 that allows the slit light from the light source unit 30 to pass, in addition to the above effect, in the second embodiment, The described effect can be obtained. Here, when the incident angle of the light beam with respect to the side surface 134a of the prism 134, the side surface 136a of the prism 136, and the side surface 135b of the prism 135 exceeds the critical angle of refraction, the arrangement of the mirror is unnecessary. FIGS. 14A and 14B are a front view and a side view of a configuration in which no mirror is arranged on the side surfaces thereof.

  Note that an image pickup head constituted by a composite prism preferably employs the structure and three-dimensional shape shown in FIG. 11A or 11B from the viewpoint of ease of manufacture, while having optical performance. From the viewpoint, it can be said that it is desirable to adopt a structure and a three-dimensional shape as shown in FIG. In other words, whether to adopt the former or the latter may be appropriately determined by comparing the ease of manufacturing and the optical performance.

(Embodiment of three-dimensional shape measuring apparatus)
FIG. 15 is a conceptual diagram for explaining an embodiment of a three-dimensional shape measuring apparatus. In this embodiment, the image pickup head 130 shown in FIG. 12A is adopted as the image pickup structure, but other image pickup structures or image pickup heads may be adopted.

  The camera unit 40 captures and acquires reflected light of the slit light at predetermined time intervals while the object P passes directly below the image pickup head 130, and sequentially outputs the image data to the image processing unit 50. The image data acquired here is complemented by two viewpoints so that there are few broken lines due to blind spots, and the reflected light of the slit light coming from the mirror 4 and the reflected light of the slit light coming from the mirror 6 are half. It is an image as shown in FIG. 16 which is a single line continuous in the horizontal direction by being accurately superimposed by the mirror 8. The image processing unit 50 measures the surface shape of the object P by analyzing the data of the image output from the camera unit 40 based on the principle of triangulation based on the shift amount from the bottom surface of the slit light. Surface shape data of the object P is calculated. According to the present embodiment, the half mirror 8 accurately superimposes the reflected light of the slit light from the two viewpoints, while adopting the same image processing unit as in the case of the one viewpoint, and increasing the surface shape of the object. It can be measured with high accuracy.

  The image pickup head 130 is supported by the support adjustment mechanism 60 and necessary position adjustment is performed. When the image pickup structure is configured as an integrated image pickup head 130 formed of a composite prism as in the present embodiment, the surface (light ray surface) occupied by the slit light emitted from the light source unit 30 in space and the mirror 4 Since the reflecting surface of the mirror 6, the reflecting surface of the mirror 6, and the light receiving surface of the half mirror 8 are parallel, the support adjusting mechanism 60 adjusts the position relative to the image pickup head 130 (for example, on the X, Y, and Z axes). Adjustment of the position and the angle around each axis) is sufficient.

  Note that the three-dimensional measurement apparatus shown in FIG. 15 is a conceptual diagram for explaining the basic configuration to the last, and an appropriate configuration can be given. For example, on the optical axis from the light source unit 30, a cylindrical lens that effectively narrows the line width of slit light applied to the object or a beam expander that expands may be interposed. Further, on the optical axis between the half mirror 8 and the camera unit 40, a resolution changing unit capable of making the vertical resolution and the horizontal resolution of the image different is inserted, and various three-dimensional The resolution in a desired direction may be increased corresponding to the shape of the object having a shape.

(Other)
In the above description and the accompanying drawings, a tablet is exemplified as the object T that is the object of the three-dimensional shape measurement of the present invention. However, the shape is not limited to that shown in the figure, and the object is of various shapes. It can be a thing. Furthermore, examples of the test object of the present invention include not only such tablets but also other pharmaceuticals (such as capsules), foods, electronic parts, mechanical parts, steel materials, and building materials, but are not limited thereto. Not a thing. In other words, as described above, by adopting a configuration in which the blind spot portion of the irradiated slit light or the portion where the light amount is insufficient is not generated, it is possible to expand the range of the target object for the three-dimensional shape measurement. is there.

1, 10 Image pickup structure 2, 4, 6, 12, 14 Mirror 8 Half mirror 20 Conveyance unit 30 Light source unit 40 Camera unit 50 Image processing unit 100, 130 Image pickup head 104, 104 ′, 106, 106 ′, 135 Prism 104a, 104a ′, 106a, 106b, 106a ′, 106b ′, 134a, 136a, 135b Prism side surface LU Upstream optical axis LD Downstream optical axis P Object

Claims (12)

A light source unit that irradiates slit light having a longitudinal axis in a direction intersecting the direction of conveyance with respect to an object to be conveyed relatively, and reflected light of the slit light that appears on the object by the irradiation An image pickup structure applied to an optical cutting method using a half mirror that superimposes images captured on the upstream side and the downstream side in the conveyance direction,
A first reflecting surface for directing the reflected light from the upstream side to the half mirror;
A second reflecting surface for directing the reflected light from the downstream side to the half mirror;
The surface that the slit light occupies in space, the first reflection surface, the second reflection surface, and the incident surface of the half mirror of the reflected light are set to be parallel to each other An image pickup structure characterized by that. A light source unit that irradiates slit light having a longitudinal axis in a direction intersecting the direction of conveyance with respect to an object to be conveyed relatively, and reflected light of the slit light that appears on the object by the irradiation An image pickup structure applied to an optical cutting method using a half mirror that superimposes images captured on the upstream side and the downstream side in the conveyance direction,
A first reflecting surface for directing the reflected light from the upstream side to the half mirror;
A second reflecting surface for directing the reflected light from the downstream side to the half mirror;
Air-converted length of two optical axes: an optical axis that reaches the half mirror via the first reflecting surface and an optical axis that reaches the half mirror via the second reflecting surface from the position where the slit light is irradiated The image pickup structure is characterized in that the first reflection surface and the second reflection surface are set so that the two are equal.   The image pickup structure according to claim 2, wherein the two optical axes form a parallelogram whose diagonal lines are not orthogonal to each other.   In addition to direct light from the light source unit by reflecting a part of the slit light emitted from the light source unit, a reflection surface for further irradiating the object with the reflected light is further provided. The image pickup structure according to any one of claims 1 to 3, wherein the image pickup structure is provided.   An image pickup head to which the image pickup structure according to any one of claims 1 to 3 is applied, wherein the half mirror, the first reflection surface, and the second reflection surface are integrated. head.   Two prisms, a prism provided with the first reflecting surface and a prism provided with the second reflecting surface, are joined together with the half mirror interposed therebetween. The image pickup head according to claim 5.   The image pickup according to claim 6, wherein one of the two prisms is configured to guide the slit to the object without refracting an optical axis of the slit light emitted from the light source unit. head.   Each of the two prisms is configured to guide to the first reflecting surface and the second reflecting surface without refracting the optical axis of the reflected light of the slit light, and one of the two prisms is the half The image pickup head according to claim 6, wherein the superimposed light from the mirror is emitted without being refracted. The first prism having the first reflecting surface, the second prism having the second reflecting surface, and the first prism and the first prism with the half mirror sandwiched between them. A third prism configured to be guided to the object without being refracted while being joined to two prisms and refracting the optical axis of the slit light emitted from the light source unit,
The first prism and the second prism are respectively configured to guide the first reflecting surface and the second reflecting surface without refracting the optical axis of the reflected light of the slit light, The image pickup head according to claim 5, wherein one of the second prisms is configured to emit the light superimposed on the half mirror without being refracted.   7. At least one of the first reflection surface and the second reflection surface is formed by a mirror disposed on a side surface of a prism on which the first reflection surface or the second reflection surface is provided, or an interface formed by the side surface and an atmosphere. The image pickup head according to any one of Items 9 to 9.   In addition to direct light from the light source unit, the reflective surface further includes a reflecting surface for reflecting the reflected light on the object by reflecting a part of the slit light emitted from the light source unit. The image pickup head according to claim 5, wherein the image pickup head is provided. A light source unit that emits slit light having a longitudinal axis in a direction that intersects the direction of conveyance with respect to an object that is relatively conveyed,
An image pickup structure according to any one of claims 1 to 4, or an image pickup head according to any one of claims 5 to 11,
A camera unit that images the reflected light superimposed by the half mirror;
A three-dimensional shape measuring apparatus comprising:

Images