JP2020118669A - Imaging apparatus - Google Patents

Abstract

To precisely observe the inner structure of a target object.SOLUTION: The imaging apparatus includes: a limiting unit for limiting a flux of light which passes through the outside of the outer shape of an illuminated object; and an imaging unit for taking an image of the flux of light, which has passed through the object, the limiting unit having a region for limiting a flux of light and the region being changed by the shape of the object. The limiting unit may control the shape of a light emitting region for irradiating the object with light and may control the shape of a light reduction region for reducing fluxes of light around the flux of light which passes through the object.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image pickup device.

Conventionally, there is known a method of observing the internal structure of an object by receiving light transmitted through the object (see, for example, Patent Document 1).
Patent Document 1 Japanese Patent Laid-Open No. 10-62362

If light that does not pass through the object is received, the observation accuracy of the internal structure of the object deteriorates.

In one aspect of the present invention, a limiting unit that limits a light flux that passes outside the outer shape of an illuminated object, and an imaging unit that captures an image of a light flux that has passed through the object, the limiting unit including: Provided is an imaging device in which a region that limits a light flux is changed depending on the shape of an object.

Note that the above summary of the invention does not enumerate all the necessary features of the present invention. Further, a sub-combination of these feature groups can also be an invention.

It is a schematic diagram which shows an example of the imaging device 10 which concerns on one Embodiment of this invention. FIG. 6 is a diagram illustrating control of a light emitting area in the light irradiation unit 40. It is a figure explaining the other example of the 2nd light emission area|region 42. It is a figure explaining the other example of the 2nd light emission area|region 42. It is a figure which shows an example of the 2nd light emission area|region 42. It is a figure explaining the light irradiated from the 2nd light emission area|region 42. It is a figure which shows an example of the light emission intensity distribution in the AA line shown in FIG. FIG. 6 is a diagram showing an arrangement example of a light receiving surface 22, an object 12, and a light irradiation surface 44 of the imaging unit 20. FIG. 9 is a diagram illustrating an example of a first calibration image 104 used in a calibration operation for determining an image blur amount. 6 is an enlarged view of an image blurring unit 52. FIG. It is a figure explaining the other example of control of the 2nd light emission area 42. It is a figure explaining the other example of control of the 2nd light emission area 42. It is a figure explaining the other example of control of the 2nd light emission area 42. It is a figure explaining an example of the light emission system in the light irradiation part 40. It is a figure explaining an example of the light emission system in the light irradiation part 40. It is a figure explaining an example of the light emission system in the light irradiation part 40. It is a figure explaining the example of adjustment of the light emission intensity in each position of the light irradiation surface 44. It is a figure explaining the example of adjustment of the light emission intensity in the 2nd light emission area 42. It is a schematic diagram which shows an example of the imaging device 210 which concerns on other embodiment of this invention. It is a figure which shows an example of the 1st imaging step S201 and the 2nd imaging step S202. It is a figure explaining the imaging device 310 which concerns on a comparative example. It is a figure explaining an example of the 1st imaging stage S201. It is a figure which shows an example of the reflection spectrum in the surface of the target object 12. It is a figure which shows the other example of the 1st imaging step S201. It is a figure explaining an example of the 2nd imaging stage S202. It is a figure explaining other examples of the 2nd imaging stage S202. It is a figure explaining other examples of the 2nd imaging stage S202. It is a figure explaining the other example of the dimming part 241.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Further, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.

FIG. 1 is a schematic diagram showing an example of an imaging device 10 according to one embodiment of the present invention. The imaging device 10 irradiates the object 12 with light and receives the light that has passed through the inside of the object 12. Thereby, the imaging device 10 captures an image showing the internal structure of the object 12. The target 12 is, for example, a crop such as a fruit, but is not limited to this. The object 12 may include a plant or an animal whose internal structure is different in shape and the like depending on an individual, and may include a processed product of at least a part of the plant or the animal. Further, the object 12 may include an industrial product such as a resin molded product.

The imaging device 10 includes a light irradiation unit 40 and an imaging unit 20. The imaging device 10 may further include a processing device 30. The light irradiation unit 40 functions as a light emitting unit that irradiates light that illuminates the object 12. The light irradiation unit 40 also functions as a restriction unit that restricts the light flux that passes outside the outer shape of the object 12. The light irradiation unit 40 of this example includes a light irradiation surface 44 that irradiates the object 12 with light. In the light irradiation unit 40, the shape of the light emitting region that irradiates the light on the light irradiation surface 44 is variable. The light irradiation unit 40 of the present example controls the shape of the light emitting region based on the outer shape of the target object 12 to limit the light flux passing outside the target object 12. Note that in FIG. 1, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined. The light irradiation surface 44 is a surface parallel to the XY plane.

For example, the light irradiation unit 40 is a surface light source that includes a plurality of light emitting elements and can independently control the light emission of each light emitting element. The light irradiation unit 40 may be a light source in which light emitting elements such as LEDs and organic EL are two-dimensionally arranged. The light irradiation unit 40 may include a surface light source that uniformly emits light, and a control unit that controls whether or not the light emitted by the surface light source passes, for each area of the surface light source. The control unit may use liquid crystal to control whether light is allowed to pass or blocked for each region. The light irradiation unit 40 may also be capable of controlling the intensity of emitted light for each region.

The light irradiation unit 40 irradiates light in a wavelength band corresponding to the internal structure of the observation target. The light irradiation unit 40 may irradiate light in a wavelength band having a large difference in absorbance between the internal structure of the observation target and other internal structures of the internal structure of the object 12. The light irradiation unit 40 may emit light having a wavelength in the near infrared band, may emit light having a wavelength in the visible band, or may emit light having a wavelength in another band.

The light with which the light irradiation unit 40 irradiates the object 12 passes through the inside of the object 12 and is emitted. The imaging unit 20 receives the light emitted through the object 12. As a result, the image capturing unit 20 captures an image including information about the internal structure of the object 12. The imaging unit 20 of this example is arranged to face the light irradiation surface 44 of the light irradiation unit 40. The imaging unit 20 may include a plurality of pixels arranged two-dimensionally and may capture a two-dimensional image of the object 12. The sensor included in the imaging unit 20 may be an image sensor such as CCD or CMOS.

The target object 12 is arranged between the imaging unit 20 and the light irradiation surface 44. The light irradiation unit 40 may irradiate light with the object 12 placed on the light irradiation surface 44. Note that the object 12 is arranged between the light irradiation surface 44 and the imaging unit 20 means that the light emitted from the light irradiation surface 44 is incident on one surface of the object 12 and It indicates an arrangement in which the light emitted from the other surface is received by the imaging unit 20. The light irradiation surface 44, the imaging unit 20, and the object 12 may be arranged on a straight line, but may not be arranged on a straight line.

The processing device 30 acquires image data of an image captured by the image capturing unit 20. The processing device 30 controls the light irradiation unit 40 based on the image data. The processing device 30 may be a part of the light irradiation unit 40. The processing device 30 is, for example, a computer including a CPU, a memory, an interface, and the like. The processing device 30 of the present example controls the light emitting area in the light irradiation unit 40 based on the acquired image data. Further, the processing device 30 compares the image data stored in the storage unit for each state of the internal structure of the object of the same type as the target object 12 with the image data acquired from the image capturing unit 20, and compares the target object 12 with the image data. You may have a discrimination|determination part which discriminate|determines the state of the internal structure of.

FIG. 2 is a diagram illustrating control of the light emitting area in the light irradiation unit 40. The imaging unit 20 of the present example acquires the first image 101 in the first imaging step S201 and acquires the second image 102 in the second imaging step S202. The second imaging step S202 is performed after the first imaging step S201. By controlling the shape of the light emitting region in the second imaging step S202 based on the shape of the target object 12 in the first image 101, the imaging unit 20 is prevented from passing through the target object 12 in the second imaging step S202. Non-transmitted light (also referred to as stray light) that reaches can be reduced.

The light irradiation unit 40 determines the shape of the light emitting region in the second imaging step S202 based on the shape of the object 12 in the first image 101. The processing device 30 acquires the shape of the object 12 in the first imaging step S201. The processing device 30 matches the shape of the light emitting region in the second imaging step S202 with the shape of the object 12. For example, the processing device 30 causes only the region below the object 12 on the light irradiation surface 44 to emit light. As a result, in the second imaging step S202, it is possible to prevent light that has not passed through the object 12 from reaching the imaging unit 20. More specifically, it is possible to suppress the occurrence of flare, which lowers the contrast of the internal structure of the target object 12 and the generation of ghosts, due to the light that does not pass through the target object 12. Therefore, the internal structure of the object 12 can be accurately observed.

The light irradiation unit 40 of the present example emits light in the first light emitting area 41 in the first imaging step S201 and emits light in the second light emitting area 42 in the second imaging step S202. In FIG. 2, the first light emitting region 41 and the second light emitting region 42 are indicated by broken lines. The second light emitting region 42 is smaller than the first light emitting region 41. As an example, the first light emitting region 41 is the entire light irradiation surface 44. That is, the first light emitting region 41 is the largest region on the light irradiation surface 44 that can emit light. By reducing the area of the second light emitting region 42, it is possible to reduce the proportion of light that has not passed through the target 12 and reaches the imaging unit 20 in the second imaging step S202.

The processing device 30 detects, based on the first image 101, the light-shielded region 111 shielded by the object 12 on the light irradiation surface 44. The processing device 30 may detect, in the first image 101, a region where the pixel value (luminance value) is smaller than a predetermined value as the light shielding region 111. The shape of the light shielding area 111 indicates the planar shape of the object 12.

The processing device 30 controls the position and shape of the second light emitting region 42 based on the position and shape of the light shielding region 111. The second light emitting region 42 includes at least a part of the light shielding region 111. The processing device 30 makes the range of the second light emitting region 42 equal to or smaller than the light shielding region 111. On the light irradiation surface 44, areas other than the second light emitting area 42 do not emit light. In FIG. 2, in the light irradiation surface 44, a region that does not emit light is hatched. As a result, the second light emitting area 42 in the second imaging step S202 can be limited to an area overlapping the object 12.

The second image 102 includes the image element 114. The image element 114 contains information about the internal structure of the object 12. As described above, in the second imaging step S202, the region of the light irradiation surface 44 that does not overlap the target 12 does not emit light. For this reason, it is possible to prevent light that has not transmitted through the object 12 from being received by the imaging unit 20, and the image element 114 can display the internal structure of the object 12 with high contrast.

FIG. 3 is a diagram illustrating another example of the second light emitting region 42. The imaging device 10 of this example simultaneously observes the internal structure of a plurality of objects 12. A plurality of objects 12 are placed on the light irradiation surface 44 of this example. The processing device 30 detects the light shielding area 111 of each target 12 in the first imaging step S201 described in FIG.

The light irradiation unit 40 emits light in the second light emitting regions 42 corresponding to the respective light shielding regions 111 in the second imaging step S202. The processing device 30 independently controls the shape, size, and position of the second light emitting region 42 for each light shielding region 111. Thereby, the internal structures of the plurality of objects 12 can be simultaneously observed.

FIG. 4 is a diagram illustrating another example of the second light emitting region 42. In FIG. 4, hatching of a region that does not emit light in the second imaging step S202 is omitted. The imaging device 10 of the present example captures an image of the object 12 moving in the first direction (X-axis direction) above the light irradiation surface 44. The position of the object 12 on the X axis in the first imaging step S201 is x1, and the position of the object 12 on the X axis in the second imaging step S202 is x2. The position of the object 12 may be the position of the center of the object 12.

When the object 12 moves, the positions of the light blocking area 111 and the second light emitting area 42 do not match. The processing device 30 of the present example determines the position of the second light emitting region 42 on the light irradiation surface 44 based on the position x2 of the object 12 in the second imaging step S202. As a result, the internal structure of the moving object 12 can be accurately observed. Information indicating the position x2 may be input in advance to the processing device 30. Information regarding the moving direction, moving speed, and timing of the second imaging step S202 of the object 12 may be input to the processing device 30. The processing device 30 may calculate the position x2 based on these pieces of information. The imaging device 10 may capture an image of the object 12 in order to acquire the position of the object 12.

FIG. 5 is a diagram showing an example of the second light emitting region 42. FIG. 5 is a diagram of the object 12 viewed from the Z-axis direction. The second light emitting region 42 of this example is smaller than the light shielding region 111. The second light emitting region 42 may be a region that is reduced inward from the outer periphery of the light shielding region 111 by the reduction amount L1. The reduction amount L1 may or may not be constant over the entire outer circumference of the second light emitting region 42.

When the second light emitting area 42 has the same size as the light shielding area 111, the light emitted in the vicinity of the outer periphery of the second light emitting area 42 reaches the imaging unit 20 without passing through the object 12. There are cases. In this case, in the second image 102, the contrast of the internal structure of the object 12 is reduced. In the present example, the second light emitting area 42 is made smaller than the light shielding area 111, so that light that has not passed through the object 12 can be suppressed from reaching the imaging unit 20.

FIG. 6 is a diagram illustrating light emitted from the second light emitting region 42. FIG. 6 is a diagram of the object 12 and the imaging device 10 as viewed from the Y-axis direction. In FIG. 6, the second light emitting region 42 has the same size as the light shielding region 111 (that is, the planar shape of the object 12 ).

The image pickup unit 20 of this example includes an image pickup device 21, a diaphragm 24, and an image pickup optical system 26. The image sensor 21 has a light receiving surface 22. The image sensor 21 may be a chip having a semiconductor substrate. The imaging optical system 26 forms an image of the light from the light irradiation unit 40 on the light receiving surface 22. The image pickup optical system 26 may include an image pickup lens. The diaphragm 24 limits the light incident on the light receiving surface 22 by adjusting the width W (the object side NA) of the opening through which the light flux passes. That is, the diaphragm 24 adjusts the diaphragm value of the imaging lens.

A part of the light emitted from the end of the second light emitting region 42 passes through the inside of the object 12 and is emitted from the object 12 as the transmitted light 46. The transmitted light 46 is converged on the light receiving surface 22 by the imaging optical system 26.

Further, a part of the light emitted from the end portion of the second light emitting region 42 becomes the non-transmissive light 48 that does not pass through the inside of the object 12. A part of the non-transmissive light 48 passes through the imaging optical system 26 and reaches the light receiving surface 22.

On the other hand, as shown in FIG. 5, the ratio of the non-transmissive light 48 passing through the imaging optical system 26 can be reduced by making the second light emitting region 42 smaller than the light shielding region 111. Thereby, in the second image 102, the contrast of the internal structure of the object 12 can be improved.

The ratio of the non-transmissive light 48 passing through the imaging optical system 26 changes depending on the aperture value of the aperture 24 (that is, the width W). The larger the width W, the easier the non-transmissive light 48 passes through the imaging optical system 26. The width W of the diaphragm 24 in this example is variable. The processing device 30 may increase the reduction amount L1 as the width W of the diaphragm 24 (that is, the object side NA) increases.

FIG. 7 is a diagram showing an example of the emission intensity distribution along the line AA shown in FIG. The line AA is a straight line passing through the center C of the second light emitting region 42 in the plan view. In FIG. 7, the horizontal axis represents the position within the light irradiation surface 44, and the vertical axis represents the emission intensity on the light irradiation surface 44. In this example, the position of the outer periphery of the light shielding region 111 is P1, the position of the outer periphery of the second light emitting region 42 is P2, and the position of the central portion of the second light emitting region 42 is Pc. In the present example, the central portion is the center C of the planar shape of the second light emitting region 42.

The outer peripheral position P2 of the second light emitting region 42 is separated from the outer peripheral position P1 of the light shielding region 111 by the reduction amount L1 inside the light shielding region 111. The emission intensity in the area between the position P2 and the position P1 may be zero. In the second light emitting region 42 inside the position P2, the light irradiation surface 44 emits light with a predetermined light emission intensity.

When the second light emitting region 42 is smaller than the light shielding region 111, the amount of light irradiated to the end portion of the target object 12 decreases, and the observation accuracy of the end portion of the target object 12 may deteriorate. In the light irradiation unit 40 of the present example, the first emission intensity I1 per unit area at the end 43 of the second light emitting region 42 is a unit in the central portion (center Pc in the present example) of the second light emitting region 42. It is made larger than the second emission intensity I2 per area.

The end portion 43 is a region of the second light emitting region 42 that is in contact with the outer circumference P2. The end portion 43 may be an area within a predetermined distance (or the number of pixels) from the outer circumference P2. For example, when the image capturing unit 20 captures an image of the target object 12 that is a uniform substance, the brightness of the end portion 43 of the target object 12 irradiated with the first emission intensity I1 and the second emission intensity I2 are applied. A distance may be set in advance so that the brightness of the central portion of the target object 12 becomes equal. By increasing the first emission intensity I1 of the end portion 43, the amount of light incident on the end portion of the object 12 can be increased. Therefore, it is possible to reduce the size of the second light emitting region 42 to reduce the non-transmitted light 48 and to maintain the light amount of the incident light on the end portion of the object 12.

The processing device 30 may control the first emission intensity I1 based on the reduction amount L1. The processing device 30 may increase the first emission intensity I1 as the reduction amount L1 is larger. The processing device 30 may reduce the first emission intensity I1 as the reduction amount L1 is smaller. The processing device 30 may increase the width of the end portion 43 as the reduction amount L1 is larger. The processing device 30 may reduce the width of the end portion 43 as the reduction amount L1 is smaller. The larger the reduction amount L1 is, the smaller the light amount incident on the edge of the object 12 is. However, by controlling the first emission intensity I1 based on the reduction amount L1, the light amount incident on the edge of the object 12 is reduced. It can be controlled appropriately. In FIG. 7, the light emission intensity at the end portion 43 is changed in two steps of the first light emission intensity I1 and the second light emission intensity I2, but the light emission intensity at the end portion 43 is changed in three or more steps. Or may change continuously.

As described in FIG. 6, the processing device 30 may also control the first emission intensity I1 when the reduction amount L1 is controlled according to the width W of the diaphragm 24. The processing device 30 may control the reduction amount L1 for other reasons. Also in this case, the processing device 30 may also control the first emission intensity I1.

FIG. 8 is a diagram showing an arrangement example of the light receiving surface 22, the object 12, and the light irradiation surface 44 of the imaging unit 20. FIG. 8 is a diagram of the object 12 and the imaging device 10 as viewed from the Y-axis direction. The light receiving surface 22 is a surface that receives light. In this example, the light receiving surface 22 and the object 12 are arranged at optically conjugate positions. The position of the object 12 may be the center of the thickness of the object 12. The light-receiving surface 22 and the object 12 do not have to be strictly conjugate with each other. For example, when the position of the object 12 has an error within 10% of the thickness of the object 12 with respect to the conjugate point, the object 12 may be placed at the conjugate point. The light receiving surface 22 and the surface of the object 12 may be arranged at optically conjugate positions.

By arranging the object 12 at a conjugate point with respect to the light receiving surface 22, it is possible to reduce moire in the captured image. However, the light irradiation surface 44 and the light receiving surface 22 are arranged at positions that are not conjugate. Therefore, the blur amount of the light irradiation surface 44 increases in the captured image. When the amount of blurring in the captured image increases, the non-transmissive light 48 from the inner light emitting region may reach the light receiving surface 22.

The processing device 30 may control the reduction amount L1 of the second light emitting region 42 based on the image blur amount on the light irradiation surface 44. The image blur amount on the light irradiation surface 44 may be preset in the processing device 30, and may be determined by the processing device 30 by a calibration operation.

FIG. 9 is a diagram illustrating an example of the first calibration image 104 used in the calibration operation for determining the image blur amount. FIG. 9 is an image in which the imaging unit 20 images the light irradiation unit 40. The light irradiation unit 40 irradiates the light with a predetermined first calibration pattern on the light irradiation surface 44 in a state where the object 12 is not arranged. On the light irradiation surface 44 of the present example, dots 50 having a preset emission intensity and shape are arranged in a predetermined array pattern. The interval between the dots 50 is larger than the image blur amount on the light irradiation surface 44. The dots 50 may be uniformly distributed in the light irradiation surface 44 at intervals of twice or more the amount of image blur. The emission intensity of each dot 50 may be any emission intensity at which the pixel value of the captured image is not saturated. The emission intensity of each dot 50 may be the same as the first emission intensity I1 described with reference to FIG. 7, or may be the same as the second emission intensity I2.

The image capturing unit 20 captures the first calibration image 104 by capturing an image of the light irradiation surface 44 that irradiates light with the first calibration pattern. The image capturing section 20 may capture the light irradiation surface 44 under the same image capturing conditions as in the second image capturing step S202. The image capturing section 20 may capture the light irradiation surface 44 under a plurality of mutually different image capturing conditions. In this case, the processing device 30 determines the image blur amount for each imaging condition. The imaging conditions include, for example, the aperture value, the distance between the imaging unit 20 and the light irradiation surface 44, and the like.

The processing device 30 calculates the image blur amount on the light irradiation surface 44 based on the first calibration image 104. The processing device 30 of the present example detects each dot 50 in the first calibration image 104 based on the array pattern of the dots 50 in the first calibration pattern. The processing device 30 detects the image blur portion 52 that appears around each dot 50 in the first calibration image 104. In this example, the image blur portion 52 is hatched. The image blur portion 52 may be a pixel area around the dot 50 having a luminance value equal to or higher than a predetermined ratio with respect to the luminance value of the dot 50.

FIG. 10 is an enlarged view of the image blur portion 52. The processing device 30 determines the image blur amount based on each of the detected image blur units 52. The image blur amount may be the distance L2 between the dot 50 and the outer peripheral edge of the image blur portion 52. The processing device 30 may determine the image blur amount for each of the dots 50 and the image blur portion 52. Thereby, the distribution of the image blur amount at a plurality of positions within the light irradiation surface 44 can be calculated. The processing device 30 stores information about the acquired image blur amount.

The processing device 30 determines the reduction amount L1 in the second light emitting region 42 based on the acquired distribution of the image blur amount. The processing device 30 may determine the reduction amount L1 of the second light emitting area 42 by using the image blur amount corresponding to the position of the second light emitting area 42. Further, the processing device 30 may determine the reduction amount L1 at a plurality of positions on the light irradiation surface 44. For example, the processing device 30 may divide the outer circumference of the second light emitting region 42 into a plurality of parts, and use the image blur amount corresponding to the position of each part to determine the reduction amount L1 in each part. ..

11, 12, and 13 are diagrams for explaining another control example of the second light emitting region 42. The processing device 30 of the present example, based on the angle of view θ of the object 12 in the second imaging step S202, the relative position of the second light emitting area 42 with respect to the object 12 or the size of the second light emitting area 42. Control

The angle of view θ of the object 12 is an angle formed by the optical axis 18 of the imaging unit 20 and a straight line connecting the imaging unit 20 and the end P3 of the object 12. The end P3 is the end of the object 12 that is closest to the imaging unit 20. Further, in the present example, among the end portions of the object 12, the end portion farthest from the imaging unit 20 is P4. When the relative position between the imaging unit 20 and the light irradiation surface 44 is known, the position of the end P3 of the object 12 on the light irradiation surface 44 can be used as the angle of view θ.

FIG. 11 shows an example in which the relative position and size of the second light emitting region 42 are constant regardless of the angle of view θ. Although the reduction amount L1 of the second light emitting region 42 is zero in FIGS. 11 to 13, the second light emitting region 42 may have the reduction amount L1 described in FIGS. 1 to 10.

As shown in FIG. 11, when the angle of view θ of the target object 12 is zero, that is, when the target object 12 is arranged immediately below the imaging unit 20, the second light emitting region 42 is covered by the target object 12. If so, the ratio of the non-transmissive light 48 from the second light emitting region 42 reaching the imaging unit 20 is small. On the other hand, when the angle of view θ increases, the area of the second light emitting region 42 that is not shielded by the object 12 with respect to the imaging unit 20 increases. For example, in the vicinity of the end P3, the second light emitting region 42 is directly observed by the imaging unit 20. Therefore, the ratio of the non-transmissive light 48 received by the imaging unit 20 increases.

FIG. 12 shows an example of controlling the relative position of the second light emitting region 42 with respect to the object 12 based on the angle of view θ. The processing device 30 of the present example shifts the position of the second light emitting region 42 in the direction from the end P3 to the end P4 based on the angle of view θ. The processing device 30 of this example does not change the shape and size of the second light emitting region 42.

This can prevent the second light emitting region 42 from being directly observed by the imaging unit 20 in the vicinity of the end P3. Therefore, the ratio of the non-transmissive light 48 received by the imaging unit 20 can be reduced. In addition, in the vicinity of the end P4, a portion in which the second light emitting region 42 is not covered by the object 12 occurs in the direction perpendicular to the light irradiation surface 44. The area is not directly observed from the image capturing unit 20. However, it is also conceivable that the non-transmissive light 49 from the area is reflected by surrounding walls, partitions, and the like to become stray light and is received by the imaging unit 20.

FIG. 13 shows an example in which the second light emitting region 42 is made smaller than the light shielding region 111 based on the angle of view θ. The reduction of the second light emitting region 42 described in FIG. 13 may be performed independently of the reduction described in FIGS. 1 to 10. The processing device 30 of the present example reduces the protrusion of the second light emitting region 42 that occurs in the vicinity of the end P4 due to the position shift of the second light emitting region 42 described in FIG.

When the processing device 30 shifts the second light emitting region 42 in the first direction by the shift amount L3, the width of the second light emitting region 42 in the first direction may be reduced according to the shift amount L3. .. The reduction amount may be the same as the shift amount L3. Thereby, when the second light emitting region 42 is shifted, the ratio of the non-transmissive light 49 received by the imaging unit 20 can be reduced.

14, FIG. 15 and FIG. 16 are diagrams illustrating an example of a light emitting method in the light irradiation unit 40. FIG. 14 is a diagram of the object 12 and the light irradiation unit 40 viewed from the Y-axis direction. The light irradiation unit 40 of the present example sets a plurality of second light emitting regions 42-1 and 42-2 at different positions for one object 12. The plurality of second light emitting regions 42-1 and 42-2 in this example may be regions obtained by dividing the second light emitting region 42 described in FIGS. 1 to 13 into a plurality of parts.

The light irradiation unit 40 causes one of the second light emitting areas 42 (for example, the second light emitting area 42-1) to emit light and performs the second imaging step S202, and then the other second light emitting area 42 ( For example, the second light emitting area 42-2) is caused to emit light, and the third imaging step S203 is executed. With such a method, it is possible to acquire three-dimensional information regarding the three-dimensional shape of the internal structure 14 of the object 12. The internal structure 14 is, for example, a crack generated in the object 12.

FIG. 15 is a diagram showing an example of the second image 102 acquired in the second imaging step S202. In the second image capturing step S202, the second light emitting region 42-1 is caused to emit light to capture the second image 102. In this example, the second light emitting region 42-1 is a region that does not overlap with the internal structure 14. In this case, as shown in FIG. 15, in the second image 102, the shadow portion 16 appears adjacent to the internal structure 14. The shadow portion 16 is arranged on the side opposite to the second light emitting region 42-1 with respect to the internal structure 14. The width of the shadow portion 16 increases according to the length of the internal structure 14 in the depth direction.

FIG. 16 is a diagram showing an example of the third image 103 acquired in the third imaging step S203. In the third image capturing step S203, the second light emitting region 42-2 is caused to emit light and the third image 103 is captured. In the present example, the second light emitting region 42-2 is a region overlapping with the internal structure 14. In this case, as shown in FIG. 16, in the third image 103, there is no shadow adjacent to the internal structure 14, or the shadow is smaller than that in the second image 102.

The processing device 30 determines the position and size of the internal structure 14 and the shadow portion 16 in the second image 102 and the third image 103, and the second light emitting region 42 and the internal structure 14 and the shadow portion 16 of the respective images. The three-dimensional information of the internal structure 14 may be calculated based on the relative position. In the present example, the two second light emitting areas 42 are made to emit light in order, but in another example, even if more second light emitting areas 42 are made to emit light in order and more images are acquired. Good. The processing device 30 has a learning unit that acquires a plurality of third images 103 and three-dimensional information of the internal structure 14 corresponding to each of the third images 103 and machine-learns the relationship between the images and the three-dimensional information. May be.

The shape of each second light emitting area 42 may be determined based on the shape of the light shielding area 111 in the first image 101. In this example, the shape of each of the second light emitting regions 42 is determined from the shape of the region obtained by dividing the light shielding region 111 into a plurality of regions.

FIG. 17 is a diagram illustrating an example of adjusting the emission intensity at each position on the light irradiation surface 44. Due to the characteristics of the optical system of the imaging unit 20, even if light is emitted with a uniform emission intensity within the light irradiation surface 44, the brightness of the light irradiation surface 44 in the captured image may not be uniform. The processing device 30 of the present example controls the distribution of the light emission intensity in each light emitting region so as to compensate the brightness distribution of the captured image caused by the characteristics of the optical system of the imaging unit 20 and the like. The processing device 30 may adjust the emission intensity distribution of one of the first emission region 41 and the second emission region 42, or may adjust both emission intensity distributions. The adjustment of the light emission intensity in this example may be combined with each aspect described in FIGS. 1 to 16.

The light irradiation unit 40 of the present example irradiates light with the second calibration pattern 106 that is predetermined on the light irradiation surface 44 in a state where the object 12 is not arranged on the light irradiation surface 44. The second calibration pattern 106 is, for example, a pattern in which the light emission intensity is uniform over the entire light irradiation surface 44. The second calibration pattern 106 may have any emission intensity that does not saturate the pixel values of the captured image. The emission intensity per unit area of the second calibration pattern 106 may be the same as the emission intensity per unit area in the first emission region 41 or the second emission region 42.

The imaging unit 20 images the second calibration pattern 106 to obtain the second calibration image 108. The processing device 30 adjusts the emission intensity at each position in each emission region based on the luminance distribution in the second calibration image 108. For example, in the second calibration image 108, the brightness value may decrease as the distance from the center of the image (that is, the position corresponding to the optical axis of the imaging unit 20) increases. In the example of FIG. 17, the second calibration image 108 has a central region 116, a middle region 112, and an outer region 110. The central region 116 is a region including the center of the image, and has an average luminance value higher than that of the other regions. The intermediate region 112 is a region that surrounds the central region 116, and has an average luminance value lower than that of the central region 116 and higher than that of the outer region 110. The outer region 110 is a region that surrounds the intermediate region 112, and has an average luminance value lower than that of the other regions.

The light irradiation unit 40 makes the emission intensity of a portion located in the outer region 110 in the first emission region 41 or the second emission region 42 higher than the emission intensity of portions located in the central region 116 and the intermediate region 112. You can do it. Similarly, in the light emitting unit 40, in the first light emitting region 41 or the second light emitting region 42, the light emission intensity of the portion located in the central region 116 is made smaller than the light emission intensity of the portions located in the outer region 110 and the intermediate region 112. May be lower.

By such processing, the brightness distribution due to the characteristics of the optical system of the imaging unit 20 can be compensated. In the example of FIG. 17, the emission intensity is controlled stepwise in a plurality of regions. In another example, the light emission intensity may be adjusted for each light emitting element of the light irradiation unit 40.

When the aperture value of the image pickup lens in the image pickup unit 20 is variable, the processing device 30 may adjust the light emission intensity distribution of the light emitting region for each aperture value of the image pickup lens. In this case, the imaging unit 20 captures the second calibration image 108 for each aperture value of the imaging lens. The processing device 30 previously acquires and stores information for adjusting the emission intensity for each aperture value of the imaging lens.

FIG. 18 is a diagram illustrating an example of adjusting the light emission intensity in the second light emitting region 42. The processing device 30 of the present example adjusts the light emission intensity distribution in the second light emitting region 42 so as to compensate for the attenuation of light according to the thickness of the object 12. The object 12 is assumed to be composed of a uniform substance. The adjustment of the light emission intensity of this example may be combined with each aspect described in FIGS.

The processing device 30 acquires pixel values (for example, brightness values) of the plurality of image positions 121 and 122 of the light shielding area 111 in the first image 101. The smaller the pixel value, the larger the attenuation of light at the image position of the target object 12, so it is estimated that the thickness is larger. In the example of FIG. 18, two image positions 121 and 122 are illustrated, but the processing device 30 may acquire the pixel values of more image positions. The processing device 30 may calculate the average of the pixel values for each of the areas obtained by dividing the light blocking area 111 into a plurality of areas.

The processing device 30 controls the light emission intensity of the plurality of light emitting positions 131 and 132 of the second light emitting area 42 based on the pixel values of the plurality of image positions 121 and 122. The light emitting position 131 corresponds to the image position 121, and the light emitting position 132 corresponds to the image position 122. The processing device 30 may increase the emission intensity of the corresponding emission position as the pixel value at the image position is smaller. Thereby, even if the target object 12 does not have a uniform thickness, the intensity of light emitted from the target object 12 can be made uniform.

FIG. 19 is a schematic diagram showing an example of an imaging device 210 according to another embodiment of the present invention. The imaging device 210 irradiates the object 12 with light and receives the light that has passed through the inside of the object 12. Thereby, the imaging device 210 captures an image showing the internal structure of the object 12. The imaging device 210 of the present example also executes the first imaging stage and the second imaging stage, similarly to the imaging device 10 described in FIGS. 1 to 18. However, the specific contents of the first imaging stage and the second imaging stage are different from those of the imaging device 10. The imaging device 210 acquires the shape of the target object 12 in the first imaging stage. The imaging device 210 suppresses stray light in the second imaging stage based on the shape of the object 12.

The imaging device 210 is different from the imaging device 10 described in FIG. 1 in the structure of the limiting unit. The structure and functions other than the restriction unit are the same as those of the imaging device 10. For example, the imaging unit 20 and the processing device 30 of the imaging device 210 have the same structure and function as the imaging unit 20 and the processing device 30 of the imaging device 10.

The imaging device 210 has a light irradiation unit 240 and a light reduction unit 241. In this example, the dimming unit 241 functions as a limiting unit that limits the light flux that passes through the outside of the object 12. The light irradiation unit 240 functions as an illumination unit that irradiates the object 12 with light. The light irradiation unit 240 may be a surface light source like the light irradiation unit 40, and need not be a surface light source. When the light irradiation unit 240 is a surface light source, the shape of the light emitting region on the light irradiation surface may not be variable. The light irradiation unit 240 in this example may be a light source whose light emitting surface has a size smaller than that of the object 12. As a result, it is possible to prevent non-transmissive light that has not transmitted through the object 12 from reaching the imaging unit 20.

The dimming unit 241 is arranged between the imaging unit 20 and the object 12 in the second imaging stage. Note that the light reduction unit 241 is disposed between the object 12 and the imaging unit 20 means that light that has passed through the object 12 passes through the light reduction unit 241 and is received by the imaging unit 20. Refers to a simple arrangement. The object 12, the object 12 and the imaging unit 20 in the second imaging stage may be arranged on a straight line, but may not be arranged on a straight line.

The imaging device 210 of this example includes a transport unit 140 that transports the object 12 in the X-axis direction. The transport unit 140 has, for example, a belt conveyor. In this case, the dimming unit 241 is arranged between the transport unit 140 and the imaging unit 20. The dimming unit 241 may be arranged on a straight line connecting the transport unit 140 and the imaging unit 20.

The light irradiation unit 240 irradiates light in the wavelength band corresponding to the internal structure of the observation target. The light irradiation unit 240 may irradiate light in a wavelength band in which the difference in absorbance between the internal structure of the observation target and other internal structures of the internal structure of the object 12 is large. The spectrum of the light emitted by the light irradiation unit 240 may be the same as the spectrum of the light emitted by the light irradiation unit 40. The light emitted by the light irradiator 240 passes through the object 12 and enters the dimming unit 241. The dimming unit 241 transmits the light from the target 12 and causes the image capturing unit 20 to receive the light. The dimming unit 241 includes a transmissive region 242 that transmits light and a dimming region 220 that diminishes light. The dimming region 220 dims the light flux around the light flux that has passed through the illuminated object 12 (that is, the light flux that does not pass through the object 12). The dimming region 220 may have a transmittance of light emitted by the light irradiation unit 240 of 10% or less, or 1% or less, as compared with the transmission region 242.

The shape of the transmission region 242 of the light reduction unit 241 is variable. The shape of the transmissive region 242 may refer to the shape in a plane (XZ plane in this example) perpendicular to the optical axis of the imaging unit 20. It should be noted that in the dimming unit 241, a region other than the transmissive region 242 may be the dimming region 220. That is, by determining the shape of the transmissive area 242, the shape of the dimming area 220 is also determined. The dimming unit 241 may have two-dimensionally arranged optical elements capable of independently controlling the light transmittance. The processing device 30 may control, for each region of the dimming unit 241, whether light is transmitted or dimmed. The processing device 30 may also control the light transmittance for each region. As an example, the dimming unit 241 has a liquid crystal panel. The processing device 30 controls the shape of the transmissive region 242 in the second imaging stage based on the shape of the object 12. For example, the processing device 30 controls the shape of the transparent region 242 to be the same as the shape of the object 12. In another example, the processing device 30 may make the shape of the transparent region 242 a shape obtained by reducing the shape of the object 12 at a predetermined rate.

By such control, in the second imaging stage, it is possible to block the non-transmissive light that has not transmitted through the target object 12 and suppress the reaching of the imaging unit 20. Therefore, the internal structure of the object 12 can be accurately observed.

FIG. 20 is a diagram showing an example of the first imaging step S201 and the second imaging step S202. In this example, the object 12 is stationary while the first imaging step S201 and the second imaging step S202 are executed. In other examples, the object 12 may be moving.

The imaging unit 20 acquires the first image 101 in the first imaging step S201. In the first imaging step S201, the light irradiation unit 240 may irradiate the object 12 with light, or may irradiate the object 12 with light from another light source.

In the first imaging step S201 of this example, the dimming unit 241 is controlled so that the entire surface becomes the transmissive region 242. The imaging unit 20 may acquire the first image 101 so that the position of the target object 12 with respect to the dimming unit 241 on the first image 101 can be determined. For example, the imaging unit 20 may acquire the first image 101 including the entire light reducing unit 241, or may acquire the first image 101 including the marker provided in the light reducing unit 241. As a result, the position of the object 12 with respect to the dimming unit 241 can be determined.

In the second imaging step S202, the dimming unit 241 determines the position and shape of the transmissive area 242 in the second imaging step S202 based on the position and shape of the object 12 in the first image 101. The position and shape of the transparent region 242 may be the same as or smaller than the position and shape of the object 12 in the first image 101. With such a configuration as well, similar to the image capturing apparatus 10, in the second image capturing step S202, it is possible to suppress light that has not transmitted through the target 12 from reaching the image capturing unit 20.

In this example, the transparent area 242 in the second imaging step S202 is smaller than the transparent area 242 in the first imaging step S201. By reducing the area of the transmissive region 242 in the second imaging step S202, it is possible to reduce the proportion of the light that has not passed through the target object 12 reaching the imaging unit 20 in the second imaging step S202.

Note that the angle of view θ of the image capturing unit 20 that captures the first image 101 in the first image capturing step S201 and the angle of view θ of the image capturing unit 20 that captures the second image 102 in the second image capturing step S202 are , And preferably the same. This makes it easy to appropriately set the shape of the transparent region 242 in the second imaging step S202 based on the shape of the target object 12 acquired from the first image 101. FIG. 20 shows an example in which the angle of view θz in the Z-axis direction is the same in the first imaging step S201 and the second imaging step S202, but the angle of view in the X-axis direction is also the first imaging step. It is preferably the same in step S201 and the second imaging step S202. In the first imaging step S201 and the second imaging step S202, it is preferable that the same imaging unit 20 is used and the angle of view of the imaging unit 20 is not changed.

FIG. 21 is a diagram illustrating an imaging device 310 according to a comparative example. The image pickup apparatus 310 of this example is different from the image pickup apparatus 210 in that it does not include the light reduction unit 241. A part of the irradiation light 47 irradiated by the light irradiation unit 240 is reflected on the surface of the object 12. The light reflected on the surface of the object 12 may reach the imaging unit 20 as non-transmissive light 48 that does not pass through the object 12 by being reflected by the surrounding environment such as the transport unit 140. Note that, in FIG. 21, the non-transmitted light 48 and the target 12 are displayed in an overlapping manner, but the non-transmitted light 48 passes through a position different from the target 12 in the X-axis direction.

When the non-transmissive light 48 reaches the imaging unit 20, the first image 101 captured by the imaging unit 20 includes the non-transmissive light 48 in addition to the target object 12. Since the non-transmissive light 48 is not attenuated in light intensity by the object 12, the non-transmissive light 48 is often brighter than the object 12 in the first image 101. Therefore, if the non-transmitted light 48 is included in the first image 101, it becomes difficult to accurately observe the internal structure of the target object 12.

On the other hand, according to the imaging device 210 described with reference to FIGS. 19 and 20, the dimming unit 241 can prevent the non-transmissive light 48 from reaching the imaging unit 20. Therefore, the internal structure of the object 12 can be accurately observed.

FIG. 22 is a diagram illustrating an example of the first imaging step S201. The imaging device 210 of this example includes a light source 244 in addition to the configuration of the imaging device 210 described with reference to FIGS. 19 and 20. The other structure is the same as the example described in FIGS. 19 and 20.

The light source 244 is arranged between the dimming unit 241 and the object 12 in the first imaging step S201. In this example, the light source 244 is arranged between the transport unit 140 and the dimming unit 241. Note that the space between the object 12 (or the transport unit 140) and the dimming unit 241 is not limited to the area on the straight line connecting the object 12 (or the transport unit 140) and the dimming unit 241. In the optical axis direction of the imaging unit 20 (Y-axis direction in this example), the position of the light source 244 may be between the position of the object 12 (or the transport unit 140) and the position of the dimming unit 241.

The dimming unit 241 of the present example transmits the reflected light from the object 12 of the light emitted by the light source 244 in the first imaging step S201. The dimming unit 241 of this example may operate so that the entire surface becomes the transmissive region 242 in the first imaging step S201. The entire surface of the dimming part 241 refers to the entire region where the transmissive region 242 and the dimming region 220 can be switched.

The imaging device 210 may include a plurality of light sources 244. The plurality of light sources 244 may irradiate the object 12 with light from different directions.

The light source 244 may emit light having a wavelength different from that of the light emitting section 240. The light emitted by the light irradiator 240 is used for observing the inside of the object 12, and therefore it is preferable that the light reflected by the surface of the object 12 is small. On the other hand, the light emitted from the light source 244 is used for observing the outer shape of the target object 12 by the reflected light, and therefore it is preferable that the surface of the target object 12 is largely reflected. Therefore, it is preferable that the light emitted from the light source 244 has a higher reflectance on the surface of the object 12 than the light emitted from the light irradiation unit 240. The reflectance on the surface of the object 12 refers to the ratio of the intensity of the light reflected on the surface of the object 12 to the intensity of the light emitted from the light source to the surface of the object 12. The ratio may be calculated by integrating light intensities in all wavelength bands in which the imaging unit 20 has sensitivity, or may be calculated using light intensities in a specific wavelength band.

The light emitted by the light source 244 preferably has a wavelength component according to the reflection spectrum on the surface of the object 12. The reflection spectrum is a spectrum showing the reflectance for each wavelength of light. The light source 244 preferably contains a wavelength component that maximizes the reflectance on the surface of the object 12.

FIG. 23 is a diagram showing an example of a reflection spectrum on the surface of the object 12. The reflection spectrum of this example has three maximum peaks 250-1, 250-2, and 250-3, but the shape of the reflection spectrum is not limited to this. In this example, the wavelengths at the vertices of the maximum peaks 250-1, 250-2, and 250-3 are n1, n2, and n3. The respective maximum peaks 250 are peaks arranged in the wavelength band in which the imaging unit 20 has sensitivity.

The light source 244 may emit light including a wavelength within the full width at half maximum of any of the maximum peaks 250. In the spectrum of the light emitted from the light source 244, the wavelength having the maximum intensity may be arranged within the full width at half maximum of any of the maximum peaks 250. In the example of FIG. 23, the peak wavelength N that maximizes the intensity of the irradiation light from the light source 244 is arranged within the full width at half maximum R3 of the maximum peak 250-3. The maximum peak 250-3 may be the maximum peak 250 having the maximum intensity P3 among the plurality of maximum peaks 250.

The light source 244 may have variable wavelength characteristics of irradiation light. For example, the light source 244 may include a plurality of light emitting devices capable of emitting light of different wavelengths. In this case, the light source 244 may control the wavelength characteristic of the irradiation light based on the wavelength at which the reflectance on the surface of the target object 12 is maximized. The wavelength at which the reflectance on the surface of the object 12 is maximized may be preset in the light source 244. In another example, information indicating the type of the object 12 may be input to the processing device 30. Information about the reflection spectrum of the object 12 may be recorded in the processing device 30 in advance for each type of the object 12. In this case, the processing device 30 controls the wavelength characteristic of the irradiation light of the light source 244 based on the reflection spectrum corresponding to the type of the object 12.

FIG. 24 is a diagram showing another example of the first imaging step S201. In this example, a two-dimensional image (first image) on the XZ plane of the object 12 is acquired by line scanning. The imaging device 210 of this example includes a scanning unit 23. The scanning unit 23 of this example acquires a two-dimensional image of the object 12 by detecting the length of the object 12 in the Z axis direction at each position in the X axis direction. In the first imaging step S201, the object 12 and the measurement position in the scanning unit 23 move relatively in the X-axis direction. In the first imaging step S201, the object 12 may be moving and the measurement position in the scanning unit 23 may be moving.

FIG. 25 is a diagram illustrating an example of the second imaging step S202. In this example, the object 12 moves so as to pass between the light irradiation unit 240 and the imaging unit 20 during the second imaging step S202. That is, the object 12 is moving even during the exposure time of the imaging unit 20.

The dimming unit 241 of the present example controls the shape of the transmissive region 242 based on the moving speed of the object 12 and the exposure time in the second imaging step S202. In this example, the position of the object 12 at the start of exposure in the second imaging step S202 is the start position 252-1 and the position of the object 12 at the end of exposure is the end position 252-2. When the object 12 is moving during the exposure time, the start position 252-1 and the end position 252-2 do not match. Therefore, if the transmissive area 242 is set in accordance with the start position 252-1, the non-transmissive light 48 easily reaches the imaging unit 20 at the end of the exposure without the transmissive area 242 and the end position 252-2 matching each other. Become.

The dimming unit 241 of this example makes the length of the transmission region 242 smaller than the length of the target 12 in the moving direction of the target 12 (X-axis direction in this example). In addition, in the Z-axis direction, the length of the transmissive region 242 may be the same as the length of the object 12. That is, the ratio of the length of the transmissive region 242 in the X axis direction to the length of the Z axis direction is smaller than the ratio of the length of the object 12 in the Z axis direction to the length in the Z axis direction. This can prevent the non-transmitted light 48 from reaching the imaging unit 20. The light reduction unit 241 sets a difference D between the length of the transmissive region 242 and the length of the object 12 in the X-axis direction based on the moving speed of the object 12 and the exposure time. The difference D may be determined by the product of the moving speed and the exposure time. That is, the difference D increases as the product of the moving speed and the exposure time increases.

The dimming unit 241 may set the transmissive region 242 in a region where the object 12 at the start position 252-1 and the object 12 at the end position 252-2 overlap each other. Thereby, the transmissive area 242 can be set in the area where the object 12 is always present during the exposure time. Therefore, it is possible to prevent the non-transmissive light 48 from reaching the imaging unit 20.

FIG. 26 is a diagram illustrating another example of the second imaging step S202. Also in this example, the object 12 moves so as to pass between the light irradiation unit 240 and the imaging unit 20 during the second imaging step S202.

The dimming unit 241 of this example moves the position of the transmissive region 242 from the start position 242-1 to the end position 242-2 according to the moving speed of the object 12 while the imaging unit 20 is exposing. In this example, the length of the transmission region 242 in the X-axis direction need not be shortened. That is, the ratio of the length of the transmission region 242 in the X axis direction to the length of the Z axis direction may be the same as the ratio of the length of the object 12 in the X axis direction to the length in the Z axis direction.

According to this example, since the transmissive region 242 follows the movement of the target object 12, it is possible to prevent the non-transmissive light 48 from reaching the imaging unit 20 even when the target object 12 moves during the exposure time. Can be suppressed. Further, since the transmissive area 242 is not reduced, the entire object 12 can be easily observed.

FIG. 27 is a diagram illustrating another example of the second imaging step S202. The imaging apparatus 210 of this example uses the control of the transparent area 242 described in FIG. 25 and the control of the transparent area 242 described in FIG. In the control described in FIG. 25, the transmissive region 242 is smaller than the object 12 by the difference D in the X-axis direction. In the control described in FIG. 26, since the transmissive area 242 is moved, the transmissivity of the end portion of the transmissive area 242 and the transmissivity of the central portion of the transmissive area 242 are set according to the response speed of the light reduction unit 241. There may be variations between them.

In this example, in the determination step S203, the light reduction unit 241 determines whether the exposure time in the second imaging step S202 is equal to or less than the reference value. The longer the exposure time, the larger the difference D shown in FIG. The dimming unit 241 may determine whether the difference D is equal to or less than the reference value. That is, you may determine whether the product of the exposure time of the imaging part 20 and the moving speed of the target object 12 is below a predetermined reference value. The dimming unit 241 may be used by dividing the reference value to be compared with the exposure time by the moving speed of the object 12. For example, when the difference D shown in FIG. 25 is 5% or less of the length of the object 12 in the X-axis direction, the light reduction unit 241 may determine the exposure time to be the reference value or less.

When the exposure time is less than or equal to the reference value, the light reduction unit 241 reduces the transmissive region 242 in the X-axis direction and fixes the position of the transmissive region 242 as described in FIG. 25 (S204). If the exposure time is longer than the reference value, the light reduction unit 241 causes the transmission area 242 to follow the movement of the object 12 as described with reference to FIG. 26 (S205). By performing these controls, the imaging device 210 acquires the second image 102 (S206). This ends the second imaging step S202.

According to this example, the control of FIG. 25 and the control of FIG. 26 are selectively used based on the exposure time of the imaging unit 20. Therefore, it is possible to acquire the appropriate second image 102 according to the exposure time of the imaging unit 20. In the present example, the dimming unit 241 performs processing such as calculation at each stage, but each processing may be performed by the processing device 30.

In another example, in the determination step S203, the determination may be performed based on the response speed of the dimming unit 241. The response speed of the dimming unit 241 is the time required to change a predetermined region of the dimming unit 241 from the dimming region 220 to the transmissive region 242. When the light reduction unit 241 is a liquid crystal panel, the response speed is also referred to as a refresh rate. As an example, the dimming unit 241 selects the process of S205 when the exposure time in the second imaging step S202 is twice or more the response speed of the dimming unit 241 and selects the process of S204 when it is less than twice. You may choose.

FIG. 28 is a diagram illustrating another example of the dimming unit 241. The dimming unit 241 of this example has regions in which the orientation angles α of the light traveling toward the imaging unit 20 are different. The orientation angle α is an angle of light emitted from the dimming unit 241 when light parallel to the Y axis enters the dimming unit 241 with respect to the optical axis of the imaging unit 20. The orientation angle α may be an angle in the YZ plane.

The dimming part 241 of this example has a different orientation angle α depending on the position in the Z-axis direction. More specifically, on the light exit surface of the dimming unit 241, the orientation angle of the region 256 near the position intersecting the optical axis of the imaging unit 20 is larger than the orientation angle of the region 254 far from the position intersecting the optical axis. small. That is, the dimming unit 241 may be set with the orientation angle α at each position so that the emitted light is focused on the imaging unit 20. With such a configuration, non-transmissive light that does not pass through the target 12 can be further suppressed from reaching the imaging unit 20. The absolute value of the orientation angle α may be 20 degrees or less, 10 degrees or less, or 5 degrees or less. Further, although the orientation angle α in the YZ plane has been described with reference to FIG. 28, the orientation angle in the XZ plane may be different for each position in the X axis direction.

An optical member that adjusts the orientation angle of each region of the dimming unit 241 may be provided between the light exit surface of the dimming unit 241 and the imaging unit 20. The optical member is, for example, a lenticular lens. By shifting the pixel cycle of the light reduction unit 241 in the Z-axis direction and the lens cycle of the lenticular lens in the Z-axis direction, the orientation angle at each position in the Z-axis direction can be made different.

Note that the control of the light irradiation unit 40 described in FIGS. 1 to 18 may be appropriately applied to the control of the light reduction unit 241 described in FIGS. 19 to 28. In this case, the light emitting region of the light irradiation unit 40 is read as a transmissive region, the light shielding region is read as a dimming region, the light emission intensity is read as a transmittance, the light emitting position is read as a transmissive position, the light emitting element is read as a transmissive pixel, and The irradiation surface may be read as a light transmitting surface.

Although the present invention has been described using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the description of the scope of claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

10... Imaging device, 12... Object, 14... Internal structure, 16... Shadow part, 18... Optical axis, 20... Imaging part, 21... Imaging element, 22 ... Light receiving surface, 23... Scan unit, 24... Aperture, 26... Imaging optical system, 30... Processing device, 40... Light irradiation unit, 41... First light emission Area, 42... Second light emitting area, 43... Edge, 44... Light irradiation surface, 46... Transmitted light, 47... Irradiated light, 48... Non-transmitted light, 49 ... Non-transmitted light, 50... Dots, 52... Image blur portion, 101... First image, 102... Second image, 103... Third image, 104... ..First calibration image, 106...Second calibration pattern, 108...Second calibration image, 110...Outside area, 111...Light shielding area, 112... ..Middle region, 114... Image element, 116... Central region, 121... Image position, 122... Image position, 131... Light emitting position, 132... Light emitting position, 140... -Conveying unit, 210... Imaging device, 220... Dimming region, 240... Light irradiation unit, 241... Dimming unit, 242... Transmissive region, 242-1... Starting position 242-2... End position, 244... Light source, 250... Maximum peak, 252-1... Start position, 252-2... End position, 254, 256... Position, 310 ...Imaging device

Claims (24)

A limiting unit that limits the light flux that passes outside the outer shape of the illuminated object,
An image pickup unit for picking up an image of the light flux that has passed through the object,
The said limitation part is an imaging device with which the area|region which restrict|limits the said light flux is changed with the shape of the said target object. A light emitting portion having a variable shape of a light emitting region for illuminating the object,
The limiting unit changes the shape of the light emitting region in the second imaging by the imaging unit based on the shape of the object in the first image obtained by the first imaging by the imaging unit. The imaging device according to. The light emitting unit,
Emits light in the first light emitting region in the first imaging,
The image pickup apparatus according to claim 2, wherein light is emitted in a second light emitting region that is smaller than the first light emitting region in the second image pickup. The second light emitting region is
The imaging device according to claim 3, further comprising at least a part of a light-shielding region that is shielded by the object in the light emitting unit, which is detected based on the first image. In a state in which the object is not arranged, the light emitting unit irradiates light with a predetermined first calibration pattern,
The image capturing unit captures the first calibration pattern by capturing the first calibration pattern,
The imaging device according to claim 4, wherein the light emitting unit determines a reduction amount of the second light emitting region with respect to the light shielding region based on the first calibration image. The light emitting unit calculates image blur amounts at a plurality of positions on the light emitting surface of the light emitting unit based on the first calibration image, and calculates a plurality of image blurring amounts on the light emitting surface based on the image blur amounts. The image pickup apparatus according to claim 5, wherein the reduction amount at the position is determined. The light emitting unit makes the first light emission intensity per unit area at the end portion of the second light emitting region larger than the second light emission intensity per unit area at the central portion of the second light emitting region. Item 6. The imaging device according to item 6. The imaging device according to claim 7, wherein the light emitting unit controls the first emission intensity based on the reduction amount. The imaging unit has a light receiving surface for receiving light,
9. The object and the light receiving surface are arranged at a conjugate position, and the light irradiation surface of the light emitting unit and the light receiving surface are arranged at a non-conjugate position. The imaging device according to. The object moves above the light emitting unit,
The imaging device according to claim 2, wherein the light emitting unit determines a position of the light emitting region based on a position of the object in the second imaging. The imaging according to claim 10, wherein the light emitting unit shifts a position of the light emitting region in the second imaging with respect to a position of the object based on an angle of view of the object in the second imaging. apparatus. The light emitting unit reduces the light emitting area in the second image capturing to be smaller than an area shielded by the object in the first image, based on an angle of view of the object in the second image capturing. The imaging device according to claim 10. The imaging unit acquires a second image by the second imaging, and then acquires a third image by a third imaging,
The light emitting unit changes the relative position of the light emitting region with respect to the object in the second imaging and the third imaging, and based on the shape of the object in the first image, The imaging device according to any one of claims 2 to 12, wherein a shape of the light emitting region in the imaging of No. 3 is determined. The imaging device according to claim 13, further comprising a processing device that calculates three-dimensional information inside the object based on the second image and the third image. In a state where the object is not arranged, the light emitting unit emits light according to a predetermined second calibration pattern,
The image capturing unit captures a second calibration image by capturing the second calibration pattern,
The imaging device according to any one of claims 2 to 14, wherein the light emitting unit adjusts the light emission intensity at each position in the light emitting region based on the second calibration image. In the image pickup unit, the aperture value of the image pickup lens is variable,
The imaging unit acquires the second calibration image for each aperture value of the imaging lens,
The imaging device according to claim 15, wherein the light emitting unit adjusts the light emission intensity for each aperture value of the imaging lens. The light emitting unit controls the light emission intensity at a plurality of positions of the light emitting region in the second imaging, based on pixel values at a plurality of positions of a region shielded by the object in the first image. Item 17. The image pickup device according to any one of items 2 to 16. An illumination unit for illuminating the object,
The limiting unit is disposed between the imaging unit and the object, and has a dimming region that dims a light beam around a light beam that passes through the illuminated object,
The shape of the dimming region in the second imaging by the imaging unit is changed based on the shape of the object in the first image obtained by the first imaging by the imaging unit. Imaging device. A light source that is disposed between the limiting unit and the object in the first imaging and illuminates the object;
The imaging device according to claim 18, wherein the limiting unit transmits reflected light of the light from the light source from the object in the first imaging. 20. The imaging device according to claim 19, wherein the light source has variable wavelength characteristics of irradiation light, and controls the wavelength characteristics of the irradiation light based on a wavelength at which the reflectance on the surface of the object is maximized. apparatus. The imaging device according to any one of claims 18 to 20, wherein the imaging unit performs the first imaging and the second imaging at the same angle of view. The object moves so as to pass between the illumination unit and the imaging unit,
The limiting unit controls the shape of the dimming region based on a moving speed of the target object and an exposure time of the imaging unit in the second imaging. The imaging device described. The object moves so as to pass between the illumination unit and the imaging unit,
When the exposure time of the imaging unit in the second imaging is equal to or shorter than a predetermined reference time in the second imaging, the limiting unit fixes the position of the dimming area while the imaging unit is exposing, 22. When the exposure time is longer than the reference time, the position of the dimming region is moved according to the moving speed of the object while the image capturing unit is exposing. Imaging device. The image capturing apparatus according to claim 18, wherein the limiting unit has regions having different orientation angles of light toward the image capturing unit.

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