JPH0875425A - Three-dimensional measuring device - Google Patents

Abstract

PURPOSE: To make a highly accurate measurement by applying a laser slit beam from the slant upper part of a member to be measured, and setting a binary threshold of an optical image in the direction of a linear part even if the concentration of a slit beam is varied according to the reflectance of the member to be measured, etc. CONSTITUTION: An image data input part 10 receives an image data from a focusing device 5. A linear direction threshold setting part 12 detects the direction of a laser slit beam 6 of the image data input into an input part 10, and outputs the threshold which varies according to its direction. Also, in a beam detecting part 11, a beam 6 is applied onto a member to be inspected 3, and the beam 6 with a density more than the threshold set at a setting part 12 is detected. A laser slit light source 4 is image-picked up by, for example, using a He-Ne laser or a semi-conductor laser with which detection can be made even in the dark with, the naked eyes. Then, a three-dimensional measuring part 14 converts the linear part 6 obtained by the detecting part 11 from an image coordinate system into an absolute coordinate system so as to measure the position, size, and form of the member 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring device using a light cutting method for a measuring member, and particularly to a position, size and shape of the measuring member by picking up an image of a laser slit beam irradiated on the measuring member and processing the image. The present invention relates to a three-dimensional measuring device that measures the

[0002]

2. Description of the Related Art Normally, as shown in FIG. 9, when three-dimensional measurement of a measuring member 3 on a conveyor 1 is performed, the slit light source 4 and an image pickup device 5 are often used by a light cutting method.
More specifically, as shown in FIG. 10, the imaging device 5
The slit ray segment 6 of the measurement member 3 is imaged by the slit ray segment 6 detected by the binarization threshold value set to a constant value in the line segment detection unit 11 from the image data captured by the image data capturing unit 10. The binary image of
The position, size, and cross-sectional shape of the measuring member 3 are measured by the three-dimensional measuring unit 14. As an example, as shown in FIG. 9A, the slit ray segment 6 of the measurement member 3 is divided into a measurement member plane line 3h, a measurement member vertical line 3v, an end face plane line 3c, and a reference line 3f.

As an example, an image of the measuring member 3 on the conveyor 1 is picked up and the image data fetching unit 10 is installed in the image processing device 31.
And a line segment detecting unit 11 and a three-dimensional measuring unit 14, the image data capturing unit 10 captures image data from the image pickup device 5, and the line segment detecting unit 11 captures a multivalued image as shown in FIG. 9C. A laser slit ray component 6 which is a binary image as shown in FIG. 9 (d) is detected by a threshold value set to a more constant value, and converted from an image coordinate system to an absolute coordinate system in the three-dimensional measuring device 14. The position, size and shape of the measuring member 3 were measured.

In this method, the binarization threshold value of the line segment detector 11 is constant in the imaging field of view 2 as shown by the line segment detector 11 in FIG. 10, and as shown in FIG. The density of the slit ray component 6 differs depending on the position of the measuring member 3 and the position of the imaging field of view 2 and the reflectance of the laser slit ray component 6 of the measuring member 3,
May have a thin vertical portion and a flat portion, and when the threshold value is constant, the slit ray component 6 of the vertical portion or the flat portion of the measuring member 3 is
Was difficult to detect with high precision.

In order to perform highly accurate measurement by the light section method, it is necessary to obtain a light section image (slit ray portion 6) having a density that can be clearly distinguished from the background and having a width as narrow as possible. The reflectance of the surface is partially different, the power distribution of the laser slit light source is a Gaussian distribution (normal distribution) as shown in FIG. 11, and the distance between the measured object 3 and the imaging device 5 is also different. The density of the light section image in the image data is not uniform and its dynamic range is generally wide.

If the density of the light-section image is too low, it becomes difficult to distinguish it from the background density, which causes erroneous measurement. If the density of the light section image is too high, saturation occurs in that part in the image pickup device 5 and blooming or smear occurs. Therefore, not only the density of the corresponding section of the light section image becomes bright, but also the line width becomes thick and the measuring member 3 It becomes difficult to accurately detect the three-dimensional information of. Therefore, the density of the light-section image is not constant in the threshold value, but the slit light ray portion 6 which is darker than the predetermined density (the light-section image having the narrowest width possible) and the brightest of the density, that is, the lowest threshold density is detected. There is a need to.

As one method of solving this problem, as described in Japanese Patent Application Laid-Open No. 62-21011, the slit light intensity is changed for the same portion of the same measuring member and the image is taken by the image pickup means. A means for temporarily storing a plurality of image data is compared with the densities of the same pixel address of the plurality of image data, and the density which is darker than a predetermined threshold and is the brightest, that is, the lowest threshold density is the pixel address. Although it can be considered to extract as a representative value of, it takes time (several seconds to several tens of seconds) to stabilize the concentration of the light source, so that it is difficult to put it into practical use by online measurement.

[0008]

Conventionally, when the measuring member 3 is three-dimensionally measured, if the slit ray component 6 on the measuring member 3 is obtained, each part of the measuring member 3, the position of the imaging visual field 2 and the slit of the measuring member 3 are determined. The density of the slit ray component 6 varies depending on the reflectance of the ray component 6, and as an example, the vertical portion is thin and the plane portion is thick, and the position and size of the measuring member 3 are detected by detecting the slit ray component 6 when the threshold value is constant. It was difficult to measure the shape with high accuracy.

An object of the present invention is to detect a density of a slit ray on the measuring member at a constant threshold value because the density of the slit ray component on the measuring member varies depending on the position of the measuring member, the position of the imaging visual field and the reflectance of the line segment of the slit light on the measuring member. Even if it is difficult to do so, by setting the threshold value according to each part of the measurement member (planar part or vertical part) or the imaging visual field position and setting the threshold value multiple times, the predetermined density (for highly accurate measurement, 3D that can measure the position, size, and shape of the measurement member with high accuracy by extracting the light-section image that is darker than the narrowest part possible and has the brightest density, that is, the density of the lowest threshold. The purpose is to obtain measurement.

[0010]

A three-dimensional measuring apparatus of the present invention is an image data capturing section and a line segment detector for three-dimensionally measuring an image of a laser slit light radiating a measurement object in a fan shape by an image pickup apparatus. Unit, a line segment direction threshold value setting unit, and a three-dimensional measuring unit.

The present invention further comprises an image data fetching section, a line segment detecting section, an imaging visual field position threshold setting section and a three-dimensional measuring section.

The present invention comprises an image data capturing section, a line segment control section, a threshold level setting section and a three-dimensional measuring section.

The present invention further comprises an image data capturing section, a line segment detecting section, a line segment direction threshold setting section, an imaging visual field position threshold setting section and a three-dimensional measuring section.

The present invention comprises an image data fetching section, a line segment control section, a line segment direction threshold setting section, a threshold level setting section and a three-dimensional measuring section.

The present invention further comprises an image data capturing section, a line segment control section, an imaging visual field position threshold setting section, a threshold level setting section and a three-dimensional measuring section.

[0016]

According to the present invention, the optical image of the laser slit light is picked up by the measuring member, the threshold value of the optical image of the measuring member is set in the direction of the line segment, and the slit ray component is detected.

Further, according to the present invention, the threshold value of the optical image of the measuring member is set by the image pickup visual field position, and the slit ray component is detected.

According to the present invention, the threshold value of the optical image of the measuring member is set a plurality of times, and the slit ray component is detected by the lowest threshold value.

Further, according to the present invention, the threshold value of the optical image of the measuring member is set according to the line segment direction and the imaging visual field position, and the slit ray segment is detected.

According to the present invention, the threshold value of the optical image of the measuring member is set a plurality of times in the direction of the line segment, and the slit ray segment is detected by the lowest threshold value.

Further, according to the present invention, the threshold value of the optical image of the measuring member is set a plurality of times depending on the image pickup visual field position, and the slit ray component is detected by the lowest threshold value.

[0022]

【Example】

Example 1. FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, an image pickup device for picking up an image of a laser slit light source 4 for irradiating a laser slit beam portion 6 and a measuring member 3 (one CCD camera 5) is arranged, and the image data capturing unit 1 is provided in the image processing apparatus 31.
By having 0, the line segment detection unit 11, the line segment direction threshold value setting unit 12, and the three-dimensional measurement unit 14, a binary image of the slit ray segment 6 on the measurement member 3 is detected and measured with high accuracy. The three-dimensional position, size and shape of the member 3 are measured.

As shown in FIG. 9, in general, when the height of the measuring portion of the measuring member 3 is the same as the reference position 3d on the conveyor 1 according to the principle of the optical cutting method, it becomes the reference line 3f and is higher than 3d. At this time, the slit light ray component 6 is refracted toward the laser light source 4 side and moves away from the reference line 3f in the imaging field of view 2 on the conveyor 1 and becomes parallel to the reference line 3f when it becomes flat on the plane portion and the upper end face of the measurement member 3. Then, since it approaches the reference position 3d when it goes down, it is possible to measure the position, size, and shape of the measuring member 3 by imaging the laser slit ray component 6.

The density of the slit light beam differs depending on the position of each part of the measuring member 3 (for example, a plane part or a vertical part),
As an example, when the density is high in the flat portion of the measuring member 3 and thin in the vertical portion, it is difficult to detect the slit ray component 6 with high accuracy with a constant threshold value. Since the direction of the slit ray component 6 changes in the vertical portion, it is possible to detect the slit ray component 6 with high accuracy by changing the threshold value by detecting the direction.

In FIG. 1, the image data capturing section 10 obtains image data from the image pickup device 5. The line segment direction threshold value setting unit 12 detects the direction of the slit ray segment 6 from the image data captured by the image data capturing unit 10 and outputs a threshold value that changes depending on the direction. As shown in FIG. 9A, the direction of the line segment is the reference line 3f if the measurement member 3 is a plane.
Is parallel to the reference line in the vertical portion, and is a straight line having an inclination angle on the reference line 3f determined by the slit rays emitted from the light source 4 in a fan shape. Therefore, the line segment detected from the image data is The threshold value is set according to the direction (for example, the plane portion and the vertical portion). That is, the threshold value is set high in the plane portion and set low in the vertical portion.

The line segment detector 11 irradiates the measuring member 3 with the laser slit light 6, and the illuminated slit light beam segment 6
From the line segment direction threshold value setting unit 12,
This is a signal processing unit for detecting the slit ray component 6 having a density equal to or higher than a threshold value.

The laser slit light source 4 is, for example, a He-Ne laser (0.63 μm) that can be detected by the naked eye in the dark.
m) and a semiconductor laser (0.69 μm) can be used for image pickup by the image pickup device 5.

The three-dimensional measuring unit 14 converts the slit ray segment 6 obtained by the line segment detecting unit 11 from the image coordinate system to the absolute coordinate system, and measures the position, size and shape of the measuring member 3. Since the position of the plane of the image coordinate system varies depending on the height of the measuring member 3 even at the same position, the height of the measuring member 3 from the reference position 3d is measured by the slit light plane equation constant and the imaging device mounting height constant and measured. The member 3 is converted from image coordinates to absolute coordinates. 2A and 2B show the positions of the measuring member 3 and the imaging device 5 as an example.

Example 2. 3 is a diagram showing another embodiment of the present invention. In FIG. 3, in the image processing apparatus 31, the image data capturing unit 10, the line segment detecting unit 11, the imaging visual field position threshold setting unit 15, and the three-dimensional measuring unit are shown. By including 14 and 14, the optical image of the measurement member 3 is captured by setting the threshold value according to the position of the imaging visual field 2, and the slit ray component 6 is detected.

As shown in FIG. 11, the laser slit light source 4
However, the power distribution is not uniform because it has a Gaussian distribution (normal distribution), the distance between the measuring member 3 and the imaging device 5 is different, and the density of the slit ray component 6 is different depending on the position of the imaging visual field 2. It is difficult to detect the slit ray component 6 with high accuracy when the threshold value is constant. Therefore, it is possible to detect the slit ray component 6 with high accuracy by changing the threshold value depending on the position of the imaging visual field 2.

The imaging visual field position threshold setting unit 15 sets a threshold value according to the position of the imaging visual field 2. Depending on the position of the imaging device 5, for example, the side of the imaging field of view 2 closer to the imaging device 5 is difficult to detect from the viewing angle, so the threshold value is low, and the side of the field of view 2 farther than the imaging device 5 is easier to detect from the viewing angle. Increase the threshold. Further, since the power is high in the center of the slit ray portion, the threshold value is raised, and the power is low at both ends, so the threshold value is lowered.

Therefore, as an example, the imaging field of view 2 is divided into three,
The threshold value is low on the side close to the image pickup device 5, high in the central portion, and is middle on the side far from the image pickup device 5. Conveyor 1
The imaging field of view 2, the measuring member 3, the slit light source 4, the imaging device 5, the image data capturing unit 10, the line segment detecting unit 11, and the three-dimensional measuring unit 14 are the same as those in the first embodiment.

Example 3. FIG. 4 is a diagram showing another embodiment of the present invention. In FIG. 4, an image data capturing unit 10, a threshold level setting unit 16, a line segment control unit 17, and a three-dimensional control unit 14 are provided in the image processing apparatus 31. Since the density of the slit ray component 6 differs depending on the position of each part of the measuring member 3, the position of the imaging visual field 2, and the reflectance of the slit ray component 6 of the measuring member 3, the slit ray component 6 has a constant value. By changing the density level of the threshold value a plurality of times, the line segment control unit 17 causes a predetermined density in each portion (flat surface portion, vertical portion) of the measuring member 3 (a line segment that is as narrow as possible for highly accurate measurement). By extracting the darker and brightest slit ray component 6 among them, that is, the lowest threshold concentration, it is possible to detect with high accuracy whether the slit ray component 6 is dense or thin.

The threshold level setting unit 16 sets the threshold value a plurality of times, but if the number of times is increased, it takes processing time. (Thus, the processing time is 0.2 seconds x 3 times = within about 0.6 seconds.)

Of the density levels detected by setting the threshold level a plurality of times from the optical image, the line segment control unit 17 compares the density with the address of the same pixel and the density is darker than a predetermined density value. The brightest density, that is, the lowest threshold density, is used as a representative value of this pixel address, and the slit light ray component 6
Is a signal processing unit for extracting

For example, as shown in FIG. 5, three threshold images are set by setting the threshold level three times. FIG. 5 (a) (high threshold level), FIG. 5 (b) (middle), FIG. c) (low)
Is obtained, and one composite image is obtained from these three images.
And the slit ray component 6 is extracted.

The conveyor 1, the imaging field of view 2, the measuring member 3, the laser slit light source 4, the imaging device 5, the slit ray component 6, the image data capturing section 10, and the three-dimensional measuring section 14 are the same as those in the first embodiment.

Example 4. FIG. 6 is a diagram showing another embodiment of the present invention. In FIG. 6, an image data capturing unit 10, a line segment direction threshold value setting unit 12, an imaging visual field position threshold value setting unit 15 are provided in the image processing apparatus 31. By including the line segment detection unit 11, it is possible to detect the slit light beam segment 6 even if the density of the slit light beam segment 6 differs depending on each part of the measurement member 3 and the position of the imaging visual field 2.

The line segment direction threshold value setting unit 12 uses the image data captured by the image data capturing unit 10 from the image data captured by the image pickup device 5 as shown in FIG. , The vertical direction) changes the direction of the slit ray component 6, so that the threshold value can be set depending on the direction of the slit ray component 6. Further, the image pickup visual field position threshold value setting unit 15 can set the threshold value depending on the position of the image pickup visual field 2 because the density of the slit ray component 6 varies depending on the position of the image pickup visual field 2.

Therefore, in the line segment detection unit 11, the line segment direction threshold value setting unit 12 is set high in the plane portion of the measuring member 3 and is set low in the vertical portion, and the image pickup visual field position threshold value setting unit 15 sets the image pickup portion. The field of view 2 is divided into three, and the imaging device 5
By setting the threshold value lower on the side closer to, higher in the central portion and higher on the side farther from the image pickup apparatus 5 and by connecting them as shown in FIG. 6, that is, by synergizing the two. By changing the threshold level, the slit ray component 6 can be detected with high accuracy.

A conveyor 1, an imaging field of view 2, a measuring member 3, a laser slit light source 4, an imaging device 5, a slit ray segment 6, an image data capturing section 10, a line segment detecting section 11, and a line segment direction threshold setting section 12 are provided. The three-dimensional measuring unit 14 is the same as that in the first embodiment. The imaging visual field position threshold setting unit 15 is the same as that in the second embodiment.

Example 5. FIG. 7 is a diagram showing another embodiment of the present invention. In FIG. 7, the image data capturing unit 10, the line segment direction threshold setting unit 12, the threshold level setting unit 16 and the line segment control in the image processing device 31 in FIG. By including the portion 17, even if the density of the slit ray component 6 is different in each part of the measuring member 3, it is possible to detect the slit ray component 6 with high accuracy.

The density of the slit ray component 6 differs depending on the position of each part of the measuring member 3 and the reflectance of the slit ray component 6 of the measuring member 3, and the density of the slit ray component 6 becomes thick or thin. Since it is not possible to detect the slit ray component 6 with high accuracy simply by changing the respective portions (planar portion, vertical portion) of, the threshold value for each portion (flat portion, vertical portion) of the measuring member 3 is changed a plurality of times to obtain a predetermined density ( In order to measure with high accuracy, it is necessary to extract the slit ray segment 6 that is darker than the line segment that is as narrow as possible and has the brightest density, that is, the lowest threshold density.

The line segment direction threshold value setting unit 12 can set the threshold value of the image data captured by the image data capturing unit 10 from the image pickup device 5 according to the position of each portion of the measuring member 3.

The line segment control unit 17 sets the threshold value in the direction of the line segment, that is, the threshold value is high in the plane portion of the measuring member 3 and is low in the vertical portion, and the threshold value is lowered a plurality of times (for example, high, middle, and low). By setting 3 times), it is possible to extract the slit ray segment 6 that is darker than a predetermined density (a line segment that is as narrow as possible for high-accuracy measurement) and that is the brightest of them, that is, the lowest threshold density. To do.

The conveyor 1, the imaging field of view 2, the measuring member 3, the laser slit light source 4, the imaging device 5, the slit ray segment 6, the image data capturing section 10, and the line segment direction threshold setting section 1
2 and the three-dimensional measuring unit 14 are the same as in the first embodiment. The threshold level setting unit 16 and the line segment control unit 17 are the same as in the third embodiment.

Example 6. FIG. 8 is a diagram showing another embodiment of the present invention. In FIG. 8, the image data capturing unit 10, the threshold level setting unit 16, the imaging visual field position threshold setting unit 15 and the line in the image processing apparatus 31 in FIG. By including the minute control unit 17, it is possible to detect the slit ray component 6 even if the density of the slit ray component 6 differs at the position of the imaging visual field 2.

The image pickup visual field position threshold value setting unit 15 can set the threshold value for the image data captured by the image data capturing unit 10 from the image pickup device 5 according to the position of the image pickup visual field 2 of the measuring member 3.

Depending on the position of the imaging field of view of the measuring member 3 and the reflectance of the slit light 6 of the measuring member 3, the slit ray component 6
Of the slit light beam 6 cannot be detected when the threshold value is constant because the density of the image is different and the density becomes thicker or thinner.
Depending on the position of the imaging field of view 2, the threshold value is changed a plurality of times and the density is darker than the predetermined density (the line segment that is as narrow as possible for high-accuracy measurement) and the brightest density, that is, the lowest threshold value. It is necessary to extract the density of slit rays.

The line segment control section 17 divides the threshold value, that is, the image pickup field into three, according to the position of the image pickup field 2. The side closer to the image pickup apparatus 5 has a lower threshold value, the central portion has a higher threshold value, and the image pickup apparatus 5 is further away. On the side, it is set to middle, and multiple times (for example, high, medium and low 3
By setting), it is possible to extract the slit ray segment 6 that is darker than a predetermined density (a line segment that is as narrow as possible for high-precision measurement) and that is the brightest, that is, the lowest threshold density. To do.

The conveyor 1, the imaging field of view 2, the measuring member 3, the laser slit light source 4, the imaging device 5, the slit light source 6, the image data capturing section 10, the imaging field of view position threshold setting section 15, and the three-dimensional measuring section 14 are implemented. Same as example 2. Further, the threshold level setting unit 16 and the line segment control unit 17 are the same as those in the third embodiment.
Is the same as

[0052]

As described above, according to the device of the present invention, the laser slit light is applied obliquely from above the measuring member to be measured, and the position of the measuring member and the image pickup device and the reflectance of the slit light of the measuring member. Even if the densities of the slit ray components differ, the binarization threshold value of the optical image is set in the direction of the line segment so that the slit ray components can be detected.

Further, according to the present invention, the binarization threshold value of the optical image is set according to the position of the imaging visual field so that the slit ray component can be detected.

According to the present invention, the binarization threshold value of the optical image is set a plurality of times so that slit light rays can be detected.

Further, according to the present invention, the binarization threshold value of the optical image is set depending on the direction of the line segment and the position of the imaging visual field, and the slit ray segment can be detected.

According to the present invention, the slit light ray segment can be detected by setting the binarization threshold value of the optical image a plurality of times depending on the direction of the line segment.

Further, according to the present invention, the binarization threshold value of the optical image is set a plurality of times depending on the image pickup visual field position, and the slit ray component can be detected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of an imaging visual field, an imaging device, and a laser light source of the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a third embodiment of the present invention.

5A and 5B are diagrams showing a threshold value change image and a composite image according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a schematic configuration of a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a schematic configuration of a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing a schematic configuration of a sixth embodiment of the present invention.

FIG. 9 is a diagram showing an example of a measuring member and an optical image.

FIG. 10 is a diagram showing a conventional three-dimensional measuring device.

FIG. 11 is a diagram showing a laser power characteristic of a laser light source.

[Explanation of symbols]

1 transport conveyor, 2 imaging field of view, 3 measuring member, 4
Laser slit light source, 5 imaging device, 6 laser slit light beam, 10 image data capturing unit, 11 line segment detecting unit, 12 line segment direction threshold setting unit, 14 three-dimensional measuring unit, 15 imaging visual field position threshold setting Section, 16 threshold level setting section, 17 line segment control section, 31 image processing apparatus.

Claims (6)

[Claims] 1. A laser slit light source for irradiating a laser slit light obliquely above an imaging visual field in which a measurement member to be measured is arranged, an imaging device for imaging an image of the measurement member, and image data from the imaging device. A line segment direction threshold value setting unit for setting a binarization threshold value for a slit light ray that is image data of the measuring member by a direction of the slit light ray that is the image data; A line segment detection unit that detects the binary image of the slit ray segment by the output of the line segment direction threshold setting unit from the image data obtained from the image data acquisition unit, and the measurement by the output of the line segment detection unit. A three-dimensional measuring device comprising: a three-dimensional measuring unit that performs three-dimensional measurement of a member. 2. A laser slit light source for irradiating a laser slit light from obliquely above an imaging visual field in which a measurement member to be measured is arranged, an imaging device for capturing an image of the measurement member, and image data from the imaging device. An image data capturing section, an image capturing visual field position threshold setting section that sets a binarization threshold value for slit light rays that is image data of the measuring member according to an image capturing position of the measuring member, and the image data capturing section. A line segment detection unit that detects the binary image of the slit light ray component by the output of the imaging visual field position threshold setting unit from the image data obtained by the three-dimensional measurement member by the output of the line segment detection unit. A three-dimensional measuring device comprising: a three-dimensional measuring unit that performs measurement. 3. A laser slit light source for irradiating a laser slit light obliquely above an imaging visual field in which a measurement member to be measured is arranged, an imaging device for imaging an image of the measurement member, and image data from the imaging device. Is obtained from the image data capturing unit, a threshold level setting unit capable of setting a binarization threshold of a line segment of slit light that is image data of the measuring member a plurality of times, and the image data capturing unit. From the image data, a line segment control unit for extracting a slit ray segment that is darker than a predetermined concentration and brightest among them, that is, a slit ray segment having the lowest threshold concentration by the output of the threshold level setting unit, and the line segment control. A three-dimensional measuring device comprising: a three-dimensional measuring unit that performs three-dimensional measurement of the measuring member based on an output of the unit. 4. An imaging field-of-view position for setting a binarization threshold value for a slit light ray, which is image data of a measurement member to be measured, according to an imaging position of the measurement member and outputting it to a line segment direction threshold value setting unit. The three-dimensional measuring apparatus according to claim 1, further comprising a threshold value setting unit. 5. A line segment direction threshold value setting unit for setting a binarization threshold value for a slit light ray which is image data of a measuring member to be measured according to a direction of the slit light ray of the measuring member. The three-dimensional measuring device according to claim 3, wherein 6. An image pickup visual field position threshold value setting unit for setting a binarization threshold value for a slit light ray which is image data of a measurement member to be measured according to an image pickup position of the measurement member. The three-dimensional measuring device according to claim 3.