JPS6393076A - Form measuring instrument - Google Patents

Abstract

PURPOSE:To obtain an external form in a short time and with high accuracy by obtaining element points adjacent to the intersecting point of equi-luminance lines for lightness of a surface element of an object to be measured from a reflectance map of a reference object and then obtaining the gradient of the lightness surface element through interpolation arithmetic. CONSTITUTION:Light sources 4A, 4B and 4C are successively turned on to obtain the reflectance maps RM1-RM3 showing the lightness corresponding to the gradient of the surface element of a reference object via one TV camera 5. Then the lightness of the surface element of an object 3 to be measured is obtained in response to those maps RM1-RM3 and based on sampling data on the object 3B obtained by means of light sources 4A-4C and via the camera 5. Then the element points adjacent to the intersecting point of the equi- luminance lines having lightness equal to that of the surface element of the object 3B are obtained from the elements of maps RM1-RM3. Then interpolation arithmetic is carried out at said element points to obtain the gradient of the surface element of the object 3B. Thus the external form data is obtained. In such a way, the form of the object 3B is measured in a short time and with high accuracy.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A: Industrial field of application B: Outline of the invention C: Conventional technology: Problems to be solved by the invention E: Means for solving the problem (Figs. 1 and 23) F: Effects (Figs. 1 and 23) Figure) Example G (Figures 1 to 6) (Gl) Configuration of Example (Figure 1) (G2) Creation of reflectance map (Figures 1 to 6) (G3) Object to be measured 3B The slope of the surface element (Figs. 1 and 2)
Figures 7 to 9) (G4) Search for reflectance maps (Figures F and 2)
(Figs. 10 to 23) (G5) Reconstruction of curved surfaces (Figs. 1 and 2, Figs. 24 and 25) (G6) Other embodiments H Effects of the invention A Industrial application FIELD OF THE INVENTION The present invention relates to a shape measuring device, and is particularly suitable for obtaining external shape information of a three-dimensional object.

B Invention 1 Existing Invention The present invention provides a shape measuring device that measures the outer shape of an object to be measured based on a reference object using one television camera. After finding the point of the element adjacent to the intersection of the isobrightness lines of the brightness of a given surface element of The inclination of the surface elements of the object to be measured can be determined in time, and the external shape of the object to be measured can thus be easily and accurately measured within a short period of time.

C. Prior Art Conventionally, as this type of shape measuring device, a so-called contact type device has been used in which a probe is applied to the surface of an object to be measured and the surface is traced.

However, the first problem with contact-type shape measuring devices is that it takes a considerable amount of time to capture data.

Secondly, when measuring the shape of particularly large objects such as airplanes and ships, or when measuring particularly minute objects such as inspecting microfabricated objects, it is difficult to There is a problem where it cannot be applied.

Third, if the object to be measured is a soft object, the surface may be bent or depressed when the probe comes into contact with it, making it impossible to measure the correct external shape.

To solve this problem, conventional methods for measuring the external shape of an object using a non-contact method include binocular stereoscopic measurement, measurement using a distance sensor using light, and monocular measurement. It is being

D Problems to be Solved by the Invention However, conventionally, it has been difficult to realize a non-contact type shape measuring device that can measure the shape of an object with sufficient precision for practical use.

The present invention has been made with the above points in mind, and is one of the monocular visual measurement methods, the photometric stereo method (Ph
This paper attempts to propose a shape measuring device that can reliably measure the external shape of an object to be measured using the otometric 5-tereo method.

E Means for Solving Problem E To solve this problem, in the present invention, a plurality of light sources 4A, 4B, and 4C are sequentially turned on to obtain a reference object through one television camera 5. Based on the sampling data DATA of 3A, the surface element S of the reference object 3A is
Brightness R+(Tar, q,) corresponding to the slope of S,
Obtain multiple reflection maps RMI, RM2, RM3 representing RZ(p, , q,), R3(p, , q3), and use the same lights m4A, 4B, 4C as the reference object 3A to create a television camera. Object to be measured 3 obtained through 5
Based on the sampling data DATA of B, the brightness It, Iz, ■3 of the surface element SS of the object to be measured 3B corresponding to the reflection maps RMI, RM2, RM3 are determined, and the reflectance maps RMI, RM2, RM3 are constructed. Among the elements, isoluminance kg whose brightness is equal to the brightness It, It, Is of a predetermined surface element SS of the object to be measured 3B
LR+(p, q), LRz(plq), LRz(
1) Point P of the element adjacent to the intersection P of Sq) (161
+11, P (+a+I+n), P (111?1
-11, P (*+1+,, -11 is calculated, and the point P (+++++ nl , P (s*I+ nl
, P (no□11, P (s*l+n-H), the surface element SS of the object to be measured 3B is
p, q), and the external shape data FOM of the object to be measured 3B is determined based on the slope (1), q) of the surface element SS.

F effect If the slope (p, q) of the surface element SS detected from the sampling data DATA obtained by imaging with one television camera 5 is integrated, the external shape data FOM representing the external shape of the object to be measured 3B is obtained. can get.

When calculating the slope (p, q) of the surface element SS, the isobrightness line t,
Rt(p, q), LRz(p, q), LR3(p,
Point P (a+ R1) of the element adjacent to the intersection P of q)
, P (#,, +y+l , P (+c+n-1),
Find P (a*I+n-1) and find the element point P (s+
+ Fil, P (@.L+111, P (Ill
++%-1, P (*By calculating the slope (p, q) of the surface element SS using interpolation in +l+n-11, the slope (p, q) of the surface element SS can be calculated with high accuracy in a short calculation time.
) can be obtained.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) Configuration of Example In FIG. 1, 1 indicates a shape measuring device, and table 2
The observation object 3 placed thereon is illuminated by a plurality of light sources, for example, three light sources 4A, 4B, and 4C arranged at different positions.

The light sources 4A, 4B, and 4C are sequentially turned on one by one, so that they can irradiate the observation object 3 with illumination light from different directions, and thus illuminate the outer surface of the observation object 3 according to its external shape. It is designed to produce different shades depending on the color.

The observation object 3 is imaged by one television camera 5, and the rusk video signal VD thereof is converted into digital data in an analog/digital conversion circuit 6 and then written into a frame memory 7.

With the above configuration, the shape information generating section 8 writes the shape information of the outer surface of the observation object 3 into the frame memory 7 as image data representing a two-dimensional brightness distribution (i.e., brightness distribution). It is formed.

The shape measuring device 1 has an image data processing device 11 made up of, for example, a personal computer, an engineering workstation, a large computer, etc.
The ATA can be input into the image data processing device 11 as an output of the shape information generating section 8.

The image data processing bag ff1l has a three-dimensional data generating section 118 and a curved surface generating section 11B, and by executing the processing steps shown in FIG.
1A creates three-dimensional data representing the inclination of the surface elements of the observation object 3 from the captured video data DATA, and at the same time generates a curved surface representing the surface shape of the observation object 3 based on the three-dimensional data in the curved surface generation section 11B. .

The three-dimensional data thus created in the three-dimensional data creation section 11A and the curved surface data created in the curved surface creation section 11B are stored via the bus 12 in an external memory 13 made of, for example, a disk storage device.

The image data processing device 11 can also read data stored in the external memory 13 via the bus 12 and display it on the graphic display 14 .

Furthermore, the image data processing device 11 reads data accumulated in the external memory 13 via the bus 12 and supplies it as machining information to the NC machine tool 15.
By driving the tools of the C machine tool 15, a product having the same external shape as the observation object 3 can be cut out.

Furthermore, in the case of the embodiment shown in FIG. 1, the image data processing device 11
transfers data stored in external memory 13 to bus 12
The robot body 1 of the robot device 15 is read out via the
By supplying the data to the robot body 16, the movement of the robot body 16 can be controlled using the data as the eyes of the robot.

(G2) Creation of reflectance map The three-dimensional data creation unit 11A of the image data processing device 11 creates a reflectance map (reflectance map) RM for the reference object 3A whose external shape is known in step SPI of FIG. At the same time, in step SP2, the object to be measured 3B is observed to obtain image data, and in step SP3, the image data of the object to be measured 3B,
The slope of the surface element is calculated based on the slope data obtained from the reflectance map.

Thereafter, the curved surface generation unit 11B of the image data processing device 110 generates the object to be measured 3 based on the slope of the surface element obtained by the process of step SP3 in step SP4 of FIG.
A curved surface representing the external shape of B is reconstructed.

First, in step SPI of FIG. 2, the three-dimensional data creation section 11A creates a reflectance map RM according to the processing procedure shown in FIG. 3.

That is, a reference object 3 whose external shape is known as the observation object 3 on the table 2 in FIG.
Regarding A, a rusk video signal VD is obtained by the television camera 5 with the first light source 4A, second light source 4B, and third light source 4C turned on in sequence.

The content of the rask video signal VD obtained at this time represents a two-dimensional grayscale image PCR corresponding to the brightness of each point on the outer surface of the reference object 3A, depending on the illumination direction of the light sources 4A, 4B, and 4C. ing.

That is, when the television camera 5 is set at an upper position on the z-axis passing through the center of the reference object 3 having a hemispherical surface,
The grayscale image PCR includes surface elements SS on the reference object 3A for a circular shape similar to that seen in a plan view of the reference object 3A.
A two-dimensional grayscale image PCR is obtained by drawing an image representing the brightness of the image as a grayscale pattern on xy orthogonal coordinates. The brightness of each point (XY, yJ) on the xy coordinates of this grayscale image PCR is determined by the direction of the television camera 5 of the reference object 3A (
In other words, the inclination of the surface element SS as seen from the observation direction) and the light source 4
The brightness is determined by the direction of the illumination light from A, 4B, or 4C.

The surface of the reference object 3A having a hemispherical external shape is xy
As the height in two directions at each point on the coordinates (xi% Yt') z = f (xl, yj)...
...It can be expressed by the equation f(Xt%'/j) representing the external shape of the reference object 3A as shown in (1).

Further, the normal vector n of the surface element SS at the point (xl, yj) on the xy coordinates of the reference object 3A can be expressed as follows (2).

Incidentally, in equation (2), a f / a x is the surface element SS (the center of which is the point (Xt, yJ)
) in the X direction, and af/ay represents the tilt in the X direction of the surface element SS. And the normal vector n is
By finding the cross product of vector a representing the inclination in the X direction as seen from point (xi, yj) on the xy plane and vector b representing the inclination in the X direction, it can be expressed as in equation (2). .

As shown in FIG. 5, the reflectance map RM is expressed by a pq orthogonal coordinate system in which the slopes a f /ax and af/ay of this surface element SS are variables.

That is, if the slope p in the X direction and the slope q in the X direction are respectively expressed as p, q) can represent the inclination of the surface element SS on the reference object 3A in all directions. The inclinations p and q correspond to the direction of the normal vector n at the point (X, yj) on the xy plane. Furthermore, since this normal vector n corresponds to the brightness of the surface element SS when viewed from the television camera 5, the position of the point (p, q) on the pq orthogonal coordinates representing the reflectance map RM is is a two-dimensional grayscale image P represented by the rask video signal VD.
It represents the brightness of the surface element SS that constitutes CR.

Therefore, on the pq orthogonal coordinates, connect points with equal brightness I,
If this is expressed as an isobrightness line expressed by a function R (p, q) with slopes p and q as shown in the following equation (5), the density image PCR (Fig. ) (therefore, the slope distribution of the surface elements SS on the surface of the reference object 3A) can be represented by the isobrightness lines of the reflectance map RM.

Here, the pattern of isoluminance lines appearing on the reflectance map RM corresponds to the brightness distribution of the surface element SS, but the brightness of the surface element SS is determined not only by its slope but also by the distribution of the surface elements constituting the surface element. The value also includes the influence of the reflection property rt (ie, the ratio of the diffuse reflection component to the specular reflection component). Therefore, in general, in order to obtain the slope of the surface element SS from the brightness of the surface element SS, it is necessary to know the reflection properties of the surface in advance and to correct this. In practice, such a configuration is extremely difficult. Have difficulty.

However, this problem can be solved by selecting a material whose surface reflection properties are the same as those of the measured object 3B as the reference object 3A, so that these elements can be included in the reflectance map RM. In practice, it is possible to obtain the correct inclination without being affected by the reflective properties of the surface, etc., without performing any correction processing on the surface. In this embodiment, an object that satisfies these conditions is selected as the reference object 3A.

In this way, the three-dimensional data creation unit 11A creates a reflectance map RM (RMI, RM2, RM3) formed by a large number of isobrightness lines expressed by equation (5).
6A, 6B, and 6C under the illumination conditions of the first, second, and third light sources 4A, 4B, and 4C. ), R+(p,,q)-1...(6)R
t(p-q)=1 ・・・・・・(
7) R3(p-q)=I...
・Reflectance map RMI, RM expressed by (8)
2. Take in the data of RM3 and store it in the external memory 13.

(G3) Inclination of surface elements of object to be measured 3B The three-dimensional data creation unit 11A performs step SP2 in FIG.
The object to be measured 3B is observed at.

At that time, the operator should move the table 2 as shown in FIG.
For example, a Darma-shaped object to be measured 3 is shown as an observation object 3 on the top.
B and the three light sources 4A described above with respect to FIG.
The object to be measured 3B is sequentially illuminated by the light sources 4A, 4B, and 4C without changing the illumination conditions by the light sources 4B and 4C.

The three gray scale images PCO (PCOl,P
Regarding CO2, PCO3), the three-dimensional data creation unit 11
A takes in brightness data representing the brightness at all points CXt, )'J) and stores it in the external memory 13.

Here, a grayscale image PCOL obtained by imaging the object to be measured 3B from above on two axes by the television camera 5,
PCO2 and PCO3 are shown in Figure 8 (A) and (B), respectively.
, (C), the different irradiation directions of the light sources 4A, 4B, and 4C result in images with different shadow positions. Video data DATA consisting of image data corresponding to this shadow is taken into the three-dimensional data creation section 11A.

In this way, the three-dimensional data creation section 11A creates the object to be measured 3B.
After completing the observation, proceed to step SP3 in FIG. 2, where the grayscale image PCO (PCOL, pc.

2, PCO3) on the xy coordinates of each point (xt , y, ) (
i-... i-1, i, i+l・old..., j=・
The brightness II, 1z on the grayscale images Pc01, PCO2, PCO3 at the specified point (X!, 'It) by sequentially specifying the old...j-1, Lj+1...)
sI, and find the isobrightness line I (-It 1 L, 13) having the same brightness as the brightness II, Iz, 11.
(Fig. 6) is stored in the external memory 3 as a reflectance map RM (RMI, RM2, RM
3) Extract from.

The brightness thus extracted! The isobrightness lines of +, It, and Is are expressed by the functions R+(pSq) and Rz(p,
q), R: + (p, q).

Therefore, the three-dimensional data creation unit 11A solves the simultaneous equations (9) to (11) to calculate the three isoluminance lines at 11%.
The intersection point (p, q) of z and Iy is obtained by superimposing the leftance maps RMI, RM2, and RM3.

(Then, based on the brightness I3, It, and Is of the point (x8, yj) on the xy coordinates when irradiated with the first, second, and third light sources, these three shooting conditions are simultaneously satisfied. Slope (
p, q) as a reflectance map RM (RMI, R
M2, RM3), it can be uniquely determined.

In this calculation process, first, the reflectance map RMl (Fig. 9(A)
)) By superimposing the isoluminance line I2 of the reflectance map RM2 obtained by irradiation with the second light source 4B, as shown in FIG. 9(B), on the isoluminance line II above. Two slope points lNC11 and INC+z that intersect with each other are determined. Next, Figure 9 (
As shown in C), one intersection I
Only N CII can be uniquely determined to be the slope SS of the surface element at the position of the point (Xl, yj).

In this way, the three-dimensional data creation unit 11A can uniquely determine the slope of the surface element SS at the point (Xl,)'j) on the xy coordinates, and in the same way, all points on the xy coordinates. By performing similar operations on
A two-dimensional gray scale image PCO (PCOI, PCO2
, PCO3), the slopes of all the surface elements SS forming the image of the observation object 3 can be obtained from the two-dimensional grayscale image.

In the case of this embodiment, since the television camera 5 is used to observe from an upper position on two axes, it becomes the background for the image of the observation object 3 in the grayscale image PCO (PCOI, PCO2, PCO3). In the part, a f / a x = af/ay = 0.

(G4) Search for reflectance map However, in reality, in the shape information 1 generation unit 8, the 10th
As shown in the figure, sampling positions separated by a predetermined interval in the X direction and the
Digital data is obtained by discretely sampling the brightness of the observation target at The reflectance map RM (RMI, RM2, RM3) created based on this is a discrete map in which elements with brightness data repeat at intervals of a predetermined slope (pr, qs), as shown in Figure 11. The information is stored in the external memory 13 in the form of a table.

Therefore, each reflectance map RM (RMI, RM2,
The isobrightness lines on RM3) are expressed in the form of a discrete equation expressed by the following equation (12).

Therefore, the grayscale image PCR (PCRl, P
A situation arises in which isoluminance lines with the same brightness as brightness f, , I2, and I3 obtained by sampling CR2, PCR3) do not necessarily connect the intersection points on the elements of the reflectance map RM, and the corresponding surface elements There are cases where the slope (p, q) cannot be determined directly from the reflectance map RM.

In the case of this example, the element point closest to the intersection of the isobrightness lines is found on the reflectance map RM, and the slope of the intersection is determined by performing interpolation calculations in the area of the element points surrounding the element point. do it like this.

Therefore, the three-dimensional data creation unit 11A executes the processing procedure shown in FIG. 12 to find the point of the element closest to the intersection.

That is, the three-dimensional data creation unit 11A performs step 5PI
Entering the processing procedure from I, in step 5P12, the reflectance map RMI is scanned as shown in FIG. Find the starting point of.

In this search for the starting point, it is determined whether or not the following formula (%) is satisfied at each element point of the reflectance map RM1.

Further, when a positive result is obtained in equation (18), it is determined whether the following equation (%) is satisfied.

Here, as shown in FIG. 14, the four element points P la
+r+1 % P (M++++Il % P (@4
11R1% P (In the cell S L +11.Fil surrounded by 111+1+FllI+, the point P (II
An isobrightness line L is drawn between I Ill and P ls+a+I+
When RI(1), q) passes, point P (11+
1%) is brighter than point P(lR+ n * I l
If it is brighter, the following formula % (20) is obtained, and a result that satisfies the formula (15) is obtained. On the contrary, the brightness of point P (s+nl is higher than that of point P(s+n
+ H), the result of the following formula % formula % (22) is obtained, and a result satisfying the formula (15) is obtained.

On the other hand, the isoluminance line LRI(p, q) is the point P f+
When passing over I+ IIl, point P (s+ nl
The brightness of R, (p, q) becomes equal to the brightness of the isoluminant line, and a result that satisfies equation (17) is obtained.

Furthermore, when the isoluminant line LR+(p, q) passes between the point P (soR) and the point P(@"I+ al, the point P
(1m++slO is brighter than point P (m*l+lI+), the following formula (24) is obtained, and an affirmative result is obtained in (16) 2.

On the other hand, the point P +s+? 1) is better at point P (*+
1++s), the following equation %(26) is obtained, and an affirmative result is obtained in equation (16).

Further, as shown in FIG. 15, equiluminance) JI L R,
If (p, q) passes over the point P fll+I+llll, then the point p,. The brightness of l+I%+ and the isobrightness line LR+
The brightness R + (p, q) of (p, q) is equal and (18
) satisfies the relationship of Eq.

At this time, the isobrightness line L passing through the point P (a*1++sl
RI (p, q) is the point P (export-・grave) and P(-・
When passing between I+++・l), the following formula % formula % (28) is obtained, or the following formula R11,□1)-11<0...
(30) RI (IllIll ml) -11>O
...The relationship (31) is obtained, and the result is (19
) can be obtained.

On the other hand, the isoluminant line LR+(p, q) is the point P(,,
When passing over s+l+a+Il, the following relationship is obtained, and a result that satisfies equation (19) is obtained.

From the above results, the three-dimensional data creation unit 11A detects a point P (11+ a) that satisfies the relationships of equations (15) to (19) with respect to the isobrightness line LR+(p, q), and is the starting point P (s., fi.) of the isoluminant line LR1 (p, q).

, the process moves to the next step 5P13, and the position of the remaining end of the isobrightness line LR1 (p, q) passing through the cell is searched.

For example, in step 5PII, if a result that satisfies equation (15) is obtained, as shown in FIG. In practice, if the spacing between each element is kept as small as practical, then on the point P.,l,1,
Points P (**+1+*) and P (fi+l+lI+l
l 0, on point P (m+1++s.1) and point P(,.

In ll”+1 and P.+R011.

On the other hand, as shown in FIG. 17, for example, (17)
The isoluminant line LRI(p-q) that passed over the point P (11+Ill) satisfies the formula is the point P (+a.1
．． , and between the point P (#(il+1%.1), the point
It passes between P (s+1+, 1+ll and the point P1°11.) and P (Ill +a+1).

Therefore, each point P (lI+11>, P (#*1+*)
,P (a+*,,1 and P (@*l+ II.,
), the isoluminance line LR+(p, q) is determined by the cell S L +III
You can check which direction you are heading.

In this way, when the remaining end of the isoluminance line t, R+(plq) is obtained, the three-dimensional data creation unit 11A moves to the next step 5P14 and calculates the next end along the isoluminance line LR+(p, q). Performs point detection of cell elements.

That is, as shown in FIG.
), calculate the starting point P(,.,7°,) by calculating equations (5) to (19), and then calculate the isoluminance line LRt(p
.
1 Move to + and change point P (a++s+I) to point of interest P (
6111+1) is stored in the memory provided in the three-dimensional data creation unit 11A. Subsequently, the three-dimensional data creation unit 11A moves to step 5P15 and stores the cell S L (
-, -, ) is the outermost periphery of the reflectance map RMI. If a negative result is obtained here, the process moves to step 5P16 and the current EK cell SL +lj+ II
li l l is the starting point P0°,... , it is determined whether the cell is a cell or not.

If a negative result is obtained here, return to step 5P13,
Again, as described above with respect to FIGS. 16 and 17, the points P (#+ a*1) and P I+a+++*+I+
Find out in which direction the isoluminant line LR, (p, q) that entered the cell S L (-, -1,) from between the points P (M+l+ n.1. and P. *+
It is determined that the point passed through *n*21 and exited, and the process moves to the next step 5P14, where the point P (**I+ fi+11 is stored in the memory as the point of interest P (16,1+□1.).

Thus, the three-dimensional data creation unit 11A performs step 5P.
By repeating the loop of 13-3P14-3P15-3P13, equal brightness 8. 'Cell through which ILR1 (p, q) passes'' S L (m+, 11, S L
(a+ Il”l), S L (s, l+ ++*1
+, S L 1mal asri... Points on the start side between raster scans P (11+ a), P (
al n. 3. ,P(s+l+w++Il,P(
a*l*+tl . . . is stored in the memory as a point of interest.

If a negative result is obtained in step 5P15 (this means that the isoluminance line LR+(p,
q) has reached the outermost cell of the reflectance map RMI), the three-dimensional data creation unit 11A moves to step 5PI7 and calculates the equal brightness St'XLR+(p-
q) ends in this direction and returns to the starting point P1°, 1°.

Next, the three-dimensional data creation unit 11A moves to step 5P18 and moves in the opposite direction to the direction tracked up to that point (in this case, from cell S L (III n) to cell S L t,ra
-r > direction)), it is determined whether or not the isobrightness line LR+(p, q) has been traced.

If a negative result is obtained here, the three-dimensional data creation section 11
A returns to step 5P13 and steps 5P13-3P
14-3P15-3P16-3P13 loop is repeated again and cells S L tam, R1 to S L +l
Isobrightness line LR+(1), q in the direction of l++ 1%-1)
).

When the remaining end of the isoluminance line LR+(1), Q) reaches the outermost cell of the reflectance map RMI, a negative result is obtained in step 5P15, and step 5P
17 and start point P (m., 3°.

Return to

Next, the three-dimensional data creation unit 11A moves to step 5P18 and moves to the opposite direction (in this case, cell SL (@+1
1>, it is determined whether or not the isoluminance line LR+(p, q) has been traced (in the direction of an a (11)). Finish the process.

On the other hand, for example, as shown in FIG.
Tracing ALR+(p, q) returns to the original starting point P
(+++., 7°, isoluminant line LR+(p,
In the case of q), when returning to the starting point P(,.,fi.), an affirmative result is obtained in step 5P16, and the process moves to step 5P19 to end the process.

Next, the three-dimensional data creation unit 11A selects each point of interest...
Find the cell...S L (III R)... in which P (m+ fil...) is located, and calculate each cell...S L (al Fl )...
Four points surrounding ``...P (IIIRI
, P (s++q++1 , P (s*1++sl ,
Brightness corresponding to P (s*L++, +11......(Rl (III II), R
2Tel 11+, R3 (III 111 ), (R1
(+*+e*Il, R!(lI+1%+1), R□(1
m+n,,l),(Rr<am+r+n),R2
(1, 11, 11, R3 (, l+ al),
(RI (lI+l+ no+1, R1(m*l+n*
1) Using Rs (salt n-n)......, find the slope (pr, qs) of the point of interest P (s,.) where the value d expressed by the following formula % is the minimum value. (hereinafter this point will be referred to as the approximate point).

As shown in FIG. 21, this means that in a coordinate space consisting of three coordinate axes based on brightness that are perpendicular to each other; The brightness of Ifl II,■, and the brightness of each element of the reflectance map RM Rr(pr, q,),
Rt(pr, qs), Rx(1)r, qs)
coordinate axis 1. ．． 1%, brightness on the coordinate space by plotting each on IC! +, It, Is and the brightness of each element of the reflectance map RM Rl (p r, q3), R1 (pl, q,), R1
Point P (pr, qs) represented by (p,,,q,)
This means that the slope (p, , qs) of the element point P (p, , q3) located at the closest distance d to this point P was found as the slope of the approximate point. .

Based on the approximate point P (111111) obtained in this way, eight points adjacent to it P (m-1n□1), P (1m-1+F1), as shown in FIG.
P (II-1+R+l), P (Anti-1)
% P (11111011s P (m*1++
a-1) sPl. 1.72, P +a*1++s+
Cell SL composed of l+, □1oll-1), S
L (IB-+++%l, S L +lj+R-1
1. For SL (@I 11), isoluminant line LRI (
plq), LR1(ri, q), and LR3(p, q). Find the cell where the intersection P8 exists.

Each (')L/S L +1l-II 11
-13, S L (II-1+ l, S L (I
II n-11, S L (*+ 11), the point P (I
I-1121-11, P (m-1+11"l), P
(lj+l+11-1+, P (a*I+noI)
Calculate equation (34) for each point, and calculate the value d (s-1o n-11, d (@-In□l) for each point.
, d (salt n-1+, d (a.I+a*1)
seek. In this case, for example, the intersection PX
(11, +1- +>, this cell S
Point P (Ill-1+R-1) of L (an Fl-1)
1 value d (11+l+ R1, is the other point P (II-
1oll-11, P detective-1, 7゜11, P (+s*
I+y+. 1° value d 111&-II1l-11, d
(*-1+no++ , d (lj, I+ll□.

will be a smaller value.

In this way, the cell 5L (lIl, 1-
When it is confirmed that there is an intersection P in I),
Next, the three-dimensional data creation unit 11A selects the cell S L T
I++ n −I.

Points of elements surrounding P (@+ 11-11 , P (I
lj+1+ 11-11 , P(s, , i, and the approximate point P (an ++u ), and perform the following interpolation calculation to find the slope (p, q) of the intersection point P.

Here, approximate point P (111+111 and point P (1
11+ 11-11, P (1m+1+ 1%-11
, P (#*I+ n), let the slopes be (p+, qz), (p+sq+), (pt%q+), and (pz, qt), respectively, and apply equation (34) to obtain the value d. dl, d2, d3 and d4 (.

As shown in FIG. 23, the point P (III 11-
1+, P (11411, 1-11% P (ll14
1+R) and the approximate point P (lIllI%l) are placed at each vertex of the square plane, the approximate point P (sr
1%) and the element point P C+*+n-+1 as its value d
Find a point Q that is internally divided by the ratio of 1 and d2.

Then the element points P(m.1.fi) and P(1141
A point Q2 that internally divides the range 111-11 by the ratio of the values d4 and d3 is found. Similarly, the element point P (l11+
,, -11 and P (-, Goose, Fl-11 and the approximate point P
(@1 n) and element point P1゜3. R, a point Q that internally divides the interval by its values d2 and d3 and di and d4, and G4
seek.

The internal division points obtained in this way Q, ,Q,,Ql,
In G4, the intersection Q between the straight line L1 connecting the internal division points Q and Qt and the straight line L2 connecting the internal division points Q and Q is determined.

Next, in this square area, a straight line LXI passing through the intersection point Q and parallel to the approximate point P (ann) and the element point P (+a.1.7) (hereinafter the point Po, 1 and the element point P
Take a straight line LX2 parallel to torn-I, and divide the straight lines LXI and LX2 by the intersection Q8, dpl:dp
2 and dql: Find dq2.

Next, the three-dimensional data creation unit 11A sets the division ratio ctp1:d.
The slope (po, qo) expressed by the following equation is determined based on p2 and dql:dq2.

This means that based on the discrete reflectance map and sampling data, the slope (po, 'qo) is closer to the slope (p, q) of the approximate point P (11 + Ill), which is the intersection point P of the isoblast lines. This means that it was found by a simple interpolation calculation to find the internal division point, and this slope (po
, qO), data closer to the actual outer shape of the object to be measured 3B can be obtained than when using the slope of the approximate point P (@+N). .

Subsequently, the three-dimensional data creation unit 11A sequentially repeats the above-mentioned arithmetic processing for the sampling points of the object to be measured 3B, thus obtaining the slopes (p, q) for all the sampling points of the object to be measured 3B.

(G5) Three-dimensional data creation unit 11A through processing steps beyond reconstruction of the curved surface.
After the three-dimensional data creation process is completed, the image data processing device 11 proceeds to step SP4 in FIG. 2, and the curved surface generation unit 11B executes the reconstruction process of the curved surface representing the external shape.

This process is performed in step SP3 with the slope p of the pixel SS.
= a f / a x, or q = a f / a
Since y has been obtained, the height f (Xt % yj) in two directions can be obtained by integrating this, so an integral calculation is performed.

As shown in FIG. 24, this calculation uses, for example, the slope p in the X direction to calculate the straight line 3'=)'J (j=...
... j-1, L j+1 ......) all sampling points on...xi-1, Xi, X□.

, . . . , perform integration.

Thus, the height f (xi, y,) of the external shape of the point (Xi,)'j) on the xy plane is ! + Mi fj (Xt) (i=...i-1, i, i+l...j
=...j-1, j, j+1...)...
...(37) It can be expressed as follows.

Equation (37) is the line y in the X direction on the grayscale image pco in FIG. 7 =...Vt-r, Yj-, 'It*I...
...In the top, the slope in the X direction p = a f /
If a x is integrated from Xt-flash to XtXl, the point (xi, y,) (l=...1-
11111+1...,j=...j-1
, j, j+1) can be determined. If this integral calculation is executed for each point in the range of the image of the object to be measured 3B, as shown in FIG. 24, a line in the direction of the object to be measured 3BOX y=...
yJ-3, yj, Yj++... Upper external shape data FOM (old... FOMy-j-+, FOM,
5.FOMy-J. 1...), and thus these external shape data (...F
OMy, j-1, 20M9. j1FOMy5j, l...
), it is possible to reconstruct the curved surface representing the external shape of the object to be measured 3B.

In the case of this embodiment, the curved surface generation unit 11B executes the integration process using the linear approximation method shown in FIG. 25, based on the video data DATA sampled from the discrete positions described above with reference to FIG.

In other words, discrete coordinate positions ......(Xs-s
,yJ), (Xi-2X)'J),
(xl-1, yj), (Xe, y,)...
・・The slope obtained for ・Old...p (i-31 hap
C stop - ffi)j% p (i-+1j'I'th °゛°°゛° is calculated as follows in step SP3 of Fig. 2, this slope......pu -s
x, p(i-HJs l) (1-11js pij・
... is the width section of the corresponding surface element ...
...LL-3, Lt-z, LL-+%Li...
It is assumed that the data is obtained at the center position of...

Here, the slope...p(i-3)j, p, □-2.
When J, p(A-1, J, pij... take a value other than 0, it can be considered that there is an image of the object to be measured 3B at the relevant surface element position, and conversely, O. By being able to think that there is a background image, (37)
The integration operation based on the formula is performed in the X direction from the plane element where the image of the object to be measured 3B starts (in the case of FIG. 25, the position of the width section Li-z).

Therefore, the integral operation result f (Xt, '/j) is f (xi, yj) = O in the width interval 5-1, and in the following width interval L i-2, the result of f (x, y,) is As the value of X increases, the width interval L L-
It increases linearly from the value at the end of 3 (=0) along the straight line determined by the slope +i-z+r.

Subsequently, when the value of X moves from the width interval Li-2 to -1, the slope switches to p(i-1)J,
The value of the integral value f(xi, yj) increases as the value of X increases within the width interval Li-1.
i-! It increases from the value at the end of , along a straight line with an inclination p(t-+)j.

Subsequently, when the value of X moves from the width section Li-1 to Li, the slope of the width section Li switches to ptj, so the integral value f
The value of (xi, yj) further increases from the value at the end of the width section Li-1 along the straight line with the pth slope.

In this way, based on the inclination data obtained at discrete sampling points (xi, yj) from the edge of the image of the object to be measured 3B, the straight line vAy =
Sampling point on y J...Xi-+
It is possible to generate external shape data FOM, J representing the external shape of the object to be measured 3B at % Xi, "io+...

Then, perform this operation on all sample link points in the y direction...
...)'j-+,'/J s 'lia+...
. . . and the result of this calculation is used to generate external shape data F representing the three-dimensional external shape of the object to be measured 3B.
OM (-...F OMy, no 1, F
OMy-J s F OMywj+1...) can be generated.

According to the above configuration, the outer shape of the object to be measured 3B is
can be reliably reconstructed using a non-contact method using two television cameras.

In this way, the object to be measured 3B is imaged under the same conditions as the conditions (i.e., the position of the light source, the position of the observation object, etc.) under which the surface shape of the reference object 3A as the observation object 3 was imaged. Therefore, there is no need for a process of aligning two two-dimensional images obtained from the reference object 3A and the measured object 3B.

In addition to this, the surface properties of the object to be measured 3B are determined by the reference object 3.
If A is made to lose once, it is possible to eliminate the need to correct the measurement results based on the properties of the surface.

(G6) Other Examples (11) In the above-mentioned example, three reflectance maps RM1, RM2,
I mentioned the case where RM3 is created, but 2
If the inclinations of all surface elements of the object to be measured 3B can be specified using one reflectance map, two light sources may be provided.

(2) In addition, in the above embodiment, after finding the points of the elements along the isobrightness line, approximate points are found from these and interpolation calculations are performed, but the method of finding the approximate points is not limited to this. First, various methods can be applied, such as sequentially determining the value d of each element point.

(3) In the above embodiment, the brightness of the intersection point P8 is determined by internally dividing the cell using the values d of the elements surrounding the cell in the cell having the intersection point P. However, the value d to be internally divided is not limited to this, and depending on the arrangement of the slopes p and q of the reflectance map, for example, the point to be internally divided by the value d2, which is the square of the value d of the point of each element, can be found. Also good.

H Effects of the Invention As described above, according to the present invention, when reconstructing the external shape of an object to be measured based on the slope data of the surface elements constituting the two-dimensional image data, the slope data of the surface elements necessary for reconstructing the external shape of the object to be measured is can be determined with high accuracy by simple calculation from the discrete reflectance map and sampling data, and the external shape of the object to be measured can be reconstructed in a short time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a shape measuring device according to the present invention, FIG. 2 is a flowchart showing its measurement processing procedure, and FIG. 3 is a route showing a method for creating a reflectance map RM for a reference object 3A. Fig. 4 is a route map for explaining the area element SS (Fig. 5 is a curve diagram showing an example of the reflectance map RM, Fig. 6 is a reflectance map formed by three light sources. Matup RMI
, RM2, RM3 route map, Figure 7 shows the object to be measured 3
A route diagram showing the image data generation method for B;
Figure 8 shows the object to be measured 3B generated by three light sources.
Figure 9 is a route map showing the method of determining the slope of the surface element SS, Figure 10 is a route map showing the sampling points of the rask video signal VD, and Figure 11 is a discrete reflectance map. 12 is a flowchart showing the isoluminance line tracing processing procedure, FIG. 13 is a route map showing the rusk scan of the reflectance map, and FIGS. 14 and 15 are used to explain the detection of the starting point. Route map, 1st
6 and 17 are route maps for explaining the search for isobright lines, and FIG. 18 is a route map for explaining the tracing of isobright lines.
Figures 19 and 20 are route maps showing the form of isobright lines;
Figure 21 is a route map showing the coordinate space with luminance as the axis, Figures 22 and 23 are route maps showing the processing procedure for calculating the slope of the intersection, and Figures 24 and 25 are route maps showing the processing procedure for calculating the slope of the intersection point. It is a route map provided for explanation of the reconfiguration method. 1... Shape measuring device, 2... Table, 3... Observation target, 3A... Reference object, 3B... Measured object , 4A, 4B, 4C...
...Light source, 5...Television camera, 6
...Analog/digital conversion circuit, 7...
... Frame memory, 8 ... Shape information generation section, 11 ... Image data processing device, IIA ...
...Three-dimensional data creation unit, IIB...Curved surface generation unit, 13...External memory, RM (RMI~
RM3)...Reflectance map, PCO (
PC01~PC03)... Grayscale image, FOM
(...FOM,,,-1,FOMA,1%
F OMy, j+1...)...External shape data, LRt(pSq), LRz(p, q),
LR3 (p, q)...Isoluminant line, P,...
・Intersection, P (m+ n), P (II-1u11-
11...Element point, P(s.1,.,...
...Starting point, S L (III 111...Cell.

Claims (1)

[Claims] Based on sampling data of a reference object obtained through one television camera by sequentially lighting a plurality of light sources, the brightness corresponding to the slope of the surface elements of the reference object is expressed. A plurality of reflectance maps are obtained, and a surface of the measured object corresponding to the reflectance map is determined based on sampling data of the measured object obtained through the television camera using the same light source as the reference object. Find the elemental brightness, and from among the elements constituting the reflectance map, find the point of the element adjacent to the intersection of the isoluminance line whose brightness is equal to the brightness of the predetermined surface element of the object to be measured, and A shape measuring device characterized in that the slope of a surface element of the object to be measured is determined by interpolation calculation at the point of an element, and the external shape data of the object to be measured is determined based on the slope of the surface element.