JP2002221411A - Method for securing measurement accuracy of non- contact type device for measuring three-dimensional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for securing measurement accuracy, by which factors of fluctuation in accuracy are considered in overall, and the accuracy is secured with high reliability in plural kinds of non-contact type device for measuring three-dimensional shapes, and the measurement accuracy can be easily secured for the plural kinds of non-contact type device for measuring the three-dimensional shapes. SOLUTION: First, the resolution of a CCD camera (sensor) in the longitudinal, lateral and vertical directions is ascertained by the verification using a first standard gauge 36. Furthermore, the measurement accuracy of the sensor in the longitudinal and lateral directions is ascertained using a second standard gauge 42. The measurement accuracy of a third standard gauge 44 measuring the circular arc of a cylinder can be secured as a determined value by the verification using the first standard gauge 36 and the second standard gauge 42. In addition, the degree of errors in the object recognition of the sensor due to the different colors and the measurement accuracy for curved surface are ascertained by the verification using the third standard gauge 44. Then, the general measurement accuracy of the sensor is calculated using the result from the verification, and the accuracy of the non-contact type device for measuring the three-dimensional shape is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for assuring the measurement accuracy of a non-contact type three-dimensional shape measuring instrument, and more particularly to a method of measuring the accuracy of various non-contact type three-dimensional shape measuring instruments. Regarding the guarantee method.

[0002]

2. Description of the Related Art Conventionally, an object to be measured (hereinafter referred to as a work).
There is a three-dimensional shape measuring instrument as a device for measuring the three-dimensional shape of the object. The three-dimensional shape measuring instruments are roughly classified into a contact type and a non-contact type. The contact-type three-dimensional shape measuring instrument makes the tip of a small diameter probe directly contact the surface of the work and traces it along the shape of the work, thereby sequentially acquiring the three-dimensional coordinate data of the work and obtaining the three-dimensional shape of the work. It recognizes. The non-contact type three-dimensional shape measuring instrument projects light such as laser light onto the work, measures the distance to the work by the reflected light reflected from the work, and converts the three-dimensional coordinate data of the work. Projecting pattern stripes on a workpiece or a workpiece that calculates three-dimensional coordinates sequentially by a stereo photography method, capturing the fringes with a camera, etc., based on the distortion of the stripes on the surface of the captured workpiece A type that acquires the three-dimensional coordinate data of the work or a type that acquires the three-dimensional coordinate data by using an image processing method with respect to the characteristic portion of the photographed image by photographing the work with a camera or the like without projecting special light. There are things. Various other schemes have been proposed.

[0003] These three-dimensional shape measuring instruments are used in various fields such as for the purpose of researching arbitrary substances and collecting data thereof, and inspecting the finishing accuracy of industrial products. Since the non-contact type has a larger amount of data than the contact type, recently, the shift to the non-contact type has been actively performed.

[0004]

When measurement is performed, the measurement data always includes a measurement error. Therefore, in order to perform highly reliable measurement, it is necessary to consider the measurement error, that is, to guarantee the measurement accuracy. For example, in the case of a contact type three-dimensional shape measuring instrument, the accuracy assurance method is defined by JIS and the like.
Defined in% confidence limits.

However, in the case of the non-contact type three-dimensional measurement, a three-dimensional shape within the measurement area (for example, about A4 size) is measured at, for example, 300,000 points or more, and the measurement distance (two-dimensional) is measured like a contact type. There is a problem that the accuracy cannot be guaranteed based on the above. In the case of non-contact three-dimensional measurement,
The accuracy is affected by length, roughness, material, angle, roundness, work color, and the like. Therefore, there is a problem that the accuracy of the non-contact type three-dimensional shape measuring instrument cannot be expressed by only one measurement accuracy, and various accuracy is entangled, so that the measurement accuracy cannot be easily guaranteed.

Furthermore, the accuracy assurance of current non-contact type three-dimensional shape measuring instruments often uses the accuracy assurance value displayed by the manufacturer of each three-dimensional shape measuring instrument. Normally, the accuracy assurance value guarantees the accuracy of the entire 3D shape measuring instrument using the accuracy of only the resolution of the sensor or camera alone, or the accuracy assurance of the entire 3D shape measuring instrument using only the measuring accuracy related to length. In many cases, accuracy assurance of the entire 3D shape measuring instrument that considers various accuracy variation factors as described above is not performed at present, and the reliability of accuracy assurance is not sufficient. There is. In addition, accuracy assurance methods are not unified for each three-dimensional shape measuring instrument, and even for non-contact three-dimensional shape measuring instruments having the same function,
At present, measurement accuracy is guaranteed based on different standards for each 3D shape measuring instrument, and the reliability of interchangeability between 3D shape measuring devices is reduced, and the measurement accuracy is guaranteed based on different standards. If performed, there is a problem that data management for each three-dimensional shape measuring instrument becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in various non-contact type three-dimensional shape measuring instruments, a highly reliable accuracy assurance has been performed by taking into account accuracy fluctuation factors in a complex manner. An object of the present invention is to provide a measurement accuracy assurance method that can easily perform measurement accuracy assurance for a three-dimensional shape measuring instrument in a unified state.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for acquiring an image of a surface of an object by a sensor having a plurality of measuring elements, thereby obtaining a tertiary surface of the object. A measurement accuracy assurance method in a non-contact type three-dimensional shape measuring instrument for measuring an original shape, wherein a slope portion image of a first standard gauge having a flat slope portion is obtained, and each measuring element is focused. Based on the interval of the measurement point group data to be obtained, the step of testing the measurement resolution in the vertical and horizontal height direction of the sensor, and a flat part image of a second standard gauge in which a plurality of flat flat parts are arranged in a stepwise manner. Get multiple times,
Based on the vertical coordinate variation of the plane portion of the measurement point group data for each measurement obtained by each measurement element, the same plane variation accuracy of the sensor and the height measurement accuracy of two different plane portions are tested. Step and obtain a cylindrical surface image of the third standard gauge having a color that changes stepwise from at least the expanding color to the contracting color on the cylindrical surface, and the measurement point group data at different positions of the colors obtained by each measuring element is obtained. Testing the shape expansion / contraction accuracy and the curved surface measurement accuracy based on the cylindrical outer shape to be formed, and calculating the total measurement accuracy of the sensor based on the result of each of the steps;
Wherein the measurement accuracy of the non-contact type three-dimensional shape measuring instrument is guaranteed based on the total measurement accuracy of the sensor.

Here, the sensor for acquiring an image is, for example, a CCD image pickup device (for example, a CCD camera) or the like, and the vertical and horizontal directions of the first standard gauge are the vertical and horizontal directions of a plane parallel to the measuring element array surface of the sensor. And the height is a direction orthogonal to the measurement element arrangement plane. In addition, the first standard gauge, the second standard gauge, and the third standard gauge are formed of, for example, metal or ceramics, and the dimensional accuracy of a predetermined portion such as flatness, roundness, and angle can be accurately measured by any measuring device. Measured as a known value. The colors assigned to the third standard gauge are arranged in the order of expansion color to contraction color, for example, white, bluish green, bluish violet, gray, blue, green, red, black, etc. ing.

According to this configuration, the resolution in the vertical and horizontal height directions of the sensor is first confirmed by the verification using the first standard gauge, and further the verification is performed using the second standard gauge, so that the height of the sensor is increased. It is possible to check how accurate the measurement is in the direction. By performing the test using the first standard gauge and the second standard gauge,
It is possible to ensure that the circular arc of the cylinder of the third standard gauge is measured with a predetermined accuracy, and also to guarantee the actual accuracy of the curved surface measurement. In addition, the degree of the shape recognition error of the sensor due to the difference in color is confirmed by the test using the third standard gauge. Then, using the result of each test step, the total measurement accuracy of the sensor is calculated, and the accuracy of the non-contact three-dimensional shape measuring instrument is assured, so that the reliability of the accuracy assurance can be easily improved. it can.

In order to achieve the above object, according to the present invention, in the above-mentioned structure, furthermore, the whole image of the fourth standard gauge in which the same continuous patterns are arranged at equal pitches on a plane is divided and acquired by the sensor. Testing the data combining accuracy based on the degree of coincidence between the combined image and the fourth standard gauge when the obtained divided data is combined so as to synthesize the entire image of the fourth standard gauge. And guaranteeing the measurement accuracy of the non-contact type three-dimensional shape measuring instrument including the data bonding test.

Here, the fourth standard gauge is composed of, for example, a plate-like member having a large area, and the same continuous pattern may have any shape. However, it is preferable that the patterns are associated with each other. A rectangular pattern may be arranged, or a plurality of parallel grooves intersecting at a predetermined angle (for example, 90 °) may be formed on the surface of the plate member, and the remaining portion may be the same continuous pattern. When the entire image of the fourth standard gauge is divided and acquired by the sensor, for example, the fourth standard gauge is divided into four and the image is sequentially acquired by the same sensor. At this time, the image to be divided may have no portion missing from the whole, and may have an overlapping portion individually.

According to this configuration, the measurement object (measured object)
If the data has a large area and it is necessary to divide the shape data by the sensor and obtain the shape data, the accuracy at the time of the data bonding process is determined based on the comparison between the actual whole image and the combined image. You can check. Therefore, by guaranteeing the measurement accuracy of the non-contact type three-dimensional shape measuring instrument including the data bonding test, the reliability of the accuracy assurance when measuring a large object with the non-contact type three-dimensional shape measuring instrument is improved. It can be easily improved.

In order to achieve the above object, according to the present invention, in the above-mentioned structure, the same continuous three-dimensional pattern is arranged at an equal pitch on a long member. Based on the degree of coincidence between the combined three-dimensional image and the fifth standard gauge when combined so as to synthesize the entire three-dimensional image of the fifth standard gauge using the divided data acquired by the sensor. Testing the spatial bonding accuracy by using
The measurement accuracy of the non-contact type three-dimensional shape measuring instrument including the space bonding accuracy is guaranteed.

Here, the same continuous three-dimensional pattern formed on the fifth standard gauge may be, for example, an arrangement of individual separated spheres, or an arrangement of cones or rectangular parallelepipeds. Further, it may be a hemispherical concave shape.

According to this configuration, the measurement object (measured object)
Is large and it is necessary to divide the large space where the measurement object exists by the sensor and acquire the shape data, based on the comparison between the actual whole stereoscopic image and the combined image that is pasted together, It is possible to confirm the bonding space accuracy at the time of processing. Therefore, by guaranteeing the measurement accuracy of the non-contact three-dimensional shape measuring instrument, including the spatial bonding test of data, the reliability of the accuracy assurance when measuring a large object with the non-contact three-dimensional shape measuring instrument is high. The degree can be easily improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram illustrating the concept of assurance of the accuracy of the measurement accuracy assurance method of the non-contact type three-dimensional shape measuring instrument according to the present embodiment.

In this embodiment, Japanese Industrial Standards (J
IS) and the accuracy verification standard (standard gauge) for the non-contact type three-dimensional shape measuring device 12 by the contact type three-dimensional shape measuring device 10 whose accuracy is guaranteed according to the International Standards Organization (ISO) standard.
Then, the non-contact type three-dimensional shape measuring instrument 12 is subjected to the accuracy assurance test using the standard gauge 14 whose accuracy is assured.

First, as a preparation before implementing the measurement accuracy assurance method of the present embodiment, as described above, JIS or ISO
The verification (accuracy assurance) of the contact type three-dimensional shape measuring instrument 10 is performed by using a prototype defined as a national standard by. The prototype is provided by each manufacturer as a reference block based on JIS and ISO standards. In the reference block,
There is a reference for length, surface roughness, angle, and the like, which guarantees the basic accuracy of the contact type three-dimensional shape measuring instrument 10. The contact type three-dimensional shape measuring instrument 10 has a probe with a small diameter at the tip, and performs the measurement by directly tracing the surface of the reference block. Then, the accuracy of the contact type three-dimensional shape measuring instrument 10 is calculated by comparing the measurement result with the dimensions of the reference block in advance, and the accuracy is assured.

Further, the accuracy of the standard gauge 14 is assured by the contact type three-dimensional shape measuring instrument 10 whose accuracy has been assured. In general, the measurement accuracy of the contact type three-dimensional shape measuring instrument 10 is 10 μm or less, so that the shape accuracy of the standard gauge 14 can be well verified.

The characteristic feature of the present embodiment is that in order to ensure sufficient accuracy of the non-contact type three-dimensional shape measuring instrument 12, a test using a plurality of types of standard gauges is performed, and a composite result of each test is referred to as a non-contact type. This is to guarantee the measurement accuracy of the three-dimensional shape measuring instrument 12.

FIG. 2 shows a schematic configuration of the non-contact type three-dimensional shape measuring instrument 12 used in the present embodiment.
The non-contact type three-dimensional shape measuring device 12 used in the present embodiment includes:
For example, it is a non-contact type three-dimensional shape measuring device of a stripe pattern projection type, in which a stripe pattern light is projected on the surface of an object to be measured (hereinafter referred to as a work) 16 by a stripe projection device 18, and Is a sensor having a plurality of measuring elements from different directions, for example, a CCD imaging device (for example, a CCD camera) 2
At 0, the stripe pattern 18a is captured. Stripe pattern 18a
Is different from the position at which the stripe projected by the CCD camera 20 is captured, the projected stripe pattern 18a looks curved along the surface shape of the work 16.
Then, by quantifying the stripe pattern 18a captured by the CCD camera 20 using the principle of triangulation, the depth dimension of each stripe can be calculated, and the three-dimensional shape of the work 16 can be measured. That is, X, Y, and X of the measurement point group measured by the plurality of measurement elements of the CCD camera 20
The shape of the work 16 is recognized by calculating the Z coordinate and analyzing the measurement point group.

In the case of the configuration shown in FIG. 2, the stripe pattern 18a captured by the CCD camera 20 is
The data is supplied to the data processing unit 26 of the second image processing unit 24, and the coordinates of each measurement point are calculated. And the shape processing unit 2
In step 8, based on the acquired measurement point data, the work 16
For example, the display unit 30 performs measurement point group data display, section line data display, shading display, and various dimension displays on the display unit 30 or the like, for example, as three-dimensional shape data. Note that in order to acquire the three-dimensional data of the work 16, it is necessary to acquire data from the work 16 in a plurality of directions. Therefore, the main body of the three-dimensional shape measuring device 22 includes a mechanism control unit 32 for controlling when the stripe projector 18 and the CCD camera 20 move around the work 16, a moving amount of the stripe projector 18 and the CCD camera 20, and a display unit. The display unit 30 also includes an operation unit 34 for operating a display mode, a processing mode in the image processing unit 28, and the like.

As described above, when acquiring the three-dimensional shape data of the work 16 with the non-contact type three-dimensional shape measuring instrument 12, it is necessary to guarantee the measurement accuracy. In the present embodiment, reliability of accuracy assurance of the non-contact three-dimensional shape measuring instrument 12 is improved by performing accuracy assurance for a plurality of items in a complex manner.

FIG. 3 et seq. Show specific examples of standard gauges used for assuring higher reliability in this embodiment. The processing of the data obtained using each of the standard gauges described below is performed by the image processing unit 24 shown in FIG.
And so on.

FIG. 3A shows an example of the first standard gauge 36 used for guaranteeing the accuracy of the resolution of the CCD camera 20 used in the non-contact three-dimensional shape measuring instrument 12. The first standard gauge 36 is formed of a three-dimensional body having a flat slope, for example, a triangular prism. FIG.
In the case of (a), an example is shown in which triangular prisms 36a and 36b having different shapes are connected at the bottom surface (upper surface). Triangular prism 3
6a, as shown in FIG. 3 (b), slope portions 38a, 38b having angles of, for example, 45 ° and 30 ° with respect to a horizontal plane.
And the triangular prism 36b is, for example, 15 ° with respect to a horizontal plane.
And inclined surface portions 40a and 40b having an angle of 10 °. As described above, the length, surface roughness, angle, and the like of the first standard gauge 36 are determined by the contact type three-dimensional shape measuring instrument 10.
It is assumed that the accuracy is guaranteed by

The non-contact three-dimensional shape measuring device 12 is manufactured by using the first standard gauge 36 whose accuracy is assured as described above.
The accuracy is guaranteed for the resolution of. That is, the stripe pattern 18a is projected on the first standard gauge 36 by the stripe projector 18 in the same manner as the normal shape measurement procedure by the non-contact type three-dimensional shape measuring device 12, and the images are captured by the CCD camera 20 from various directions. . Stripe pattern 1 with CCD camera 20
8a, the stripe pattern 18a has a slope 38
The distance between the CCD camera 20 and the first standard gauge 36 changes according to the angles of a, 38b, 40a, and 40b.
The focus state is different and the appearance is different. Then, the measurement point group data (X coordinate: horizontal direction, Y coordinate: vertical direction, Z coordinate) acquired by the measuring element of the CCD camera 20 in a focused state (a state in which the stripe pattern 18a is clearly captured) : Height direction) is, for example, as shown in FIG.
become that way. The horizontal interval of the measurement point group data at this time becomes the resolution in the horizontal direction (X coordinate direction) of the CCD camera 20, and the vertical interval of the measurement point group data corresponds to the vertical direction (Y coordinate) of the CCD camera 20. Direction), and the interval in the height direction of the measurement point group data becomes the resolution in the height direction (Z coordinate direction) of the CCD camera 20. For example, taking the height direction as an example, if the focus is on the slope portion 40b of 10 ° and there is no interval in the height direction of the measurement point group data,
The resolution in the height direction of the CCD camera 20 is “0”. Also, the interval in the height direction of the measurement point group data is 1
In the case of 0 μm, it can be verified that the resolution in the height direction is “10 μm”. Similarly, the resolution in the horizontal direction and the vertical direction can be verified (steps related to the verification of the resolution).

Next, in the above-described test regarding the resolution, a test is performed to determine how much variation each measurement element performs measurement. FIG. 4A shows an example of the second standard gauge 42 used for guaranteeing the accuracy of measurement variation of the CCD camera 20 used in the non-contact type three-dimensional shape measuring instrument 12. Second standard gauge 42
Has a shape in which a plurality of flat plane portions 42a are arranged in a stepwise manner. FIG. 4A shows an example in which the flat portion 42a is formed in a step shape on the base member 42b. As described above, it is assumed that the accuracy of the length, surface roughness, angle, and the like of the second standard gauge 42 is guaranteed by the contact type three-dimensional shape measuring instrument 10.

The non-contact type three-dimensional shape measuring device 12 can be obtained by using the second standard gauge 42 whose accuracy is thus guaranteed.
And the two different plane portions 42.
Accuracy is guaranteed for the measurement accuracy in the height direction a. Also in this case, as shown in FIG. 4 (b), the stripe pattern 18a is projected on the second standard gauge 42 by the stripe projector 18 in the same manner as the normal shape measurement procedure using the non-contact type three-dimensional shape measuring device 12, The image is captured by the CCD camera 20 from a plurality of directions. Also in this case, the stripe pattern 1 is
By capturing 8a, measurement point group data (X coordinate: horizontal direction, Y coordinate: vertical direction, Z coordinate: height direction) can be obtained. The measurement point group data obtained at this time is, for example, as shown in FIG. Originally, when there is no measurement variation among the measurement elements of the CCD camera 20, the measurement point group data (X, Y, Z coordinates) is the same regardless of the measurement direction. However, when the measurement elements have measurement variations, when the measurement point group data for each measurement is superimposed, FIG.
As shown in (c), a variation m occurs in the measurement accuracy of the same plane portion 42a, and a variation n in the height direction of two different plane portions 42a occurs. The variation m, n at this time
, The CCD camera 20 has the same plane measurement accuracy,
For example, if m = 3 μm or the measurement accuracy in the height direction is
For example, it can be verified that n = 5 μm (a step of a test for a plane).

When the three-dimensional shape is captured by the CCD camera 20, if the three-dimensional surface is colored, the three-dimensional shape may appear to expand or contract depending on the color. That is, when a color that reflects light, such as white, is colored on the three-dimensional surface, the three-dimensional object appears to expand more than actual. Such a color is called an expanded color. Conversely, when the three-dimensional surface is colored with a color that absorbs light such as black, the three-dimensional object appears to contract more than it actually is. Such a color is called a contraction color. The third standard gauge 44 shown in FIG.
It is used to test how much the measurement element 0 performs measurement with respect to the difference in color.

The third standard gauge 44 is formed of a cylinder having a high degree of roundness (the diameter along the axis is the same in all parts), and a color that changes stepwise from an expanded color to a contracted color is formed in a band shape on its surface. It is colored. Here, the gradual change from the expansion color to the contraction color means, for example, white, blue-green, blue-violet, yellow, gray, blue,
Green, red, black, etc. As described above, it is assumed that the accuracy of the length, surface roughness, roundness, and the like of the third standard gauge 44 is guaranteed by the contact type three-dimensional shape measuring instrument 10.

The non-contact three-dimensional shape measuring device 12 is manufactured by using the third standard gauge 44 whose accuracy is thus guaranteed.
The accuracy of shape expansion / contraction by the surface color of the sample is examined. Also in this case, as shown in FIG. 5B, the fringe projector 18 is used in the same manner as the normal shape measurement procedure using the non-contact three-dimensional shape measuring device 12.
, The stripe pattern 18a is projected on the third standard gauge 44, and the image is captured by the CCD camera 20 for each surface color. Also in this case, the stripe pattern 18a is
, Measurement point group data (X coordinate: horizontal direction, Y coordinate: vertical direction, Z coordinate: height direction) can be obtained. The measurement point group data obtained at this time is, for example, as shown in FIG.
(C). In this case, if there is no measurement variation due to the color of each measuring element, the third standard gauge 44 having the same shape (diameter) is measured even if the surface color is different, so the measurement point group data should be the same. It is. But,
Actually, as described above, apparent expansion and contraction due to color occurs, and therefore, as shown in FIG.
For example, black, red, and green are recognized as cylinders having different diameters.
Therefore, by comparing the measurement point group data for each color, it is possible to test how much the measurement element of the CCD camera 20 has a measurement accuracy for a color difference (a color-related verification step). For example, if the surface color of the measurement target is black, red, green, or the like, the measurement accuracy due to the difference in color can be shown to be, for example, 3 μm. At this time, it is also possible to determine which color can be measured with predetermined accuracy in the measuring element of the CCD camera 20. At this time, by comparing the known dimension (especially roundness) of the third standard gauge 44 with the measurement point group data, it is possible to also guarantee the accuracy of measuring the curved surface of the measurement element of the CCD camera 20. (Step of testing for curved surface measurement accuracy).

As described above, a non-contact type three-dimensional shape measuring instrument 1 is obtained by performing a test relating to the resolution, a test relating to the plane, a test relating to the color, and a test relating to the accuracy of measuring the curved surface.
In step 2, the test of the measurement accuracy is performed in a complex manner, and the total measurement accuracy of the CCD camera 20 is calculated (step related to accuracy calculation). For example, resolution test, plane test, color test,
The largest value in the curved surface measurement accuracy test, such as an accuracy of 10 μm, is calculated and displayed as the accuracy of the non-contact three-dimensional shape measuring instrument 12. At this time, one total accuracy may be displayed, or the results of each resolution test, plane test, color test, and curved surface measurement accuracy test may be shown, and further the total accuracy may be shown. By using each test result, it is possible to perform highly reliable accuracy guarantee by considering factors of accuracy variation in a complex manner. Also,
By performing each test, it is possible to easily unify the accuracy assurance methods for various non-contact three-dimensional shape measuring instruments.
In addition, it is possible to easily manage the acquired three-dimensional data by unifying the accuracy assurance methods.

Incidentally, the non-contact type three-dimensional shape measuring device 12
May be large, such as a vehicle body, but there is a limit to the data area that can be obtained by one shot of the CCD camera 20. In such a case, in order to acquire the entire data, it is necessary to sequentially divide the area that can be acquired by the CCD camera 20 and acquire the divided areas, and then connect the divided and acquired data. In order to improve the measurement reliability of the non-contact type three-dimensional shape measuring instrument 12, a test concerning the joining is also required.

FIG. 6A shows a fourth standard gauge 46 used for testing the bonding accuracy. In the case of the fourth standard gauge 46 of the present embodiment, the same continuous patterns are arranged at equal pitches on the plane of the base 46a having the flatness. In the case of FIG. 6A, as shown in a partially enlarged manner, the same continuous pattern (frustum) is formed by forming V grooves 46b in the vertical and horizontal directions at the same pitch on the surface of the base 46a. ing. Of course, any pattern such as a circle or a triangle may be used as long as adjacent patterns are associated with each other. As described above, it is assumed that the accuracy of each length, surface roughness, and the like of the fourth standard gauge 46 is guaranteed by the contact type three-dimensional shape measuring instrument 10.

The non-contact type three-dimensional shape measuring instrument 12 is used by using the fourth standard gauge 46 for which the accuracy is guaranteed as described above.
Test the data bonding at the time of obtaining the divided data. Also in this case, as shown in FIG. 6B, the stripe pattern 18a is projected on the fourth standard gauge 46 by the stripe projector 18 in the same manner as the normal shape measurement procedure by the non-contact type three-dimensional shape measuring device 12, The image is captured by the CCD camera 20. As described above, when the measurement object (measured object) is large, C
Since all data cannot be acquired by one shot of the CD camera 20, for example, the fourth standard gauge 46 is divided into four areas, and either the CCD camera 20 or the fourth standard gauge 46 is moved to each area. CC image
It is captured by the measuring element of the D camera 20. At this time, the divided images need not have any portions missing from the entire fourth standard gauge 46, and may have individual overlapping portions. Also in this case, by capturing the stripe pattern 18a with the CCD camera 20, the measurement point group data (X coordinate: horizontal direction, Y coordinate:
(Vertical direction, Z coordinate: height direction). The measurement point group data obtained at this time is attached so as to synthesize the entire image of the fourth standard gauge 46, for example, as shown in FIG. Then, the degree of coincidence between the overall dimensions recognized in the overall image formed by bonding and the known overall dimensions of the fourth standard gauge 46 is calculated. That is, as shown in FIG. 6C, a test is performed to determine whether or not the data has been completely bonded (step relating to the bonding test).
When the bonding is not completely (fitted), the bonding accuracy in the vertical direction is, for example, 2 μm, and the bonding accuracy in the horizontal direction is, for example, 3 μm.

As described above, the resolution test, the plane test,
By performing a color test, a curved surface measurement accuracy test, and a bonding test, when the measurement target has a large area and it is necessary to divide the shape data with a CCD camera and obtain the actual shape data, Accuracy at the time of the data joining process can be confirmed based on the comparison between the entire image and the combined image that has been attached. As a result, the measurement accuracy of non-contact type 3D shape measuring instruments, including data stitching test, is guaranteed, so the reliability of accuracy assurance when measuring large objects with non-contact type 3D shape measuring instruments Can be easily improved.

Further, when performing bonding, it is necessary to consider spatial bonding accuracy.

FIG. 7 (a) shows a fifth standard gauge 48 used for testing the spatial accuracy of bonding. In the case of the fifth standard gauge 48 of the present embodiment, the same continuous three-dimensional pattern is arranged at an equal pitch on a long member 48a having a flatness. In the case of FIG. 7A, a plurality of individually fixed spheres 48b are arranged on a rod-shaped stand. The length and surface roughness of the fifth standard gauge 48, the spherical body 4
As described above, it is assumed that the accuracy of the arrangement pitch of 8b is guaranteed by the contact type three-dimensional shape measuring instrument 10 as described above. Note that this three-dimensional pattern is not limited to a sphere, but may have any shape such as a cone or a rectangular parallelepiped. Further, it may be a hemispherical concave shape.

Using the fifth standard gauge 48 whose accuracy is assured in this way, the non-contact type three-dimensional shape measuring instrument 12 is used.
Test the spatial accuracy of data stitching at the time of obtaining the divided data. Also in this case, as shown in FIG. 7A, the stripe pattern 18a is projected on the fifth standard gauge 48 by the stripe projector 18 in the same manner as the ordinary shape measurement procedure using the non-contact three-dimensional shape measuring device 12, The image is captured by the CCD camera 20. As mentioned above, when the measurement target is large, CCD
Since all data cannot be acquired by one shot of the camera 20, for example, the fifth standard gauge 48 is divided into two areas in the longitudinal direction, and either the CCD camera 20 or the fifth standard gauge 48 is moved. The image of each area is captured by the measuring element of the CCD camera 20. Also in this case, by capturing the stripe pattern 18a with the CCD camera 20, measurement point group data (X coordinate: horizontal direction, Y coordinate: vertical direction, Z coordinate: height direction) can be obtained. The measurement point group data obtained at this time is pasted so as to combine the whole image of the fifth standard gauge 48 as shown in FIG. 7B, for example, and the overall dimensions recognized by the pasted whole image are combined. , And the pitch distance of the sphere 48b is compared with the known overall dimensions and pitch distance of the fifth standard gauge 48 to calculate the degree of coincidence. That is, as shown in FIG. 7B, a test is performed to determine whether or not the data has been completely combined spatially (step relating to the spatial combination test). In this case, it is possible to display such that the bonding accuracy of the entire length is, for example, 2 μm. In addition, since the pitch comparison of the individual spheres 48b can be performed, it is also possible to perform the accuracy test when the data in the length direction is cumulatively added. Further, the accuracy of the bonding accuracy in the height direction (vertical displacement of the bonded portion in the vertical direction) can be indicated as, for example, 1 μm.

As described above, the resolution test, the plane test,
By performing color verification, curved surface measurement accuracy verification, and space bonding verification, if the measurement object has a large area and it is necessary to divide the shape data with a CCD camera and acquire the shape data, The spatial accuracy at the time of the data joining process can be confirmed based on the comparison between the whole image of the above and the combined image that has been joined. As a result, by guaranteeing the measurement accuracy of the non-contact three-dimensional shape measuring instrument including the spatial bonding test of data, the accuracy assurance when measuring a large workpiece with the non-contact three-dimensional shape measuring instrument is improved. Reliability can be easily improved. Of course, by performing the test using the fifth standard gauge 48 in addition to the test using the fourth standard gauge 46 described above, the reliability of the accuracy assurance can be further improved.

After performing the various tests described above, the results are shown comprehensively. In this case, the test result of the fourth standard gauge 46 or the fifth standard gauge 48 is the first standard gauge 36
Since the results of the verification of the third standard gauge 44 are included in the results, the results of the verification of the fourth standard gauge 46 or the fifth standard gauge 48 are displayed as the accuracy of the non-contact three-dimensional shape measuring instrument 12. At this time, one total accuracy may be displayed, or the results of each resolution test, plane test, color test, curved surface measurement accuracy test, bonding test, space bonding test, and the total accuracy may be displayed. .

It should be noted that in the above-described embodiment,
The shape of the fifth standard gauges 36, 42, 44, 46, 48 is an example, and the first standard gauge 36 may have a flat slope portion, and the second standard gauge 42 may have a plurality of flat standard gauges. The third standard gauge 44 only needs to be colored with a color that changes stepwise from at least an expanding color to a contracting color on the cylindrical surface. It is only necessary that the same continuous patterns are arranged at equal pitches on a plane, and the fifth standard gauge 48 is only required that the same continuous three-dimensional patterns are arrayed at equal pitches on a long member. Even if it is changed arbitrarily, the accuracy described in the present embodiment can be guaranteed, and the same effect can be obtained.

Further, by performing the above-described composite accuracy assurance, a non-contact type three-dimensional shape measuring instrument having a desired measuring accuracy can be selected from various non-contact type three-dimensional shape measuring instruments. If it becomes necessary to make the selection, it is possible to easily make the selection.

[0046]

According to the present invention, highly reliable accuracy can be easily assured by complexly examining accuracy variation factors. In addition, by performing complex verifications on various non-contact type three-dimensional shape measuring instruments, it is possible to maintain the interchangeable reliability of the non-contact type three-dimensional shape measuring instruments and easily manage mutual acquired data. Will be possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an accuracy assurance concept of a measurement accuracy assurance method of a non-contact type three-dimensional shape measuring instrument according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a schematic configuration of a non-contact type three-dimensional shape measuring instrument according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a first standard gauge used in a measurement accuracy assurance method of the non-contact type three-dimensional shape measuring instrument according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating a second standard gauge used in a measurement accuracy assurance method of the non-contact three-dimensional shape measuring instrument according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a third standard gauge used in a measurement accuracy assurance method of the non-contact type three-dimensional shape measuring instrument according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a fourth standard gauge used in a method for assuring measurement accuracy of the non-contact type three-dimensional shape measuring instrument according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a fifth standard gauge used in a measurement accuracy assurance method of the non-contact type three-dimensional shape measuring instrument according to the embodiment of the present invention.

[Explanation of symbols]

10 contact type three-dimensional shape measuring device, 12 non-contact type three-dimensional shape measuring device, 14 accuracy verification standard device, 16 DUT,
18 fringe projector, 20 CCD camera, 22 three-dimensional shape measuring instrument main body, 24 image processing section, 26 data processing section,
28 shape processing unit, 30 display unit, 32 mechanism control unit,
34 operation unit, 36 first standard gauge, 42 second standard gauge, 44 third standard gauge, 46 fourth standard gauge, 48 fifth standard gauge.

Claims (3)

[Claims] An image of a surface of an object to be measured is acquired by a sensor having a plurality of measuring elements, and a measurement accuracy assurance method for a non-contact type three-dimensional shape measuring instrument for measuring a three-dimensional surface of the object to be measured is provided. There is obtained a slope portion image of the first standard gauge having a flat slope portion, and the height and width of the sensor based on the interval of the measurement point group data obtained by each measuring element when focused. A step of verifying the measurement resolution in the direction, and acquiring a plurality of plane images of the second standard gauge in which a plurality of flat planes are arranged in a stepwise manner, and measuring point group data for each measurement acquired by each measuring element Examining the same-plane variation accuracy of the sensor and the measurement accuracy in the height direction of the two different planar portions based on the vertical coordinate variation of the planar portion; Acquire a cylindrical surface image of the third standard gauge having a color that changes in a stepwise manner, and based on the cylindrical outer shape formed by the measurement point group data at different positions of the color acquired by each measuring element, the shape expansion / contraction accuracy and the curved surface Verifying the measurement accuracy, and calculating the total measurement accuracy of the sensor based on the result of each of the steps; and measuring the non-contact three-dimensional shape measuring instrument based on the total measurement accuracy of the sensor. A measurement accuracy assurance method characterized by performing accuracy assurance. 2. The method according to claim 1, further comprising: dividing and acquiring an entire image of a fourth standard gauge in which identical continuous patterns are arranged on a plane at an equal pitch by the sensor; Testing the data bonding accuracy based on the degree of coincidence between the bonded image and the fourth standard gauge when the entire image of the fourth standard gauge is bonded so as to be synthesized, and the data bonding is performed. A measurement accuracy assurance method characterized by performing measurement accuracy assurance of a non-contact type three-dimensional shape measuring instrument including verification. 3. The method according to claim 1, further comprising the step of dividing and acquiring the whole image of the fifth standard gauge, in which the same continuous three-dimensional pattern is arranged at an equal pitch on the long member, by the sensor. Spatial bonding accuracy based on the degree of matching between the bonded three-dimensional image and the fifth standard gauge when the entire three-dimensional image of the fifth standard gauge is bonded so as to be synthesized using the divided data obtained by the sensor. And a step of verifying, and performing the measurement accuracy assurance of the non-contact type three-dimensional shape measuring instrument including the spatial bonding accuracy.