JP2000193433A - Method and device for measuring 3-dimension form and storage medium where 3-dimension form measuring program is stored - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a distance image data with no degraded precision for easier handling. SOLUTION: A space code specifying process A3 where a space code is specified for each position corresponding to each light-reception element based on the order of measurement lights received in a light-reception process A2, a measurement impossible point extracting process A4 wherein a light-reception element which did not receive the measurement light is extracted from the light-reception elements on a light-reception plane, an interpolation process A5 wherein an interpolation value is calculated based on a space code value at the light-reception element near the measurement impossible point for the space code at the measurement impossible point extracted in the measurement impossible point extracting process A4, a distance calculation process A6 which calculates, for each light-reception element, a distance from an original point to the surface of an object to be measured, on a pre-set coordinate system based on the space code calculated in the space code processing processes A3-A5 and the position of light-reception element, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a three-dimensional shape and a storage medium storing a three-dimensional shape measuring program, and in particular, to measure the position of the surface of a measuring object with high accuracy. The present invention relates to a method and an apparatus for measuring a three-dimensional shape, and a storage medium storing a three-dimensional shape measurement program.

[0002]

2. Description of the Related Art Conventionally, in order to measure a three-dimensional shape, an irradiation angle of a laser beam and a C which receives a return beam of the laser beam are used.
The distance to the surface of the object to be measured is calculated based on the principle of triangulation based on the position of the light receiving element of the CD. The irradiation angle of the laser beam is called an angle code or a space code. The space code irradiates the defined slit light, and the angle code of the slit light can be used as the space code. Then, the distance to the object to be measured can be calculated from the angle code of the slit light and the pixel position that has received the slit light of the angle code.

[0003]

However, in the above-mentioned conventional example, the slit light may be thin depending on the inclination of the object to be measured, and is smaller than the size of the light receiving element, and the distance between the light receiving elements is small. In the case where the return light is located at a position, there is a disadvantage that an unmeasurable pixel exists. In addition, if the slit light is made thinner to improve the spatial resolution, a measurement impossible point similarly occurs. Then, when the distance image data is generated from the space-coded image in which the holes are vacant, there is a disadvantage that the data becomes a state in which holes are pierced in the surface of the measurement object.

If holes are present in the distance image data, the process of generating polygons from the distance image data and the process of extracting shape features such as steps and ridges (edges) of the object to be measured become complicated. , There was an inconvenience.

As a method of image processing for removing the influence of noise, for example, there is a filtering processing called a local spatial filter. In this process, noise is removed by replacing the data of the target pixel with the maximum value, minimum value, median value, etc. of the nearby value using the data (brightness) of the neighboring image of the target pixel. However, in order to remove noise, it is necessary to perform a filtering process on the entire image, and after the filtering process, there is a disadvantage that data of pixels other than the noise is also changed. Since the spatially coded image output from the three-dimensional measurement device is converted into three-dimensional coordinates using the pixel position and the code value, a change in the code value is not preferable in terms of accuracy.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for measuring a three-dimensional shape capable of improving the disadvantages of the prior art, and in particular, generating range image data that can be easily handled without reducing accuracy. The purpose is to provide.

[0007]

Therefore, according to the present invention, there is provided an irradiation step of irradiating measurement light corresponding to a space code for dividing a space including an object to be measured, and a measurement light irradiated in this irradiation step. A light receiving step in which light is received by each light receiving element two-dimensionally arranged on a light receiving plane at a predetermined angle with respect to a light irradiation angle, and each light receiving step is performed based on an order of measurement light received in the light receiving step. A space code processing step of calculating a space code for each position corresponding to the element, and measurement from an origin in a predetermined coordinate system based on the space code calculated in the space code processing step and the position of the light receiving element Calculating a distance to the surface of the object for each light receiving element. In addition, the spatial code processing step includes a non-measurable point extracting step of extracting light receiving elements that did not receive the measurement light among the light receiving elements on the light receiving plane, and a non-measurable point extracted in the non-measurable point extracting step. And a complementary step of calculating a complementary value based on the value of the space code in the light receiving element near the unmeasurable point. This aims to achieve the above-mentioned object.

[0008] In the irradiation step, a slit light or a spot light, each of which defines an angle code, is irradiated as measurement light. In the light receiving step, measurement light is received using, for example, an area type CCD sensor. In the spatial code processing step, a spatially coded image is generated according to the type of the measurement light, for example, based on the order of the slit light having the maximum luminance value in the case of slit light. Then, in the distance calculation step, the distance to the measurement target is calculated based on the principle of triangulation according to the angle of the measurement light (space code) and the pixel position of the space-coded image. At this time, for example, the focus position of the light reception may be set as the origin, or one point of a space including the measurement target may be set as the origin by performing calibration.

In the spatial code processing step, in the unmeasurable point extracting step, the light receiving elements which did not receive the measurement light among the light receiving elements on the light receiving plane are extracted. Then, even if a pixel that does not receive slit light or the finest pattern light occurs for various reasons in the light receiving step, the light receiving element that cannot receive light or the pixel position of the corresponding spatially coded image is extracted. Subsequently, in a complementing step, a complement value based on the value of the spatial code at the light receiving element near the non-measurable point is calculated for the spatial code of the non-measurable point. Then
The complementary value is stored at the unmeasurable point without changing the normally calculated space code. For this reason, the distance image data composed of the array of distances calculated in the distance calculation step represents a continuous shape without holes.

A three-dimensional shape measuring apparatus according to the present invention comprises: an irradiating means for irradiating measurement light corresponding to a space code for dividing a space including an object to be measured; and a measuring light irradiated by the irradiating means. A light receiving means having light receiving elements arranged two-dimensionally on a light receiving plane forming a predetermined angle with respect to an irradiation angle; and each light receiving element based on an order of measurement light received by each light receiving element of the light receiving means. And a space code processing means for calculating a space code for each position corresponding to. Moreover, the space code storage means for storing the space code calculated by the space code processing means at a pixel position corresponding to each light receiving element, and the space code stored at each pixel position and the pixel of the space code storage means. Distance calculating means for calculating, for each light receiving element, a distance from an origin in a predetermined coordinate system to each surface of the measuring object based on the predetermined coordinate system. Then, the spatial code processing means extracts an unmeasurable point extracting unit that extracts pixels for which no spatial code has been stored, and a spatial code of the unmeasurable point extracted by the unmeasurable point extracting unit in the vicinity of the unmeasurable point. A complementary value calculation unit that calculates a complementary value based on the space code stored in the pixel.

Here, the space code processing means specifies a space code for each position of the light receiving element in accordance with the type of the measurement light, and generates a space-coded image. Then, the space code storage means stores the space code. Subsequently, the unmeasurable point extraction unit specifies the pixel position of the spatially coded image corresponding to the pixel that did not receive the measurement light. For example, the pixel that cannot be measured is extracted by referring to the space code that is kept at the initial value or the flag indicating whether the space code is stored. Then, the complement value calculation unit complements the spatial code of the unmeasurable point extracted by the unmeasurable point extraction unit. That is, the space code stored in the pixel near the unmeasurable point is read, and the space codes near, for example, 4 or 8 are read, and the average or median of these values is used as a complement value. Therefore, the space-coded image and the distance image data calculated based on the space-coded image are continuous data. In the calculation of the complement value, assuming that the median value of the neighboring values excluding the initial value is the same, the blind spot area is left as it is, and only holes generated due to structural reasons of the CCD are complemented.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an irradiation step A1 for irradiating measurement light corresponding to a space code that divides a space including a measurement target, and an irradiation angle of the measurement light irradiated in this irradiation step A1 are predetermined. The light receiving step A2 receives the measurement light by the light receiving elements arranged two-dimensionally on the light receiving plane at an angle, and the light receiving elements correspond to the light receiving elements based on the order of the measurement light received in the light receiving step A2. A space code specifying step A3 for specifying a space code for each position.

Further, following the spatial code specifying step A3, a measurement impossible point extracting step A4 for extracting a light receiving element which has not received the measurement light among the light receiving elements on the light receiving plane, and a measurement impossible point extracting step A4 Complementation step A for calculating a complement value based on the value of the space code at the light receiving element near the measurement impossible point for the space code of the measurement impossible point extracted in
5 and the distance from the origin in the predetermined coordinate system to the surface of the object to be measured in a predetermined coordinate system based on the space code calculated in the space code processing steps A3 to A5 and the position of the light receiving element. And a distance image data output step of outputting the distance image data calculated in the distance calculation step A6.

In the unmeasurable point extracting step A4, the pixels in which the spatial code is not stored are searched from the spatially coded image having the same arrangement as the array of the light receiving elements, thereby extracting the light receiving elements which have not received the measuring light. You may do it. Further, the space code specifying step A3 includes a light receiving flag setting step of setting a light receiving flag indicating whether or not measurement light has been received for each light receiving element, and the unmeasurable point extracting step A4 performs measurement with reference to the light receiving flag. A configuration may be provided that includes a light receiving flag reference step of searching for an impossible point.

As described above, in the present embodiment, it is determined whether or not the measurement point is an effective measurement point, and further, the measurement in the spatially coded image is impossible by utilizing the continuity property of the spatial code. The pixel position is detected. By recording, for example, the median value of the code of the neighboring image only at the pixel position where measurement was impossible, the code is complemented to the pixel that cannot be measured without changing the correct data. The determination as to whether or not the pixel is a valid measurement point may be made, for example, by using the fact that data remains at an initial value for a pixel that cannot be measured, or by accessing a memory address (pixel position) during measurement. A flag indicating whether or not it is used is used.

FIG. 2 is an explanatory diagram showing the principle of distance measurement using a space code. In the example shown in FIG.
The irradiation means for realizing 1 includes a laser light source 22 and a galvanomirror 23. In the light receiving step A2, the camera 3 is used. Laser light source 22, Galvano mirror 2
As shown in FIG. 2, the camera 3 and the camera 3 are on a floor surface (horizontal surface).
Are located on the same plane which is horizontal with respect to. Also,
The galvanometer mirror 23 is disposed at a distance of l from the optical axis of the camera 3 and rotates around a vertical direction (parallel to the slit light R) with respect to the horizontal scanning line of the light receiving element 31 of the camera 3. . With this arrangement, it is possible to move the slit light R in the parallel direction along the horizontal scanning line of the light receiving element 31 and allow the light receiving element 31 of the camera 3 to receive the light.

The space code is, for example, a value that is increased at regular intervals in the scanning direction of the galvano scanner 23 in accordance with the value of θ shown in FIG. Projection angle θ for any pixel
And the angle α of the slit light R position from the camera 3 is specified from the x component of the position coordinates of each pixel (FIG. 2).
Is a right angle.) Further, since the separation distance l between the camera 3 and the galvanometer mirror 23 is a known value, it can be obtained from, for example, the distance h = l · sin θ / sin (α + θ). The value of θ is determined by the scanning angle of the galvano scanner, and the value of α is determined by the position of the light receiving element that has received the light. Therefore, from these two angles and the predetermined distance l, the position of the position irradiated with the measurement light is determined. The distance h to the surface of the measurement object can be calculated.

FIGS. 3 and 4 are explanatory diagrams showing examples of space codes. In FIG. 3A and FIG. 4A, the space code is represented by shading, and the space code shown in black is the minimum,
The space code shown in white is the largest. In the example shown in FIG. 3 (A), black spots appear intermittently, which are unmeasurable points. As shown in FIG. 3B, the spatial code at the unmeasurable point is minimized. On the other hand, when the complementing process is performed, FIG.
As shown in FIG. If the measurement object is a plane, the spatial code monotonically increases as the horizontal pixel coordinates increase.

FIG. 5 shows an example of the complementing process in the complementing step A5. There are various methods of complementation in the complementing step A5. For example, the complement value of the measurement impossible point may be specified based on a space code other than the initial value among the values near the measurement impossible point. That is, the spatially coded image is raster-scanned to search for an unmeasurable point (for example, an initial value such as 0). Next, the central value of the code at the pixel position near the unmeasurable pixel is obtained and replaced with the code “0” at the unmeasurable point. FIG. 5A shows an example of eight neighborhoods, and FIG. 5B shows an example of four neighborhoods.

As a specific example of the complementing process, if the target pixel is a point at which measurement is impossible, the median value of the eight neighboring codes is recorded at the target pixel position. In addition, among the neighboring code values, the median of the non-zero code values may be recorded at the target pixel position. Further, among the neighboring code values, an average value of non-zero values may be recorded at the target pixel position. Then, it is not affected by the unmeasurable point due to the blind spot.

In the complementing step A5, when the complementing value of the unmeasurable point becomes a value that continuously decreases or increases in the scanning direction of the measuring light while the spatial code increases or decreases, the complementing is performed. A step of correcting the value may be provided. This is, as shown in FIGS. 3 and 4,
Since the space code increases (or decreases) irrespective of the shape of the object to be measured, a complementary value such that the space code decreases, for example, three times in a predetermined increasing direction is deleted. Then, an incorrect complement value is not stored in the value of the pixel at the edge from the surface of the measurement object to the blind spot.

FIG. 6 is a block diagram showing a configuration of a three-dimensional shape measuring apparatus suitable for carrying out the three-dimensional shape measuring method according to the present embodiment. As shown in FIG. 6, the three-dimensional shape measuring apparatus according to the present embodiment includes an irradiation unit 2 that irradiates measurement light corresponding to a space code that divides a space including a measurement target,
A light receiving means 3 having light receiving elements arranged two-dimensionally on a light receiving plane at a predetermined angle with respect to the irradiation angle of the measuring light irradiated by the irradiation means 2; and each light receiving element of the light receiving means 3 And a space code processing means 4 for calculating a space code for each position corresponding to each light receiving element based on the order of measurement light received by the light receiving element.

The measuring apparatus further includes a space code storage means 42 for storing the space code calculated by the space code processing means 4 at a pixel position corresponding to each light receiving element.
And calculating the distance from the origin in the predetermined coordinate system to each surface of the measurement object for each light receiving element based on each pixel position of the space code storage means 42 and the space code stored in the pixel. And distance calculating means 100 for calculating the distance.

Then, the spatial code processing means 4 extracts the unmeasurable point extracting unit 4B for extracting the pixels in which the spatial code is not stored and the spatial code of the unmeasurable point extracted by the unmeasurable point extracting unit 4B. And a complementary value calculation unit 4C that calculates a complementary value based on a space code stored in a pixel near the unmeasurable point.

Of the space code processing means, the unmeasurable point extraction unit 4B and the complement value calculation unit 4C can be realized by using an arithmetic device such as a computer. In this case, the arithmetic unit includes a storage unit that stores the three-dimensional measurement program, a CPU that functions as a non-measurable point extracting unit 4B by executing the program, and a RAM that is a main storage device of the CPU. Have. This three-dimensional measurement program is a command for operating the arithmetic device,
An unmeasurable point extraction command for extracting a pixel in which the spatially coded image is not stored among the pixels of the space coded image, and the unmeasurable point for the spatial code of the pixel extracted according to the unmeasurable point extraction instruction And a complementary command for calculating a complementary value based on the value of the space code in the light receiving element in the vicinity of. Thereby, the configuration shown in FIG. 6 is realized, and the processing shown in FIG. 1 is performed by using the configuration shown in FIG.

[0026]

Next, an embodiment of a three-dimensional shape measuring process will be described with reference to the drawings. <Calibration> FIGS. 7 to 9 show examples of the configuration of the three-dimensional shape measuring apparatus. As shown in FIG. 2, the distance to the object to be measured can be calculated from the individual irradiation angles and the pixel positions of the light receiving elements. However, in practice, it is difficult to adjust the angle of view of the camera and the adjustment at the time of installation. In the present embodiment, the relationship between the spatial code and the pixel position is calibrated for reasons such as the property and the value in the coordinate system including the measurement object is easy to handle.

Generally, an imaged screen is detected by a planar CCD image sensor. , The camera coordinate system is Xc-
It is obtained by a two-dimensional coordinate system of Yc. When the relationship between the object coordinate system and the camera coordinate system is represented by a homogeneous coordinate system expression, it is represented by the following equation (1). Here, the matrix C for converting the object coordinate system into the camera coordinate system is called a camera parameter.

[0028]

(Equation 1)

On the other hand, since the projector obtains the displacement in one-dimensional direction, the obtained coordinate system is only one-dimensional Xp. When the relationship between the projector coordinate system and the object coordinate system is represented by a homogeneous coordinate system expression, it is represented by the following equation (2).
Here, a matrix P for transforming the object coordinate system into the projector coordinate system is called a projector parameter.

[0030]

(Equation 2)

By developing these parameters and organizing them simultaneously, the following equations (3), (4) and (5) are obtained.

[0032]

(Equation 3)

Therefore, if an inverse matrix exists in the matrix Q, the object coordinate system V = (X, Y, Z) can be obtained from the camera coordinate system (Xc, Yc) and the projector coordinate system Xp. When the three-dimensional shape is measured by each of the above-described methods, it is necessary to obtain the camera parameters and the projector parameters in advance in order to obtain the matrix Q.

First, a bright / dark image of the reference cube B is captured by a CCD camera and a coded image is captured by a slit projector by a spatial coding method. Then, the bright and dark images are binarized to take out the index portion, and the intersections obtained by virtually connecting the opposing indices in the plane of each cube and obtained in a grid shape are extracted as reference points (Xi, Yi, Zi). .

When calculating the camera parameters, the position coordinates of the reference point (known) on the object coordinate system and the pixel positions on the image sensor of the CCD camera on the captured image (position coordinates on the camera coordinate system ( Xci, Yci)) are stored in pairs.

The position coordinates (X) of the reference point on the object coordinate system
i, Yi, Zi) and position coordinates (Xci, Yc) on the camera coordinate system.
i), the following equations (6) and (7) obtained from the above equations (3) and (4) hold.

[0037]

(Equation 4)

C11... C21... Of the equations (6) and (7)
To find a total of 12 unknowns of C34, it is necessary to detect points on the camera coordinate system for at least six or more reference points that are not on the same plane. The unknown can be obtained by the least square method.

FIG. 7 shows an example of a three-dimensional measuring device and a calibration device. The three-dimensional shape measuring apparatus includes a projector 202 as an irradiation mechanism that irradiates irradiation light with position coordinates in a certain one-dimensional direction to the measurement target, and a camera that captures the measurement target irradiated with the irradiation light 3 and an image processing board 201 for calculating three-dimensional image data of the object to be measured from an image captured by the camera 3.

The projector 202 can irradiate stripe-shaped pattern light at different pitches.
Operation control such as designation of irradiation timing and pattern light pitch is performed by the host computer 200. Also,
Instead of the pattern light, slit light may be applied. The projector coordinate system, which is a one-dimensional coordinate system, is formed in the direction in which the stripes are arranged (the direction perpendicular to the pattern light).

The CCD camera 3 has a light receiving element for outputting a luminance signal according to the luminance of the received light. This light receiving element is a pixel arranged in a plane. A camera coordinate system, which is a two-dimensional coordinate system, is formed corresponding to the plane of the CCD image sensor, and the position of each pixel corresponds to the position coordinates of the coordinate system.

The image processing board 201 includes the projector 2
02 and the CCD camera 3 are synchronized, and three-dimensional shape data is calculated based on the output of the CCD camera 3.

Next, a calibration device of the three-dimensional shape measuring device will be described. The calibration device includes a calibration two-dimensional gauge 202 having a plurality of indices 222 in a known arrangement on a smooth plane 221, and the gauge 202 is attached to the plane 221.
A uniaxial numerical control table 230 that is movably held in a direction perpendicular to the axis, and a uniaxial numerical control controller 240 that is provided in the uniaxial numerical control table 230 and that serves as adjusting means for adjusting the amount of movement of the calibration two-dimensional gauge 202. Have.

As shown in FIG. 7, the calibration two-dimensional gauge 202 has a single plane 221 of a square.
1 is held in the uniaxial numerical control table 230 so as to face the CCD camera 3 and the projector 202.
Then, the optical axis of the objective lens of the CCD camera 3 and one plane 2
The normal to 21 is parallel. That is, thereby, the pattern light is emitted from the projector 202 to the one plane 221, the CCD camera 3 can capture a bright and dark image on the one plane 221, and the host computer 200
Three-dimensional coordinate data described later can be obtained via the image processing board 201.

The object coordinate system, which is a three-dimensional coordinate system, is set with reference to the calibration two-dimensional gauge 202. That is, in the calibration two-dimensional gauge 202 at the position shown in FIG. 7 (this position is assumed to be the current position), as shown in FIG. The origin is set horizontally rightward, and the Y-axis of the coordinate system is set vertically downward with the same angle of one plane 21 as the origin. Further, as shown in FIG. 8B, the Z axis of the coordinate system is
Are set to the opposite side to the CCD camera 3 along the normal direction of the one plane 221 with the same angle as the origin.
In this embodiment, the distance from the origin of the object coordinate system is calculated based on the space code and the pixel position.

Further, one plane 221 of the two-dimensional calibration gauge 202 is colored white, and an index 222 which is a black point for determining the reference point 23 is attached thereon. Index 222
As shown in FIG. 8A, five are arranged at equal pitch p on four sides of a square having each side parallel to the X-axis and Y-axis. The indices on the sides facing each other correspond to the indices on the other side, respectively, and as shown by the dotted line in FIG. Are connected by a straight line parallel to. The intersection of each straight line connecting the corresponding indices is the reference point 223. These reference points 223
5 × 5 = 25 cells are developed in a grid on one plane 21. Each index 21 is located on a known position coordinate in the object coordinate system described above, and accordingly, the position coordinate of each reference point 23 is also known.

The one-axis numerical control table 230 includes a holding member 231 of the two-dimensional calibration
The ball screw 32 that feeds the holding member 31 in the axial direction, and a stepping motor 33 that drives the ball screw 32 under numerical control by the single-axis numerical controller 4 are provided.

The one-axis numerical controller 240 receives a numerical input of the feed amount in the Z direction from the host computer 200, controls the drive of the stepping motor 233 by the corresponding drive amount, and controls the two-dimensional It can be positioned at any position in the direction. At the time of calibration, the one-axis numerical control table 230 is usually set so that the feed direction of the calibration two-dimensional gauge 202 is parallel to the optical axis of the objective lens of the CCD camera 3, and the calibration two-dimensional gauge 202 is moved in the Z direction. Is sent four times from the current position with a feed amount equal to the pitch p of the reference point 223.

The host computer 200 controls the operation of the three-dimensional shape measuring device and the calibrating device and calculates the measurement information. The operation of the automatic calibration system of the three-dimensional shape measuring apparatus shown in FIG.
This is performed by a program input in advance at 00.

FIG. 9 is a flowchart showing the operation of this embodiment. Hereinafter, a calibration operation of the three-dimensional shape measuring apparatus performed prior to the three-dimensional shape measurement of the present embodiment will be described based on this.

The variable step stored in the host computer 200 is initialized to 0 (step S1).

Then, the laser light output from the projector 202 of the three-dimensional shape measuring apparatus is continuously projected, and the image of each index provided on one plane of the two-dimensional calibration gauge 202 is captured by the CCD camera 3. Obtain light and dark images. Thereby, the host computer 200 sets the camera coordinate system Xc-Yc as a two-dimensional coordinate system in the storage area (step S2).

Next, a gray code pattern (pattern light on a stripe) is sequentially emitted from the projector 202 and a spatially coded image is captured by the CCD camera 3.
The host computer 200 obtains a space code from the captured image, and thereby sets a projector coordinate system Xp as a one-dimensional coordinate system in the storage area (step S3).

The captured light-dark image is binarized, and the center-of-gravity pixel (center) of each circular index 222 is obtained (step S4).

In the host computer 200, a virtual intersection of a straight line connecting the indices 22 facing each other is obtained by calculation as a real coordinate reference point 23 for calibration (step S).
5).

Then, in the storage area of the host computer, the position coordinates (Xc-Yc) of each reference point 223 on the camera coordinate system and the position coordinates Xp of the projector coordinate shape are stored as data corresponding to each other (step S).
6).

The host computer 200 increments the step (step S7) and moves the calibration two-dimensional gauge 202 in the Z direction by a distance of the pitch p (step S8).

It is confirmed whether or not the imaging of the calibration two-dimensional gauge 202 has been performed five times, that is, whether or not the movement in the Z-axis direction has been performed four times (step S9). The operation of step S8 is repeated. If it has reached, the camera parameters and the projector parameters are obtained based on the stored data to calculate the system parameters (step S10). Then, the calibration is completed.

In this embodiment, a three-dimensional shape measuring apparatus 1 for measuring a three-dimensional shape based on a spatial coding method is used.
Although the example in which the calibration work is performed for 00 is shown, the present invention is also effective for a measuring device that measures a three-dimensional shape by scanning one slit light or a measuring device based on another method.

As described above, the relationship between the pixel position and the space code is calibrated in advance using the calibration device shown in FIG.
Then, in the actual measurement, the distance from the origin in the object coordinate system can be calculated from the space code and the pixel position.

<Measurement> In order to obtain a space-coded image, there are a light cutting method using slit light, a pattern light projection method using a time-series space coding pattern (gray coding pattern), and the like. Regarding the pattern light projection method, in the projection of the pattern light, holes are unlikely to occur other than the blind spot area and the abnormality of the light receiving element itself. On the other hand, in the calculation processing of the spatially coded image by the slit light projection, a hole may be generated. Therefore, an example of the shape measurement of the measurement object will be described below using the light section method as an example.

FIG. 10 is a block diagram of the present embodiment.
Here, an irradiation unit 2 that scans the measurement object S with the slit light R, a camera 3 that images the slit light R that moves by scanning from a direction different from the irradiation unit 2 a plurality of times, and a plurality of captured images And a space code processing means 4 for calculating a space code (angle code) from the data.

The three-dimensional shape measuring apparatus outputs the three-dimensional image data calculated by the space code processing means 4 to the computer 100 connected via the digital I / O board 102, as shown in the figure. Meanwhile, computer 1
00 calculates a three-dimensional shape based on the angle coded image (space coded image) from the space code processing means 4 and its pixel position. In this calculation, a distance in the object coordinate system is calculated using camera parameters and the like calculated using the above-described calibration device.

The irradiating means 2 includes a laser light source 22 for irradiating one slit-shaped laser beam (hereinafter, referred to as a slit beam R) driven by a laser driver 21, and an illuminating slit beam R for measuring an object to be measured. A galvanometer mirror 23 that reflects to the S side, and a galvanometer scanner 2 that rotates the galvanometer mirror 23 to scan the slit light R with respect to the measurement target S.
4, a scanner driver 25 for controlling the drive of the galvano scanner 24, and a projection angle command generation circuit 26 for outputting a projection angle command to the scanner driver 25 based on the angle signal from the space code processing means 4.

The slit light R emitted from the laser light source 22 is a rod-shaped light along the vertical direction (up and down direction in FIG. 10) with respect to the floor surface at the time of measurement. The object S to be measured is scanned by moving in the vertical direction. Also, the slit light R
Is set in advance so as to be perpendicular to the horizontal scanning line of the light receiving element 31 of the camera 3.

The light emitting angle command generating circuit 26 outputs a light emitting angle signal from the memory address generating circuit 46 of the space code processing means 4 and, based on the signal, outputs a galvano scanner 2 signal.
4 is performed.

The laser light source 22, the galvanometer mirror 2
As shown in FIG. 2, the camera 3 and the camera 3 are on a floor surface (horizontal surface).
Are located on the same plane which is horizontal with respect to. Then, the galvanomirror 23 rotates around a vertical direction (a direction parallel to the slit light R) with respect to the horizontal scanning line of the light receiving element 31 of the camera 3. With this arrangement, it is possible to move the slit light R in the parallel direction along the horizontal scanning line of the light receiving element 31 and allow the light receiving element 31 of the camera 3 to receive the light.

In this embodiment, the light receiving element 31 is provided with 256 pixels in the horizontal scanning line direction, and 243 such horizontal scanning lines, and a total of 256 × 243 pixels are regularly arranged. I have. The output of the luminance signal from each pixel is performed for each horizontal scanning line in the arrangement order in the horizontal scanning line direction. At this time, a period during which the luminance signal of one horizontal scanning line is output is called an output period, and a period between an output period during which no output is performed and an output period is called a blanking period. Further, each pixel on one horizontal scanning line outputs in the arrangement order during the output period. Then, outputs from all the pixels are sent to the space code processing means 4 as video signals. As described above, in this embodiment, the camera 3 has the same space code as the number of pixels in the horizontal scanning line direction.

The camera 3 captures an image by dividing one scan of the slit light R by the number of pixels (256) on the scanning line. For this reason, the scanning range angle of the galvano scanner 24 is divided into 256, and synchronization is achieved by a horizontal and vertical synchronization signal output from a synchronization circuit 43 of the space code processing unit 4 described later in order to perform imaging at each angle.

FIG. 1 is a block diagram of the spatial code processing means 4.
It is shown in FIG. The space code processing means 4 includes a light receiving element 31
A peak detector 5 for detecting and specifying the maximum value of the luminance output from each pixel for each scanning line,
In response to the detection, the pixel position detector 8 detects and specifies the position on the scanning line for the pixel that outputs the maximum luminance, and the luminance memory 41 having a recording area of the luminance individually corresponding to each pixel of the light receiving element 31. Based on the luminance detected by the peak detection unit 5 and the position of the pixel detected by the pixel position detection unit 8, the magnitude of the recording luminance recorded in the recording area of the corresponding pixel in the luminance memory 41 is compared. A second comparing circuit 6 as a comparing section, and a third selecting circuit 7 as a first updating section for updating the recording luminance of the luminance memory 41 to the value of the detected luminance when the detected luminance is larger than the recording luminance. And an angle coding memory 42 having a recording area of a projection angle individually corresponding to each pixel.

Further, the spatial code processing means 4 includes a synchronizing circuit 43 for synchronizing the camera 3 in the horizontal and vertical directions, an A / D conversion circuit 44 for quantizing the luminance signal of the video signal from the camera 3, and a luminance memory. 41 and angle coded memory 42
And a memory address creation circuit 46 for creating an address.

The memory address generating circuit 46 counts the horizontal synchronizing signal from the synchronizing circuit 43 to determine the horizontal scanning line number at which the pixel currently being output from the light receiving element 31 is located. Indicates that the output is being performed. Hereinafter, this is referred to as a vertical address y).

Further, the memory address creation circuit 46
Horizontal drive frequency (number of pixels in a scanning line 768, 14.318)
MHz) is divided by 3 (to make the number of pixels in the scanning line 256), and the position of the pixel currently being output from the light receiving element 31 on the horizontal scanning line (the number of pixels from the end on the horizontal scanning line) Indicates whether the horizontal address x is output.

The vertical synchronizing signal from the synchronizing circuit 43 is counted, and a projection angle signal is created and output to the irradiation means 2. Further, in the memory address creation circuit 46, a clear signal of a temporary brightness memory 51 of the peak detection unit 5 and a temporary location memory 81 of the pixel position detection unit 8, which will be described later, is created for each output of one horizontal scanning line by a horizontal synchronization signal. And output.

The luminance signal quantized by the A / D conversion circuit 44 is output to the peak detector 5. The peak detection unit 5 includes a temporary luminance memory 51 for recording only the luminance at the maximum level on one scanning line, and a signal level of a luminance signal quantized by the A / D exchange circuit 44 (hereinafter simply referred to as “luminance”). ") And the maximum luminance memory 5 in the scanning line.
A first comparison circuit 53 that compares the luminance recorded with the first and outputs which luminance is higher, and selects the higher luminance based on the output of the first comparison circuit 53;
And a first selection circuit 54 for updating the recording luminance in the temporary luminance memory 51.

Since the temporary luminance memory 51 described above only needs to record a luminance signal for one pixel, its storage capacity is luminance resolution × 1 (8 bits). The contents of the temporary luminance memory 51 are cleared to 0 during each horizontal blanking period (for each horizontal scanning line).

With the above configuration, the peak detector 5 detects and records the maximum level of the luminance signal for each scanning line.

When the peak detector 5 detects the maximum luminance on one scanning line, the pixel position detector 8 simultaneously outputs the horizontal address x of the pixel outputting the maximum luminance.
Is detected. The pixel position detection unit 8 includes a temporary position memory 81 that records only the horizontal address x of the pixel that outputs the maximum luminance on one scanning line, and a horizontal address corresponding to each pixel sequentially output from the memory address generation circuit 46. x, the first comparison circuit 53 of the peak detection unit 5 described above.
And a second selection circuit 82 that overwrites the temporary position memory 81 with the horizontal address x of the pixel that outputs the maximum luminance selected by the output.

The above-mentioned temporary position memory 81 stores 25
It is enough to be able to record which of the six pixels it is, so its storage capacity is 256 × 1 (8 bits). The contents of the temporary position memory 81 are cleared to 0 during each horizontal blanking period (for each horizontal scanning line).

With the above configuration, the pixel position detector 8 outputs the horizontal address x of the pixel that outputs the maximum luminance for each scanning line.
Are detected and recorded.

Each temporary luminance memory 51 has a gate 91
Via the second comparison circuit 6 and the third selection circuit 7
The recording luminance in the temporary luminance memory 51 is output to these when the gate 91 is closed. on the other hand,
The temporary position memory 81 is connected to the luminance memory 42 and the angle coding memory 42 via a gate 92, and when the gate 92 is closed, the horizontal address x in the temporary position memory 81 is output to them.

Each of these gates 91 and 92 is connected to the memory address generation circuit 46 and receives the output of the horizontal synchronizing signal of the light receiving element 31. These gates 91 and 92 are normally open, and are closed when it is input from the horizontal synchronization signal that the light receiving element 31 is in the flyback period.

The gates 91 and 92 are connected to the light receiving element 3
1 constitutes an output synchronizing unit 9 for simultaneously outputting the recorded contents of the temporary luminance memory 51 and the temporary position memory 81 during the flyback period.

Next, the luminance memory 41 will be described.
In the luminance memory 41, a recording area of luminance corresponding to each pixel of the light receiving element 31 is formed (see FIG. 13). In each recording area of the luminance memory 41, a luminance set in advance to a value smaller than 0 to a value smaller than the luminance of the normal slit light is recorded.

As described above, when the gates 91 and 92 are closed, the maximum luminance is output from the temporary luminance memory 51 to the second comparison circuit 6, and the horizontal address x is output from the temporary position memory 81 to the luminance memory 41. Is done. The current vertical address y is always output from the memory address creation circuit 46 to the luminance memory 41.

As a result, to the luminance memory 41, it is specified which of the pixels of the light receiving element 31 is the pixel which has output the maximum luminance from the horizontal address x and the vertical address y. The recording luminance is output to the second comparison circuit 6 from the recording area to be recorded.

In the second comparison circuit 6, the temporary luminance memory 5
The luminance from 1 is compared with the luminance already recorded in the luminance memory 41, and which is higher is output. The third selection circuit 7 receives the output of the second comparison circuit 6 and, when the luminance from the temporary luminance memory 51 is high, the luminance memory 41
Is updated to the luminance of the temporary luminance memory 51; otherwise, the recording luminance of the luminance memory 41 is maintained as it is.

Next, the angle encoding memory 42 will be described. The angle coded memory 42 stores the light receiving element 31
The recording area of the projection angle θ of the slit light R (which is synonymous with the rotation angle of the galvanomirror 23 in this case) θ corresponding to each pixel is provided.

The angle encoding memory 42 has
A fourth selection circuit 45 as a second updating unit for updating the projection angle θ of each recording area is also provided. The fourth selection circuit 45 is connected to the second comparison circuit 6 that operates when the gate 91 is closed, and at the same time, emits a light emission angle signal indicating the current light emission angle θ from the memory address creation circuit 46. Is entered.

On the other hand, the current vertical address y is always input from the memory address creation circuit 46 to the angle coding memory 42, and the maximum luminance is output from the temporary position memory 81 by closing the gate 92. The horizontal address x of the pixel is input. As a result, the pixel which has output the maximum luminance from the horizontal address x and the vertical address y to the angle coding memory 42 is identified as one of the pixels of the light receiving element 31, and the fourth selection is performed. The input state by the circuit 45 is awaited.

The fourth selection circuit 45 includes a second comparison circuit 6
When the luminance of the temporary luminance memory 51 is higher than the luminance of the temporary luminance memory 51 and the luminance of the luminance memory 41, the light projection angle θ from the memory address creation circuit 46 is recorded in the corresponding recording area. However, if the luminance memory 41 outputs that the luminance is high, the update is not performed. As described above, since the third and fourth selection circuits 7 and 45 are both updated by the output of the second comparison circuit 6, when the luminance of the temporary luminance memory 51 is updated with respect to the luminance memory 41, Only, the projection angle θ to the angle coding memory 42
(Update if already recorded) is performed.

Here, the recording of each of the above-mentioned luminance memory 41 and angle coding memory 42 is cleared to 0 at the start of measurement.

FIG. 12A shows the slit light R imaged on the light receiving element 31. At this time, the scanning range by the irradiation mechanism is divided into 256, and imaging is performed for each of the divided ranges.
It will be represented by the number 56. FIG. 12B shows the luminance level detected from each pixel along the horizontal scanning line of scanning line number 1. According to this figure, a maximum luminance level is observed at a position x0 in the horizontal scanning line direction, and this can be regarded as slit light.

When the functions of the above sections are combined, the three-dimensional shape measuring apparatus 10 regards the pixel which has detected the maximum luminance on the horizontal scanning line during the output period as the irradiation position of the slit light, and sets the maximum luminance for each scanning line. Then, the horizontal address x of the pixel in which is detected is obtained, and the projection angle of the irradiated slit light is obtained, thereby completing the angle encoding memory 42. With this, when the projection angle is obtained for each pixel address, the camera 3 can determine the projection angle from the measurement target S imaged at each address.
, And the computer 100 measures the three-dimensional shape.

For this reason, first, for the horizontal scanning line that is currently in the output period, the peak luminance among the luminances output from the pixels on the horizontal scanning line is specified by the peak detecting section 5 and the temporary luminance memory 51 stores the maximum luminance. Be recorded. In addition, during the output period, the horizontal address x of the pixel that outputs the maximum luminance is specified by the pixel position detection unit 8 and is recorded in the temporary position memory 81.

The maximum luminance and the horizontal address x recorded in each of the memories 51 and 81 are held until the output period ends and a blanking period is reached. It is output to 41 or the angle coding memory 42 side. As described above, since the luminance and the horizontal address x are suspended during the output period, the luminance determined to be the maximum in the course of the processing is processed on the downstream side (to the luminance memory 41 and the angle encoding memory 42). Record)
Is not done.

Then, based on these outputs and the output of the vertical address y and the projection angle signal by the memory address creation circuit 46, the brightness of the address specified by the second comparison circuit 6 and the third selection circuit 7 is reduced. The memory 41 is compared and updated. That is, by performing the above-described comparison or update on all the horizontal scanning lines with respect to the captured images at all the projection angles, the highest is achieved through all the captured images captured at the respective projection angles for all the pixels. Only the changed luminance is stored in the luminance memory 41.

Further, since the angle coding memory 42 is provided with the fourth selection circuit 45 connected to the second comparison circuit 6, the same applies to all pixels for each light emission angle. Only the light projection angle when the highest luminance is detected through all the captured images is stored in the angle coding memory 42.

Then, the completed angle encoding memory 42
And the computer 100 measures the three-dimensional shape.

Here, the arithmetic processing method of the spatial code processing means 4 will be described with reference to simple examples shown in FIGS. Here, the number of pixels of the light receiving element 31 of the camera 3 is 3 ×
3 (horizontal direction × vertical direction). Also,
It is assumed that all recording areas of the luminance memory 41 and the angle coding memory 42 have been reset to 0 before the start of measurement.

Since the number of pixels in the horizontal direction is three, the image is taken at the rotation angles θ 0, θ 1, θ 2 of the galvanomirror 23 corresponding to which the slit light R is imaged in each pixel unit. .

First, the processing when the light projection angle θ = θ0 will be described with reference to FIG. First, an image captured by the light receiving element 31 of the slit light R when the projection angle θ = θ0 is shown in FIG.
It is shown in (A). In the light receiving element 31, the horizontal direction indicates a horizontal address x (numbers assigned to pixels in order from the left in the figure), and the vertical direction indicates a vertical address y (numbers assigned to horizontal scanning lines in order from the top in the figure). I do. Also,
FIG. 13B shows the luminance memory 41 before update recording.

In the output period of the horizontal scanning line of the vertical address y = 1 of the light receiving element 31, the detected luminance of each pixel is sequentially output, and the peak detector 5 specifies the maximum luminance as 200 by the end of the output period. At the same time, the horizontal address x is specified as x = 1. Then, when shifting to the flyback period, the specified maximum luminance is compared with the recording luminance of the luminance memory 41, and thereafter, the maximum luminance is updated as the recording luminance (FIG. 13C). Simultaneously with the updating of the luminance memory 41, the contents of the recording area of the horizontal address x = 1 and the vertical address y = 1 in the angle encoding memory 42 are
The projection angle θ0 at that time is updated (FIG. 13
(D)).

The same processing is performed by setting the vertical addresses y = 2 and y =
3 (E) and (F) show the updating of the luminance memory 41 and the angle coding memory 42 when y = 2, and FIGS. 3 (G) and 3 (H) show the case where y = 3. The update of the luminance memory 41 and the angle encoding memory 42 at the time is shown.)

Next, the processing when the light projection angle θ = θ1 will be described with reference to FIG. First, an image captured by the light receiving element 31 of the slit light R when the light projection angle θ = θ1 is shown in FIG.
It is shown in (A). Based on this, the subsequent processing updates the luminance memory 41 for y = 1 (FIG. 14B) and updates the angle coded memory 42 in the same manner as when θ = θ0 (FIG. 14C). )).

Further, the same processing is performed with the vertical address y =
2 and y = 3 ((D) and (E) in FIG. 4 show the luminance memory 41 and the angle coded memory 4 when y = 2).
2 (F) and (G) show the updating of the luminance memory 41 and the angle coding memory 42 when y = 3).

Finally, the processing when the light projection angle θ = θ2 will be described with reference to FIG. First, an image captured by the light receiving element 31 of the slit light R when the light projection angle θ = θ2 is shown in FIG.
It is shown in (A). Based on this, the subsequent processing updates the luminance memory 41 for y = 1 (FIG. 15B) and updates the angle coding memory 42 in the same manner as when θ = θ0 (FIG. 15C). )).

When the vertical address y = 2, the slit light is not irradiated on the light receiving element 31, so that light other than the slit light (for example, other parts of the object to be measured is irradiated on the horizontal scanning line). Noise, such as reflected light of the slit light, is specified as the maximum luminance. However, since it is almost impossible that the luminance exceeds the luminance already recorded on the luminance memory 41, the detected luminance is updated on the luminance memory 41. Never.

Further, for the vertical address y = 3,
The maximum brightness and horizontal address x are specified, whereby
Recording luminance and angle coding memory 4 on luminance memory 41
2 is updated. (FIG. 15D,
(E)).

As a result, the processing of the captured images at all the projection angles is completed, and the angle encoding memory 42 is completed. All the data in the angle encoding memory 42 is output to the computer 100.

Further, a computer (arithmetic device) 100
In the angle code data (spatial coded image) stored in the angle coded memory, an unmeasurable point is extracted,
Further, a complement value is calculated. After that, the distance in the object coordinate system is calculated from the complemented angle code (space code) and the pixel position stored in the angle coding memory 42.

FIGS. 16 and 17 are flowcharts showing an example of processing up to calculation of an angle code.

First, the camera 3 and the irradiating means 2 are synchronized by the synchronization circuit 43 and the memory address creation circuit 46, and irradiation and imaging of the slit light R on the measuring object S are performed (step S1). With this synchronization, the slit light is imaged on the light receiving element 31 while changing its position for each pixel in the horizontal scanning line direction.

First, in accordance with the captured image at the light projection angle 1, the luminance is output from the horizontal scanning line of the scanning line number 1 in the order in which the pixels on the scanning line are arranged. The output period for all the pixels on one horizontal scanning line at this time is the output period for the horizontal scanning line (step S2).

The peak detecting section 5 based on the captured image
, The maximum luminance is detected for each horizontal scanning line, and at the same time, the horizontal address of the pixel outputting the maximum luminance is detected based on the detection (step S3). The maximum luminance detected at this time is stored in the temporary luminance memory 51, and the horizontal address x is stored in the temporary position memory 81.

The above detections are continued until the end of the output period of one horizontal scanning line, and finally, the maximum luminance and horizontal address of the horizontal scanning line are obtained based on the outputs of all the pixels. And recorded (step S
4).

When the transition from the output period to the flyback period is completed, the gates 91 and 92 of the temporary luminance memory 51 and the temporary position memory 81 are closed (step S5).

When the gate 91 is closed, the maximum luminance in the horizontal scanning line of the scanning line number 1 is output from the temporary luminance memory 51 to the second comparison circuit 6. The second comparison circuit 6 compares the detected maximum luminance with the luminance recorded at the address (x, y) = (x0, 1) in the luminance memory 41 (steps S6 and S7). If the detected maximum luminance is higher, the recording luminance of the address (x0, 1) of the luminance memory 41 is updated by the third selection circuit 7 to the detected maximum luminance value (step S8). .

Note that the luminance memory 41 at this time is initialized in advance before the start of measurement and has a recording luminance of 0, and therefore, if the luminance level of the slit light R is attained, normal updating is performed. Further, when the light projection angle has advanced to 2 or later, the maximum luminance may have already been updated for the same address by the detection based on the captured image up to that point. If the luminance is high, it is updated.

When the brightness memory 41 is updated, the address (x, y) of the angle coding memory 42 is (x0,
Also in 1), the projection angle 1 at that time is recorded (step S9).

On the other hand, if the detected maximum luminance level is lower, the luminance memory 41 is not updated, and at the same time, the angle coded memory 42 is not recorded (step S10).

Then, for one slit light R, the above steps are repeatedly performed for all the horizontal scanning lines (step S11). Thereby, the position (horizontal address x) of each slit light at the light projection angle 1 in the horizontal scanning line direction is recorded on the angle encoding memory 42.

When the processing is completed for one slit light, an image of the slit light at the next projection angle is picked up, and the above steps are repeated (step S12). Then, when the processing of the slit light at all the projection angles is completed, the information recorded in the angle encoding memory 42 is output to the computer 100 as the measurement data (step S13). The computer 100 performs the complementing process and the three-dimensional shape calculation based on the output from the angle coding memory 42 and displays the result (step S14).

In the present embodiment, if the set luminance level of the recording luminance is not high enough to prevent the recording of the detected luminance of the slit light, it is assumed that there is a portion where the slit light is not irradiated, or that the slit light is not irradiated. It is possible to prevent noise from being selected and taken in when only dark illumination is performed. This is because the noise is considerably lower than the luminance of the slit light, and if the luminance of about half of the slit light is input to the luminance memory 41 in advance as in the above example, the luminance of the noise less than this is lower than the luminance of the slit light. This is because there is no update record.

<Complement> Next, complement processing will be described. In the present embodiment, the initial value of the coded image before measurement (for example, 0)
Is determined as an unmeasurable point. That is, the space code recording memory inside the measuring device is initialized with a constant value before measurement. After the measurement is completed, the pixel in which the initial value is recorded is processed as an unmeasurable point (pixel). As shown in FIG. 18A, when the initial value of the angle code is set to 0, the measured angle code 42c is not stored in the angle-coded memory 42 after the measurement when there is an unmeasurable point. Initial value 4
It remains at 2d. Therefore, in order to search for an unmeasurable point, the initial value 42d may be searched.

A flag indicating whether or not each pixel of the angle encoding memory has been accessed may be provided. That is, a 1-bit memory access flag may be provided, and determination may be made based on the flag. Increase the space code recording memory by 1 bit. For example, if the light projection angle code is from 0 to 255, 8 + 1 = 9 bits. Before measurement, the flag bit is set to 1 (or 0).
Memory address (pixel position) accessed during measurement
Is set to 0 (or 1). By examining the flag after measurement, it is possible to detect a measurement impossible point (pixel). In the example shown in FIG. 18B, assuming that the initial value of the flag is 1, only the unmeasurable point 42e is set to 1 after measurement, and the flag of the pixel storing the angle code is set to 0. As a result, an unmeasurable point is extracted.

FIG. 20 is an explanatory diagram for explaining an example of the reason why an unmeasurable point has occurred. As shown in FIG.
In a solid-state imaging device such as D, since the CCD 32 for vertical transfer is provided between the light receiving elements 31, there is a boundary region between pixels. If the slit light R enters this boundary region at a certain projection angle, the slit positions at the projection angle are R1 and R2 in the figure, and the projection angle is set at the pixel position indicated by the reference numeral 42d in the figure. It is not recorded and cannot be measured.

As shown in FIG. 21, when the object to be measured is illuminated with slit light at different light projection angles, the positions of the slit light in the image may be R3, R4, and R5. Also in this case, the light projection angle is not recorded at the pixel position indicated by the reference numeral 42d in the figure, and it becomes an unmeasurable point.

[0129] Further, a blind spot where illumination is not applied is also an unmeasurable point. However, in this case, it is possible to supplement the data in the blind spot area by joining the results of measurements from different angles. That is, since a blind spot area generally exists in a wide range in an image, in the present proposal complemented by the median value, there is no influence on the blind spot area if there is no data in a neighboring pixel. For example, if the value of the neighboring pixel is 0, the complemented data is also 0.

FIG. 22 shows the spatial code values of a part (6 × 6 area) of the measured spatially coded image. In this example, an unmeasurable point is detected with a code value of 0. In FIG.
Unmeasurable points are indicated by reference numerals 42d and 42e. From the neighboring codes, the pixel denoted by reference numeral 42f is 123, and the reference numeral 42g
The pixel indicated by is estimated to be 122. When this pixel is subjected to a smoothing process using a median value other than 0 of the data in the vicinity of the four surroundings, the result of FIG. 23 is obtained.

When comparing FIG. 22 with FIG. 23, correct measurement data is not affected and the pixel indicated by reference numeral 42f has 12 pixels.
3. The number of pixels indicated by reference numeral 42g is 122, and smoothing is performed as expected. In this example, the data at the points A and B are complemented by using the median of the codes near the four points near the unmeasurable point. Instead of the median value, the average value of the neighboring codes excluding the unmeasurable point may be used.

FIG. 24 is a flowchart showing an example of the complementing process during the calculation process of the three-dimensional shape indicated by reference numeral 14 in FIG. Here, the number of pixels is 256 × 256 (x × y),
Let the spatially coded image be Code (x, y). FIG.
, The values of x and y are initialized to 0 (step C1). Subsequently, an unmeasurable point is detected (step C2). If the point cannot be measured (step C3), a median value is calculated (step C4). If x is not equal to 255, the value of x is counted up (step C).
6) Return to step C2. When the horizontal scanning is completed, the value of y is counted up next (step C7,
8) Continue the complementing process. This is repeated until completion in the vertical scanning direction.

FIG. 25 is an explanatory diagram showing an example of the complementing process. As shown in FIG. 25, if the complementing process is not performed, a three-dimensional shape having many holes will be formed. However, if the complementing process is performed, distance image data having a continuous surface can be obtained.

As described above, according to the present embodiment, a pixel that cannot be measured is detected, and the filtering process is performed only on the pixel. Therefore, the complementing process can be performed without changing the correct measurement data. In the distance image generated after the interpolation, polygon generation can also be performed by connecting adjacent pixels in sequence, thereby facilitating polygon generation. In addition, since jump edge detection and the like can be performed by differentiating neighboring pixels, feature extraction processing such as a step of a measurement target can be simplified.

[0135]

Since the present invention is constructed and functions as described above, according to this, in the unmeasurable point extracting step, the light receiving elements which did not receive the measurement light among the light receiving elements on the light receiving plane are extracted. Then, in the complementing step, the normally calculated space code is changed in order to calculate a complementary value based on the value of the space code in the light receiving element near the unmeasurable point for the space code of the unmeasurable point. Without, a complementary value can be stored in the measurement impossible point of the spatially coded image corresponding to the light receiving element that could not receive light for various reasons, and further, in the complementing step, based on the value near the measurement impossible point. Since the interpolation value is calculated, an accurate interpolation value can be calculated based on the continuity of the spatial code. Therefore, even if a discontinuity occurs in the spatial code, the spatial code is calculated in the interpolation process. Be continuous Then, it is possible to effectively prevent a state in which a hole for one pixel is formed on the surface of the measurement object, and therefore, for example, polygon generation is also performed by sequentially connecting adjacent pixels. And therefore,
Polygon generation based on range images becomes easier,
To provide an unprecedented superior three-dimensional shape measurement method capable of simplifying feature extraction processing such as a step of a measurement object and thus generating easily-handled distance image data. Can be.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a space code shown in FIG. 1, a position of a light receiving element, and a distance to an object to be measured.

3A and 3B are explanatory diagrams showing an example of a space-coded image having an unmeasurable point; FIG. 3A is a diagram showing a space code in shades; FIG. 3B is a diagram in FIG. It is a figure which shows the example of the space code cut | disconnected by the arrow of FIG.

4A and 4B are explanatory diagrams illustrating an example of a space-coded image after a complementation process. FIG. 4A is a diagram illustrating a space code by shading, and FIG. 4B is a diagram in FIG. It is a figure showing the example of the space code cut by the arrow.

5A and 5B are explanatory diagrams showing an example in which neighboring pixels are referred to in the complementing process shown in FIG. 1; FIG. 5A is a diagram showing an example of eight neighboring pixels, and FIG. It is a figure showing an example.

FIG. 6 is a block diagram showing a configuration of a three-dimensional shape measuring apparatus according to the present invention.

7 is a perspective view showing an example of a calibration device for calibrating the three-dimensional measurement device shown in FIG.

8 is a diagram showing the calibration two-dimensional gauge disclosed in FIG. 7, wherein FIG. 8 (A) is a front view and FIG. 8 (B) is a side view.

FIG. 9 is a flowchart illustrating an example of a calibration process performed by the device illustrated in FIG. 7;

FIG. 10 is a block diagram showing a configuration of a three-dimensional measuring apparatus using a light section method.

FIG. 11 is a block diagram showing an example of a spatial code processing means shown in FIG.

FIG. 12 (A) is a CCD imaging slit light.
FIG. 12B is an explanatory diagram illustrating an image sensor, and FIG. 12B is an explanatory diagram illustrating outputs of pixels forming a horizontal scanning line of a scanning line number 1 in an arrangement order.

FIG. 13 is an explanatory diagram showing a simplified configuration for explaining the operation of the space code processing means. FIG. 13 (A) shows a CCD image sensor for capturing the first slit light, and FIG.
FIG. 3B shows an initialized luminance memory, and FIG.
FIG. 13C shows a luminance memory in which the luminance of the first scanning line obtained by imaging the slit light in FIG. 13A is recorded, and FIG. 13D is based on the luminance memory in FIG. 4 shows a recorded angle coded memory. FIGS. 13 (E) to 13 (H) show a state in which a luminance memory and an angle coded memory are recorded for each scanning line in the same manner.

FIG. 14 is a continuation explanatory view of FIG. 13 showing a simplified configuration for explaining the operation of the calculating means, and FIG. 14 (A) shows a CCD image sensor for capturing the second slit light;
FIG. 14B shows a luminance memory in which the luminance of the first scanning line obtained by imaging the slit light in FIG. 14A is recorded, and FIG. 14C shows the luminance memory in FIG. 14B. 3 shows an angle coded memory recorded on the basis of this. FIGS. 14D to 14G show a state in which a luminance memory and an angle coded memory are similarly recorded for each scanning line.

FIG. 15 is a continuation explanatory view of FIG. 5 showing a simplified configuration for explaining the operation of the calculation means, and FIG. 15 (A) shows a CCD image sensor that has captured a third slit light; 15B shows a luminance memory in which the luminance of the first scanning line obtained by imaging the slit light in FIG. 15A is recorded, and FIG. 15C is based on the luminance memory shown in FIG. Fig. 7 shows an angle coded memory recorded in the memory. And FIG.
5 (D) shows a luminance memory recording the luminance of the third scanning line, and FIG. 15 (E) shows an angle coded memory recorded based on the luminance memory of FIG. 15 (D).

FIG. 16 is a first part of a flowchart illustrating an example of a space code generation process based on the light section method with the configuration illustrated in FIG. 10;

FIG. 17 is a second half of a flowchart showing an example of processing for generating a space code based on the light section method with the configuration shown in FIG. 10;

FIG. 18 is an explanatory diagram showing an example of an unmeasurable point extraction process. FIG. 18A is a diagram showing an initial value of a code.
FIG. 8B is a diagram illustrating an example of a code after measurement.

19 is an explanatory diagram showing another example of the unmeasurable point extraction process. FIG. 19A shows an initial value of a code, and FIG. 19B shows an example of a code after measurement. FIG.

FIG. 20 is an explanatory diagram for explaining the reason why an unmeasurable point occurs.

FIG. 21 is an explanatory diagram for explaining another reason why an unmeasurable point occurs.

FIG. 22 is an explanatory diagram illustrating an example of a space-coded image having a measurement impossible point.

FIG. 23 is an explanatory diagram showing an example in which the space code image shown in FIG. 22 is complemented.

FIG. 24 is a flowchart illustrating an example of a complementing process.

FIG. 25 is an explanatory diagram showing the result of the complementing process;
FIG. 25A is a diagram illustrating an example of distance image data calculated from the spatially coded image before the complementing process, and FIG. 25B is an explanatory diagram illustrating an example of a distance image calculated from the spatially coded image after the complementing process. It is.

[Explanation of symbols]

 2 Irradiation mechanism 3 Camera 4 Calculation means 31 Light receiving element 41 Luminance memory 42 Angle coding memory R Slit light S Object to be measured

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Nakajima 2-1, Sakuranamiki, Tsuzuki-ku, Yokohama-shi, Kanagawa Prefecture S-Suzuki Co., Ltd. Technical Research Institute F-term (reference) 2F065 AA04 AA53 FF01 FF04 GG04 HH05 HH12 JJ03 JJ26 LL13 QQ31 UU05

Claims (5)

[Claims] An irradiation step of irradiating measurement light corresponding to a space code for dividing a space including a measurement object, and forming a predetermined angle with respect to an irradiation angle of the measurement light irradiated in the irradiation step. A light receiving step of receiving the measurement light with each light receiving element two-dimensionally arranged on the light receiving plane, and a space code for each position corresponding to each light receiving element based on the order of the measurement light received in the light receiving step. The space code processing step to be calculated, and the distance from the origin in the coordinate system predetermined on the basis of the space code and the position of the light receiving element calculated in the space code processing step to the surface of the measurement object. A three-dimensional shape measuring method comprising: a distance calculating step of calculating for each light receiving element; wherein the spatial code processing step extracts light receiving elements not receiving the measurement light among light receiving elements on the light receiving plane. A non-measurable point extracting step, and a complementing step of calculating a complementary value based on a value of a spatial code at a light receiving element near the non-measurable point with respect to the spatial code of the non-measurable point extracted in the non-measurable point extracting step. A three-dimensional shape measuring method comprising: 2. The spatial code processing step includes a light receiving flag setting step of setting a light receiving flag indicating whether or not the measurement light has been received for each of the light receiving elements. 2. The three-dimensional shape measuring method according to claim 1, further comprising a light receiving flag reference step of searching for an unmeasurable point by referring to the flag. 3. The method according to claim 1, wherein the complementing step includes a step of specifying a complement value of the unmeasurable point based on a space code other than an initial value among the neighboring values of the unmeasurable point. The three-dimensional shape measurement method described. 4. An irradiating means for irradiating measurement light corresponding to a space code for dividing a space including a measurement object, and forming a predetermined angle with respect to an irradiation angle of the measuring light radiated by the irradiating means. A light receiving means having light receiving elements arranged two-dimensionally on a light receiving plane, and a space for calculating a space code for each position corresponding to each light receiving element based on the order of measurement light received by each light receiving element of the light receiving means. A space code storage unit for storing a space code calculated by the space code processing unit at a pixel position corresponding to each of the light receiving elements; and a pixel position of the space code storage unit and the corresponding pixel. A distance calculating means for calculating, for each of the light receiving elements, a distance from an origin in a predetermined coordinate system based on a space code stored in the light receiving element. In the three-dimensional shape measuring apparatus, the spatial code processing means extracts a pixel in which the spatial code is not stored, a measurement impossible point extraction unit, and a measurement impossible point extracted by the measurement impossible point extraction unit. A complementary value calculation unit for calculating a complementary value based on a space code stored in a pixel near the unmeasurable point with respect to the space code. 5. An irradiation device for irradiating measurement light corresponding to a space code for dividing a space including an object to be measured, and irradiating the measurement light irradiated by the irradiation device with respect to an irradiation angle of the measurement light. A light-receiving device that receives light at each light-receiving element two-dimensionally arranged on a light-receiving plane that forms a predetermined angle, and a position corresponding to each light-receiving element based on the order of measurement light received by the light-receiving device. A space code processing device that calculates a space code, and a distance from an origin in a predetermined coordinate system based on a space-coded image generated by the space code processing device to a surface of the measurement target is defined by each light receiving element. A storage medium storing a three-dimensional shape measurement program for measuring the shape of the measurement object using a three-dimensional shape measurement device including a calculation device that calculates the three-dimensional shape, The state measurement program includes, as commands for operating the arithmetic device, a measurement impossible point extraction command for extracting a pixel in which the space coded image is not stored among the pixels of the space coded image, and a measurement impossible point extraction command for A complement command for calculating a complement value based on the value of the spatial code at the light receiving element near the unmeasurable point for the spatial code of the pixel extracted according to the three-dimensional shape measuring program. Storage medium that stores.