Distance measuring device

Abstract

A distance measuring device is provided with: a light projecting unit that projects light including a plurality of different types of wavelength bands; a first imaging unit and a second imaging unit disposed such that the fields of view overlap each other; and a lens for imaging an object on the sensor surface of the first imaging unit. The light projecting unit projects pattern light in which light of a plurality of types of wavelength bands is distributed in a predetermined pattern into a range in which an object is present and the field of view of the first imaging unit and the field of view of the second imaging unit overlap. The sensor surface of the first imaging unit and the main surface of the lens are arranged so as not to be parallel to each other.

Description

Technical Field

[0001] The present disclosure relates to a distance measuring device. Background Art

[0002] Conventionally, a distance measuring device that processes an image obtained by a stereo camera to measure the distance to an object has been known. In this device, parallax is detected based on the images captured by each camera. A pixel block having the highest correlation with an object pixel block on one image (reference image) is searched for on another image (reference image). The search range is set in the separation direction of the cameras with the same position as the object pixel block as the reference position. The pixel offset amount of the pixel block extracted by the search with respect to the reference position is detected as parallax. Based on this parallax, the distance to the object is calculated by triangulation.

[0003] The stereo camera system (distance measuring device) of Patent Document 1 satisfies the Scheimpflug condition along at least one of the sensor region and the optical path of the lens.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-536887 Summary of the Invention

[0007] In Patent Document 1, since the optical system is configured to satisfy the Scheimpflug condition, it is possible to focus on an object disposed at a short distance and an object disposed at a long distance at the same time.

[0008] However, a structure for improving the resolution is not described in Patent Document 1.

[0009] The distance measuring device according to an embodiment of the present disclosure includes: a light projecting unit that projects light including a plurality of different wavelength bands; a first imaging unit and a second imaging unit that are arranged so that their fields of view overlap each other; and a lens that images an object on a sensor surface of the first imaging unit. The light projecting unit projects patterned light in which the plurality of wavelength bands are distributed in a given pattern to a range where the object exists and the fields of view of the first imaging unit and the second imaging unit overlap. The sensor surface of the first imaging unit and the main surface of the lens are arranged so as not to be parallel to each other.

[0010] According to the present disclosure, the resolution of the distance measuring device can be improved. Brief Description of the Drawings

[0011] Figure 1 It is a diagram showing a basic structure of the distance measuring device according to the first embodiment.

[0012] Figure 2 This is a diagram showing the structure of the distance measurement device according to the first embodiment.

[0013] Figure 3 This is a diagram showing the schematic structure of the distance measurement device according to the first embodiment.

[0014] Figure 4 This is a diagram schematically showing the method of setting a pixel block according to the first embodiment with respect to the first image.

[0015] Figure 5 This is a diagram showing the structure of the filter according to the first embodiment.

[0016] Figure 6 This is a diagram showing the first image and the second image according to the first embodiment.

[0017] Figure 7 This is a diagram for explaining the wavelength band of the light source output according to the first embodiment.

[0018] Figure 8 This is a flowchart for explaining the calibration process according to the first embodiment.

[0019] Figure 9 This is a diagram for explaining the method of searching for an object pixel block according to the first embodiment.

[0020] Figure 10 This is a diagram showing an example of the pattern light according to the second embodiment. Detailed Embodiment

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0022] (First Embodiment)

[0023] Figure 1 This is a diagram showing the basic structure of the distance measurement device 1 according to the first embodiment.

[0024] As Figure 1 shown, the distance measurement device 1 includes a first imaging unit 10, a second imaging unit 20, and a light projecting unit 30.

[0025] The first imaging unit 10 images the range of the visual field 10a facing the positive Z-axis direction. The second imaging unit 20 images the range of the visual field 20a facing the positive Z-axis direction. The first imaging unit 10 and the second imaging unit 20 are arranged and configured to be separated by a given distance (baseline length) in the X-axis direction so that the visual fields 10a and 20a overlap each other. The imaging direction of the first imaging unit 10 may be slightly inclined from the positive Z-axis direction toward the second imaging unit 20, and the imaging direction of the second imaging unit 20 may be slightly inclined from the positive Z-axis direction toward the first imaging unit 10. The positions of the first imaging unit 10 and the second imaging unit 20 in the Z-axis direction and the Y-axis direction are the same as each other.

[0026] The light projecting unit 30 projects patterned light 30a in which light is distributed in a given pattern onto the overlapping range 130 of the visual field 10a and the visual field 20a. The projection direction of the patterned light 30a based on the light projecting unit 30 is the positive Z-axis direction. The patterned light 30a is projected onto the surface A1s of the object A1 existing in the overlapping range of the visual fields 10a and 20a.

[0027] The distance measuring device 1 measures the distance D0 to the object A1 by searching for stereo corresponding points of the captured images respectively captured by the first imaging unit 10 and the second imaging unit 20. At this time, the patterned light 30a is projected from the light projecting unit 30 onto the surface A1s of the object A1. As a result, the pattern of the patterned light 30a is projected in the captured images of the first imaging unit 10 and the second imaging unit 20. Therefore, even when the surface A1s of the object A1 is a solid color, stereo corresponding points can be searched with high accuracy, and the distance D0 to the surface A1s of the object A1 can be accurately measured.

[0028] Figure 2 FIG. is a diagram showing the structure of the distance measuring device 1 according to the first embodiment.

[0029] The first imaging unit 10 includes an imaging lens 11 and an imaging element 12. The imaging lens 11 has a focal length and condenses light from the visual field 10a onto the imaging surface 12a (sensor surface) of the imaging element 12. The imaging lens 11 may not be a single lens and may be constituted by combining a plurality of lenses. The imaging element 12 is a monochromatic image sensor. The imaging element 12 is, for example, a CMOS image sensor. In addition, the imaging element 12 may be a CCD.

[0030] The second imaging unit 20 has the same structure as the first imaging unit 10. Specifically, the second imaging unit 20 includes an imaging lens 21 and an imaging element 22. The imaging lens 21 has the same focal length as the imaging lens 11, and condenses the light from the field of view 20a onto the imaging surface 22a (sensor surface) of the imaging element 22. The imaging lens 21 may not be a single lens, and may be constituted by combining a plurality of lenses. The imaging element 22 is a monochromatic image sensor. In addition, the imaging element 22 is, for example, a CMOS image sensor. The imaging element 22 may also be a CCD.

[0031] The light projecting unit 30 includes: light sources 31 to 33, an optical system 34, a filter 35, and a projection lens 36.

[0032] The light sources 31 to 33 emit lights of different wavelength bands. For example, the light source 31 emits light in a wavelength band near red, the light source 32 emits light in a wavelength band near green, and the light source 33 emits light in a wavelength band near blue. The light sources 31 to 33 are, for example, light emitting diodes. In addition, the light sources 31 to 33 may be other types of light sources such as semiconductor lasers.

[0033] The optical system 34 includes collimating lenses 341 to 343, dichroic mirrors 344, 345. The collimating lenses 341 to 343 convert the lights emitted from the light sources 31 to 33 into substantially parallel lights respectively. The dichroic mirror 344 transmits the light incident from the collimating lens 341 and reflects the light incident from the collimating lens 342. The dichroic mirror 345 transmits the light incident from the dichroic mirror 344 and reflects the light incident from the collimating lens 343. In this way, the lights emitted from the light sources 31 to 33 are integrated and guided to the filter 35.

[0034] The filter 35 generates pattern light 30a in which a plurality of types of light regions having different wavelength bands are distributed in a given pattern from the lights of each wavelength band guided from the optical system 34.

[0035] The projection lens 36 projects the pattern light 30a generated by the filter 35. The projection lens 36 may not be a single lens, and may be constituted by combining a plurality of lenses.

[0036] The distance measuring device 1 has a structure of a circuit unit including a first imaging processing unit 41, a second imaging processing unit 42, a light source driving unit 43, a brightness adjustment unit 44, a measuring unit 45, a control unit 46, and a communication interface 47.

[0037] The first imaging processing unit 41 and the second imaging processing unit 42 control the imaging elements 12, 22, and perform processing such as brightness correction and camera calibration on the pixel signals of the first image and the second image output from the imaging elements 12, 22 respectively.

[0038] The light source drive unit 43 drives the light sources 31 to 33 respectively with the drive current values set by the brightness adjustment unit 44.

[0039] Based on the pixel signals (brightness) of the second image input from the second imaging processing unit 42, the brightness adjustment unit 44 sets the drive current values of the light sources 31 to 33 for the light source drive unit 43. Specifically, the brightness adjustment unit 44 sets the drive current values (light emission amounts) of the light sources 31 to 33 so that the maximum brightness based on the light from the light sources 31 to 33 obtained based on the pixel signals from the second imaging unit 20 is not saturated.

[0040] The measurement unit 45 performs a comparison process on the first image and the second image respectively input from the first imaging processing unit 41 and the second imaging processing unit 42 to perform a stereo corresponding point search, and obtains the distance to the surface A1s of the object A1 for each pixel block on the first image. The measurement unit 45 sends the distance information of all the pixel block amounts obtained to an external device via the communication interface 47.

[0041] That is, the measurement unit 45 sets a pixel block (hereinafter referred to as "object pixel block") to be the acquisition object of the distance on the first image, and searches for a pixel block corresponding to the object pixel block, that is, a pixel block that best matches the object pixel block (hereinafter referred to as "matching pixel block") within a specified search range on the second image. The measurement unit 45 obtains the pixel offset amount between the pixel block (hereinafter referred to as "reference pixel block") located at the same position as the object pixel block on the second image and the matching pixel block extracted from the second image through the above search, and calculates the distance to the surface A1s of the object A1 at the position of the object pixel block based on the obtained pixel offset amount.

[0042] The measurement unit 45 and the communication interface 47 may also be constituted by a semiconductor integrated circuit composed of an FPGA (Field Programmable Gate Array). In addition, these units may also be constituted by other semiconductor integrated circuits such as a DSP (Digital Signal Processor), a GPU (Graphics Processing Unit), and an ASIC (Application Specific Integrated Circuit).

[0043] The control unit 46 is constituted by a microcomputer or the like, and controls each unit according to a given program stored in the built-in memory.

[0044] Figure 3 It is a diagram showing the schematic configuration of the distance measurement device according to the first embodiment. Figure 3Illustrate the configurations of the first imaging unit 10, the second imaging unit 20, and the object A1. As Figure 3 shown, the extension lines of the main surface 11s of the imaging lens 11 in the first imaging unit 10, the imaging surface 12a of the imaging element 12, and the surface A1s of the object A1 are configured to intersect at a point. Similarly, the extension lines of the main surface 21s of the imaging lens 21 in the second imaging unit 20, the imaging surface 22a of the imaging element 22, and the surface A1s of the object A1 are configured to intersect at a point. In this way, the imaging surface 12a (sensor surface) of the first imaging unit and the main surface 11s of the imaging lens 11 are configured to be non-parallel to each other, and the imaging surface 22a (sensor surface) of the second imaging unit 20 and the main surface 21s of the imaging lens 21 are configured to be non-parallel to each other. Specifically, the first imaging unit 10 and the second imaging unit 20 are configured to satisfy the Scheimpflug condition with respect to the surface A1s of the object A1. With this configuration, both the first imaging unit 10 and the second imaging unit 20 can focus on either an object farther from the imaging unit or an object closer to the imaging unit. In addition, in Figure 3 , the angles formed by the main surface 11s of the imaging lens 11 and the imaging surface 12a of the imaging element 12, and the angle between the main surface 21s of the imaging lens 21 and the imaging surface 22a of the imaging element 22 are both θ', which are the same.

[0045] Figure 4 is a diagram schematically showing a method of setting a pixel block with respect to the first image. Specifically, Figure 4 in (a) shows a method of setting the pixel block 102 with respect to the entire first image 100, Figure 4 and (b) in Figure 4 magnifies a part of the region of the first image 100 for illustration. In addition,

[0046] As Figure 4 shown in (a) and (b) in Figure 3 , the first image 100 is divided into a plurality of pixel blocks 102 each including a given number of pixel regions 101. The pixel region 101 is a region corresponding to one pixel on the imaging element 12. That is, the pixel region 101 is the smallest unit of the first image 100. In the examples of (a) and (b) in Figure 3 , one pixel block 102 is composed of nine pixel regions 101 arranged in three rows and three columns. However, the number of pixel regions 101 included in one pixel block 102 is not limited to this.

[0047] Figure 5 is a diagram showing the structure of the filter according to the first embodiment. Specifically, Figure 5 in (a) is a diagram schematically showing the structure of the filter 35. Figure 5 in (b) is Figure 5A diagram showing an enlarged view of a part of (a). Figure 5 (a) and (b) show the state of the filter 35 as viewed from the light incident surface 35a side.

[0048] As Figure 5 As shown in (a) and (b), in the filter 35, a plurality of types of filter regions 351 to 354 are formed in a given pattern. In Figure 5 In (a) and (b), the types of the filter regions 351 to 354 are represented by different types of shading. The filter regions 351 to 354 selectively transmit light of different wavelength bands to form light regions of different hues. Here, the filter region 351 forms a light region corresponding to the hue "red", the filter region 352 forms a light region corresponding to the hue "orange", the filter region 353 forms a light region corresponding to the hue "green", and the filter region 354 forms a light region corresponding to the hue "blue". The characteristics of the light sources 31 to 33 and the filter regions 351 to 354 will be described later.

[0049] The size of each of the filter regions 351 to 354 is set, for example, to a size substantially corresponding to one pixel block on the imaging elements 12 and 22. For example, in Figure 5 The region B1 indicated by the dashed line in (b) is a region corresponding to the region of the pixel block (the pixel blocks 102 and 202 used in the above stereo corresponding point search) composed of three vertical pixels and three horizontal pixels on the imaging elements 12 and 22. That is, when the distance D0 to the surface A1s of the object A1 is a reference distance (for example, the middle distance in the ranging range), the light in this region B1 is projected onto the region of the pixel block composed of three vertical pixels and three horizontal pixels on the imaging elements 12 and 22. In addition, the size of each of the filter regions 351 to 354 is not necessarily limited to the size corresponding to one pixel. The size of each of the filter regions 351 to 354 can be larger or smaller than the size corresponding to one pixel block. Also, in Figure 5 In (b), each of the filter regions 351 to 354 is rectangular and has the same size, but the sizes of the filter regions 351 to 354 can also be different from each other, and their shapes can also be other shapes such as square or circular.

[0050] The filter regions 351 to 354 are preferably arranged such that different types of filter regions are included in the region B1 corresponding to all the pixel blocks used in the stereo corresponding point search, and more preferably arranged such that all the types of filter regions 351 to 354 are respectively included in these regions B1. In addition, the arrangement pattern of the filter regions included in the region B1 corresponding to the pixel block is preferably at least within the search range R0 of the stereo corresponding point search (refer toFigure 3 is unique (random) for each pixel block at each search position.

[0051] When the filter regions 351 to 354 are configured in this way, as will be described later, the brightness of the light passing through the filter regions 351 to 354 is made different from each other, whereby the brightness distribution of the light within the pixel block can be made unique for each pixel block. As a result, the accuracy of the stereo corresponding point search can be improved, and the accuracy of distance measurement can be improved.

[0052] Figure 6 FIG. (a) shows the first image 100 according to the first embodiment. Figure 6 FIG. (b) shows the second image 200 according to the first embodiment. In addition, Figure 6 FIGS. (a) and (b) are the first image 100 and the second image 200 before the calibration process described later.

[0053] As Figure 6 shown in FIG. (a), in the first image 100, from the right side to the left side of the drawing, the width of the point light in the left - right direction becomes narrower. Also, as Figure 5 shown in FIG. (b), in the second image 200, from the left side to the right side of the drawing, the width of the point light in the left - right direction becomes narrower. Specifically, in the first image 100, the width of the point light in the left - right direction is wider in the first region T1 on the left side of the drawing, and the width of the point light in the left - right direction is narrower in the second region T2 on the right side of the drawing. In the second image 200, the width of the point light in the left - right direction is narrower in the third region T3 on the left side of the drawing, and the width of the point light in the left - right direction is wider in the fourth region T4 on the right side of the drawing. This is because the first photographing unit 10 and the second photographing unit 20 are configured to satisfy the Scheimpflug condition with respect to the object A1, so that the width in the width direction of the point light on the side closer to the photographing unit becomes wider, and the width in the width direction of the point light on the side farther from the photographing unit becomes narrower. Therefore, in the first image 100 and the second image 200, the resolution on the side farther from the photographing unit is reduced. In the first embodiment, by performing the calibration process described later, even when the optical system is configured to satisfy the Scheimpflug condition, a reduction in resolution can be suppressed.

[0054] Figure 7 is a diagram for explaining the wavelength band of the output of the light source according to the first embodiment.

[0055] Figure 7 FIG. (a) is a chart showing the spectral outputs of the light sources 31 to 33. The spectral outputs of the light sources 31 to 33 are represented by a solid line (E11), a dotted line (E12), and a dashed line (E12), respectively. Here, the vertical axis of the chart is normalized by the maximum output of the light source 31.

[0056] The light source 31 emits light with a central wavelength near 610 nm and an emission bandwidth of about 80 nm. The light source 32 emits light with a central wavelength near 520 nm and an emission bandwidth of about 150 nm. The light source 33 emits light with a central wavelength near 470 nm and an emission bandwidth of about 100 nm.

[0057] Figure 7 (b) of is a graph showing the spectral transmittance of the filter regions 351 to 354. The spectral transmittances of the filter regions 351 to 354 are represented by a solid line (E21), a single-dot dash line (E22), a dotted line (E23), and a dashed line (E24), respectively. Here, the vertical axis of the graph is normalized by the maximum transmittance of the filter region 351.

[0058] The filter region 351 starts from near 570 nm, and as the wavelength increases, the transmittance increases and maintains the maximum transmittance above near 650 nm. The filter region 351 mainly transmits the light from the light source 31 and forms a light region (dot light) with the hue "red". The maximum transmittance of the filter region 352 is near 560 nm, and it has a spectral characteristic with a transmission wavelength width of about 160 nm. It mainly transmits the light from the light source 31 and the light from the light source 32 and forms a light region (dot light) with the hue "orange". The maximum transmittance of the filter region 353 is near 520 nm, and it has a spectral characteristic with a transmission bandwidth of about 150 nm. It mainly transmits the light from the light source 32 and forms a light region (dot light) with the hue "green". The maximum transmittance of the filter region 354 is near 460 nm, and it has a spectral characteristic with a transmission bandwidth of about 150 nm. It mainly transmits the light from the light source 33 and forms a light region (dot light) with the hue "blue".

[0059] Here, a filter having four types of spectral transmittances has been described, but it is not limited thereto. For example, by adding a filter having a spectral transmittance that transmits multiple wavelength regions from the wavelength regions of the light sources 31 to 33, light regions (dot lights) with more different hues can be formed.

[0060] Next, a method for the measurement unit 45 to calculate the distance index value based on the first image 100 and the second image 200 will be described.

[0061] Figure 8 is a flowchart for explaining the calibration process according to the first embodiment.

[0062] The measurement unit 45 reads the first image 100 captured by the first imaging unit 10 and the second image 200 captured by the second imaging unit (step S1). Specifically, the measurement unit 45 reads Figure 6 the first image 100 and the second image 200 of (a) and (b) of .

[0063] When the reading of the first image 100 and the second image 200 is completed (Yes in step S2), the measurement unit 45 generates calibration data (step S3). Specifically, the measurement unit 45 replaces the image within the third region T3 of the second image 200 with the image within the first region T1 of the first image 100, thereby interpolating the third region T3, which is part of the second image 200, with the first region T1, which is part of the first image 100. Similarly, by replacing the image within the second region T2 of the first image 100 with the image within the fourth region T4 of the second image 200, the fourth region T4, which is part of the second image 200, interpolates the second region T2, which is part of the first image 100. That is, in the first image 100, the measurement unit 45 replaces the low-resolution region, i.e., the second region T2, with the high-resolution region, i.e., the fourth region T4, in the second image 200. Similarly, in the second image 200, the measurement unit 45 replaces the low-resolution region, i.e., the third region T3, with the high-resolution region, i.e., the first region T1, in the first image 100. Thereby, the first image 100 and the second image 200 can increase the depth of field of the distance measurement device and simultaneously increase the resolution of the image. After that, the measurement unit 45 normalizes the first image 100 and the second image 200. Specifically, a process is performed to make the left and right widths of the images of the light at each point in the first image 100 and the second image 200 the same. Through the above processing, Figure 6 the first image 100 and the second image 200 in (a) and (b) are respectively converted to Figure 5 the first image 100 and the second image 200 in (a) and (b).

[0064] The measurement unit 45 saves the first image 100 and the second image 200 generated in step S3 as calibration data (step S4).

[0065] After step S4, the measurement unit 45 reads out the first image 100 and the second image 200 saved as calibration data and executes the object pixel block search method described below. In addition, before executing the object pixel block search method, corrections for standardization are performed on the first image 100 and the second image 200. Specifically, corrections are made to the first image 100 and the second image such that the widths of the light at each point in the left and right directions are uniform.

[0066] Figure 9 is a diagram for explaining the object pixel block search method according to the first embodiment. Specifically, Figure 9 (a) of is a diagram schematically showing a state in which an object pixel block TB1 is set on the first image 100, Figure 9 (b) of is a diagram schematically showing in order to Figure 9The figure of the search range R0 set on the second image 200 by searching the object pixel block in (a).

[0067] In Figure 9 In (b) for convenience, the second image 200 obtained from the second imaging unit 20 is divided into a plurality of pixel blocks 202 in the same manner as the first image 100. The pixel block 202 includes the same number of pixel regions as the above-mentioned pixel block 102.

[0068] In Figure 9 In (a), the object pixel block TB1 is the pixel block 102 to be processed among the pixel blocks 102 on the first image 100. Further, in Figure 9 In (b), the reference pixel block TB2 is the pixel block 202 on the second image 200 corresponding to the object pixel block TB1.

[0069] The measurement unit 45 determines the reference pixel block TB2 corresponding to the object pixel block TB1 on the second image 200. And the measurement unit 45 sets the position of the determined reference pixel block TB2 as the reference position P0 of the search range R0, and sets the range extending in the separation direction from the reference position P0 to the first imaging unit 10 and the second imaging unit 20 as the search range R0.

[0070] The extending direction of the search range R0 is set to the direction in which the pixel block (matching pixel block MB2) corresponding to the object pixel block TB1 on the second image 200 is shifted from the reference position P0 due to parallax. Here, the search range R0 is set to the range of 11 pixel blocks 202 arranged in the right direction (the direction corresponding to the X-axis direction of Figure 1 ). However, the number of pixel blocks 202 included in the search range R0 is not limited to this.

[0071] The measurement unit 45 searches for the pixel block (matching pixel block MB2) corresponding to the object pixel block TB1 in the set search range R0. Specifically, the measurement unit 45 shifts the search position pixel by pixel to the right direction from the reference pixel block TB2, and calculates the correlation value between the object pixel block TB1 and each search position. The correlation value uses, for example, SSD (Sum of Squared Difference) or SAD (Sum of Absolute Difference). And the measurement unit 45 determines the pixel block at the search position with the highest correlation in the search range R0 as the matching pixel block MB2.

[0072] Further, the measurement unit 45 obtains the pixel offset of the matching pixel block MB2 with respect to the reference pixel block TB2. Then, based on the obtained pixel offset and the separation distance between the first imaging unit 10 and the second imaging unit 20, the measurement unit 45 calculates the distance to the surface A1s of the object A1 by triangulation. The measurement unit 45 performs the same process for all the pixel blocks 102 (target pixel blocks TB1) on the first image 100. Thus, when the distances at all the pixel blocks 102 are obtained, the measurement unit 45 sends this distance information to an external device via the communication interface 47.

[0073] The distance measurement device 1, for example, in addition to being fixedly used, is also provided, for example, at the end effector (such as a gripping part) of a robotic arm that performs operation actions in a factory. In this case, during the operation process of the robotic arm, the control unit 46 of the distance measurement device 1 receives an instruction to obtain a distance from the robot controller via the communication interface 47. According to this instruction, the control unit 46 causes the measurement unit 45 to measure the distance between the position of the end effector and the surface A1s of the object A1 to be operated on, and sends the measurement result to the robot controller via the communication interface 47. Based on the received distance information, the robot controller performs feedback control on the movement of the end effector. Thus, when the distance measurement device 1 is provided at the end effector, it is desirable for the distance measurement device 1 to be small and lightweight.

[0074] (Second Embodiment)

[0075] In the first embodiment, by mutually replacing the regions that are low-resolution regions and the regions that are high-resolution regions in the first image and the second image, the high-resolution of the distance measurement device is achieved. In contrast, in the second embodiment, the light projecting unit 30 projects the pattern light 30a in consideration of the first image 100 and the second image 200 captured by the first imaging unit 10 and the second imaging unit 20, thereby achieving the high-resolution of the distance measurement device.

[0076] Figure 10 FIG. is an example of the pattern light according to the second embodiment. Specifically, Figure 10 FIG. (a) shows the pattern light 30a projected when the first imaging unit 10 captures the first image 100, Figure 10 FIG. (b) shows the pattern light 30a projected when the second imaging unit 20 captures the second image 200.

[0077] In Figure 10 FIG. (a), from the left side to the right side of the drawing, the width of the pattern light 30a in the left-right direction becomes narrower. In Figure 10In (b), from the right side to the left side of the drawing, the width of the pattern light 30a in the left-right direction becomes narrower. As described above, since the first imaging unit 10 and the second imaging unit 20 are arranged to satisfy the Scheimpflug condition with respect to the object A1, the width in the width direction of the point light on the side closer to the imaging unit becomes wider, and the width in the width direction of the point light on the side farther from the imaging unit becomes narrower. Therefore, the pattern light is projected such that the width in the width direction of the point light on the side closer to the imaging unit is narrower, and the width in the width direction of the point light on the side farther from the imaging unit is wider. That is, when the pattern light shown in (b) of Figure 10 is not projected and the pattern light shown in (a) of Figure 10 is projected, the first imaging unit 10 acquires the first image. When the pattern light shown in (a) of Figure 10 is not projected and the pattern light shown in (b) of Figure 10 is projected, the second imaging unit 20 acquires the second image. Thereby, the width of the point light in the first image 100 and the second image 200 can be made constant. Thus, Figure 10 the pattern light shown in (a) of Figure 10 is generated based on the inclination of the surface A1s of the object A1 with respect to the imaging surface 12a (sensor surface) of the first imaging unit 10,

[0078] and the pattern light shown in (b) of Figure 8 is generated based on the inclination of the surface A1s of the object A1 with respect to the imaging surface 22a (sensor surface) of the second imaging unit 20.

[0078] In addition, in the second embodiment, when generating the calibration data in step S3 in Figure 8 , the process of mutually replacing a part of the first image 100 and the second image 200 is not performed, and only the process of normalizing the first image 100 and the second image 200 is performed.

[0079] In addition, in each of the above embodiments, a movable part for changing the orientation of the photographing lenses 11 and 21 may be provided. Thereby, by changing the orientation of the photographing lens 11 according to the orientation of the surface A1s of the object A1, the first photographing unit 10, the second photographing unit, and the object A1 can be arranged to satisfy the Scheimpflug condition with respect to the surface A1s of any orientation of the object A1.

[0080] In addition, in each of the above embodiments, the light projecting unit 30 includes three light sources 31 to 33 that emit lights of different wavelength bands, but one or more light sources may be provided.

[0081] -Symbol Explanation-

[0082] 1 Distance measuring device

[0083] 10 First imaging unit

[0084] 20 Second imaging unit

[0085] 11, 21 Photographing lens (lens)

[0086] 12, 22 Photographing element

[0087] 12a, 22a Photographing surface (sensor surface)

[0088] 30 Light projecting unit

[0089] 30a Pattern light

[0090] 31 - 33 Light sources

[0091] 45 Measuring unit.

Claims

1. A distance measuring device, comprising: A light projecting unit that projects light including a plurality of different wavelength bands; A first imaging unit and a second imaging unit that are arranged such that their fields of view overlap; and A lens that forms an image of an object on the sensor surface of the first imaging unit, The light projecting unit projects pattern light in which the plurality of wavelength bands are distributed in a given pattern onto a range where the object is present and the fields of view of the first imaging unit and the second imaging unit overlap, The sensor surface of the first imaging unit and the main surface of the lens are arranged so as not to be parallel to each other.

2. The distance measuring device according to claim 1, wherein The sensor surface of the first imaging unit, the main surface of the lens, and the surface of the object are arranged to satisfy the Scheimpflug condition.

3. The distance measuring device according to claim 1, wherein The distance measuring device further comprises: A measurement unit that measures the distance to the surface of the object onto which the pattern light is projected based on a first image acquired by the first imaging unit and a second image acquired by the second imaging unit, The measurement unit interpolates the second image based on the first image.

4. The distance measuring device according to claim 1, wherein The distance measuring device further comprises: A measurement unit that measures the distance to the surface of the object onto which the pattern light is projected based on a first image acquired by the first imaging unit and a second image acquired by the second imaging unit, The light projecting unit projects a first pattern light and a second pattern light, The first pattern light is generated based on the inclination of the surface of the object with respect to the sensor surface of the first imaging unit, The second pattern light is generated based on the inclination of the surface of the object with respect to the sensor surface of the second imaging unit, The first imaging unit acquires the first image when the first pattern light is projected, The second imaging unit acquires the second image when the second pattern light is projected.

5. The distance measuring device according to claim 1, wherein The distance measuring device further comprises: A movable unit that changes the orientation of the lens.

Images