JP2003269935A - Measurement method of three-dimensional surface shape, measurement device for three-dimensional surface shape, computer program and computer program recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measurement method of a three-dimensional surface shape capable of rapid and accurate measurement. <P>SOLUTION: A measurement object surface 2 is scanned with a linear slit beam 3a, and a parameter indicating a projecting position is measured. The image of the slit beam 3a on the surface of the measurement object 2 is photographed at an angle different from the projecting direction of the slit beam, the values of the parameter when the intensity of the sequentially memorized images of the slit beam 3a is maximized are determined with respect to the respective pixels, and set as the values of the respective pixels by an image compositing means 12. Based on the values of the respective pixels, the three-dimensional surface shape of the measurement object surface is obtained. At that time, the value of the parameter when the intensity of the sequentially memorized images of the slit beam 3a is maximized is found by an interpolation method on the basis of the intensity of the sequentially memorized images of the slit beam 3a and the value of the parameter at that time. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional surface shape measuring method for non-contact measurement of a three-dimensional surface shape using an optical cutting method, a three-dimensional surface shape measuring device, and a computer for executing these. And a computer program recording medium having the computer program recorded therein.

[0002]

2. Description of the Related Art As a means for measuring a three-dimensional surface shape, an optical cutting method using image processing has long been known. This is the first in the "Image Processing Handbook" (Shokodou Co., Ltd.)
As described on pages 398 and 399, for the DUT,
A phenomenon in which the light beam pattern formed on the object surface when the slit light from the slit light source is irradiated corresponds to the cross-sectional shape of the measured object at the slit light irradiation position when observed from a direction different from the irradiation direction. Is a method that has been widely used from the past because of its simplicity, non-contact property, and quantitative property.

In measuring the shape of a three-dimensional free-form surface using this optical cutting method, the light beam pattern was obtained by observing the light beam pattern with a television camera while moving the slit light using a rotating mirror or the like. By processing the video signal, the light cutting line (the shape of the light beam pattern) in the screen is extracted every moment, and the curved shape is constructed by reconstructing it. As an optical system configuration, an optical spot scanner is used as a light source instead of the slit light source, and a PSD (Po
sition Sensitive Detector) There is also a method of using a high-speed optical spot position detector known as a sensor.

Although such a light cutting method has various advantages, in order to detect and identify each point on the object to be measured, a light cutting line within the screen is extracted for each screen. The process is indispensable, and as a result, there arises a problem in measurement accuracy or reliability as described below. (1) Deterioration of measurement accuracy and spatial resolution due to the shape of the object to be measured; (2) Degradation of measurement reliability due to the surface reflectance of the object to be measured;
A method based on a new idea as described in Japanese Patent No. 5654 and Japanese Patent Publication No. 6-25655 is invented, and as a result, accurate three-dimensional surface shape measurement has become possible.

These methods scan a surface of an object to be measured with a linear slit light, and show a parameter indicating a projection position of the slit light (for example, when the light projector is rotated to perform scanning, a rotation angle of the light projector). , The position of the light projector is measured when the light projector is moved in parallel for scanning, and the image of the slit light on the surface of the object to be measured is imaged from an angle different from the light projection direction of the slit light. Then, the image intensity of the slit light and the value of the parameter are sequentially stored in the pixel memory, and the value of the parameter is determined for each pixel when the intensity of the image of the slit light sequentially stored becomes maximum. , The step of setting the value of each pixel, and the three-dimensional surface shape of the surface of the measured object is obtained based on the value of each pixel. Since the measurement principle is described in detail in the above-mentioned patent publication and is well known, only a part of it will be described in the section of the embodiment of the present invention, and the detailed description will be omitted.

[0006]

As described above, the methods described in JP-B-6-25654 and JP-B-6-25655 (hereinafter referred to as "basic invention") are as follows.
This is an epoch-making method that solves the problems of the conventional light-section method all at once. This makes it possible to measure a three-dimensional surface shape with high accuracy and without contact.

However, recently, higher precision is required for measuring the three-dimensional surface shape, and high-speed measurement is required. For example, in order to perform measurement at high speed, it is necessary to scan the surface of the object to be measured with slit light at high speed. However, on the other hand, CC
An image pickup device typified by D requires a certain accumulation time, and has a predetermined time for picking up one image. Therefore, the intensity of the reflected light read into the pixel and the value of the parameter are sampled and discrete.

However, in the basic invention, the value of the parameter when the maximum received light intensity is obtained for each pixel is the value of the pixel, and the three-dimensional surface shape is measured based on this value. Therefore, when the intensity of the reflected light read into the pixel and the value of the parameter are discrete, the value of the parameter when the maximum intensity is truly shown,
It may appear in the middle of sampling and may not be obtained as measurement data. This becomes more remarkable as the scanning speed of the slit light is increased.

In addition, in the image pickup apparatus, each pixel has a predetermined size, so that there is a problem that the measurement resolution is limited by this. That is, it cannot be known to which part of the pixel the value of the parameter when the intensity of the received reflected light shows the maximum value corresponds.

The present invention has been made in view of such circumstances, and is a method for measuring a three-dimensional surface shape, which is an improvement of the basic invention, and which enables high-speed and accurate measurement. An object of the present invention is to provide a computer program for causing a computer to execute these, and a computer program recording medium recording the computer program.

[0011]

A first means for solving the above-mentioned problems is to perform a step of scanning the surface of the object to be measured with a linear slit light, and a parameter indicating the projection position of the slit light. The step of measuring, the image of the slit light on the surface of the object to be measured is imaged from an angle different from the projection direction of the slit light, the image intensity of the slit light and the value of the parameter are sequentially pixelized. A step of storing in a memory, for each pixel, when the intensity of the image of the slit light sequentially stored is maximum, to determine the value of the parameter,
A method for measuring a three-dimensional surface shape, comprising: a step of setting a value of each pixel; and a step of obtaining a three-dimensional surface shape of a surface of an object to be measured based on the value of each pixel, the method being sequentially stored. A method for determining the value of the parameter when the intensity of the image of the slit light becomes maximum is a method for obtaining by an interpolation method based on the intensity of the image of the slit light and the value of the parameter at that time which are sequentially stored. Is a three-dimensional surface shape measuring method (claim 1).

This means is basically an application of the principle of the basic invention, but the value of the parameter when the intensity of the image of the slit light becomes maximum is sequentially stored in the slit light. The feature is that it is obtained by the interpolation method based on the intensity of the image and the value of the parameter at that time.

That is, in the basic invention, the light intensity sequentially input to each pixel is compared with the stored one,
If the newly input light intensity is larger than the stored one, the stored value is updated to determine the value of the parameter when the intensity of the image of the slit light becomes maximum. In, the intensity of the image of the slit light and the value of the parameter at that time are sequentially stored, and using these values, the value of the parameter when the intensity of the image of the slit light is maximized by the interpolation method. Looking for.

Therefore, even if the intensity of the slit light image and the parameter values at that time are obtained only discretely,
It is possible to accurately obtain the value of the parameter when the intensity of the image of the slit light becomes maximum. Therefore, if the three-dimensional surface shape is measured using the value of the parameter when the obtained intensity of the slit light image is maximum, the measurement can be performed accurately even if the scanning is performed quickly. In addition, accurate measurement can be performed without being restricted by the resolution of pixels.

As described above, the value of the "parameter" is, for example, the rotation angle of the projector when the projector is rotated to perform scanning, or the position of the projector when the projector is moved in parallel to perform scanning. The numerical data that determines the position of the slit light is common to all means and all means including this means.

Further, "sequentially storing" does not necessarily mean that
It does not mean to store all the measurement data, and includes, for example, only storing data for a predetermined number of light intensities from the highest light intensity, if necessary. , Common to all means and all claims.

The second means for solving the above-mentioned problems is as follows.
In the first means, the interpolation method is the maximum n of the measured intensities of the slit light (n ≧ 3 is an integer).
Let I _j (j = 1 to n) be the intensities of the respective objects and x _j be the value of the parameter corresponding to each of them.
The following x is a value of the parameter when the intensity of the image of the slit light is maximum (claim 2).

[0018]

[Equation 2]

The present means sets the centroid of the maximum n pieces of measurement data of the intensity of the slit light as the value of the parameter when the intensity of the image of the slit light is maximum. According to the findings of the inventors, n = 3, n = 5
It turned out that a sufficiently good accuracy can be obtained. This means is characterized in that it is possible to obtain the value of the parameter when the intensity of the image of the slit light becomes maximum with a simple method and a small amount of data.

A third means for solving the above problems is
In the first means, the interpolation method sets the maximum m intensities of the measured intensity of the slit light as I _j (j = 1 to m), and the corresponding parameters _Where x _j is the value of the above, an equation of f (x) I = f (x), which is an n-th order polynomial (n <m) showing the relationship between the intensity I of the slit light and the parameter x, is calculated from these values. The value of x which is obtained by solving or regression calculation and which maximizes I is used as the value of the parameter when the intensity of the image of the slit light becomes maximum (claim 3). ).

This means measures the intensity I of the slit light measured.
Is a value of the parameter when the intensity of the image of the slit light is maximized by approximating with an n-th degree polynomial of the parameter, and it is more complicated than the second means, but more accurate data can be obtained. can get. According to the knowledge of the inventors, 2
The following polynomial gives a sufficiently accurate approximation. In this case, a minimum of three data sets should be adopted, and it is preferable to select three data sets having the highest reflection intensity. When using 3 or more sets of data, it is calculated by regression calculation.

A fourth means for solving the above problems is
In the first means, the relationship between the intensity I of the slit light to be measured and the parameter x is I = a * g (b * x + c) by a function g with a, b, and c as constants. When it is known that the relationship can be approximated by the following equation, the values of a, b, and c are determined based on the actually measured data, and then, when these values are used, the value of x that maximizes I When the intensity of the slit light image is maximum,
It is a feature that it is a value of the parameter (claim 4).

Depending on the shape of the slit light, the shape of the intensity distribution of the light on the surface to be measured when the object to be measured is irradiated is determined, and only the intensity or the way of spreading is the surface shape of the symmetrical object to be measured. May be determined. In such a case, according to this means, the minimum of three sets of measurement data (preferably three sets that give the maximum light intensity) are used to measure the parameters of the above-mentioned parameters when the intensity of the slit light image is maximum. The value can be determined. When using 3 or more sets of data, it is calculated by regression calculation.

The fifth means for solving the above-mentioned problems is as follows.
Slit light projecting means for projecting linear slit light on the surface of the object to be measured, means for measuring a parameter indicating the projected position of the slit light, and an image of the slit light on the surface of the object to be measured. The image is captured from an angle different from the projection direction of the slit light, and a pixel memory for sequentially storing the image intensity of the slit light and the value of the parameter at that time,
For each pixel, when the intensity of the image of the slit light sequentially stored is maximum, the value of the parameter is determined, and the pixel value determining means as the value of each pixel, based on each of these pixel values, The pixel value determining means includes shape calculating means for obtaining a three-dimensional surface shape of the surface of the object to be measured.
Based on the sequentially stored image intensity of the slit light and the value of the parameter at that time, when the intensity of the image of the slit light is maximized, the value of the parameter has a function of determining by an interpolation method. A three-dimensional surface shape measuring device (claim 5).

According to this means, the first means can be realized.

A sixth means for solving the above-mentioned problems is as follows.
The value of the parameter indicating the position of the slit light projected onto the surface of the object to be measured by the slit light projecting means for projecting the linear slit light, and the slit on the surface of the object to be measured imaged at that time The intensity of the image of the light, the procedure of storing in the pixel memory, the intensity of the image of the slit light stored in the pixel memory and the value of the parameter, when the intensity of the image of the slit light is maximum, the parameter The value of is determined for each pixel by the interpolation method and is set as the value of each pixel, and based on the value of each pixel, the 3
A computer program (claim 6) having a procedure for obtaining a dimensional surface shape.

The seventh means for solving the above-mentioned problems is as follows.
A computer program recording medium (Claim 7) in which the computer program as the sixth means is recorded.

According to the sixth means and the seventh means,
The first means can be realized by a computer, and the main part of the fifth means can be formed by a computer.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. Prior to that, the principle of measurement of a three-dimensional surface shape which is the basis of the present invention will be described. Figure 1
As shown in FIG. 2, the slit light 3a spread in the direction perpendicular to the paper surface is obliquely projected onto the surface of the object to be measured 2 placed on the reference surface 1, and the slit light 3a is used, for example, by the rotating mirror 4. The image is taken by the television camera 8 from directly above the object 2 to be measured, for example, while moving in the lateral direction of the drawing. At this time,
On the monitor TV 8a connected to the TV camera 8,
It is observed that the linear reflection pattern of the slit light on the surface of the object moves in the horizontal direction of the screen.

The line shape of the reflection pattern of the slit light 3a reflects the unevenness information on the surface of the object. In the conventional light cutting method, the line shape of the reflection pattern is extracted every moment and reconstructed. The three-dimensional shape of the object to be measured is measured by.

In this embodiment, the slit light 3
On the basis of a video signal output from the television camera 8 showing that the linear reflection pattern of a is moving on the object surface, for each pixel in the screen, the object surface corresponding to the pixel is displayed. An image is synthesized with the slit light projection angle at the moment when the slit light passes through the position as the value of the pixel. In the image synthesized in this way, the value in each image is
The image corresponds to the elevation angle when looking up the slit light rotation center of the rotating mirror 4 from the position of the object surface corresponding to the pixel. Therefore, if the composite image is represented by θ (x, y) using the coordinate system (x, y) of the corresponding object surface, the object surface profile f (x, y) is based on FIG. It can be obtained by the following equation by a simple geometric calculation. f (x, y) = z _0- (x ₀ -x) tan θ (x, y) (1)

As an application example of this measuring principle, the following measuring method can be easily considered. First, as a first application example, by performing the above measurement on the reference plane (1) and using the obtained composite image, the parameters x _{0 to} z
_This is a method of omitting ₀ . That is, the combined image θ ₀ (x, y) on the reference plane (1) is set to f (x, y) = 0 in the equation (1), and tan θ ₀ (x, y) = z ₀ / (x ₀ −x) (2) Therefore, by eliminating z ₀ or x ₀ from the equation (1), the object plane profile f (x, y) is obtained by the following equation. f (x, y) = {tan θ ₀ (x, y) -tan θ (x, y)} × (x ₀ -x)… (3)

[0033]

[Equation 3]

Further, as a second application example, two criteria
Perform the above measurement for the planes f (x, y) = 0 and f (x, y) = d.
Parameters by using the obtained composite image
x₀And z₀Both are omitted. That is, the second
Image θ on the reference plane of ₁(x, y) is the odor of equation (1)
By setting f (x, y) = d, the following equation is obtained. tan θ₁(x, y) = (z₀-d) / (x₀-x)… (5) Therefore, the relationship between Eqs. (2) and (5) should be substituted into Eq. (1).
And by x₀And z₀To eliminate f (x, y) into the form
I want it.

[0035]

[Equation 4]

In this embodiment, the surface to be measured is coded with the slit light projection angle. However, the means is not necessarily required to directly measure the slit light projection angle, and an equivalent rotation, for example, rotation. Under the assumption that the rotation angle of the mirror or the rotation angular velocity of the rotation mirror is constant, the surface to be measured is coded once after the start of scanning of the rotation mirror, etc., and then processed to calculate slit light. It may be converted into a projection angle.

Further, as can be seen from the equations (1) to (6),
Composite image θ (x,
y) is the tangent of all tan θ (x,
Since it is used in the form of y), it may be possible to suddenly code with the tangent of the slit light projection angle instead of the slit light projection angle at the time of the initial image combination.

An example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram of a three-dimensional surface shape measuring apparatus which is an example of the embodiment of the present invention. An object 2 to be measured is placed on a reference plane 1 which is a reference for measurement. The slit light emitted from the slit light source 3 is reflected by the rotating mirror 4 and projected onto the measured object 2 obliquely from above. The rotating mirror 4 is driven by a motor 6 controlled by a motor controller 5, and is driven so that the slit light 3a scans the measured object 2 on the reference surface 1 over the entire surface.

At this time, the position (x ₀ , z ₀ ) of the central axis of rotation of the rotating mirror 4 with respect to the reference plane 1 is to be measured accurately. Further, the angle of the rotating mirror 4 with respect to the reference plane 1 is configured to be detected by a rotation angle sensor 7 mounted in association with the shaft of the motor 6.
It is input to the surface shape measuring device 9 via the motor controller 5 so that the slit light projection angle θ with respect to the measured object 2 can be calculated every moment.

On the other hand, the surface of the object 2 to be measured is photographed by the television camera 8 arranged so that its optical axis is orthogonal to the reference plane 1, and the obtained video signal is the surface shape measuring device 9
Entered in.

The surface shape measuring device 9 is roughly classified into a shape calculation circuit 10 as an image calculation means for performing shape calculation by image combination, and a slit light projection angle θ from the output of the rotation angle sensor 7 to calculate the shape calculation circuit. It comprises a light projection angle calculation circuit 11 to be inputted to 10, and a sequence controller 12 for controlling a command to the motor controller 5 and a calculation timing control to the shape calculation circuit 10.

In measuring the shape, the surface shape measuring device 9 drives the motor 6 via the sequence controller 12 based on a start signal given from the outside to set the rotating mirror 4 to the initial position. Then, the rotation of the rotary mirror 4 is started, and the scanning with the slit light 3a is started.

The shape calculation circuit 10 has an image synthesizing circuit 13 to be described later in its input section, and at the same time when the scanning of the slit light source 3 is started, the video signal input from the television camera 8 is processed moment by moment, For each pixel in the screen, an image combining operation is performed in which the projection angle at the moment when the slit light passes through the pixel is read from the projection angle calculation circuit 11 and used as the value of the pixel during one scanning period of the slit light 3a. To do.

After the calculation of the composite image θ (x, y) is completed, the shape calculation circuit 10 uses the height calculation circuit 14 based on the instruction of the sequence controller 12 to calculate the height profile f (x, y) according to the equation (1). ) Is calculated, and this data is stored and accumulated in the three-dimensional shape memory 15.

The height profile data stored in the three-dimensional shape memory 15 is appropriately transferred to the computer or CAD system based on a command from the host computer or CAD system.

FIG. 3 is a schematic configuration diagram showing an example of the image synthesizing circuit 13 which is a component of the shape measuring apparatus 9. The image synthesizing circuit 13 processes a video signal input from the television camera 8 and, for each pixel, a predetermined number of maximum luminances (for example, when the predetermined number is 3, the maximum luminance, the next largest luminance, Further, a maximum brightness image calculation unit 18 having a function of calculating and storing the next largest brightness (3) and a function of storing the slit light projection angle θ at the moment when the predetermined number of maximum brightnesses are obtained. And a synchronization circuit 20, a memory address generation circuit 21, and an output control circuit 22 for controlling these.

The maximum brightness calculating section 18 A / D-converts and digitizes the video signal based on the timing signal output from the synchronizing circuit 20 centering on the maximum brightness image memory 23 which is a buffer memory for the maximum brightness image calculation. A /
The D conversion circuit 24, the maximum brightness image memory 25 for controlling the reading and writing of the data of the address of the maximum brightness image memory designated by the memory address generation circuit 21,
It is composed of a comparison circuit 26 and a switch circuit 27 which compare the value of the corresponding pixel of the image input from the television camera with the image of the maximum brightness memory and selectively output the larger value.

The comparison circuit 26 works as follows. now,
If the maximum brightness image memory 23 stores n maximum brightness values for each pixel, a new A / D conversion circuit 24
The brightness corresponding to the pixel input more is compared with the maximum brightness of these n pieces, and the n pieces from the largest of these (n + 1) pieces of brightness are returned to the maximum brightness image memory via the switch circuit 27. 23.

On the other hand, the composite image arithmetic unit 19 is mainly composed of a composite image memory 28 for storing the composite image arithmetic result. The composite image memory is the maximum brightness image memory 2
The area for storing the data of the slit light projection angle θ giving the maximum brightness of n pieces stored in 3 in FIG. 3 and the slit light projection angle θ giving the maximum brightness described later are combined and combined. It consists of two areas that are stored as images.

In the former area, n maximum luminances are newly written in the maximum luminance image memory 23 by a command from the comparison circuit 26, and at the same time, a new slit light projection angle θ giving the n maximum luminances. The data of is stored.
That is, when the data of n pieces of maximum brightness is not updated, the data is maintained as it is, and when the data is updated, the slit light corresponding to the brightness excluded from the maximum brightness image memory 23. The projection angle θ is erased, and a new value of the projection angle θ is read instead.

In this way, when one scan is completed, the maximum brightness image memory 23 and the above-mentioned areas of the composite image memory 28 have the maximum brightness up to the nth position in the scan and the maximum brightness thereof. Slit light projection angle θ
Will be stored for each pixel. These are arranged in time series, and a set (I _j , θ _j ) (j of the data I _j corresponding to the luminance and the slit light projection angle θ _j corresponding to the data I j
= 1 to n) are created for each pixel.

The image synthesizing memory control circuit 29 calculates the slit light projection angle θ _IMAX giving the true maximum brightness I _MAX for each pixel from these data as follows.

The first method is to express the brightness I from (I _j , θ _j ) by a (n-1) th order polynomial of the slit light projection angle θ, and maximize the polynomial of the slit light projection angle θ. θ to θ
_The method is _{IM AX} .

In the second method, n is an integer of 3 or more,

[0055]

[Equation 5]

The method is as follows.

In the third method, the relationship between the measured brightness I of the slit light and the slit light projection angle θ is a, b, c.
When it is known that the function g can be approximated by a relational expression of I = a * g (b * θ + c), the values of a, b, and c are determined based on the measured data. After that, when these values are used, the value of θ that maximizes I is obtained.

With this arrangement, the slit light projection angle θ
When the brightness I of the slit light is as shown in FIG. 4, in the basic invention, θ ₄ is the slit light projection angle giving the maximum brightness, whereas in the present embodiment, the sampling interval is Θ _IMAX , which is a point in the middle of, can be recognized as the slit light projection angle that gives the maximum brightness, and the resolution and accuracy can be increased accordingly.

The image synthesizing memory control circuit 29 controls the slit light projection angle θ _IMAX which gives the maximum brightness in this way.
Is calculated for each pixel, a composite image is created based on θ _IMAX for each pixel, and stored in the composite image memory 28. The composite image calculated in this way is transferred to the next arithmetic circuit via the output control circuit 22.

In the above embodiment, the height calculation circuit 14 calculates the equation (1), but in order to improve the calculation accuracy as described above, z ₀ or x _{0 of the} equation (1) is calculated. Can be omitted.

In this case, a synthetic image is obtained for the reference plane 1 in the same manner as the object to be measured, and the synthetic image is set to θ.
₀ (x, y), the synthesized image θ (x, y) of the object to be measured and the synthesized image θ ₀ (x, y) of the reference plane are respectively temporarily stored in the object plane synthesis memory 30 and After storing each in the reference plane synthesis memory 31, the height calculation circuit 14a
A three-dimensional shape is obtained by calculating the equation (4).

Further, both z ₀ and x _{0 in} the equation (1) can be omitted. In this case, in addition to the reference plane 1,
Provide a second reference plane (parallel to the reference plane 1 and distance d
Distance), a composite image θ (x, y) of the object 2 to be measured,
Composite image theta ₀ of the reference surface 1 _(x, y) and the second composite image θ _{1 (x,} y) of the reference plane determined by the similarly respectively, each once the object plane synthesis memory 30 as shown in Figure 5 After being stored in the reference plane synthesis memory 31 and the second reference plane synthesis memory 32, the three-dimensional shape is obtained by computing the equation (6) in the height computing circuit 14a.

Since the composite image of the reference plane 1 and the second reference plane only needs to be created once, the first created composite image can be used as it is for the second and subsequent measurements. Further, since the composite image of the reference plane 1 and the second reference plane has a simple structure, a calculation function is added to the shape calculation circuit 10 to calculate the virtual reference plane by the equations (2) and (5). It is also possible to obtain the composite image obtained in step 3 and store it in the memories 31 and 32, respectively.

The main part which controls the operation of the three-dimensional surface shape measuring apparatus described above can be constituted by a computer such as a microcomputer. In that case, a function as a three-dimensional surface shape measuring apparatus can be provided by creating a program for performing the above-described arithmetic processing, storing the program in a storage medium, and executing the program.

[0065]

As described above, according to the present invention,
A method for measuring a three-dimensional surface shape, which improves the basic invention and enables high-speed and accurate measurement, a three-dimensional surface shape measuring device, a computer program for causing a computer to execute these, and a computer program recorded therein It is possible to provide the computer program recording medium.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of measurement of a three-dimensional surface shape, which is the basis of the present invention.

FIG. 2 is a schematic configuration diagram of a three-dimensional surface shape measuring apparatus that is an example of an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing an example of the image composition circuit shown in FIG.

FIG. 4 is a diagram illustrating a method of obtaining a slit light projection angle that gives a true maximum brightness.

FIG. 5 is a block diagram showing another example of a surface shape calculation circuit.

[Explanation of symbols]

1: Reference plane, 2: Object to be measured, 3: Slit light source, 4:
Rotating mirror, 5: motor controller, 6: motor,
7: Rotation angle sensor, 8: TV camera, 9: Surface shape measuring device, 10: Shape calculation circuit, 11: Projection angle calculation circuit, 12: Sequence controller, 13: Image combination calculation circuit, 14: Height calculation circuit , 15: three-dimensional shape memory, 18: maximum luminance image calculation unit, 19: composite image calculation unit, 20: synchronization circuit, 21: memory address generation circuit,
22: output control circuit, 23: maximum brightness image memory, 2
4: A / D conversion circuit, 25: maximum brightness image memory control circuit, 26: comparison circuit, 27: switch circuit, 28: composite image memory.

Continued front page    (72) Inventor Hirotaka Yamamoto             3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture             SP R & D D Building 339 Hamano E Co., Ltd.             Inside engineering F term (reference) 2F065 AA53 BB05 FF04 HH05 HH12                       JJ03 JJ09 LL13 LL62 MM16                       QQ29 QQ31 UU05                 5B057 AA01 BA02 BA17 CA02 CA08                       CA11 CA16 CB02 CB08 CB13                       CB16 CD14 CE08 DA07 DB03                       DB05 DB09 DC22 DC36

Claims (7)

[Claims] 1. A step of scanning a linear slit light on a surface of an object to be measured, a step of measuring a parameter indicating a projection position of the slit light, and an image of the slit light on the surface of the object to be measured. A step of sequentially capturing the image intensity of the slit light and the value of the parameter in the pixel memory by capturing an image from an angle different from the projection direction of the slit light, and the slit sequentially stored for each pixel. When the intensity of the light image is maximized, the value of the parameter is determined, and the value of each pixel is determined, and based on the value of each pixel,
A method for measuring a three-dimensional surface shape of a surface of an object to be measured, the method comprising: The determination method is a method of obtaining by an interpolation method based on the intensity of the image of the slit light and the parameter values at that time which are sequentially stored.
Dimensional surface shape measurement method. 2. The method for measuring a three-dimensional surface shape according to claim 1, wherein the interpolation method uses a maximum of n (integer of n ≧ 3) of the measured intensities of the slit light. When the intensities are I _j (j = 1 to n) and the values of the corresponding parameters are x _j , the following x of the parameters when the intensity of the image of the slit light becomes maximum is given. A method for measuring a three-dimensional surface shape, which is a value. [Equation 1] 3. The method for measuring a three-dimensional surface shape according to claim 1, wherein the interpolation method calculates the maximum m intensities of the measured slit light intensities by I respectively.
_j (j = 1 to m), where x _j is the value of the corresponding parameter, an n-th order polynomial (n <m that indicates the relationship between the intensity I of the slit light and the parameter x from these values ) F (x) I = f (x) is solved by an equation, or a regression calculation is performed to obtain a value of x that maximizes I. When the intensity of the image of the slit light is maximized, A method for measuring a three-dimensional surface shape, which is a value. 4. The method for measuring a three-dimensional surface shape according to claim 1, wherein the relationship between the intensity I of the slit light to be measured and the parameter x is a function g with a, b, and c as constants. When it is known that I can be approximated by the relational expression I = a * g (b * x + c), the values of a, b, and c are determined based on the measured data, and then these values are calculated. When used, the value of x that maximizes I is set to the maximum intensity of the image of the slit light,
A method for measuring a three-dimensional surface shape, which is a value of the parameter. 5. A slit light projecting means for projecting a linear slit light onto the surface of the object to be measured, a means for measuring a parameter indicating a projected position of the slit light, and a surface of the object to be measured. An image of the slit light is imaged from an angle different from the projection direction of the slit light, a pixel memory for sequentially storing the image intensity of the slit light and the value of the parameter at that time, and for each pixel, When the intensity of the image of the slit light sequentially stored becomes maximum, the value of the parameter is determined, and a pixel value determining unit that sets the value of each pixel,
It has a shape calculation means for obtaining a three-dimensional surface shape of the surface of the object to be measured based on each of these pixel values, and the pixel value determination means has the intensity of the image of the slit light sequentially stored and the corresponding time. A three-dimensional surface shape measuring apparatus having a function of determining the value of the parameter by an interpolation method when the intensity of the slit light image is maximum based on the value of the parameter. 6. A value of a parameter indicating the position of the slit light projected onto the surface of the object to be measured by the slit light projecting means for projecting linear slit light, and the object to be measured imaged at that time. The intensity of the slit light image is maximized based on the procedure of storing the intensity of the slit light image on the surface in the pixel memory and the intensity of these slit light images and the parameter values stored in the pixel memory. At this time, the procedure of determining the value of the parameter for each pixel by the interpolation method to obtain the value of each pixel, and the procedure of obtaining the three-dimensional surface shape of the surface of the measured object based on the value of each pixel A computer program having: 7. A computer program recording medium on which the computer program according to claim 6 is recorded.