JP2002107127A - Shape-measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape-measuring apparatus which can measure appropriate three-dimensional shape with fewer number of measurement procedures. SOLUTION: The shape-measuring apparatus has a mirror placed on a measurement stage, a transparent glass plate, disposed in parallel to the mirror and above the mirror, a measuring head including a slit light-irradiating means and an imaging element for measuring the shape of an object to be measured by a light-section method, a position-detecting means for detecting the position of the measuring head, and a calculating means for obtaining the three- dimensional shape of the object to be measured, on the basis of images imaged by the imaging element of the measuring head and the position of the measuring head detected by the position-detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring device for measuring a three-dimensional shape, and more particularly to a shape measuring device suitable for measuring the shape of a foot.

[0002]

2. Description of the Related Art In general, the size of a shoe is usually expressed by the length from the heel to the fingertip. It is. When trying to make shoes according to the shape of each person's foot, it is necessary to measure the three-dimensional shape of the foot, but at present, using a measure, foot length, foot width, foot position (around the foot)
It only measures the size of limited parts such as.

On the other hand, there is known an active stereo type shape measuring apparatus which irradiates a spot light or a slit light to an object to be measured and restores a three-dimensional shape from a position of an optical image observed on the surface of the object to be measured. . This shape measuring device scans spot light or slit light with a rotating mirror in order to measure the surface shape of an object to be measured. The magazine "Measurement and Control" (1999 Vol.38 No.4 P285-P288 ) Describes a system for measuring the shape of a foot using such a shape measuring device.

In this system, a single shape measuring device can measure only the shape of a portion observed from the device and cannot measure the shape of a hidden portion such as the opposite side. The shape of the entire foot is measured by arranging the shape measuring devices around the foot and synthesizing the measurement results of the twelve shape measuring devices on a computer.

However, in this system, since a plurality of shape measuring devices are arranged around the foot, not only the system becomes large and expensive, but also the results of measurement by the plurality of shape measuring devices are synthesized with high accuracy. There is a problem that becomes difficult.

On the other hand, the applicant of the present application has already developed a shape measuring apparatus that performs measurement by holding a compact measuring head in a hand and moving the measuring head around an object to be measured. 2000-39310). In this shape measuring device, the position and orientation of the measuring head are measured by taking images of a plurality of markers attached to the measuring head from above using two cameras.

In this proposal, since it is necessary to photograph the entire moving range of the measuring head from the two upper cameras, two cameras are installed at positions away from the object to be measured in order to widen the common field of view of the cameras. As a result, a large installation space is required. In addition, when a part of the marker of the measuring head is out of the common field of view of the two cameras, or is hidden by the measuring object or the hand of the measurer holding the measuring head, the shape of the measuring object can be measured. Therefore, the measurer must always be careful that the markers of the measuring head are imaged by the two cameras.

Incidentally, in order to measure the shape of the instep surface and the back surface of the foot using one measuring head, it is necessary to measure the shape in two separate steps. In order to simultaneously measure the shape of the back of the foot and the back of the foot, two measuring heads, one for measuring the back of the foot and the other for measuring the back of the foot, are required.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shape measuring apparatus capable of measuring an appropriate three-dimensional shape with a small number of measuring procedures.

[0009]

SUMMARY OF THE INVENTION A shape measuring apparatus according to the present invention comprises a mirror mounted on a measuring table, a transparent glass plate arranged in parallel with and above the mirror, slit light irradiating means, and an image pickup device. And a measuring head for measuring the shape of the object to be measured by a light cutting method, a position detecting means for detecting the position of the measuring head, and an image picked up by an image sensor of the measuring head, which is detected by the position detecting means. Calculating means for obtaining a three-dimensional shape of the object to be measured based on the position of the measuring head, wherein the calculating means converts slit light appearing above the surface of the plate glass on the image plane of the image sensor of the measuring head. By extracting, a first three-dimensional shape of the normal image of the measured object in the world coordinate system is obtained.
Means, a second means for obtaining the projection coordinates of the virtual image position of the mirror with respect to the lowest point of the normal image on the imaging surface of the imaging device, and using the obtained projection coordinates as a starting point, in the upward direction on the image surface of the imaging device, Third means for obtaining a three-dimensional shape of the virtual image of the measured object in the world coordinate system by tracing the slit light corresponding to the virtual image of the measured object, and a mirror surface of the three-dimensional mirror for the virtual image of the measured object And a fourth means for obtaining a three-dimensional shape of the object by combining a three-dimensional shape symmetrical with respect to the three-dimensional shape and a three-dimensional shape of the normal image of the object.

As a third means, when the slit light corresponding to the virtual image of the object to be measured is being traced and another slit light intersects with the slit light being tracked, the upper left direction and the upper right direction are determined. Among them, one provided with a means for tracking slit light extending in a predetermined direction is used.

Further, as a third means, when a slit light corresponding to a virtual image of an object to be measured is being traced, in a region where another slit light intersects with the slit light being tracked, a predetermined value before the intersection is obtained. Based on the position of the slit light corresponding to the virtual image of the device under test extracted on the horizontal line and the position of the slit light extracted a predetermined horizontal line ahead thereof, the virtual image position between them is determined by linear interpolation. Determined, based on the position of the slit light corresponding to the virtual image of the measured object extracted on the predetermined horizontal line after the intersection, and the position of the slit light extracted a predetermined horizontal line earlier than that,
A device having means for obtaining a virtual image position therebetween by primary interpolation is used.

As the position detecting means, for example, means for detecting the position of the measuring head by a stereo method using two cameras is used.

It is preferable that a guide means for regulating the attitude of the measuring head is provided so that the light beam emitted from the slit light irradiating means of the measuring head is emitted perpendicular to the light reflecting surface of the mirror. It is preferable that the guide means regulates a moving path of the measuring head. Further, it is preferable to include a driving unit for moving the measuring head along the guide unit.

[0014]

Embodiments of the present invention will be described below.

[1] Description of schematic configuration of shape measuring device

FIG. 1 shows a schematic configuration of a shape measuring apparatus.

An arc-shaped guide rail 204 is fixed to the measuring table 201. A flat mirror 205 is disposed in a region surrounded by the guide rail 204. Mirror 205
Is a stainless steel mirror 2 having a light reflecting surface on the surface.
05 is used. Further, a transparent glass plate 206 is arranged above the mirror 205 with an interval. Mirror 205
Between the transparent glass plate 206 and the transparent glass plate 206, a spacer (not shown) is interposed at a peripheral portion thereof. The foot 100 as an object to be measured is placed on the glass plate 206. Further, a column 202 which is detachable from the measurement table 201 is attached to the measurement table 201, and a horizontal bar 203 is attached to an upper portion thereof.

The shape measuring device comprises a measuring head 10 which is manually moved along a guide rail 204 by a measurer, stereo cameras 21 and 22 attached to both ends of a horizontal bar 203, their control and various calculations. And a control device 30 including a personal computer for performing the above operations. Each of the imaging lenses of the stereo cameras 21 and 22 is provided with a band-pass filter 23 for selectively transmitting the frequency band of light emitted by the marker 14 shown in FIG.

[2] Description of Schematic Configuration of Measuring Head 10

FIG. 2 shows a schematic configuration of the measuring head 10 in FIG.

The measuring head 10 comprises a casing 11 having a rectangular parallelepiped shape and having a front opening, and a casing 11 housed in the casing 11.
CCD camera 12 and slit light source 13, and six LED light sources 14 a to 14 provided on the upper surface of casing 11.
And a marker 14 composed of 14f. As the slit light source 13, a semiconductor laser is used. In this embodiment, the casing 1
When viewed in the opening direction of No. 1, a slit light source 13 is disposed at a left position, and a CCD camera 12 is disposed at a right position.

The measuring head 10 is movably mounted along a guide rail 204 by a support mechanism (not shown). The measurement head 10 is attached to the guide rail 204 by a support mechanism (not shown) so that the light beam emitted from the slit light source 13 is emitted along a plane perpendicular to the stainless steel mirror 205. Posture is regulated.

Six LED Light Sources 1 Constituting Markers 14
In order to specify the direction of the measuring head 10, the positions 4 a to 14 f are not symmetrical with respect to a point but are symmetrical with respect to the center line of the measuring head 10. Here, the casing 1
LED light sources 14b, 14c, 14d, 14
The five points e and 14f are arranged so as to form a rectangle, and the LED light source 14a is arranged at the center of gravity of the five points. In order to measure the position and direction of the measuring head 10 in a three-dimensional space, at least three LEs are used as markers.
A D light source is sufficient, but the use of four or more LED light sources improves the measurement accuracy of the position and direction of the measurement head 10 in a least square manner.

Further, the shape measuring device 10 includes an encoder 16 for detecting the position of the shape measuring device 10 on the guide rail 204. The output of the encoder 16 is input to the control device 30.

[3] Description of the measurement principle of the shape measuring device

FIG. 3 shows the measurement principle of the shape measuring device.

The coordinates of a measurement point A are measured using the measurement head 10 which is moved on the guide rail 204 by a measurer. The measured coordinates are referred to as coordinates (X
c, Yc, Zc). The camera coordinate system is a coordinate system that moves as the measuring head 10 moves.

On the other hand, the shape of the DUT 100 is represented by a fixed coordinate system, and this coordinate system is called world coordinates. The coordinates of the measurement point measured by the measurement head 10 in the world coordinate system are defined as (Xw, Yw, Zw). Since the shape of the DUT 100 needs to be described in the world coordinate system, the coordinates (Xc, Yc, Zc) in the camera coordinate system of the measurement point A measured by the measuring head 10 are converted to the world coordinate system. This conversion is performed using the rotation matrix R representing the movement of the measuring head 10 and the translation vector t based on the following equation 1.

[0029]

(Equation 1)

In this embodiment, as shown in FIG.
The origin of the world coordinate system (Xw, Yw, Zw) is set at the focal position of one of the stereo cameras 21 and 22. The Zw axis of the world coordinate system is set in the optical axis direction of the camera 21. The Yw axis of the world coordinate system is set in a direction orthogonal to the Zw axis and extending from the origin to the rear of the shape measuring device. The Xw axis of the world coordinate system is set to a direction orthogonal to the Zw axis and extending from the origin to the upper right of the shape measuring device.

In this embodiment, a mirror coordinate system (Xu, Yu, Zu) is further set as shown in FIG. The origin of the mirror coordinate system is set at the intersection of the Zw axis of the world coordinate system and the mirror surface of the stainless steel mirror 205. The Xu axis of the mirror coordinate system is set to an axis passing through the origin and projecting the Xw axis of the world coordinate system onto a mirror surface. The Zu axis in the mirror coordinate system passes through the origin and is set in the normal vector direction of the mirror. The Yu axis in the mirror coordinate system is set to the cross product of the Xu axis and the Z axis in the mirror coordinate system.

In this embodiment, the coordinates (Xc, Yc, Zc) in the camera coordinate system of the measuring point A measured by the measuring head 10 are converted to the world coordinate system (Xw, Y
w, Zw), and then the mirror coordinate system (Xu,
Yu, Zu). The coordinates (Xw, Yw, Zw) of the world coordinate system are converted to the coordinates (Xu, Y) of the mirror coordinate system.
u, Zu) will be described later.

[4] Explanation of the problem of the sole measurement via the glass plate

In this embodiment, as shown in FIG.
Glass plate 2 placed above stainless steel mirror 205
The device under test 100 is arranged on the reference numeral 06. In this example, the distance from the upper surface of the stainless steel mirror 205 to the upper surface of the glass plate 206 is set to 30 mm. In the mirror coordinate system, the Zu coordinate on the upper surface of the stainless steel mirror 205 is 0, and the Zu coordinate on the upper surface of the glass plate 206 is 30.

As described above, the DUT 100 is placed on the glass plate 206 placed above the stainless steel mirror 205, and the stainless steel mirror 2 is
When the shape of the sole (sole) of the measured object shown in FIG. 05 is measured, more sole shapes can be measured than when the measured object 100 is arranged on the stainless steel mirror 205. become able to.

However, as shown in FIG. 6, there is a problem that a false reflection image reflected by the upper surface of the glass plate 206 is erroneously extracted. Further, since light passes through the glass plate 206, there is a problem that the light is affected by refraction of light by the glass plate 206. The shape measuring apparatus according to this embodiment solves the above-mentioned problems.

[5] Description of measurement processing procedure by shape measurement device

The shape measurement by this shape measuring device is executed according to the following processing procedure.

(1) First Step (Preprocessing 1): Control is performed by associating information on each measurement position of the measurement head 10 in the world coordinate system with the output value of the encoder 16 at each measurement position of the measurement head 10. It is stored in a memory (not shown) mounted on the device 30.

(2) Second step (Pre-processing 2): A conversion formula for converting the coordinates (Xw, Yw, Zw) in the world coordinate system into the coordinates (Xu, Yu, Zu) in the mirror coordinate system is obtained. .

(3) Third Step (Pre-processing 3): The position of the slit light from the slit light source 13 on the mirror surface of the stainless steel mirror 205 on the image of the CCD camera 12, and
The position of the slit light on the image of the CCD camera 12 on the surface of the glass plate 206 is acquired and stored in a memory (not shown).

(4) Fourth step: Using the measuring head 10, the coordinates of the measuring point on the object to be measured in the mirror coordinate system are obtained by the light cutting method. By the way, when an attempt is made to measure a measurement point on an object to be measured by the light section method, as described above, the CCD camera 12 of the measurement head 10 reflects the normal image of the object to be measured and the stainless mirror 205. Virtual image,
The false reflection image reflected on the surface of the glass plate 206 is captured. In the fourth step, the coordinates of the normal image of the object to be measured and the coordinates of the virtual image reflected on the stainless steel mirror 205 are extracted, and the coordinates of the false reflection image reflected on the surface of the glass plate 206 are not extracted. .

(5) Fifth Step: Of the measurement points in the world coordinate system, the coordinates on the virtual image reflected on the stainless steel mirror 205 are converted into the coordinates on the normal image.

Hereinafter, each of these steps will be described.

[6] Description of First Step

FIG. 7 is a flowchart for explaining the procedure of the first step.

First, the measuring head 10 is moved to the guide rail 20.
4 (step 1), and the output value of the encoder 16 at that position is stored in the memory of the control device 30 (step 2).

Next, the coordinates of the marker 14 provided on the measuring head 10 in the world coordinate system are measured by the stereo cameras 21 and 22. Since this position measurement method is well known as a stereo method, its description is omitted (step 3).

Next, the coordinates of the LED light sources 14a to 14f constituting the marker 14 in the camera coordinate system are respectively expressed by (Xc
i, Yci, Zci), and the stereo camera 2
Each LED light source 14a-14 measured by 1 and 22
Let the coordinates of f in the world coordinate system be (Xwi,
Ywi, Zwi). Here, i is 1, 2,. Each coordinate (Xci, Yci, Zci) of the camera coordinate system of each of the LED light sources 14a to 14f is known.

A rotation matrix R1 representing the movement of the measuring head 10
And a translation vector t1 into a matrix R1 satisfying the following equation 2.
And a vector t1 (step 4). And
The obtained matrix R1 and vector t1 are stored in the memory in association with the output value of the encoder 16 previously stored in the memory (step 5).

[0051]

(Equation 2)

Then, the measuring head 10 is connected to the guide rail 2.
04, and repeat the processing of steps 2 to 5 for all the measurement positions (step 6,
7). Thereby, table data in which the output value of the encoder 16 is associated with the rotation matrix R1 and the translation vector t1 at that position is generated and stored in the memory of the control device 30.

[7] Description of Second Step

In the second step, first, the glass plate 206 provided on the measuring table 201 is removed. Then, the stainless steel mirror 205 provided on the measuring table 201 is covered with an opaque thin plate (white plate), and the coordinates on the thin plate in the world coordinate system are measured by the stereo method.

Next, on the basis of the coordinates of the obtained point on the thin plate in the world coordinate system, the equation A _M Xw + B _M Yw + C _M Zw + D _M representing the plane of the stainless steel mirror 205 is obtained.
= 0 is calculated. In calculating the equation of the plane, it is sufficient that there are at least three points on the flat plate.

Instead of covering the stainless steel mirror 205 with an opaque thin plate and measuring it, at least three markers are provided on the stainless steel mirror 205 and the positions of the markers are measured to calculate the equation of the plane of the stainless steel mirror 205. You may do so.

Further, using the measuring head 10, the equation A _M Xw + B _M Yw expressing the plane of the stainless steel mirror 205.
+ C _M Zw + D _M = 0 may be obtained. That is, the stainless steel mirror 205 provided on the measuring table 201 is covered with an opaque thin plate, and the thin plate is imaged by the measuring head 10, and coordinates of three points (coordinates in the camera seat system) for obtaining the flat surface of the thin plate are obtained. Extract. The coordinates of the extracted three points in the camera coordinate system are converted into a rotation matrix R1 corresponding to the position of the measuring head 10 and a translation vector t1 obtained in the first step.
Is converted into coordinates in the world coordinate system. Based on the obtained coordinates of the three points in the world coordinate system, the equation of the plane of the thin plate in the world coordinate system is obtained.

A conversion formula for converting the coordinates (Xu, Yu, Zu) of the mirror coordinate system into the coordinates of the world coordinate system (Xw, Yw, Zw) into the coordinates of the mirror coordinate system is as follows.
The equation representing the plane of 5 is expressed as A _M Xw + B _M Yw + C _M Zw
If + D _M = 0, it is expressed by the following equation (3).

[0059]

(Equation 3)

Therefore, the coordinates (X
w, Yw, Zw) to the coordinates (Xu, Yu,
The conversion equation to be converted to Zu) is obtained by the following Equation 4.

[0061]

(Equation 4)

[8] Description of Third Step

In the third step, first, the glass plate 206
Put a thin white plate on top. Then, the slit light source 13 of the measuring head 10 outputs slit light,
By capturing the slit light illuminated on the white plate on the glass plate 206 by the camera 12, the position of the slit light intersecting the surface of the glass plate 206 on the image of the CCD camera 12 is acquired and stored in the memory.

Next, the glass plate 206 is removed, and a thin white plate is placed on the stainless mirror 205. Then, the slit light is output from the slit light source 13 of the measuring head 10 and the stainless steel mirror 205 is output by the CCD camera 12.
By imaging the slit light illuminated on the upper white plate, the position of the slit light intersecting the mirror surface of the stainless steel mirror 205 on the image of the CCD camera 12 is acquired and stored in the memory.

A straight line Lg in FIG. 8 shows an image of the slit light intersecting with the surface of the glass plate 206 on the image of the CCD camera 12, and a straight line Lm in FIG. The image of the slit light intersecting with the mirror surface of the stainless steel mirror 205 is shown. Since a normal image and a virtual image of the object to be measured cannot exist between the glass plate 206 and the mirror surface of the stainless steel mirror 205, the slit light appearing in the region between these straight lines Lg and Lm during shape measurement is It is determined that the slit light is not a slit light corresponding to the normal image and the virtual image of the object to be measured, but is a false slit light.

[8] Description of Fourth Step

In the fourth step, an object to be measured is placed on the glass plate 206 and measurement is performed. In this case, since the stereo cameras 21 and 22 are not used, the support 202 is removed from the measurement table 201 as shown by an arrow in FIG.

First, a method of measuring the position of the measuring point by the measuring head 10 will be described.

As shown in FIG. 9, the camera coordinate system is C
With the optical center of the CD camera 12 as the origin, the optical axis direction is Zc
This is a coordinate system in which the horizontal axis of the CCD camera 12 is the Xc axis and the vertical direction of the CCD camera 12 is the Yc axis. CCD
The image plane S of the camera 12 is located at a focal distance f from the origin. That is, the image plane S is a plane parallel to the Xc-Yc plane and Zc = f.

The position measuring method itself by the measuring head 10 is a known measuring method called a light section method. A predetermined point on a line on the surface of the DUT 100 on which the slit light from the slit light source 13 is irradiated is defined as a measurement point A.

The coordinates of the measurement point A in the mirror coordinate system (X
u, Yu, Zu) will be described.

The pixel coordinates (in PIX units) of point A ′ corresponding to measurement point A observed on image plane S with respect to measurement point A are represented by (X
p, Yp). The image coordinates (Xp, Yp) are converted into sensor coordinates (Xs,
Ys, f). Note that f in the sensor coordinates (Xs, Ys, f) of the observation point A ′ is the CCD camera 12
Is known as the focal length. Cx is the Xp coordinate of the center of the image, and Cy is the Yp coordinate of the center of the image.

[0073]

(Equation 5)

The sensor coordinates (X
s, Ys, and f), the equation of the plane representing the slit light in the camera coordinate system _{A L Xc + B L Yc +} C L Zc + D L =
Using 0, the coordinates are converted into coordinates (Xc, Yc, Zc) in the camera coordinate system based on the following Expression 6. Note that the equation of the plane representing the slit light is obtained by calibration of the measuring head 10.

[0075]

(Equation 6)

The coordinates (Xc, Y) of the obtained camera coordinate system
c, Zc) is converted into coordinates (Xw, Yw, Zw) in the world coordinate system based on the following equation (7).

[0077]

(Equation 7)

The obtained coordinates (Xw, Y
w, Zw) is converted into coordinates (Xu, Yu, Zu) in the mirror coordinate system based on the following equation (8).

[0079]

(Equation 8)

FIG. 11 shows a processing procedure executed in the fourth step.

FIG. 10 shows an example of the slit light imaged by the CCD camera 12. In FIG. 10, L1 indicates slit light (normal image) directly applied to the measured object, L2 indicates slit light corresponding to a virtual image reflected on the mirror surface of the stainless steel mirror 205, and L3 and L4 indicate
The slit light corresponding to the false reflection image reflected on the surface of the glass plate 206 is shown.

First, as shown in FIG. 10, slit light L is extracted line by line downward from the top of the screen (step 11). Each time the slit light is extracted, the pixel coordinates (Xp, Y) of the width center (center of gravity) position of the slit light are extracted.
p) is converted to the coordinates (Xu, Y) of the mirror coordinate system by the method described above.
u, Zu) to obtain the position data of the measurement point. Then, the obtained coordinates (Xu,
It is determined whether Zu of (Yu, Zu) is less than 30 mm (step 12). That is, the position of the measurement point is
It is determined whether or not the position is below the glass plate 206.

If it is not determined in step 12 that the position of the measurement point is below the glass plate 206, the position data obtained in step 11 is stored in the memory as position data for the normal image (step 13). Then, the process returns to step 11.

In step 12, the position of the measurement point is
Steps 11 and 1 until it is determined to be below 06.
Steps 2 and 13 are repeated.

If it is determined in step 12 that the position of the measurement point is below the glass plate 206, the coordinates of the measurement point measured one line before the measurement point are set to the lowest point of the normal image. (Step 14). The lowest point position of the normal image is indicated by P1 in FIG.

Next, the position of the virtual image by the stainless mirror 205 with respect to the lowest point of the normal image is obtained in the mirror coordinate system (step 15). That is, assuming that the coordinates of the lowest point of the normal image in the mirror coordinate system are (Xu1, Yu1, Zu1), the coordinates of the virtual image position of the lowest point of the normal image in the mirror coordinate system are (Xu1, Yu).
1, -Zu1).

Next, the coordinates in the mirror coordinate system of the virtual image position of the lowest point of the normal image are converted into the coordinates (Xp, Yp) in the pixel coordinate system (step 16).

If the coordinates of the virtual image position of the lowest point of the normal image in the mirror coordinate system are represented by (Xu, Yu, Zu) for convenience of explanation, first, the virtual image position of the lowest point of the normal image is calculated. The coordinates (Xu, Yu, Zu) in the mirror coordinate system are converted into coordinates (Xw, Yw, Zw) in the world coordinate system based on the following equation (9).

[0089]

(Equation 9)

The obtained coordinates (Xw,
Yw, Zw) is converted into coordinates (Xc, Yc, Zc) in the camera coordinate system based on the following Expression 10.

[0091]

(Equation 10)

The obtained coordinates (Xc, Y) of the camera coordinate system
c, Zc) is converted into coordinates (Xs, Ys, f) in the sensor coordinate system based on the following equation (11).

[0093]

[Equation 11]

The coordinates of the obtained sensor coordinate system (Xs, Y
s, f) is converted into coordinates (Xp, Yp) in the pixel coordinate system based on the following Expression 12.

[0095]

(Equation 12)

Then, the coordinates (X
(p, Yp) is inversely corrected for glass refraction based on a previously calculated inverse correction equation for glass refraction (step 17). Since the slit light is refracted when the slit light passes through the glass plate 206, the coordinates (Xp, Y) of the obtained pixel coordinate system are obtained.
p) is corrected to the pixel coordinates when there is refraction. The position represented by the coordinates (Xp ′, Yp ′) after correcting the glass refraction is represented by P2 in FIG.

Conversion of the coordinates in the pixel coordinate system when there is glass refraction to the coordinates in the pixel coordinate system when there is no glass refraction is called glass refraction correction. The coordinates in the pixel coordinate system when there is no glass refraction are referred to as glass. Conversion to coordinates in the pixel coordinate system when there is refraction is referred to as glass refraction inverse correction.

A method for obtaining the glass refraction correction formula and the glass refraction reverse correction formula will be described. Stainless mirror 205
A color plate on which a specific pattern (for example, a lattice) is printed is placed on the mirror surface of the color plate. When the glass plate 206 is present,
A specific pattern is imaged by the CCD camera 12 separately when the glass plate 206 does not exist. Based on the obtained two types of images, a glass refraction correction equation and a glass refraction inverse correction equation are experimentally obtained.

Next, the coordinates (Xp ′,
Yp ') as the initial position of the tracking process,
A virtual image tracking process is performed (step 18).

FIG. 12 shows a virtual image tracking processing procedure.

First, as shown in FIG. 10, slit light existing within the search window 50 having a predetermined width is extracted upward from the initial position P2 (Xp ', Yp') of the tracking process line by line (see FIG. 10). Step 21). When the slit light is extracted, it is determined whether or not there is only one slit light in the search window (step 22).

If only one slit light exists in the search window, glass refraction correction is performed on the pixel coordinates (Xp, Yp) of the barycentric position of the slit light (step 23). That is, the pixel coordinates (Xp, Yp) of the position of the center of gravity of the slit light are converted into the pixel coordinates when there is no glass refraction.

Then, the pixel coordinates (X
By converting (p, Yp) into coordinates (Xu, Yu, Zu) in the mirror coordinate system, the position data of the measurement point is obtained and stored in the memory (step 24). Then, it is determined whether or not the tracking position has reached the normal image area (step 25). In this determination, the pixel coordinates (Xp, Yp) of the measurement point are calculated using the stainless steel mirror 2 obtained in the third step (preprocessing 3).
The position Lm on the image of the CCD camera 12 of the slit light from the slit light source 13 on the mirror surface 05 and the glass plate 20
The determination is made by determining whether or not the slit light on the surface of No. 6 exists in a region between the position Lg on the image of the CCD camera 12 and the slit light. Pixel coordinates (Xp, Y
If p) is in the area between the straight lines Lm and Lg, the tracking position
It is determined that the position has reached the normal image area . If the position data of the measurement point extracted in the line of interest calculated in step 24 reaches the normal image area at the tracking position, the processing ends. If the tracking position has not reached the normal image area, step 2
Return to 1.

In step 22, if there are two or more slit lights in the search window, the outermost width W1 of the slit light in the search window on the line of interest is extracted (step 26). Also, returning one line, the width of the search window 50 is increased, and the outermost width W2 of the slit light within the search window width is extracted (step 2).
7). Then, it is determined whether or not the outermost width W2 is larger than the outermost width W1 (Step 28).

When two or more slit lights exist in the search window in the line of interest n, the slit light L2 is traced upward as shown in FIG. And the other slit light L4 is L
Fig. 1 shows the case where the user approaches the point where he wants to cross 2
As shown in FIG. 3B, when the slit light L2 is being traced in the upward direction, from the intersection of the slit light L2 and L4, the point where these slit lights L2 and L4 are branched into two approaches. There is a case.

In the case of FIG. 13A, the outermost width W2 of the slit light within the search window width is extracted by expanding the width of the search window in the line (n-1) one line before the target line n. In this case, W2 is larger than the outermost width W1 of the slit light at the line of interest.

On the other hand, in the case of FIG. 13B, the width of the search window is increased in the line (n-1) one line before the line of interest n, and the outermost width W2 of the slit light within the search window width is increased. Is extracted, W2 is smaller than the outermost width W1 of the slit light at the line of interest.

If it is determined in step 28 that the outermost width W2 is larger than the outermost width W1, as shown in FIG. 13A, when the slit light L2 is being traced upward, It is determined that the other slit light L4 has approached the vicinity of the point where it is about to cross L2. In this case, the pixel coordinates (Xp, Yp) of the barycentric position Qa of the left slit light among the two slit lights extracted in the target line are obtained (step 29).

The reason why the slit light on the left side is selected is as follows.
The arrangement of the CCD camera 12 and the slit light source 13 is as shown in FIG.
In the case where the peripheral edge of is a curved surface that expands toward the lower side, the slit light L2 for the false reflection image is different from the slit light L2 for the virtual image as shown in FIG. Because it is considered to cross toward.

Next, as shown in FIG. 13 (a), the slit light is extracted by moving forward 5 lines from the line of interest, and the pixel coordinates (Xp, Yp) of the center of gravity Qb are obtained (step 30). Then, based on the pixel coordinates (Xp, Yp) of Qa obtained in step 29 and the pixel coordinates (Xp, Yp) of Qb obtained in step 30, the barycentric position of the slit light for four lines therebetween Are obtained by primary interpolation (step 31).

From the line of interest obtained in this way, 5
Glass refraction correction is performed on the pixel coordinates (Xp, Yp) of the slit light for six lines up to the line destination line (step 23). Then, the pixel coordinates (Xp, Yp) after the glass refraction correction are converted to the coordinates (Xu, Yu,
Zu), the position data of each measurement point is obtained and stored in the memory (step 24). Then, it is determined whether or not the tracking position has reached the normal image area (step 2).
5). If the tracking position has reached the normal image area, the process ends. If the tracking position has not reached the normal image area, the process returns to step 21.

In step 28, if the outermost width W2 is smaller than the outermost width W1, as shown in FIG. 13B, when the slit light L2 is being traced upward,
From the intersection of the slit lights L2 and L4, it is determined that these slit lights L2 and L4 have approached the point where they have branched into two. In this case, the pixel coordinates (Xp, Yp) of the barycentric position Qc of the right slit light among the two slit lights extracted in the line of interest are obtained (step 32).

Next, returning five lines from the line of interest, the slit light is extracted, and the pixel coordinates (X
(p, Yp) is obtained (step 33). Then, the pixel coordinates (Xp, Yp) of Qc obtained in step 32
And the pixel coordinates (Xp,
Yp), the image coordinates of the barycentric position of the slit light for the four lines therebetween are determined by primary interpolation (step 34).

From the line of interest obtained in this way, 5
Glass refraction correction is performed on the pixel coordinates (Xp, Yp) of the slit light for six lines up to the line before the line (step 23). Then, the pixel coordinates (Xp, Yp) after the glass refraction correction are converted to the coordinates (Xu, Yu,
Zu), the position data of each measurement point is obtained and stored in the memory (step 24). At this time, since the coordinates of the mirror coordinate system with respect to the slit light for five lines other than the line of interest are already stored in the memory, these stored data are rewritten.

Then, it is determined whether or not the tracking position has reached the normal image area (step 25). If the tracking position has reached the normal image area, the process ends. If the tracking position has not reached the normal image area, the process returns to step 21.

The processing of the fourth step as described above is performed for every observation position on the guide rail 204 while moving the measuring head 10 along the guide rail 204.

[8] Description of Fifth Step

When the processing of the fourth step is performed at all observation positions on the guide rail 204, a set of coordinates (Xu, Yu, Zu) in the mirror coordinate system of the measurement point is set as shown in FIG. 100 images are generated. In FIG. 14, the broken line is the normal image I ₁ of the foot 100, and the solid line is the virtual image I 1 of the foot 100 reflected on the stainless steel mirror 205.
₂

[0119] In the fifth step, 'seeking, resulting symmetrical image I _2' symmetrical image I ₂ with respect to the plane of the stainless steel mirror 205 of the virtual image I ₂ (Zu = 0) to the normal image I ₁ Synthesis By doing so, an image of the foot 100 as shown in FIG. 15 is obtained.

As shown in FIG.
The arch of foot 100 is made of stainless steel.
Virtual Image I Reflected in Ra 205_TwoGenerated based on
Statue I _Two', And the shape of the foot 100 is more faithful
The shape has been reproduced.

As described above, according to the above-described embodiment, the normal image of the foot 100 as the object to be measured is
Since the image generated based on the virtual image reflected in 5 is synthesized, it is possible to supplement the image of a concave portion such as the arch of the foot 100, and to generate an appropriate three-dimensional shape of the foot 100. It becomes possible.

At this time, since an image (virtual image) and a side surface (normal image) of a concave portion such as the arch of the foot 100 are measured at the same time, an appropriate three-dimensional shape can be measured with a small number of measurement procedures. .

According to the above embodiment, the light beam emitted from slit light source 13 is
Since the attitude of the measuring head 10 is regulated so that the light is emitted along a plane perpendicular to the
The luminous flux emitted from the slit light source 13 directly to the foot 100 and the light flux
The light beam irradiated at 00 is overlapped. Accordingly, the light beam reflected by the stainless steel mirror 205 does not generate an erroneous image, and the measurement can be performed with high accuracy.

According to the above-described embodiment, after the initial setting in the first and second steps is completed, the stereo cameras 21 and 22 are detached from the measuring table 201 to measure the object to be measured. Therefore, the size of the measuring device can be reduced.

Even if the trajectory of the guide rail 204 changes due to the movement of the measuring device or the like, the accuracy can be maintained by installing the stereo cameras 21 and 22 and updating the table data.

In the above embodiment, the measuring head 10 is manually moved by the measurer. However, the measuring head 10 is automatically moved to the guide rail 2 using a motor.
You may make it move along 04. With this configuration, the measurement object can be automatically measured without the measurer touching the measurement head 10.

[0127]

According to the present invention, by arranging a mirror on a measuring table, not only a real image of an object to be measured but also a virtual image reflected on the mirror can be used for measurement. It becomes possible to generate a three-dimensional shape of the device under test by the procedure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a first configuration of a shape measuring device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a schematic configuration of a measuring head in the shape measuring device of FIG.

FIG. 3 is an explanatory view illustrating a measurement principle in the shape measuring apparatus of FIG. 1;

FIG. 4 is a schematic diagram showing a world coordinate system and a mirror coordinate system.

FIG. 5 is a schematic view showing that the sole of a foot can be measured.

FIG. 6 is a schematic diagram showing that reflected light from a glass plate is extracted by a CCD camera.

FIG. 7 is a flowchart illustrating a processing procedure in a first step.

FIG. 8 is a CCD camera 12 obtained in a third step.
5A and 5B show an image of the slit light intersecting with the surface of the glass plate 206 on the image of FIG. 7A and an image of the slit light intersecting with the mirror surface of the stainless steel mirror 205 on the image of the CCD camera 12 obtained in the third step. It is a schematic diagram.

FIG. 9 is an explanatory diagram illustrating a measuring method for measuring the position of a measuring point using the measuring head of FIG. 2;

FIG. 10 is a schematic diagram for explaining a process of a fourth step.

FIG. 11 is a flowchart illustrating a processing procedure of a fourth step.

FIG. 12 is a flowchart illustrating a processing procedure of step 18 in FIG. 11;

FIG. 13 is a schematic diagram for explaining the process of step 18 in FIG. 11;

FIG. 14 is an explanatory diagram showing an image of a foot obtained in a fourth step.

FIG. 15 is an explanatory diagram showing an image of a foot obtained in a fifth step.

[Explanation of symbols]

 Reference Signs List 10 measuring head 12 CCD camera 13 slit light source 14 marker 16 encoder 21 stereo camera 22 stereo camera 201 measuring table 204 guide rail 205 stainless steel mirror 206 glass plate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Hiroaki Yoshida 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Shinpei Fukumoto 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. F-term (reference) 2F065 AA53 BB28 CC16 DD06 FF01 FF02 FF05 FF09 FF15 FF26 GG06 GG07 GG25 HH05 JJ03 JJ05 JJ26 LL00 LL12 MM09 QQ23 SS13 4F050 AA01 A02 LA01 NA02

Claims (7)

[Claims] 1. A mirror mounted on a measuring table, a transparent glass plate arranged in parallel with the mirror and above the mirror, a slit light irradiating means and an image pickup device, and an object to be measured by a light cutting method. A measuring head for measuring the shape, position detecting means for detecting the position of the measuring head, and an object to be measured based on the image taken by the image sensor of the measuring head and the position of the measuring head detected by the position detecting means. Calculating means for obtaining a three-dimensional shape of the object, by extracting slit light appearing above the surface of the plate glass on the image plane of the image sensor of the measuring head, thereby obtaining a normal image of the object to be measured. First means for obtaining a three-dimensional shape in a world coordinate system; second means for obtaining projection coordinates of a virtual image position by a mirror with respect to the lowest point of the normal image onto an imaging surface of an image sensor; opening the obtained projection coordinates As a point, by tracking the slit light corresponding to the virtual image of the device under test upward in the image plane of the image sensor, a third three-dimensional shape of the virtual image of the device under test in the world coordinate system is obtained. The means and the three-dimensional shape of the object to be measured are synthesized by synthesizing the three-dimensional shape of the mirror of the three-dimensional shape with respect to the virtual image of the object and the three-dimensional shape of the normal image of the object to be measured. The fourth to seek
Means, comprising: 2. The method according to claim 1, wherein when tracking the slit light corresponding to the virtual image of the object to be measured, if another slit light intersects with the slit light being tracked, the third means is directed to an upper left direction and an upper right direction. 2. The shape measuring apparatus according to claim 1, further comprising: means for tracking slit light extending in a predetermined direction. 3. The method according to claim 1, wherein when the slit light corresponding to the virtual image of the object to be measured is being tracked, in a region where another slit light intersects with the slit light being tracked, a predetermined value before the crossing is determined. Based on the position of the slit light corresponding to the virtual image of the device under test extracted on the horizontal line and the position of the slit light extracted a predetermined horizontal line ahead of it, the virtual image position between them is determined by linear interpolation. Based on the position of the slit light corresponding to the virtual image of the device under test extracted on the predetermined horizontal line after the intersection and the position of the slit light extracted a predetermined horizontal line before that, based on the virtual image between them 3. The shape measuring apparatus according to claim 2, further comprising means for obtaining a position by primary interpolation. 4. The shape measuring apparatus according to claim 1, wherein the position detecting means detects the position of the measuring head by a stereo method using two cameras. 5. The apparatus according to claim 1, further comprising guide means for regulating a posture of the measuring head such that a light beam emitted from the slit light irradiating means of the measuring head is emitted perpendicular to the light reflecting surface of the mirror. The shape measuring device according to any one of claims 1, 2, 3, and 4, wherein 6. The shape measuring apparatus according to claim 5, wherein the guide means regulates a moving path of the measuring head. 7. The shape measuring apparatus according to claim 6, further comprising driving means for moving the measuring head along the guide means.