JP2010014505A - Three-dimensional shape measuring apparatus and three-dimensional shape measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional shape measuring apparatus for irradiating an object to be measured with lights at a plurality of angles, and accurately measuring the surface shape at an optimal angle. <P>SOLUTION: The three-dimensional shape measuring apparatus 10 has a light-emitting system 1 with a plurality of light sources 1a-1c, an imaging optical system 7, and an image processing section 8. A plurality of the light sources 1a-1c included in the light-emitting system 1 have different angles between an optical axis of the imaging optical system 7 and optical axes of a plurality of the light sources 1a-1c, in a predetermined plane containing the optical axis of the imaging optical system 7, and are disposed so as to irradiate the same region on a surface of the object to be measured 2. The imaging optical system 7 captures the lights irradiated by the light sources 1a-1c of the light-emitting system 1. The image processing section 8 obtains a plurality of the images, selects an optimal portion, calculates shape information, and measures a three-dimensional shape. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method.

Conventionally, there is a light cutting method as one of methods for measuring a three-dimensional shape of an object without contact. The light cutting method is based on the principle of triangulation, projecting line-shaped light onto the object to be measured, imaging the line light deformed according to the shape of the object to be measured with a camera, and determining the surface shape of the object to be measured. How to get. FIG. 4 shows the principle of measurement by a conventionally known light cutting method. As shown in FIG. 4, when the light emitted from the light source 51 passes through the slit 52, it becomes line-shaped light (hereinafter referred to as line light 53). When the measurement target object 2 is irradiated with the line light 53, a light cutting line 54 is formed on the measurement target object 2. When the light cutting line 54 is imaged with a camera, an image 55 is obtained. One point P on the light cutting line 54 is imaged at P ′, and attention is paid to the triangle formed by connecting the light source 51, the point P, and the point P ′, the distance L between the light source 51 and the point P ′, the light source 51 and the point P ′. The angle θ ₁ formed by the line segment connecting P ′ and the line segment 53a connecting the light source 51 and the point P, and the angle θ ₂ formed by the line segment connecting the point P and the point P ′ and the line segment connecting the light source 51 and the point P ′ are Known. Since the triangle is determined to be one when the angles of one side and both ends thereof are known, the three sides and three angles of the triangle are obtained, and the position of the point P ′ can be measured. If the line light 53 is scanned and other points are similarly obtained, the three-dimensional shape of the object can be obtained. As a three-dimensional shape measurement apparatus using such a light cutting method, an apparatus is disclosed that irradiates line light from a plurality of light sources to different positions of a measurement target object and measures the three-dimensional shape of the measurement target object. (For example, refer to Patent Document 1).
(For example, refer to Patent Document 1).
JP 2001-255125 A

  However, in this conventional light cutting method, as shown in FIG. 5A, when the inclination of the measurement object surface 2 ′ and the irradiation angle of the line light 53 are substantially equal, as shown in FIG. Compared with the case where the inclination of the measurement object surface 2 ′ and the irradiation angle of the line light 53 are not equal, the width 61 of the optical cutting line increases, resulting in deterioration in accuracy and spatial resolution, and the measurement object surface Depending on 2 ', there is an angle characteristic of scattered light, and the imaging optical system detects scattered light from the object surface 2' to be measured.

  The present invention has been made in view of such a problem, irradiating light to substantially the same region of the measurement target object from a plurality of angles, to obtain imaging data at an angle suitable for measurement of the surface shape, It is an object of the present invention to provide a three-dimensional shape measuring apparatus and a three-dimensional shape measuring method capable of highly accurate measurement.

  In order to solve the above problems, a three-dimensional shape measuring apparatus according to the present invention has a plurality of light sources, a light projecting system that irradiates light on the surface of the measurement target object from different directions, and a light source of the light projecting system An imaging optical system that captures light emitted from each of the measurement target objects, and an image processing unit that processes an image of the measurement target object corresponding to each of the light sources captured by the imaging optical system Is done. Each of the plurality of light sources included in the light projecting system is different in the angle formed between the optical axis of the imaging optical system and the optical axis of each light source within a predetermined plane including the optical axis of the imaging optical system. It is arranged to irradiate substantially the same area on the surface of the target object, and the image processing unit calculates shape information by selecting an optimum part from the image of the measurement target object corresponding to each of the light sources. .

  In such a three-dimensional shape measuring apparatus, each of the plurality of light sources included in the light projecting system is preferably configured to irradiate the measurement target object with slit light.

  At this time, the image processing unit irradiates the measurement target object with a plurality of slit lights, and among the plurality of slit images captured by the imaging optical system, the slit image having the maximum intensity or the width in the short direction is It is preferable to calculate the shape information of the measurement target object using the minimum slit image.

Further, in such a three-dimensional shape measuring apparatus, each of the plurality of light sources included in the light projecting system is configured to emit light having different wavelengths, and the imaging optical system is configured to emit light having different wavelengths from the plurality of light sources. And a plurality of image sensors for detecting the image of the object to be measured by receiving the light separated for each wavelength, and the light source for the straight line perpendicular to the optical axis of the imaging optical system. The inclination of the optical axis is θ, the inclination of the imaging surface of the imaging device with respect to a straight line perpendicular to the optical axis of the imaging optical system is θ ′, and the imaging optical system starts from the position where the optical axis of the light source and the optical axis of the imaging optical system intersect. Where a is the distance to the principal plane of the imaging optical system, and b is the distance from the rear principal plane of the imaging optical system to the position of the imaging element on the optical axis of the imaging optical system, a × tan θ ′ = b × tan θ
It is preferable to arrange the image sensor so as to satisfy the above condition.

  In such a three-dimensional shape measuring apparatus, the imaging optical system is a double-sided telecentric optical system, has one imaging element, and measures by switching on and sequentially switching a plurality of light sources of the light projecting system. It is preferable that the object is irradiated with light and an image of the object to be measured for each of the light sources is detected by one image sensor.

  Alternatively, the imaging optical system is a double-sided telecentric optical system, and has one color imaging device, and each of the light beams with different wavelengths irradiated from the plurality of light sources of the light projecting system to the measurement target object It is preferable to be configured to detect an image of the measurement target object with respect to each of the light sources by receiving the light with a color image sensor and separating and imaging each light as a color signal.

  The three-dimensional shape measurement method according to the present invention includes a light projecting system that has a plurality of light sources and irradiates light on the surface of the measurement target object from different directions, and a measurement target object from each of the light sources of the light projection system. An imaging optical system for imaging the light emitted to the object, and a method for measuring the three-dimensional shape of the object to be measured by a three-dimensional shape measuring apparatus, wherein each of the plurality of light sources of the light projecting system is imaged optically The angle between the optical axis of the imaging optical system and the optical axis of each light source is different within a predetermined plane including the optical axis of the system, and is arranged so as to irradiate substantially the same region of the surface of the object to be measured. The system captures the light irradiated to the measurement target object from each of the light sources of the light projecting system, calculates the shape information by selecting the optimum part from the image of the measurement target object corresponding to each of the light sources. Features.

  When the three-dimensional shape measurement apparatus and the three-dimensional shape measurement method according to the present invention are configured as described above, light is applied to substantially the same region of the measurement target object from a plurality of angles, which is suitable for measurement of the surface shape. Image data at an angle is obtained, and high-precision measurement of a three-dimensional shape is possible.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the three-dimensional shape measuring apparatus 10 according to the present embodiment includes a light projecting system 1 having a plurality of light sources (three light sources 1a to 1c in the case of FIG. 1), an imaging lens 3, It is composed of a plurality of optical elements (two optical elements 4a and 4b in the case of FIG. 1), an optical path length correction plate 5, and a plurality of imaging elements (three imaging elements 6a to 6c in the case of FIG. 1). An imaging optical system 7 that detects an image of the measurement target object 2, and an image processing unit 8 that processes the image of the measurement target object 2 corresponding to each of the light sources imaged by the imaging optical system 7. Yes. As described above, this is because the projected line width is narrowest when the optical axis of the light projecting system 1 is perpendicularly incident on the surface of the object 2 to be measured, and the light intensity of the scattered light is also reduced. This is because it becomes stronger, and it is desirable to image under conditions as close to normal incidence as possible. In order to realize this, in the three-dimensional shape measuring apparatus 10, a plurality of light sources (1a to 1c) constituting the light projecting system 1 are arranged in a predetermined plane including the imaging optical system 7, and the imaging is further performed. The angle of the optical axis of the light source (1a to 1c) with respect to the optical axis of the optical system 7 is arranged so as to be different from each other, and from the plurality of light sources (1a to 1c) constituting the light projecting system 1, approximately It is comprised so that light may be irradiated to the same area.

  Note that the three-dimensional shape measuring apparatus 10 may be configured to irradiate the measurement target object 2 with slit-shaped light from the light projecting system 1 using a slit or the like and receive the light with the imaging optical system 7.

  The light reflected by the measurement target object 2 is deformed according to the shape of the measurement target object 2 and is imaged by the imaging optical system 7. The image processing unit 8 extracts an optimum portion from a plurality of captured image data and calculates shape information (coordinates), thereby enabling accurate measurement of the three-dimensional shape of the measurement target object 2.

  In the three-dimensional shape measuring apparatus 10, the plurality of light sources 1 a to 1 c constituting the light projecting system 1 are configured to irradiate light having different wavelengths, and the imaging optical system 7 includes a plurality of light projecting systems 1. You may comprise so that it may have the optical element 4 which can branch the light of a different wavelength from these light sources 1a-1c, and the several image pick-up element 6 which each receives the light branched for every wavelength. As the optical element 4, it is preferable to use a dichroic prism, a dichroic mirror, or the like. By having such a configuration, in the imaging optical system 7, after the light irradiated from each of the light sources 1a to 1c of the light projecting system 1 and reflected by the measurement object 2 is branched for each wavelength by the optical element 4, Light is received by the image sensors 6a to 6c corresponding to the respective wavelengths. In this case, the projection angle of each wavelength (as shown in FIG. 1, in the plane including the optical axis of the imaging optical system 7 and the light sources 1 a to 1 c, the line orthogonal to the optical axis of the imaging optical system 7 and each line By tilting the image sensors 6a to 6c according to the Scheinproof law according to the angles θa to θc with the optical axes of the light sources 1a to 1c, it becomes possible to measure the entire surface of the measurement target object 2 with high accuracy. By separating the light from the plurality of light sources 1a to 1c of the light projecting system 1, the shape can be measured by one scan.

  Hereinafter, the arrangement of the image sensor 6 according to the Scheinproof law will be described. As shown in FIG. 2, Scheimpflug's law is such that one extension line of each of the object plane 21 of the measurement target object 2, the main plane 22 of the imaging optical system 7, and the image plane 23 of the imaging element 6 (see FIG. 2). 2), the main plane from the position of the object plane 21 on the optical axis (the position where the optical axes of the light sources 1a to 1c of the light projecting system 1 and the optical axis of the imaging optical system 7 intersect). The distance from the main plane 22 to the position of the image plane 23 on the optical axis of the imaging optical system 7 is b, and the object plane 21 is inclined with respect to a straight line perpendicular to the optical axis of the imaging optical system 7. Where θ is θ and the inclination of the image plane 23 with respect to a straight line orthogonal to the optical axis of the imaging optical system 7 is θ ′, these relationships are expressed by the following equation (1).

a × tan θ ′ = b × tan θ (1)

  Further, in this three-dimensional shape measuring apparatus 10, the imaging optical system 7 may be constituted by a bilateral telecentric optical system, and the magnification of the imaging optical system 7 when the positions of the object plane and the image plane are shifted in the optical axis direction. Change can be prevented. Further, each of the light sources 1a to 1c constituting the light projecting system 1 is switched on / off, or separated as a color signal by using the light projecting system 1 and the color imaging device 6 having the multicolor light sources 1a to 1c. You may make it image. With such a configuration, it is not necessary to use a plurality of image sensors 6 corresponding to the number of light sources of the light projecting system 1, and it is possible to receive and process with one image sensor 6.

[First embodiment]
Hereinafter, specific examples of the above-described three-dimensional measuring apparatus 10 will be described. First, the configuration of the non-contact three-dimensional shape measuring apparatus 10 according to the first embodiment will be described with reference to FIG. The three-dimensional shape measuring apparatus 10 shown in FIG. 1 includes a projection system 1 having a plurality of light sources, an imaging lens 3, a plurality of dichroic prisms 4 for branching light beams, an optical path length correction plate 5, and the same number of light sources. And an image processing unit 8 for processing the image of the measurement target object 2 corresponding to each of the light sources imaged by the imaging optical system 7. In the first embodiment and the following embodiments, the light projecting system 1 has three light sources 1a, 1b, and 1c. From the light sources 1a to 1c, line lights having different wavelengths λa, λb, and λc are irradiated to the measurement target object 2 from different projection angles θa, θb, and θc through slits (not shown) (light source). The way of thinking about the arrangement of 1a to 1c is as described above). Here, the dichroic prism 4 includes a first dichroic prism 4c that reflects only light having a wavelength λc, and a second dichroic prism 4b that reflects only light having a wavelength λb. The image sensor 6 includes first to third image sensors 6a, 6b, and 6c that receive light having wavelengths λa, λb, and λc, respectively.

  Here, regarding the positional relationship between the dichroic prism 4 and the image sensor 6, the distance from the first dichroic prism 4c to the third image sensor 6c and the distance from the first dichroic prism 4c to the first image sensor 6a. The distance from the second dichroic prism 4b to the second image sensor 6b, the distance from the second dichroic prism 4b to the first image sensor 6a, and the optical path length of the optical path length correction plate 5 and the second dichroic prism The optical path lengths of 4b are equal. Then, based on these positional relationships, the image sensors 6a to 6c are arranged to be inclined with respect to the optical axis in accordance with the above-mentioned Scheinproof law. As a result, the image pickup devices 6a to 6c are respectively set to θa ′, θb ′, θc ′ in accordance with the image plane 23 obtained from the above formula (1) based on the positional relationship between the dichroic prism 4 and the image pickup device 6 described above. Tilt at an angle of. By arranging in this way, images in focus on the entire surface of each of the image sensors 6a to 6c are obtained.

  In such a three-dimensional shape measuring apparatus 10 according to the first embodiment, the line lights having the wavelengths λa, λb, and λc from the light sources 1 a to 1 c constituting the light projecting system 1 are orthogonal to the optical axis of the imaging optical system 7. The measurement object 2 is irradiated from the directions of angles θa, θb, and θc with respect to the straight line. The line light reflected by the measurement target object 2 is deformed according to the shape of the measurement target object 2 and is formed as an image of the measurement target object 2 through the imaging lens 3. At that time, the line light transmitted through the imaging lens 3 is separated by the first dichroic prism 4c. The first dichroic prism 4c reflects only the light with the wavelength λc emitted from the light source 1c, and transmits the other light with the wavelengths λa and λb (that is, separates only the light with the wavelength λc). The light having the wavelength λc reflected by the first dichroic prism 4c passes through the optical path length correction plate 5 and reaches the image sensor 6c. On the other hand, of the light having the wavelengths λa and λb transmitted through the first dichroic prism 4c, the light having the wavelength λb is reflected by the second dichroic prism 4b, and the light having the wavelength λa is transmitted and separated. .

  The light having the wavelength λb is reflected by the dichroic prism 4b and then reaches the image sensor 6b. The light having the wavelength λa is transmitted through the dichroic prism 4b and then reaches the image sensor 6a. Since each of the image sensors 6a to 6c is inclined and arranged in accordance with the above-mentioned Scheinproof law, three images that are in focus on the entire surface of these image sensors 6a to 6c are obtained. The images (detection signals) obtained by the image pickup devices 6a to 6c are transmitted to the image processing unit 8. In the image processing unit 8, image data having a narrow light section line and high light intensity among these images. By extracting this part and calculating the shape information (coordinates), it is possible to measure the three-dimensional shape with respect to the measurement target object 2 with high accuracy.

[Second Embodiment]
Next, the configuration of the three-dimensional measuring apparatus 10 according to the second embodiment will be described with reference to FIG. The three-dimensional measuring apparatus 10 in FIG. 3 includes a light projecting system 1 having a plurality of light sources 1 a to 1 c, an imaging lens 3, and an imaging optical system 7 including one imaging element 6, and imaging with the imaging optical system 7. And an image processing unit 8 that processes an image of the measurement target object 2 corresponding to each of the light sources. The imaging lens 3 includes a front group lens 3a and a rear group lens 3b, and is arranged so that the position of the rear focus of the front group lens 3a and the position of the front focus of the rear group lens 3b coincide. ing. Further, a stop 31 is disposed at the position of the rear focal point of the front group lens 3a (the position of the front focal point of the rear group lens 3b), and the imaging lens 3 according to the second embodiment is a bilateral telecentric optical system. . Such a double-sided telecentric optical system can prevent the magnification of the imaging optical system 7 from changing even if the position of either the object plane or the image plane is shifted in the optical axis direction.

  In such a three-dimensional shape measuring apparatus 10 according to the second embodiment, line lights having wavelengths λa to λc are picked up from the three light sources 1a to 1c of the light projecting system 1 as in the first embodiment. The measurement object 2 is irradiated from the directions of angles θa, θb, and θc with respect to a straight line orthogonal to the optical axis of the system 7. The line light deformed in accordance with the shape of the measurement target object 2 is formed as an image of the measurement target object 2 on the imaging surface of the image sensor 6 by the imaging lens 3 of the bilateral telecentric optical system. At this time, in the second embodiment, the light sources 1a to 1c are turned on / off to turn on the light in order, and the respective light cutting lines when the light sources 1a to 1c are turned on are supplied to the image sensor 6. To image each.

  In this way, the image processing unit 8 turns on each of the light sources 1a to 1c in order, and among the three images obtained by the imaging device 6, the image processing unit 8 generates image data with a narrow light section line and high light intensity. A part is extracted, shape information (coordinates) is calculated, and an accurate three-dimensional shape is measured. In this way, by sequentially lighting the light sources 1a to 1c constituting the light projecting system 1, only one image sensor 6 is required, and the three-dimensional shape measuring apparatus 10 can be configured at low cost. In the second embodiment, the wavelengths of the light sources 1a to 1c are different from each other. However, since the images are taken by switching the light sources 1a to 1c on and off, the wavelengths of the light sources 1a to 1c may be the same. Is possible.

[Third embodiment]
Finally, the three-dimensional measuring apparatus 10 according to the third embodiment will be described. The three-dimensional shape measuring apparatus 10 of the third embodiment has the same configuration as the three-dimensional measuring apparatus 10 of the second embodiment shown in FIG. 3, and a light projecting system 1 having a plurality of light sources 1a to 1c. An image pickup optical system 7 composed of the image pickup lens 3 and one image pickup device 6, and an image processing unit 8 that processes an image of the measurement target object 2 corresponding to each of the light sources imaged by the image pickup optical system 7. , And is configured. The imaging lens 3 is a bilateral telecentric optical system having a front group lens 3 a, a rear group lens 3 b, and a diaphragm 31. In the third embodiment, a color image sensor is used as the image sensor 6.

  In such a three-dimensional shape measuring apparatus 10 according to the third example, line light of wavelengths λa to λc from the three light sources 1a to 1c of the light projecting system 1 is picked up by the imaging optical system, as in the second example. The measurement object 2 is irradiated from directions of angles θa, θb, and θc with respect to a straight line orthogonal to the optical axis 7. Then, the line light deformed according to the shape of the measurement target object 2 is formed as an image of the measurement target object 2 on the imaging surface of the image sensor 6 by the imaging lens 3 of the both-side telecentric optical system. In the third embodiment, since the color image pickup device 6 is used, the light of each wavelength transmitted through the image pickup lens 3 is separated and picked up as a color signal. Therefore, the wavelengths of the light rays emitted from the three light sources 1a to 1c are preferably three colors of RGB in accordance with the pixels of the color image sensor 6. In addition, when using an image sensor for a single color, a filter having a transmission wavelength band corresponding to the wavelength of the light source is arranged on the turret on the incident surface side of the image sensor, and these are realized by switching them in order. it can.

  The image processing unit 8 extracts a portion of the image data having a narrow light section line and a high light intensity from the images picked up in this way, and calculates shape information (coordinates). Measure the three-dimensional shape with high accuracy. Further, only one color image sensor 6 is required, and the three-dimensional shape measuring apparatus 10 can be configured at a low cost.

It is explanatory drawing for demonstrating the structure of the three-dimensional shape measuring apparatus of 1st Example which concerns on this invention. It is explanatory drawing for demonstrating the principle of Scheinproof's law. It is explanatory drawing for demonstrating the structure of the three-dimensional shape measuring apparatus of 2nd Example and 3rd Example based on this invention. It is explanatory drawing for demonstrating the principle of the optical cutting method of a prior art. It is explanatory drawing for demonstrating that the area of an optical cutting line changes with angles of a line light and an object surface, (a) is the optical cutting when the inclination of an object surface and the irradiation angle of a line light are substantially equal The line width is shown, and (b) shows the width of the light section line when the inclination of the object plane and the irradiation angle of the line light are not equal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light projection system 1a, 1b, 1c Light source 2 Object to be measured 3 Imaging lens 4 Optical element 4a, 4b, 4c Dichroic prism 5 Optical path length correction plate 6 Imaging element 7 Imaging optical system 8 Image processing part 10 Three-dimensional shape measuring apparatus

Claims (7)

A light projecting system having a plurality of light sources and irradiating light from different directions on the surface of the object to be measured;
An imaging optical system for imaging light irradiated on the measurement target object from each of the light sources of the light projecting system;
An image processing unit that processes an image of the measurement target object corresponding to each of the light sources imaged by the imaging optical system,
Each of the plurality of light sources included in the light projecting system has a different angle between the optical axis of the imaging optical system and the optical axis of each of the light sources within a predetermined plane including the optical axis of the imaging optical system. , Arranged to irradiate substantially the same region of the surface of the measurement object,
The three-dimensional shape measuring apparatus, wherein the image processing unit calculates shape information by selecting an optimum part from the image of the measurement target object corresponding to each of the light sources.   The three-dimensional shape measuring apparatus according to claim 1, wherein each of the plurality of light sources included in the light projecting system is configured to irradiate the measurement target object with slit light.   The image processing unit includes a plurality of slit images captured by the imaging optical system by irradiating the measurement target object with a plurality of slit lights, or the slit image having the maximum intensity, or in a short direction. The three-dimensional shape measuring apparatus according to claim 2, wherein shape information of the measurement target object is calculated using the slit image having a minimum width. Each of the plurality of light sources included in the light projecting system is configured to emit light having different wavelengths,
The imaging optical system includes: an optical element capable of separating light of different wavelengths from the plurality of light sources; and a plurality of imaging elements for receiving the light separated for each wavelength and detecting the image of the measurement target object. Have
The inclination of the optical axis of the light source with respect to a straight line perpendicular to the optical axis of the imaging optical system is θ, the inclination of the imaging surface of the imaging element with respect to a straight line perpendicular to the optical axis of the imaging optical system is θ ′, and the light source The distance from the position where the optical axis of the imaging optical system intersects the optical axis of the imaging optical system to the main plane of the imaging optical system is a, and the rear main plane of the imaging optical system on the optical axis of the imaging optical system Assuming that the distance to the position of the image sensor is b, the following formula: a × tan θ ′ = b × tan θ
The three-dimensional shape measuring apparatus according to any one of claims 1 to 3, wherein the imaging element is arranged so as to satisfy the above condition. The imaging optical system is a double-sided telecentric optical system and has one imaging element,
The plurality of light sources included in the light projecting system are sequentially turned on to illuminate the measurement target object, and the one image sensor detects an image of the measurement target object for each of the light sources. The three-dimensional shape measuring apparatus according to any one of claims 1 to 4. The imaging optical system is a double-sided telecentric optical system, and has one color imaging device,
By receiving each light having different wavelengths irradiated to the measurement target object from the plurality of light sources included in the light projecting system with the one color image sensor, and separating and imaging each light as a color signal, The three-dimensional shape measuring apparatus according to claim 1, configured to detect an image of the measurement target object with respect to each of the light sources. A light projecting system having a plurality of light sources and irradiating light from different directions on the surface of the object to be measured;
A three-dimensional shape measurement device that measures a three-dimensional shape of the measurement target object by a three-dimensional shape measurement apparatus having an imaging optical system that images light irradiated on the measurement target object from each of the light sources of the light projecting system A method,
The angle between the optical axis of the imaging optical system and the optical axis of each of the light sources is different within a predetermined plane including the optical axis of the imaging optical system for each of the plurality of light sources included in the light projecting system. , Arranged to irradiate substantially the same area of the surface of the measurement object,
The imaging optical system images the light irradiated on the measurement target object from each of the light sources of the light projecting system, and selects an optimum portion from the image of the measurement target object corresponding to each of the light sources. And calculating shape information.

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