JP2010164377A - Surface profile measurement device and surface profile measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a surface profile with an effect of multiple reflection light suppressed while employing an optical cutting method. <P>SOLUTION: Laser light, reflected at a surface of a measured object, is initially received to photograph a surface profile of the measured object by an imaging part which moves by a predetermined step amount in a direction of photographing optical axis, and an optical cut image which contains a profile line image of the surface of the measured object is taken at each step position of the imaging part. Then an optical cut image, where a profile line image is focused, is defined from optical cut images at each step position, and a profile line image of the surface of the measured object and a noise optical image due to the multiple reflection are discriminated using the defined optical cut image. An image treatment to remove the discriminated noise optical image from the optical cut image is carried out based on the discriminated result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an object surface shape measuring system and a surface shape measuring method using a light cutting method.

  Conventionally, as one of methods for measuring the surface shape of an object, there is a method called a light cutting method using the principle of triangulation (for example, “Today Yoshizawa,“ Latest optical three-dimensional measurement ”, Asakura Shoten, November 2006) 20th pages 13-23).

FIG. 19 shows the basic principle of triangulation using light.
The height D of the measurement object 112 is an angle α formed by the distance L between the light irradiation unit 111 and the imaging unit 113, and the light irradiation unit 111, the imaging unit 113, and the measurement object 112 (light reflection point). , Β is determined as follows.
D = {tan α * tan β / (tan α + tan β)} * L * sin β (Equation 1)

  In order to easily obtain height information by the light cutting method, the axis in the length direction of the line light and the camera coordinates of the imaging unit 113 with respect to the plane including the optical axis of the light irradiation unit 111 and the optical axis of the imaging unit 113 The apparatus is configured such that one axis (for example, the X axis) is vertical.

FIG. 20 shows the relationship between the height D of the measurement object 112 and the camera coordinate system position of the shape line image in the case of the above-described apparatus configuration.
The line light 122 projected from the line light irradiation unit 121 is diffusely reflected on the surface of the measurement object 123, and the light forms an image on the two-dimensional image sensor 125 via the imaging lens 124. When the height of the measurement object 123 is different, the coordinate values (for example, Yi, Yj) of the shape line image on the axis (for example, the Y axis) different from the camera coordinate axis are different. The height H (Hi, Hj) from the reference position is determined as follows by the coefficient a, the constant b, and the coordinate value Y obtained in advance.
H = a * Y + b [Formula 2]

FIG. 21 shows an example of a surface shape measurement system using a light cutting method.
The line light 122 thrown from the line light irradiation unit 121 generates a shape line 126 by reflected light on the surface of the measurement object 123. The surface shape of the measuring object 123 is measured from the coordinate data of the shape line image 129 in the light section image 128 acquired by the imaging unit 127.

For the coordinate value for obtaining the height, the barycentric coordinate of the shape line image is often used for the purpose of improving the measurement accuracy. 22 and 23 show the relationship between the shape line image and its barycentric coordinates.
In general, the line light has an intensity distribution in the width direction, and there are uneven unevenness on the surface of the measurement object, so that the shape line image 129 that is a diffuse reflection light image of the line light is And a brightness distribution caused by them (see, for example, the enlarged image 128M). Since the coordinate value in units of sub-pixels is obtained by the centroid calculation, the measurement accuracy can be improved as compared with the case where the pixel coordinate having the maximum brightness is simply used.

  For example, as shown in FIG. 23, the Y-axis centroid coordinates at an arbitrary X-coordinate value Xi can be calculated by measuring the light intensity of each Y-coordinate value at Xi. In this example, the Y-axis centroid coordinates Yc are the shape light centroids. As obtained.

  As the light source for the light cutting method, laser light that can reduce the width of the line light is mainly used. As a mechanism for generating line light, there are a method of extending light from a light source in a line shape with a cylindrical lens or the like, and a method of scanning spot light condensed on a measurement object at high speed with a galvanometer mirror or the like. The measurement system using the optical cutting method can be configured with a combination of standard parts, and has a high measurement capability for surfaces with a large tilt angle, enabling high-speed measurement. It is used for surface shape measurement.

  However, the light cutting method has a problem of noise light generation due to multiple reflection. Noise light tends to be generated when the measurement object has a groove-like recess and its surface is specular. With reference to FIGS. 24 to 26, a mechanism for generating noise light will be described.

  As shown in FIGS. 24 to 26, the line light 122 is reflected by the side surface A of the groove-shaped recess of the measurement object 123 to generate the shaped light 129a, but the side surface B (the specularly reflected light of the shaped light 129a faces each other) When reflected in (B0 part), noise light 130a is generated. Alternatively, the noise light 131a is generated by reflecting the diffusely reflected light of the shaped light 129a on the side surface B (for example, B1 to B3) facing each other. Similarly, the noise light 130b and 131b are generated with respect to the shaped light 129b generated on the side surface B. As can be seen from the bird's-eye view of FIG. 24, noise light due to multiple reflection is basically generated in a space different from the plane including the shape line 126. However, the position and orientation of the irradiation unit, imaging unit, measurement object, and measurement are measured. It appears in various forms depending on the shape and surface condition of the object.

Such noise light gives an incorrect result in the above-described centroid calculation. With reference to FIG. 27 and FIG. 28, an example in which an incorrect barycentric coordinate is derived by noise light is shown.
As shown in the light section image 140 in FIG. 27 and the enlarged image 128M around Xi in FIG. 28, the data of the noise light images 130 and 131 due to multiple reflections are added to the data of the shape light image 129. It will be. For example, in the example of FIG. 28, a surplus centroid Ye different from the original Y-axis centroid coordinate Yc is obtained as the shape light centroid.

  As a first method for removing the influence of noise light due to multiple reflection, there is generally a method of reducing the influence of multiple reflected light by image processing using a plurality of images having different irradiation conditions or a plurality of images having different imaging conditions. Are known. For example, Patent Document 1 proposes a method using two slit light beams.

  As a second method for more positively removing noise light in the light-cut image, a method has been proposed in which noise light is not imaged using a difference in polarization components of light rays. For example, in Patent Document 2, the irradiation light is circularly polarized light, and the reflected shaped light and noise light are transmitted only through the shaped light using a combination of a quarter wavelength plate and a polarizing plate by utilizing the difference in the rotation direction of the circularly polarized light. And proposed a method of imaging.

JP 2004-219154 A Japanese Patent No. 2641552

  However, the first method weakens the influence of the multiple reflected light by image processing, and does not remove the noise light image in the light-cut image, so it is not a fundamental solution. In addition, the surface to be measured often has a fine, complex and irregular surface shape, and the surface reflected light contains a mixture of regular reflection components and diffuse reflection components. Will be included. In such a case, the combination of the quarter wavelength plate and the polarizing plate in the second method cannot block all noise light.

  The present invention has been made in view of such a situation, and enables the surface shape to be measured satisfactorily while suppressing the influence of multiple reflected light while using a light cutting method.

  In order to solve the above-described problem, the present invention first captures a laser beam reflected from the surface of the measurement object and captures the surface shape of the measurement object by an imaging unit that moves in a predetermined step amount in the imaging optical axis direction. Then, a light section image including a shape line image of the surface of the measurement object at each step position of the imaging unit is acquired. Then, a light section image in which the shape line image is in focus is identified from the light section image at each step position, and the shape line image of the surface of the measurement object and the noise light image due to multiple reflection are used using the identified light section image. Is determined. Based on the determination result, image processing is performed to remove the determined noise light image from the light-cut image.

  According to the above configuration, the surface of the measurement object is imaged by the imaging unit that moves in the imaging optical axis direction by a predetermined step amount, and the shape line image of the measurement object surface and noise due to multiple reflections from the light cut image at each step position. Discriminate the light image. For example, this processing is performed by utilizing a difference in pixel value caused by a spatial generation point of the shape line image and the noise light image due to multiple reflection. Then, the noise light image is removed from the light cut image based on the determination result.

  As described above, according to the present invention, the surface shape can be satisfactorily measured while suppressing the influence of multiple reflected light while using the light cutting method.

It is a figure which shows the structure of the surface shape measuring system which concerns on the 1st Embodiment of this invention. It is a figure which shows the positional relationship of the measuring object, line laser light source, imaging lens, and camera of FIG. It is a figure (1) for demonstrating the principle of the removal of the influence of the noise light by multiple reflection. It is a figure (2) for demonstrating the principle of the removal of the influence of the noise light by multiple reflection. It is the figure which showed a mode that the imaging focus position was shifted from the back side of a shape line to this side, and it imaged. It is a figure which shows the light cutting image at the time of shifting an imaging focus position. It is a flowchart of the surface shape measurement process using the imaging focus position shift of FIG. It is a figure which shows an example of the pixel value with respect to F coordinate. It is a figure which shows an example of the focusing total pixel number with respect to F coordinate. It is a figure which shows the example of the light cutting image for every F coordinate. It is a figure which shows the example of the shape data computed by the gravity center calculation from the focused light cutting image of FIG. It is a figure which shows the example of the several light cutting image from which a focus position differs. It is a figure which shows the example of the light cutting image obtained by applying the surface shape measuring method of this invention. It is a figure which shows the example of the total data which showed the relationship between an image number and the total number of focused pixels. It is a figure which shows the example of the total data which showed the relationship between an image number and contrast value. It is a figure which shows the example of the total data which showed the relationship between an image number and a pixel total value. It is a figure which shows the example of the total data which showed the relationship between an image number and a pixel average value. It is a figure which shows the example of the total data which showed the relationship between an image number and a pixel average value (moving average). It is a figure which shows the basic principle of a triangulation method. It is a figure which shows the relationship between the height of a measuring object and the camera coordinate system position of a shape line image at the time of applying the triangulation method of FIG. It is a figure which shows the example of the surface shape measuring system using the conventional light cutting method. It is a figure (1) for demonstrating the relationship between a shape line image and its gravity center coordinate. It is FIG. (2) for demonstrating the relationship between a shape line image and its gravity center coordinate. It is a bird's-eye view which shows an example of noise light expression. It is a figure which shows the example of the light cutting image containing the noise light of FIG. It is a figure for demonstrating noise light, A is the noise light by the side A side, B is the noise light by the side B side. It is a figure (1) for demonstrating the relationship between the shape line image by multiple reflection, and its gravity center coordinate. It is FIG. (2) for demonstrating the relationship between the shape line image by multiple reflection, and its gravity center coordinate.

Hereinafter, an example of the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The description will be given in the following order.
1. First Embodiment [Configuration of Surface Shape Measurement System]
[Principle of removing the influence of noise light]
[Flow of surface shape measurement]
[Measurement data example]
[Examination of parameters]

<1. First Embodiment>
In the present embodiment, like the measurement object 123 of FIG. 24 referred to in the description of the prior art, the surface shape measurement of the measurement object in which a groove-like recess is formed on the surface of the object on which the shape line is formed. Further, the present invention is applied. Needless to say, the shape of the object that can be measured by the present invention is not limited to this example.

[Configuration of surface shape measurement system]
FIG. 1 shows a configuration of a surface shape measurement system according to a first embodiment of the present invention.
The present embodiment includes a line laser light source 1, a camera 2, an imaging lens system 3, a uniaxial stage 4, a laser drive circuit 5, a motor drive circuit 6, a computer 10, a display device 11, and an operation unit 12.

  The line laser light source 1 irradiates the surface of the measurement object 123 with line laser light. Instead of using the line laser light source, the spot light may be linearly scanned by a galvanometer mirror or a polygon mirror.

  The camera 2 captures the reflected light reflected by the measuring object 123 from the light emitted from the line laser light source 1 and outputs the image data to the computer 10.

  The imaging lens system 3 is for imaging the reflected light of the measurement object 123 on the image sensor of the camera 2.

  The uniaxial stage 4 is equipped with a motor (not shown), and moves the camera 2 in the optical axis direction based on a drive signal from the motor drive circuit 46. As this motor, for example, a step-in motor, a piezo motor, or the like is applied, but it is not limited to this example as long as the step movement of a predetermined distance such as 1 μm unit is possible.

  The laser drive circuit 5 supplies a drive signal to the line laser light source 1 based on a control signal from the computer 10 and causes the line laser light source 1 to emit line laser light corresponding to the drive signal.

  The motor drive circuit 6 supplies a drive signal to the motor of the single axis stage 4 based on a control signal from the computer 10 to move the camera 2.

The computer 10 includes a laser control circuit 7, a motor control circuit 8, an image input circuit 9, a control unit 10A, and an image processing unit 10B.
The laser control circuit 7 supplies a control signal according to the command from the control unit 10A to the laser drive circuit 5, and controls the drive signal generated by the laser drive circuit 5 to adjust the level of emitted light, the timing of emission, and the like. To do.

  The motor control circuit 8 supplies a control signal according to the command of the control unit 10A to the motor drive circuit 6 and controls the drive signal generated by the motor drive circuit 6 to determine the movement amount and movement timing of the single-axis stage 4 and the like. To be adjusted.

  The image input circuit 9 is for capturing image data of the measurement object 123 captured by the camera 2 into the computer 10.

  The control unit 10A includes, for example, an MPU (Micro Processing Unit) or the like, and controls each unit of the computer 10 using a ROM (Read Only Memory), a RAM (Random Access Memory), or the like (not shown).

  The image processing unit 10B performs image processing on the image data input to the image input circuit 9 and outputs the image data to the display device 11 or the memory 10C. For example, as will be described later, in response to the determination result of the control unit 10A, a process is performed to erase the noise shape image due to multiple reflection from the selected light-cut image and generate image data from which the influence of the noise light is removed.

  A display device 11 for data output and an operation unit 12 for data input are connected to the computer 10. For example, a mouse device or a keyboard can be used as the operation unit 12.

The operation of the surface shape measurement system configured as described above will be briefly described.
First, the line laser light source 1 is output-controlled by the laser control circuit 7 and the laser drive circuit 5 based on an instruction from the computer 10, and the emitted light from the line laser light source 1 forms an image on the surface of the measurement object 123. The reflected light from the measurement object 123 is picked up by the imaging lens system 3 and the camera 2, and the image data is taken into the computer 10 through the image input circuit 9. The uniaxial stage 4 to which the imaging lens system 3 and the camera 2 are attached is arbitrarily arranged in the imaging optical axis direction by the motor control circuit 8 and the motor drive circuit 6 based on an instruction from the computer 10 in parallel with the capture of the image data. Movement, for example, a predetermined step amount.

FIG. 2 shows a positional relationship among the measurement object 123, the line laser light source 1, the imaging lens system 3, and the camera 2 shown in FIG.
The line laser optical axis, the imaging lens system 3 and the optical axis of the imaging system of the camera 2 are all arranged in the same plane. In addition, the line laser optical axis and the optical axis of the imaging system intersect at an angle of 90 degrees, and are arranged so as to be symmetrical with respect to the perpendicular to the surface of the measurement object 123. This is to ensure that all shape lines are included in a certain imaging focal plane. By doing so, the depth of focus of the shape lines can be made equal and good measurement can be performed. The moving axis of the uniaxial stage 4 and the optical axis of the imaging system are installed so as to be parallel. Hereinafter, the length direction of the line laser light is defined as the X axis, the line laser optical axis is defined as the Y axis, and the optical axis of the imaging system is defined as the F axis. The surface of the measurement object, the imaging focus, the camera pixel, and the like are within this XYF coordinate space. It shall be handled in In the case of this example, the X axis is perpendicular to the paper surface.

[Principle of removing the influence of noise light]
Next, with reference to FIGS. 3 and 4, the principle of removing the influence of noise light caused by multiple reflection will be described.
FIG. 3 shows the relationship between the F coordinate and the X coordinate for image data. FIG. 4 is a graph showing the relationship between the F coordinate and the pixel value I for image data.

  This principle is based on the Shape from Focus method. The following briefly describes the Shape from Focus method. A camera captures an object, changes the relative distance f between the imaging system and the object in the direction of the imaging optical axis, and obtains an image sequence with slightly different focal positions. Focusing on an arbitrary pixel (xl, ym) in the image sequence, the pixel value changes depending on the relative distance f, and the distance fk at which the pixel value becomes the maximum value indicates the in-focus position, that is, the object surface position. Become. In the example shown in FIG. 3, when the relative distance f is changed to f1, f2,..., Fk,..., FN−1, fN, the pixel value I of an arbitrary pixel (xl, ym) becomes I1, I2, .., Ik,. In this example, when the relative distance f is fk, since the pixel value I of the arbitrary pixel (xl, ym) is the maximum value (maximum value) Ik, it can be determined that the in-focus state is achieved. By performing the same processing for all the pixels of each image, the surface shape of the object can be obtained.

  When this Shape from Focus method is applied to a surface shape measurement system, noise light due to shape lines and multiple reflections can be regarded as a point light source at a point where the light is finally reflected before being received by the camera. Therefore, the pixel value has the maximum value when the imaging focus position coincides with the reflection location.

  FIG. 5 shows a state where the imaging focus position is shifted little by little from the back side to the near side of the shape line. FIG. 6 shows a light cut image when the imaging focus position is shifted little by little.

At the initial position fs of the camera 2, since the imaging focus (corresponding to the imaging focal plane Fs) is not aligned with the shape line image 29 or the final reflection location of the noise light due to multiple reflection, no image is formed. It becomes. In the following description, the camera position may be referred to as “camera position”.
Subsequently, the imaging focus position is shifted little by little, and when the optical axis of the line laser beam finally exists in the imaging focal plane (position fM), that is, when the imaging focus is focused on the reflection portion of the shape line image 29. The shape line is imaged, but the noise light due to multiple reflections remains blurred (image 22).
If the imaging focus position is shifted as it is, the shape line image 29 is blurred without being formed, and noise light due to multiple reflection is formed (screens 23 and 24).
Further, when the camera 2 is moved to the end position fe and the imaging focus position (corresponding to the imaging focal plane Fe) is shifted, the shape line image 29 and noise light due to multiple reflections are again not formed but become a blurred image 25. .

[Flow of surface shape measurement]
Next, the flow of the surface shape measurement of this embodiment will be described.
FIG. 7 is a flowchart of the surface shape measurement process using the imaging focus position shift of FIG.

  In step S <b> 1, the control unit 10 </ b> A controls the laser control circuit 7 to irradiate the measurement object 123 with the line laser light, and captures a light cut image with the camera 2. After this process is completed, the process proceeds to step S2.

  In step S2, the operator moves the camera 2 to the initial position fs by operating the operation unit 12 while observing the light cut image picked up by the camera 2 at this time, and also sets the end position fe and the movement step amount fd (for example, 1 μm) is set. The set value is stored in the memory 10C or the like by the control unit 10A. After this process is completed, the process proceeds to step S3.

  In step S3, the image input circuit 9 acquires a light section image at the initial position fs of the camera 2, and the control unit 10A records the position f of the camera 2 at that time in the memory 10C (in this case, f = fs). ). After this process ends, the process proceeds to step S4.

  In step S4, the control unit 10A controls the motor control circuit 48 to shift the focal position by the movement step amount fd set in step S2, and drives the uniaxial stage 4 to move the camera 2. After this process ends, the process proceeds to step S5.

  In step S5, the image input circuit 26 acquires a light-cut image at the position of the camera 2 after movement, and the control unit 10A records the position f at that time (f = fs + fd * n: n is the number of steps). After this process ends, the process proceeds to step S6.

  In step S6, the control unit 10A determines whether or not the camera 2 is the end position fe set in step S2, and if it is the end position fe, the process proceeds to step S7. On the other hand, if it is not the end position fe, steps S4 and S5 are repeated until the end position fe set in step S2 is reached.

  In step S7, the control unit 10A uses all the images acquired at each camera position up to step S6 to determine the position f at which the pixel value is maximum for all the pixels as shown in FIG. 8, that is, the in-focus position. Ask. After this process ends, the process proceeds to step S8. Please refer to the description of FIG. 4 for FIG. As a method for specifying the pixel having the maximum pixel value, various methods such as a method using a contrast, a pixel total value, a pixel average value, and a pixel average value (moving average) can be applied.

  In step S8, the control unit 10A uses the result of FIG. 8 to obtain the camera position fM that maximizes the total number of focused pixels as shown in FIG. After this process ends, the process proceeds to step S9.

  In step S9, only the pixel value information of the focused pixel of the light section image at the camera position fM is stored in the memory, and the pixel values of the other pixels are set to zero. The image processing unit 10B reads pixel value information of each pixel of the light section image at the camera position fM from the memory 10C, and obtains shape line image shape data from the centroid calculation.

  Then, the camera 2 is moved in the XY plane, and the series of surface shape measurement processing shown in FIG. 7 is performed for a predetermined measurement position within the measurement target range of the measurement target surface, and the unevenness of the entire measurement target surface is determined. taking measurement.

  10 illustrates the images 21 to 25 (see FIG. 6) acquired between the initial position fs and the end position fe of the camera. In this case, the shape line image 29 of the image 22 at the position fM is shown. Only the pixel value information of the constituent pixels is stored in the memory. The pixel values of the other noise light image 30 (corresponding to the noise light image 130) and the noise light image 31 (corresponding to the noise light image 131) are set to zero. Finally, as shown in FIG. 11, the noise light images 30 and 31 are removed from the image 22 to obtain a light cut image 22 </ b> A of only the shape line image 29.

[Measurement data example]
Hereinafter, examples of measurement data on the surface of an object obtained by applying the present invention will be introduced.
FIG. 12 is a diagram illustrating an example of a plurality of light cut images having different in-focus positions. The image 41 is an example focused on the lower part (arrow) of the noise light image due to multiple reflection. The image 42 is an example focused on the upper part (arrow) of the noise light image caused by multiple reflection. 43 is an example focused on a shape line (arrow) (corresponding to the image 22) Here, when the present invention is applied, noise light due to multiple reflection is removed as shown in FIG. An image in which a relatively large amount of information on the pixel values of the pixels constituting the image remains is obtained.

[Examination of parameters]
Here, a parameter suitable for specifying the position on the F coordinate of the camera corresponding to the object surface position is examined.

FIG. 14 shows an example of total data indicating the relationship between the image number and the total number of focused pixels.
The total number of focused pixels is the parameter described with reference to FIG. The measurement object is the same as the measurement object of the light section image shown in FIG. In this example, the camera position is moved by 50 steps to obtain 50 images of the measurement object, and the same applies to FIGS. 15 and 16. Note that the image 43 in FIG. 12 is the 29th acquired image among the 50 images.

FIG. 15 shows an example of total data indicating the relationship between the image number and the contrast value.
As described above, the contrast value is obtained, for example, by measuring the difference (contrast) of the luminance value between the central pixel and the surrounding pixels for all the pixels.

FIG. 16 shows an example of total data showing the relationship between the image number and the pixel total value.
The pixel total value is the sum of the pixel values of all the pixels of the light section image.

FIG. 17 shows an example of total data indicating the relationship between the image number and the pixel average value.
The pixel average value is an average value of pixel values for all pixels of the light section image.

FIG. 18 shows an example of total data showing the relationship between the image number and the pixel average value (moving average).
The pixel average value is obtained by calculating an average value of pixel values of adjacent image numbers (two or more) for the entire light-cut image.

  From the total data of FIGS. 14 to 18, the maximum value is obtained when the image number is 29 in the pixel average value (FIG. 17) and the pixel average value (moving average: FIG. 18). Further, although there is variation in the pixel total value (FIG. 16), a value close to the maximum value is obtained. These parameters are likely to be preferred by the present invention.

  Here, supplementing the explanation in the column of the prior art, there is an increasing demand in the industry for measuring the surface shape of a fine object having a size of several tens of μm. For example, optical devices and their molds are one of such fine objects, but the surface state is specular, and recent devices have increased the inclination angle, so existing surfaces have increased. With the shape measuring device, it has become impossible to measure with high accuracy.

  The light cutting method is suitable for measuring an optical device and its mold because of its high ability to measure a surface with a large tilt angle. There is also an advantage that the measurement time is short. However, with respect to the groove-shaped portions whose side surfaces are opposed to each other, the measurement accuracy is deteriorated due to the generation of multiple reflected light in the optical device having a specular surface or its mold.

  In the present invention configured as in the above-described embodiment, it is possible to remove (suppress) the adverse effect of the multiple reflected light, which is a problem, while using the light cutting method. As a result, it is possible to measure the surface shape with high accuracy while taking advantage of the measurement capability of the surface having a large inclination angle and the short measurement time. Further, in the mechanism for removing the adverse effects of the multiple reflected light according to the present invention, the shape light image that is the basis of the shape data cannot be damaged, so that highly reliable shape data can be obtained.

  The series of processes performed by the computer described above can be executed by hardware or can be executed by software. Needless to say, the function for executing these processes can also be realized by a combination of hardware and software. When a series of processing is executed by software, it is possible to execute various functions by installing a computer in which a program constituting the software is incorporated in dedicated hardware, or by installing various programs. For example, it is installed from a program recording medium in a general-purpose computer or the like.

  Further, in the present specification, the processing steps are not limited to processing performed in time series in the order described, but also processing executed in parallel or individually (for example, Parallel processing or object processing).

  When executed by software, the program may be processed by a single computer or may be distributedly processed by a plurality of computers. Furthermore, the program may be transferred to a remote computer and executed.

  The embodiment described above is a specific example of a preferred embodiment for carrying out the present invention, and therefore various technically preferable limitations are given. However, the present invention is not limited to these embodiments unless otherwise specified in the above description of the embodiments. For example, the materials used in the above description, the amount used, the processing time, the processing order, the numerical conditions of each parameter, etc. are only suitable examples, and the dimensions, shapes, and arrangement relationships in the drawings used for the description Etc. are also schematic drawings showing an example of the embodiment. Therefore, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Line laser light source, 2 ... Camera, 3 ... Imaging lens system, 4 ... Uniaxial stage, 5 ... Laser drive circuit, 6 ... Motor drive circuit, 7 ... Laser control circuit, 8 ... Motor control circuit, 9 ... Image input Circuit: 10 ... Computer 10A ... Control Unit 10B ... Image Processing Unit 10C ... Memory 11 ... Display Device 12 ... Operation Unit 21-25, 22A, 31-33 ... Light Cut Image 29 ... Shape Line Image , 123 ... measurement object

Claims (5)

An imaging unit that receives laser light reflected from the surface of the measurement object and images the surface shape of the measurement object;
A moving mechanism for moving the imaging unit in the imaging optical axis direction by a predetermined step amount;
A shape line image acquisition unit that acquires a light section image including a shape line image of the surface of the measurement object at each step position of the imaging unit;
A light section image in which the shape line image is in focus is identified from the light section images at each step position, and the shape line image on the surface of the measurement object and the noise light image due to multiple reflection are obtained using the identified light section image. A control unit for determining;
An image processing unit that performs processing for removing the determined noise light image from the light-cut image based on the determination result. The surface shape measurement system according to claim 1, wherein an angle formed by the optical axis of the laser beam and the imaging optical axis is 90 degrees. The controller is
A plurality of light-cut images acquired by the imaging unit are analyzed, and a noise light image is discriminated using a difference in pixel value caused by a spatial generation point of a shape light image and a noise light image due to multiple reflection. 2. The surface shape measuring system according to 2. The control unit identifies a light-cutting image in which a shape line image is in focus from the plurality of light-cutting images, stores information on pixel values of pixels satisfying a predetermined condition from the light-cutting image, and Save the pixel values of other pixels in the memory as 0,
The image processing unit performs a process of erasing a pixel having a pixel value of 0 from a light-cut image in which the shape line image is focused based on information on a pixel value of each pixel stored in the memory. The surface shape measuring system according to claim 3. A first step of receiving laser light reflected from the surface of the measurement object and imaging the surface shape of the measurement object by an imaging unit that moves in a predetermined step amount in the imaging optical axis direction;
A second step of acquiring a light section image including a shape line image of the surface of the measurement object at each step position of the imaging unit;
A light section image in which the shape line image is in focus is identified from the light section images at each step position, and the shape line image on the surface of the measurement object and the noise light image due to multiple reflection are obtained using the identified light section image. A third step of determining;
And a fourth step of performing image processing for removing the discriminated noise light image from the light-cut image based on the discrimination result.