WO2024154528A1

WO2024154528A1 - Three-dimensional measurement device

Info

Publication number: WO2024154528A1
Application number: PCT/JP2023/045741
Authority: WO
Inventors: 将隆辻本
Original assignee: 株式会社デンソーウェーブ
Priority date: 2023-01-18
Filing date: 2023-12-20
Publication date: 2024-07-25
Also published as: JP2024101649A

Abstract

This three-dimensional measurement device comprises: a projection unit; an imaging unit that images an object on which a striped pattern is projected by the projection unit; a measurement unit that uses luminance information obtained from the captured image captured by the imaging unit to measure a three-dimensional shape of the object by a phase shift method; and a control unit that controls the projection unit. The imaging unit is provided with an imaging element that outputs event data including two-dimensional point data that specifies the position of a pixel that has changed in brightness when receiving light, and generates the captured image from the event data. The imaging element outputs event data of positive polarity when the brightness changes to become brighter, and outputs event data of negative polarity when the brightness changes to become darker. The control unit outputs a projection start signal at a projection start timing of the striped pattern. The measurement unit obtains the luminance information for each pixel in the captured image on the basis of a time difference between an output time of the projection start signal and an output time of event data after the output of the projection start signal.

Description

3D measuring device

This disclosure relates to a three-dimensional measuring device that measures the three-dimensional shape of a measurement object.

　Conventionally, devices that use the phase shift method are known as three-dimensional measuring devices that measure the three-dimensional shape of a measurement object. The phase shift method is a technique for performing three-dimensional measurement of a measurement object onto which multiple stripe pattern images are projected by projecting multiple stripe pattern images with shifted phases. A three-dimensional measuring device disclosed in Patent Document 1 below is known as a technology for performing three-dimensional measurement using the phase shift method in this way. This three-dimensional measuring device assigns stripes of each phase to light of a different wavelength, projects a stripe pattern image composed of these stripes onto the measurement object, and photographs the measurement object onto which this stripe pattern image is projected with a color camera. Then, each color component is extracted from the photographed image and the phase is calculated in a single photograph. This aims to reduce the time required to measure the three-dimensional shape.

Incidentally, the event camera disclosed in Patent Document 2 is known as a technology for generating images of measurement objects at higher speeds. This event camera is a brightness value differential output camera that was developed inspired by the retinal structure of living organisms. The event camera detects changes in brightness for each pixel and outputs the pixel's coordinates, time, and the polarity of the brightness change as event data. With this configuration, the event camera has the characteristic of not outputting pixel information with no brightness changes, which is output by conventional cameras, in other words, redundant data. This reduces the amount of data communication and lightens the image processing load, making it possible to generate images of measurement objects at higher speeds.

Patent No. 3723057 US Patent Application Publication No. 2016/0227135

However, in the captured image of the object to be measured, which is generated using the event data output from the event camera, although it is possible to ascertain whether or not there is a change in brightness on a pixel-by-pixel basis from the captured image, it is not possible to directly measure the brightness value. For this reason, it is not possible to measure the three-dimensional shape of the object to be measured using three-dimensional measurement methods such as the phase shift method, which use brightness values.

The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a three-dimensional measurement device that can measure the three-dimensional shape of a measurement target using event data.

A three-dimensional measuring device according to an embodiment of the present disclosure includes a projection unit that projects a predetermined stripe pattern onto a measurement target area, an imaging unit that images a measurement target placed in the measurement target area onto which the predetermined stripe pattern is projected, a measurement unit that measures the three-dimensional shape of the measurement target by a phase shift method using luminance information obtained from the image captured by the imaging unit, and a control unit that controls the projection unit, the imaging unit includes an imaging element that outputs event data including two-dimensional point data that identifies the position of a pixel that has experienced a luminance change when light is received, and generates the captured image from the event data output from the imaging element, the imaging element outputs positive event data in the case of a luminance change that becomes brighter, and outputs negative event data in the case of a luminance change that becomes darker, the control unit outputs a projection start signal at the start timing of projection of the predetermined stripe pattern, and the measurement unit obtains the luminance information for each pixel in the captured image based on the time difference between the output time of the projection start signal and the output time of the event data after the output of the projection start signal.

In each pixel of the captured image, the higher the luminance value, the longer the time difference between the output time of the positive polarity event data (hereinafter also referred to as the occurrence time) and the occurrence time of the negative polarity event data. In this way, since there is a correlation between the luminance value and the above time difference, luminance information can be obtained based on the time difference between the occurrence time of the positive polarity event data and the occurrence time of the negative polarity event data in pixel units in the captured image. In addition, the occurrence time of the positive polarity event data coincides with the output time of the projection start signal, and the negative polarity event data is output after the output time of the projection start signal. Therefore, luminance information can be obtained for each pixel based on the time difference between the output time of the projection start signal when the above-mentioned specified stripe pattern is projected and the occurrence time of the event data output after the output time of the projection start signal. Using the luminance information obtained in this way, the three-dimensional shape of the measurement object can be measured by the phase shift method. Therefore, it is possible to measure the three-dimensional shape of the measurement object using the event data. In particular, the above-mentioned three-dimensional measuring device does not obtain the occurrence times of both the positive polarity event data and the negative polarity event data, but only obtains the occurrence time of the event data output after the input of the projection start signal. This shortens the processing time and speeds up image generation of the measurement object. In other words, the three-dimensional shape of the measurement object can be measured more quickly.

1 is a block diagram showing a schematic configuration of a three-dimensional measuring apparatus according to a first embodiment. 1A and 1B are diagrams illustrating a state in which a stripe pattern for a general phase shift method is projected onto a measurement object. FIG. 1 is a diagram for explaining three-dimensional measurement by a phase shift method. 11 is a diagram illustrating the relationship between the time difference between the occurrence time of positive polarity event data and the occurrence time of negative polarity event data (i.e., ON time) and the luminance value (i.e., luminance information). 11A and 11B are diagrams illustrating the R, G, and B light emission states of a certain pixel when a stripe pattern is projected. 5B is a diagram illustrating the R-color light emission state, the G-color light emission state, and the B-color light emission state in a pixel different from the pixel in FIG. 5A. 11A and 11B are diagrams illustrating the relationship between the projection start timing, the projection end timing, the input timing of the projection start signal, the input timing of the projection end signal, and the imaging start timing and the imaging end timing. 11 is a diagram for explaining an example of creating a stripe pattern in which the horizontal axis indicates pixels and the vertical axis indicates ON time. 7B is a diagram illustrating the time difference between the occurrence time of negative polarity event data obtained for each pixel when the stripe pattern shown in FIG. 7A is captured and the input time of a projection start signal. FIG. 1 is a hardware configuration diagram of a three-dimensional measuring apparatus according to a first embodiment. FIG. 4 is a flowchart showing processing of the three-dimensional measuring apparatus according to the first embodiment.

First Embodiment
Hereinafter, a first embodiment of the three-dimensional measuring device of the present disclosure will be described with reference to the drawings. The three-dimensional measuring device 10 according to this embodiment is a device that measures the three-dimensional shape of a measurement object 50. As shown in FIG. 1 and FIG. 2, the device includes a control unit 11, a projection unit 20, an imaging unit 30, and a measurement unit 40. The control unit 11 is responsible for overall control. The projection unit 20 projects a predetermined stripe pattern for the phase shift method onto the measurement object 50. The imaging unit 30 captures the measurement object 50 onto which the predetermined stripe pattern is projected. The measurement unit 40 measures the three-dimensional shape of the measurement object 50 from the captured image. The three-dimensional measuring device 10 configured in this manner measures the three-dimensional shape of the measurement object 50, such as a workpiece, which is attached to the hand of a robot and moves relatively to the hand at high speed. Here, the relative movement refers to the relative movement between the movement of the three-dimensional measuring device 10 attached to the hand of the robot and the movement of the measurement object 50. When the position of the three-dimensional measuring apparatus 10 is fixed, the relative movement is the movement of the measurement object 50 .

In FIG. 2, for convenience, a specified stripe pattern having up to 13 stripes is illustrated in a simplified form. More specifically, a typical stripe pattern is represented as a sine wave pattern, so the light and dark parts of the stripe pattern have the same width. However, in FIG. 2, for convenience, the width of the dark parts is reduced and they are represented by lines. Also, although the number of stripes is 13 or more in the embodiment, it is abbreviated to 13.

As shown in FIG. 8, the three-dimensional measuring device 10 has a processor 101 and a memory 103 as a hardware configuration. For example, the three-dimensional measuring device 10 may have a microcomputer. The microcomputer may have a CPU (Central Processing Unit), a system bus, an input/output interface, a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, etc. In addition to a program related to robot control, the memory 103 pre-stores a program related to control of the projection unit 20 and a program for executing control processing using the three-dimensional measurement results by the measurement unit 40. The functions of the control unit 11 and the measurement unit 40 may be realized by the above hardware configuration.

The projection unit 20 is a so-called DLP (registered trademark) projector. The projection unit 20 is controlled by the control unit 11 to project a predetermined stripe pattern, which will be described later, by reflecting light from a light source with a DMD (Digital Micromirror Device) element. The DMD element has fine mirrors corresponding to each pixel of the image projected on the screen, and the fine mirrors are arranged in an array. The DMD element changes the angle of each mirror to switch (i.e., turn ON/OFF) the light emitted to the screen in microsecond units. That is, the projection unit 20 functions to project a predetermined stripe pattern by controlling the ON/OFF reflection of incident light by the DMD, which has multiple mirrors arranged in an array, for each mirror by the control unit 11. For this reason, the control unit 11 changes the gradation (i.e., brightness) of the reflected light depending on the ratio of the time each mirror is ON to the time it is OFF. This makes it possible to display gradations based on the image data of the image to be projected.

In such a configuration, the longer the light emission time of the single pulse light emitted once within the unit time secured for each light emission state, the brighter the light emission state becomes, so that the light emission state can be specified according to the light emission time. If the coordinates of each pixel in FIG. 2 are (1, 1) at the top left and (k, l) at the bottom right, the projection unit 20 is equipped with mirrors corresponding to k×l pixels (for example, 1140×912). Also, for example, consider a case where R (red), G (green), and B (blue) colors are prepared as light incident on the DMD element. In this case, an R light emission state in which R light is emitted by reflecting on the mirror, a G light emission state in which G light is emitted by reflecting on the mirror, and a B light emission state in which B light is emitted by reflecting on the mirror are repeated in a short, predetermined cycle. A color image can be projected by individually adjusting the light emission time of each light emission state. For this reason, the control unit 11 sets the ON/OFF timing of reflection within the unit time for each mirror according to the above-mentioned predetermined stripe pattern.

The imaging unit 30 is a so-called event camera. The imaging unit 30 has an imaging element that outputs event data (specifically, two-dimensional point data, time, and polarity of brightness change) including two-dimensional point data that identifies the position of a pixel that has undergone a brightness change when light is received. The imaging unit 30 generates an image from the event data output from the imaging element. For this reason, the imaging unit 30 outputs event data of positive polarity (i.e., positive brightness change) when a brightness change occurs in which the pixel becomes brighter due to receiving light, and outputs event data of negative polarity (i.e., negative brightness change) when a brightness change occurs in which the pixel becomes darker due to the disappearance of the light. Image data of the measurement object 50 is generated by plotting the two-dimensional point data of multiple event data output within a certain period of time as points on a specified plane. The imaging unit 30 outputs the image data or event data (i.e., two-dimensional point data, time, and polarity of brightness change) generated in this way to the measurement unit 40.

The measurement unit 40 is controlled by the control unit 11. The measurement unit 40 measures the three-dimensional shape of the measurement object 50 by the phase shift method based on an image captured by the imaging unit 30 of the measurement object 50 onto which a predetermined stripe pattern is projected from the projection unit 20.

Generally, in the phase shift method, a phase value θ corresponding to a distorted value according to the surface shape of a measurement object 50 is obtained based on a grating image (i.e., a stripe image) which is an image of the measurement object 50 onto which a predetermined stripe pattern (i.e., a pattern in which the luminance changes periodically in a first direction and the luminance does not change in a second direction perpendicular to the first direction) is projected. In the phase shift method, a sine wave pattern specified from the luminance value I(x, y, n) of the following formula (1) is adopted. That is, when the number of phase shifts is N, the luminance values I(x, y, n) of N phase-shifted grating images (i.e., stripe images) are expressed by formula (1).
I (x, y, n) = a (x, y) cos {θ (x, y) + 2πn/N} + b (x, y) ... (1)
Here, point (x, y) is one point (i.e., one pixel) in the grid image. a(x, y) is the luminance amplitude. b(x, y) indicates background luminance. θ(x, y) indicates the phase value of the grid where n=0. The distance to point (x, y) is measured according to the phase value θ(x, y) calculated from the luminance values I(x, y, n) of the N grid images.

Specifically, for example, consider a case where three grating images are obtained in one period formed by the above-mentioned R, G, and B light emission states. In this case, N=3, and the luminance value I(x, y, 0) in the R light emission state, the luminance value I(x, y, 1) in the G light emission state, and the luminance value I(x, y, 2) in the B light emission state are obtained from the captured image. In this case, the specified stripe pattern for the phase shift method is configured so that the phases of the sine wave pattern consisting of only R, the sine wave pattern consisting of only G, and the sine wave pattern consisting of only B are shifted by 2π/3.

When the luminance values I(x,y,0), I(x,y,1), and I(x,y,2) at point (x,y) in the captured image are obtained, the measurement unit 40 uses the above formula (1) to obtain the phase value θ(x,y). The measurement unit 40 measures the distance to point (x,y) according to the phase value θ(x,y) thus obtained. By measuring the distance to each point (x,y) of the captured measurement object 50 in this manner, the three-dimensional shape of the measurement object 50 can be measured.

For example, when determining the distance from the three-dimensional measuring device 10 to point P1 in FIG. 3, the measuring unit 40 determines the phase value θ of point P1 and information on which stripe the point P1 is on (i.e., stripe number) from N captured images of the imaging unit 30 in a state where a predetermined stripe pattern is shifted and projected by the projection unit 20 N times. From the phase value θ and stripe number thus determined, the angle θp1 at the projection unit 20 and the angle θc1 at the imaging unit 30 are determined. Since the distance between the projection unit 20 and the imaging unit 30 (i.e., parallax Dp) is known, the distance to point P1 can be determined by triangulation. Similarly, the distance to point P2 in FIG. 3 can be determined by triangulation based on the angle θp2 at the projection unit 20 and the angle θc2 at the imaging unit 30, which are determined from the phase value θ of point P2 determined from the N captured images and the stripe number. By performing this calculation over the entire measurement area, three-dimensional measurement can be performed.

Here, the three-dimensional measurement process performed by the measurement unit 40 when measuring the three-dimensional shape of the measurement object 50 using the phase shift method will be described in detail with reference to FIGS.
In this embodiment, an event camera is used as an imaging unit for accurately imaging the measurement target 50 that moves relatively at high speed. In such a configuration, event data corresponding to pixels where a luminance change occurs is output. However, since the event data does not include a luminance value, the luminance values (i.e., I(x,y,0), I(x,y,1), I(x,y,2)) required for the phase shift method cannot be directly obtained.

On the other hand, after positive polarity event data is output when light emission starts, negative polarity event data is output when light emission ends. Therefore, the longer the time difference between the output of positive polarity event data and the output of negative polarity event data, the brighter the image becomes. That is, for each pixel of the captured image, the higher the luminance value, the longer the time difference between the occurrence time of positive polarity event data and the occurrence time of negative polarity event data. For this reason, as shown in FIG. 4, the luminance value (i.e., luminance information) can be obtained based on the time difference between the occurrence time of positive polarity event data and the occurrence time of negative polarity event data at each pixel in the captured image (i.e., the ON time in FIG. 4). Note that in FIG. 4 and FIG. 5 described later, the output of positive polarity event data is indicated by an upward arrow, and the output of negative polarity event data is indicated by a downward arrow.

For example, assume that in a pixel, as illustrated in FIG. 5A, the R light emission state, the G light emission state, and the B light emission state are repeated at a predetermined cycle of 3Tp (unit time Tp). In such a light emission state, positive polarity event data is generated and output at the timing when the R light emission starts (e.g., t11 in FIG. 5A), and negative polarity event data is generated and output at the timing when the R light emission ends (e.g., t12 in FIG. 5A). After that, positive polarity event data is generated and output at the timing when the G light emission starts (e.g., t13 in FIG. 5A), and negative polarity event data is generated and output at the timing when the G light emission ends (e.g., t14 in FIG. 5A). After that, positive polarity event data is generated and output at the timing when the B light emission starts (e.g., t15 in FIG. 5A), and negative polarity event data is generated and output at the timing when the B light emission ends (e.g., t16 in FIG. 5A).

Also, for example, in a pixel different from the pixel in FIG. 5A, as illustrated in FIG. 5B, positive polarity event data is generated and output at the start of R emission (e.g., t21 in FIG. 5B), and negative polarity event data is generated and output at the end of R emission (e.g., t22 in FIG. 5B). After that, positive polarity event data is generated and output at the start of G emission (e.g., t23 in FIG. 5B), and negative polarity event data is generated and output at the end of G emission (e.g., t24 in FIG. 5B). After that, positive polarity event data is generated and output at the start of B emission (e.g., t25 in FIG. 5B), and negative polarity event data is generated and output at the end of B emission (e.g., t26 in FIG. 5B).

Here, the longer the time from when the R light emission starts to when the R light emission ends, the brighter the R light will be. Therefore, the R luminance value can be calculated based on the time from when the R light emission starts to when the R light emission ends. Similarly, the G luminance value can be calculated based on the time from when the G light emission starts to when the G light emission ends. The B luminance value can be calculated based on the time from when the B light emission starts to when the B light emission ends.

Therefore, it is possible to obtain a luminance value (i.e., luminance information) based on the time difference between the occurrence time of positive polarity event data and the occurrence time of negative polarity event data at each pixel in the captured image. In the example of FIG. 5A, it is possible to obtain a luminance value I(x, y, 0) in the R-color light emission state based on t12-t11, which is the time difference between the occurrence time of positive polarity event data and the occurrence time of negative polarity event data in the R-color light emission state. Similarly, it is possible to obtain a luminance value I(x, y, 1) in the G-color light emission state and a luminance value I(x, y, 2) in the B-color light emission state based on the time difference t14-t13 and the time difference t16-t15. Using each luminance value obtained in this way, it is possible to measure the three-dimensional shape of the measurement object 50 by the phase shift method. In other words, it is possible to measure the three-dimensional shape of the measurement object 50 using the event data. Note that the calculation of the luminance value based on the time difference may be performed, for example, based on the correspondence between the time difference and the luminance value.

Next, a configuration for further speeding up three-dimensional measurement by utilizing a projection start signal output from the control unit 11 to the measurement unit 40 at the timing when projection of a specified stripe pattern starts, which is a characteristic configuration of this embodiment, will be described using an example of projection in unit time Tp. Note that in this embodiment, when projection of a specified stripe pattern starts, all DMD elements of the projection unit 20 are in the ON state. Also, the darker the DMD element that projects, the shorter the time from the ON state to the OFF state (i.e. the ON time).

In this embodiment, the control unit 11 outputs a start light emission instruction signal to the projection unit 20 to start projecting a predetermined stripe pattern. The projection unit 20, upon receiving this start light emission instruction signal, starts projecting the predetermined stripe pattern. As shown in FIG. 6, the control unit 11 outputs a projection start signal S1 synchronized with the start light emission instruction signal to the measurement unit 40 and the imaging unit 30. The control unit 11 also outputs an end light emission instruction signal to the projection unit 20 to end the projection of the predetermined stripe pattern. The projection unit 20, upon receiving this end light emission instruction signal, ends the projection of the predetermined stripe pattern. The control unit 11 outputs a projection end signal S2 synchronized with the end light emission instruction signal to the measurement unit 40 and the imaging unit 30.

The imaging unit 30 starts imaging when the projection start signal S1 is input from the control unit 11, and ends imaging when the projection end signal S2 is subsequently input. Therefore, in the imaging unit 30, positive polarity event data is output for all pixels when the projection start signal S1 is input. Thereafter, in the imaging unit 30, negative polarity event data is output later for brighter pixels before the projection end signal S2 is input. Note that the imaging unit 30 may end imaging after a specified time has elapsed from the input time of the projection start signal S1 (i.e., the output time of the projection start signal S1) without using the projection end signal S2.

For this reason, in the measurement unit 40, positive polarity event data is input from the imaging unit 30 for all pixels at the timing when the projection start signal S1 is input from the control unit 11. After that, negative polarity event data is input from the imaging unit 30 at different timings for each pixel.

In other words, the occurrence time of positive polarity event data coincides with the input time of the projection start signal S1, and negative polarity event data is output after the input time of the projection start signal S1. Therefore, it is possible to obtain brightness information for each pixel based on the time difference between the input time of the projection start signal S1 when the above-mentioned specified stripe pattern is projected and the occurrence time of the event data output after that input time.

For example, consider the case where a stripe pattern created as shown in FIG. 7A is projected from the projection unit 20. In this case, the measurement unit 40 to which the projection start signal S1 is input can obtain brightness information for each pixel based on the time difference between the input time of the projection start signal S1 and the occurrence time of the negative polarity event data output after that input time (i.e., the ON time in FIG. 7B), without obtaining the input time of the positive polarity event data from the imaging unit 30, as shown in FIG. 7B.

In the example of FIG. 5A, since the unit time Tp is known, it is not necessary to acquire the input time t11 of the positive polarity event data at the start of R light emission, the input time t13 of the positive polarity event data at the start of G light emission, and the input time t15 of the positive polarity event data at the start of B light emission. In other words, it is possible to obtain luminance information for each pixel based on the time difference between the input time of the projection start signal S1 and the input time t12 of the negative polarity event data at the start of R light emission, the input time t14 of the negative polarity event data at the start of G light emission, and the input time t16 of the negative polarity event data at the start of B light emission, as well as the unit time Tp.

As described above, in the three-dimensional measuring device 10 according to this embodiment, the imaging unit 30, which images the measurement object 50 onto which a predetermined stripe pattern is projected from the projection unit 20, is equipped with an imaging element that outputs event data including two-dimensional point data that identifies the position of pixels that have experienced a luminance change when light is received, and generates an image from the event data output from the imaging element. This imaging element outputs positive event data in the case of a brighter luminance change, and outputs negative event data in the case of a darker luminance change. The control unit 11 outputs a projection start signal S1 to the measurement unit 40 at the start of projection of the predetermined stripe pattern, and the measurement unit 40 calculates luminance information for each pixel in the captured image based on the time difference between the input time of the projection start signal S1 from the control unit 11 and the occurrence time of the event data output after that input time.

In this way, luminance information can be obtained for each pixel based on the time difference between the input time of the projection start signal S1 when a predetermined stripe pattern is projected and the occurrence time of the event data output after that input time. The luminance information obtained in this way can be used to measure the three-dimensional shape of the measurement object 50 by the phase shift method. In particular, the three-dimensional measuring device 10 only needs to obtain the occurrence time of the event data output after the input of the projection start signal S1, without obtaining the occurrence times of both positive polarity event data and negative polarity event data for all pixels. This shortens the processing time and further speeds up the generation of an image of the measurement object 50. In other words, the three-dimensional shape of the measurement object 50 can be measured more quickly.

The present disclosure is not limited to the above-described embodiment, and may be embodied as follows, for example.
(1) In the above embodiment, the luminance information (i.e., the luminance value) is obtained for each pixel based on the time difference (i.e., ON time) between the input time of the projection start signal S1 and the occurrence time of the event data output after the input time. However, the luminance information is not limited to this, and may be obtained for each pixel based on the OFF time. Specifically, after the start of projection of a predetermined stripe pattern, all the DMD elements of the projection unit 20 may change from the ON state to the OFF state at the same timing. The measurement unit 40 may obtain the luminance information (i.e., the luminance value) for each pixel based on the time difference (i.e., OFF time) between the input time of the signal for transition to the OFF state output after the projection start signal S1 and the occurrence time of the positive polarity event data output after the input time.

(2) In the above embodiment, the three-dimensional measuring device 10 moves while attached to the hand of a robot, and measures the three-dimensional shape of a measurement object that moves relatively. However, the three-dimensional measuring device 10 is not limited to this, and may be used, for example, in a fixed state to measure the three-dimensional shape of a measurement object that moves on a conveyor line.

(3) The projection unit 20, the imaging unit 30, and the measurement unit 40 may each be arranged separately as components of the three-dimensional measurement device 10. In addition, the measurement unit 40 may be an information processing terminal capable of wireless or wired communication with the projection unit 20 and the imaging unit 30.

(4) In the above embodiment, the predetermined stripe pattern projected by the projection unit 20 with N shifts is composed of R, G, and B light emission states, where N=3. However, the predetermined stripe pattern is not limited to this, and may be composed of, for example, periodically changing light and dark parts.

The three-dimensional measuring device 10 may also perform processing as shown in the flowchart of FIG. 9. Specifically, the three-dimensional measuring device 10 projects a stripe pattern and outputs a projection start signal (step S201). The three-dimensional measuring device 10 captures an image of the object onto which the stripe pattern is projected (step S203). The three-dimensional measuring device 10 generates a captured image from the event data output from the image sensor (step S205). The three-dimensional measuring device 10 calculates luminance information based on the time difference between the output of the projection start signal and the output of the event data (step S207). The three-dimensional measuring device 10 measures the three-dimensional shape based on the luminance information (step S209).

Claims

a projection unit that projects a predetermined stripe pattern onto a measurement target area;
an imaging unit that images a measurement object disposed in the measurement object area onto which the predetermined stripe pattern is projected;
a measurement unit that measures a three-dimensional shape of the measurement object by a phase shift method using luminance information obtained from an image captured by the imaging unit;
A control unit that controls the projection unit;
A three-dimensional measuring apparatus comprising:
the imaging unit includes an imaging element that outputs event data including two-dimensional point data that identifies a position of a pixel that has experienced a luminance change when light is received, and generates the captured image from the event data output from the imaging element;
the imaging device outputs positive event data when the luminance changes to brighter, and outputs negative event data when the luminance changes to darker;
the control unit outputs a projection start signal at a projection start timing of the predetermined stripe pattern,
the measurement unit determines the luminance information for each pixel in the captured image based on a time difference between an output time of the projection start signal and an output time of event data after the output of the projection start signal.
Three-dimensional measuring device.
the projection unit includes a plurality of mirrors corresponding to a plurality of pixels in the captured image for projecting the predetermined stripe pattern, and reflects projection light on all of the plurality of mirrors at the projection start timing;
the time difference is a time difference between an output time of the projection start signal and an output time of negative polarity event data after the output of the projection start signal;
The three-dimensional measuring apparatus according to claim 1 .
the projection unit includes a plurality of mirrors corresponding to a plurality of pixels in the captured image for projecting the predetermined stripe pattern, and stops reflection of the projection light from all of the plurality of mirrors at the projection start timing;
the time difference is a time difference between an output time of the projection start signal and an output time of positive polarity event data after the output of the projection start signal;
The three-dimensional measuring apparatus according to claim 1 .