JP2000193429A - Shape measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measuring device wherein even an object with a complex shape can be measured stably with high precision. SOLUTION: In a range finder sensor 10 wherein an angle to a surface 1a to be measured can be adjusted, two pairs of condenser lenses 12a and 12b and line CCD cameras 13a and 13b are provided at right and left positions symmetrically each other related to the laser beam projection direction of the laser light source 11, and the received light intensity in the two CCD cameras 13a and 13b is compared with each other, for controlling the tilt of the range finder sensor 10 so that they agree each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus for measuring the surface shape of an object to be measured by a triangulation method utilizing reflection of a laser beam, and more particularly, to an angle capable of always optimizing a tilt angle with respect to a surface to be measured. The present invention relates to an apparatus having a distance measuring sensor with a correction function.

[0002]

2. Description of the Related Art As a shape measuring device used in an automobile production process or the like, the surface shape of a work (object to be measured) is represented by X, X,.
There is a three-dimensional measuring machine for measuring as three-dimensional coordinate values of Y and Z. As such a three-dimensional measuring device, a non-contact type three-dimensional measuring device for measuring a surface shape by using reflection of a laser beam has been developed in recent years (for example, Japanese Patent Application Laid-Open No. 5-164525).
JP-A-8-43046).

In this apparatus, a distance measuring sensor having a laser light source and an array type light receiving element is attached to the tip of a measuring head movable in three axes of X, Y and Z, and this distance measuring sensor is covered. While sequentially moving (scanning) from point to point along the measurement surface, the surface to be measured is irradiated with laser light and the reflected laser light is received by the light receiving element, and the reflected light on the light receiving element array is received. The distance between the distance measurement sensor and each measurement point is calculated based on the triangulation method from the change in the position, and the value of this distance is expressed as X
The shape of the surface to be measured is obtained by converting the coordinates into the coordinate values of each measurement point in the YZ orthogonal coordinate system.

In such a case, the distance measuring sensor is usually composed of a laser light source, a set of condenser lens and a line CCD camera (hereinafter simply referred to as "CCD camera").
The relationship between the change ΔR in the light receiving position of the CD camera and the displacement ΔL between the measured surface and the displacement ΔL is created in advance by calibration, and the relationship ΔL = f (ΔR) is used to determine the relationship between the distance measuring sensor and each measurement point. The distance is calculated.

[0005]

In such a coordinate measuring machine, in order to perform accurate measurement, it is necessary to irradiate a laser light beam as perpendicular to the surface to be measured as possible. This is because the condensing lens collects the irregular reflection component of the laser beam and causes the CCD camera to receive the component. However, the intensity of the reflected light is the largest in the direction of so-called specular reflection (reflection in accordance with the law of reflection). This is because the amount of light condensed by the condensing lens decreases as the angle formed by the converging lens and the angle to the surface to be measured deviates from a right angle, that is, 90 degrees, and it becomes difficult for the CCD camera to receive diffusely reflected components. However, conventional three-dimensional measuring machines do not have a mechanism for always applying a laser beam at right angles to the surface to be measured, that is, a mechanism for detecting the angle of inclination and correcting the angle. In particular, in the case of a workpiece (measurement object) having a complicated shape in which the direction of the surface to be measured changes in a complicated manner, it is difficult to always ensure stable light reception, and accurate measurement can be stably performed. There was a problem that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is a shape measuring apparatus capable of stably and accurately measuring an object to be measured having a complicated shape. It is intended to provide a device.

[0007]

The above object of the present invention is achieved by the following means. (1) A shape measuring apparatus according to the present invention is a shape measuring apparatus for measuring a surface shape of an object to be measured by a triangulation method utilizing reflection of a laser beam, wherein a laser light source and a laser light emitting direction of the laser light source are provided. A distance measuring sensor including two array-type light receiving elements arranged at symmetrical left and right positions, a rotation mechanism that relatively varies an inclination angle of the distance measuring sensor with respect to a measured surface, and the two Control means for comparing the light receiving intensities of the light receiving elements and controlling the rotation mechanism so that the light receiving intensities coincide with each other. (2) The light receiving element is a one-dimensional CCD image sensor. (3) The control means stores an angle correction table, which is prepared in advance, and indicates a relationship between a difference between light receiving intensities of the two light receiving elements and a correction amount of an inclination angle of the distance measuring sensor with respect to a surface to be measured. The light receiving intensity of the two light receiving elements is compared to obtain a difference between the two, and the angle between the laser light emitting direction and the surface to be measured is made a right angle based on the obtained light receiving intensity difference and the angle correction table. The amount of correction required for this is obtained and output to the rotation mechanism. (4) At this time, when the absolute value of the obtained correction amount is equal to or more than a predetermined value, the control unit outputs the correction amount to the rotating mechanism. (5) a moving mechanism for relatively moving the distance measuring sensor in a vertical direction and a horizontal direction at a predetermined measuring pitch in accordance with the shape of the surface to be measured, and the control means includes: The distance between the distance measuring sensor and each measuring point is calculated based on a triangulation method from the change in the light receiving position on the light receiving element, and the obtained distance value is compared with a predetermined reference value to determine the difference between the two. , And calculates a correction position that eliminates the difference between the obtained distances and outputs the corrected position to the moving mechanism. (6) At this time, the control means outputs the correction position to the moving mechanism when the obtained absolute value of the distance difference is equal to or greater than a predetermined value.

[0008]

According to the present invention, the following effects can be obtained for each claim.

According to the first to third aspects of the present invention, the light receiving intensities of the two light receiving elements disposed at symmetric positions in the distance measuring sensor are matched, in other words, the laser light emitting direction and the light receiving direction are adjusted. Since the tilt angle of the distance measurement sensor with respect to the measured surface is controlled so that the angle formed with the measured surface is a right angle, stable light reception can always be performed in accordance with the direction of the measured surface, and a complex shaped object can be obtained. Even with a measured object, it is possible to stably perform high-precision measurement.

According to the fourth aspect of the present invention, the angle correction is performed only when the correction amount is large, instead of performing the angle correction every measurement point, so that the motion is faster than in the case where the correction is performed every time. That is, the measurement time per line (one scan) can be reduced without sacrificing the measurement accuracy.

According to the fifth aspect of the present invention, in addition to the angle correction, the distance correction is performed so that the distance between the distance measuring sensor and the surface to be measured is constant. , And more stable and accurate measurement can be performed.

According to the sixth aspect of the present invention, the distance correction is not performed every time for each measurement point, but is performed only when the difference from the reference distance is large. From this point as well, the movement becomes faster, and the measurement time per line (one scan) can be reduced without sacrificing the measurement accuracy.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a distance measuring sensor used in the shape measuring apparatus according to the present invention.

The distance measuring sensor 10 has a laser light source (for example, a laser light emitting element) 11 and a laser light emitting direction of the laser light source 11 (here, a direction perpendicular to the bottom surface of the distance measuring sensor 10). Two sets of condenser lenses 12a, 12b and line C arranged at symmetric left and right positions
It is composed of CD cameras 13a and 13b. This line CCD camera (hereinafter simply referred to as "CCD camera")
Reference numerals 13a and 13b denote array type light receiving elements, which are composed of, for example, one-dimensional CCD image sensors. One CCD camera, for example, 13a, is used for distance measurement as in the past, and the other CCD camera, for example, 13b, is used exclusively for angle detection (or angle adjustment). . The condensing lenses 12a and 12b are for condensing the irregular reflection components of the laser light and causing the CCD cameras 13a and 13b to receive the light as described above.

In this configuration, two CCD cameras 1
The light receiving positions R1 and R2 on the CCD cameras 13a and 13b always indicate the same position because the light receiving positions 3a and 13b are completely symmetrical with respect to the laser beam emission direction, but the light receiving intensity (light receiving amount) is measured. It is asymmetrical according to an angle α formed by the distance sensor 10 with the measured surface 1a of the workpiece 1 (this angle α is also an angle formed between the laser light emitting direction and a perpendicular to the measured surface 1a; hereinafter, also referred to as an “inclination angle”). Becomes That is, as described above, the intensity of the reflected light is the largest in the regular reflection direction A, and the larger the inclination angle α, the more the CCD camera 13
a, 13b and the angle .theta.1, .theta.2 between the measured surface 1a and the difference .DELTA.
.theta. (= .theta.1 -.theta.2) becomes large, and at that time, there is a difference between the angles .beta.1 and .beta.2 between the respective light receiving directions and the regular reflection direction A, so that the light receiving intensity of each CCD camera 13a, 13b becomes the inclination angle .alpha. Becomes asymmetric in accordance with. In the example of FIG.
Since the light receiving direction of the camera 13a is farther from the regular reflection direction A than the light receiving direction of the CCD camera 13b, the CCD 13
The light receiving intensity of the camera 13a becomes weaker than the light receiving intensity of the CCD camera 13b. At this time, the left and right CCD cameras 13
The difference between the received light intensities a and 13b is a value corresponding to the magnitude of the inclination angle α (or the difference Δθ between the angle formed with the surface to be measured 1a) (when α = 0, the received light intensity difference = 0). . As for the relationship between the inclination angle α and the angle difference Δθ (= θ1−θ2), the following equation, α = Δθ / 2 = (θ1−θ2) / 2, is established by a simple geometric calculation. .

In the present invention, focusing on this point, the distance measuring sensor 10 is attached to the rotating mechanism so that the left and right CCD cameras 13a and 13b always have the same light receiving intensity, that is, the difference between the left and right light receiving intensity is reduced. Distance measuring sensor 1 so that it becomes zero
By controlling the inclination of 0, the value of the inclination angle α is made zero,
Thus, the laser beam is always irradiated on the measured surface 1a of the work 1 at right angles.

FIG. 2 is an overall configuration diagram of a shape measuring apparatus according to one embodiment of the present invention.

This shape measuring apparatus has a measuring head 30 which can be moved vertically and horizontally by a moving mechanism 20a having a vertical axis and a horizontal axis. The measuring head 30 has a rotating mechanism 20b for angle adjustment. The distance measuring sensor 10 described above is attached via the above. The movement mechanism 20a and the rotation mechanism 20b constitute a positioning device 20 (see FIG. 4) such as a robot for positioning (including rotation) the distance measurement sensor 10. The distance measuring sensor 10 includes the moving mechanism 2
While moving in the vertical and horizontal directions according to the surface shape of the work 1 by means of 0a, the workpiece 1 is scanned at a predetermined measurement pitch in the direction S (scanning direction) in the figure, and the rotation mechanism 20b adjusts the angle with respect to the surface 1a to be measured. Will be Note that FIG. 3 illustrates the position and inclination of the distance measurement sensor 10 at four measurement points B, C, E, and F for reference.

FIG. 3 is a block diagram of a control system of the shape measuring apparatus of FIG. Here, the position and the inclination of the distance measurement sensor 10 are illustrated at the measurement point C in FIG.

The distance measuring sensor 10 is connected to two camera controllers 40a and 40b. One camera controller 40a is for controlling the distance measuring CCD camera 13a, and the other camera controller 40a is
b is for controlling the CCD camera 13b for angle adjustment. These two camera controllers 40a,
40b are each connected to the control computer 50. Data signals indicating the light receiving position and the light receiving intensity of the reflected light received by each of the CCD cameras 13a and 13b are input to the control computer 50 via the corresponding camera controllers 40a and 40b. As described above, the light receiving positions of the left and right CCD cameras 13a and 13b are the same, but the light receiving intensities V1 and V2 indicated by the output voltage V are provided.
Is different depending on the inclination angle α with respect to the surface to be measured 1a (see the figure).

The control computer 50 includes:
Three drivers 60 for controlling the driving of the above-described positioning device 20 (which comprises a moving mechanism 20a and a rotating mechanism 20b)
a, 60b and 60c are connected. Driver 60a
Is a vertical axis driver for performing drive control of the vertical axis of the moving mechanism 20a, and the driver 60b is
The driver 60c is a left and right axis driver for performing drive control of the left and right axes of a, and the driver 60c is an angle adjustment axis driver for performing drive control of the angle adjustment axis of the rotation mechanism 20b.

FIG. 4 is a block diagram showing a more detailed configuration of the control system of FIG. The portions already described with reference to FIGS. 1 to 3 will be described only briefly.

In the distance measuring sensor 10, a laser light source 11 is provided.
A distance measuring CCD camera 13a and an angle adjusting CCD camera 13b are provided at symmetrical positions.
Light receiving signals from the CCD cameras 13a and 13b are input to the corresponding camera controllers 40a and 40b. Data indicating the light receiving position R and the light receiving intensity V1 is input from the ranging camera controller 40a to the CPU 51 of the control computer 50, and only data indicating the light receiving intensity V2 is exclusively output from the angle adjusting camera controller 40b. The data is input to the CPU 51 of the control computer 50. The CPU 51 is connected to files 52, 53, and 54 that store an angle error table, a distance table, and measurement point sequence data, which will be described later. As will be described later in detail, the CPU 51 controls each of the camera controllers 40a and 40a.
A correction command for performing the angle adjustment is created based on the received light intensity data from 0b and the angle correction table in the file 52, and based on the received light position data from the camera controller 40a and the distance table in the file 53. The distance to the surface to be measured 1a is calculated, and a correction value for the distance is created based on the distance, or three-dimensional coordinate value data indicating the surface shape of the work is calculated. The correction command for the angle adjustment and the correction command for the distance are output to the drivers 60a to 60c of the corresponding axes as part of the positioning command, similarly to the scan data programmed in advance. Specifically, the correction command for the angle adjustment is output to the angle adjustment axis driver 60c, and the rotation mechanism 20 of the positioning device 20 is rotated.
b, and a scanning distance correction command and normal scanning data are transmitted to the vertical axis driver 60a and the left and right axis driver 6a.
0b to drive the moving mechanism 20 of the positioning device 20. Further, a manual operation panel 55 called a pendant is connected to the CPU 51. By operating the pendant 55, the operator can measure the measurement head 3
Manual positioning of 0 and setting of necessary data
It can input or teach an operation program.

The angle error table 52 includes left and right CCDs.
The angle θ1 between the cameras 13a and 13b and the surface to be measured 1a,
The relationship between the difference .DELTA..theta.2 (.theta.1 -.theta.2) and the difference .DELTA.V (= V1 -V2) between the light receiving intensities (light receiving amounts) V1 and V2 of the respective CCD cameras 13a and 13b at that time is obtained by calibration in advance, and a table is obtained. It is a thing. As described above, the inclination angle of the distance measurement sensor 10 (the distance measurement sensor 10
Since the relational expression of α = Δθ / 2 is established between the angle difference Δθ (= angle formed by the workpiece 1 and the surface 1a to be measured) and the angle difference Δθ (= θ1−θ2), the angle difference Δθ is determined. Thus, the inclination angle α of the distance measuring sensor 10 at that time can be detected. As the measurement state, when the inclination angle α = 0 (that is, θ1 = θ2), that is, when it is the best state that the laser beam is irradiated at right angles to the measurement surface 1a of the work 1, the inclination angle is The angle α is a correction amount of the angle to the optimum measurement state (see FIG. 5). For example, when the output voltage (light receiving intensity) of the CCD camera 13 is expressed in a range of 0 to 5 V, the angle error table is as shown in FIG. In practice, the unit of the received light intensity (output voltage) is a finer table (for example, 0.01 V unit).

The distance table 53 is a data table showing the relationship between the light receiving position (bit position) R of the CCD camera 13 and the measured distance L at that time. This is because the distance between the distance measuring sensor 10 and each measurement point is, as described above, a CCD.
Since it can be calculated from the change ΔR of the light receiving position R of the camera 13 based on a triangulation method, a CCD
A reference distance between the reference light receiving position on the camera 13 and the surface to be measured is set in advance, and the relationship between the change ΔR in the light receiving position and the displacement ΔL with respect to the surface to be measured is determined in advance by a predetermined relationship ΔL = f (ΔR). Therefore, the distance measurement sensor 10 has a certain measurement range. For example, 2048 bit CCD
FIG. 8 shows an example of the distance table in the case where the distance measurement sensor 10 having the camera 13 and the measurement range of 200 to 400 mm is used (see FIG. 7).

The measurement point sequence data 54 is point sequence group data of three-dimensional coordinate value data finally obtained, and indicates the surface shape of the work 1. The three-dimensional coordinate value data indicating the surface shape of the work 1 is obtained by synthesizing each axis position of the positioning device 20 at each measurement point and the measurement distance (one-dimensional data) of the distance measurement sensor 10. For example, FIG. 10 shows an example of measurement point sequence data of N measurement points 1, 2,..., N on three dimensions as shown in FIG.

Next, an example of the procedure of the three-dimensional shape measuring process by the shape measuring apparatus configured as described above will be described with reference to the flowchart of FIG.

First, the measuring head 30 is manually operated by operating the pendant 55 connected to the control computer 50.
Is moved to the measurement start position (S1).

Next, the user operates the pendant 55 to input data necessary for measuring the work 1, for example, a measurement pitch P and a horizontal scanning distance D (S2).

When the above measurement preparation is completed, the distance measuring sensor 10 is driven to perform the measurement (S3). In particular,
The laser light source 11 is driven to irradiate the laser light onto the surface to be measured 1a, and the light receiving position R and the light receiving intensities V1, V2 of the reflected light are detected by the left and right CCD cameras 13a, 13b. Here, the light receiving position R and the light receiving intensity V1 of the reflected light are detected by the left distance measuring CCD camera 13a, and the light receiving intensity V1 of the reflected light is detected by the right angle adjusting CCD camera 13b.
2 is detected. The detected data is input to the CPU 51 of the control computer 50 via the camera controllers 40a and 40b. The CPU 51 determines the angle difference Δθ based on the input left and right received light intensity data V1, V2 and the angle correction table (see FIG. 6) in the file 52.
(= Θ1−θ2), and further, the obtained angle difference Δθ
The inclination angle α of the distance measuring sensor 10 is calculated from the above (see FIG. 5). Further, the CPU 51 determines that the input light receiving position data R
The distance L from the surface to be measured 1a is obtained based on the distance L and the distance table in the file 53 (see FIG. 8), and the obtained distance L and the respective axial positions of the positioning device 20 at that time are combined to form a tertiary Original coordinate value data, that is, measurement point sequence data (FIG. 1)
0).

When the measurement is completed in step S3, the angle of the distance measuring sensor 10 with respect to the surface to be measured 1a is evaluated (S3).
4). That is, it is optimal to perform the measurement while maintaining the angle θ1 = θ2 (that is, Δθ = 0) with respect to the measurement target surface 1a as described above. When the angle is corrected, the movement slows down.
Since the measurement time per line (one scan) becomes longer, the angle difference Δ1 between θ1 and θ2 within a range not sacrificing the measurement accuracy
It is preferable not to perform the angle correction until θ (= θ1−θ2) becomes large to some extent. The criterion at that time can be set arbitrarily within a range that does not sacrifice the measurement accuracy. Here, for example, the inclination angle α (= Δθ
When (/ 2) becomes ± 10 degrees or more, the angle is corrected. For example, in the example of FIG. 12, when the distance measurement sensor 10 is moved from the measurement state of G to the next measurement point without rotating, the state of H is obtained. The inclination angle α of the sensor 10 is equal to the set value (±
10 degrees) or more. If the inclination angle α of the distance measuring sensor 10 is equal to the set value (±
10 degrees) or more, the left-right angle difference Δθ (= θ1−θ)
2) is large, so that the angle adjusting axis of the rotation mechanism 20b (for example, the wrist axis of the robot) is corrected by the inclination angle α, and H
Is changed to the state of I where α = 0.

The distance measuring sensor 1 for the surface to be measured 1a
A distance evaluation of 0 is performed (S5). That is, since the distance measurement sensor 10 has a measurement range as described above, the distance measurement sensor 1
It is desirable that the distance L between 0 and the surface to be measured 1a be as constant as possible (reference distance). However, if the distance is corrected for each measurement point one by one, the movement becomes slow and one line (1 Since the measurement time per scan becomes longer, it is preferable that the distance correction is not performed until the difference between the measurement distance L and the reference distance increases to some extent within a range that does not sacrifice the measurement accuracy. Regarding the criteria at that time,
Although it can be set arbitrarily without sacrificing the measurement accuracy, here, for example, the measurement distance L is equal to the reference distance ± 10%.
When this is the case, distance correction is performed. For example, in the example of FIG.
When 0 is translated and moved to the next measurement point without rotating it, the state of K is obtained. The K measurement state is subjected to distance evaluation (and the above-described angle evaluation), and the measurement distance L is a predetermined value with respect to the reference distance. It is determined whether there is a difference of (± 10%) or more. If the measured distance L is equal to or more than the reference distance ± 10% as a result of the distance evaluation, the distance measuring sensor 10 and the measured surface 1
Since the distance L to the distance a is too far from the reference distance, the vertical and horizontal axes of the moving mechanism 20a are corrected so that the distance L between the distance measuring sensor 10 and the surface to be measured 1a becomes the reference distance. Move K closer or farther and change the state of K to L3
= Change to the state of M at the reference distance. The state of K is distance,
Since both angles exceed the set value, the state of M is obtained by correcting both the distance and the angle.

The order of the angle evaluation and the distance evaluation may be reversed.

Thereafter, based on the results of the angle evaluation in step S4 and the distance evaluation in step S5, it is determined whether the angle or distance of the distance measuring sensor 10 needs to be corrected (S6). Specifically, as described above, the inclination angle α is equal to the set value (± 10 degrees).
Then, it is determined whether or not the difference between the measured distance L and the reference distance is equal to or greater than a set value (± 10%).

If correction is necessary (S6: Y
ES), that is, when the inclination angle α is equal to or more than the set value (± 10 degrees) or the difference between the measured distance L and the reference distance is equal to or more than the set value (± 10%),
An axis position where the inclination angle α is zero (that is, the laser beam emission direction is perpendicular to the surface to be measured 1a) and the distance L between the distance measuring sensor 10 and the surface to be measured 1a is a reference distance is calculated, and the obtained axis is calculated. After moving the three axes (the angle adjustment axis, the vertical axis, and the horizontal axis) to the position (S7), the process returns to step S3, and the measurement is performed again.

On the other hand, when there is no need for correction (S
6: NO), that is, the inclination angle α is the set value (± 10 degrees)
Smaller than the tolerance of the error and the measurement distance L
If the difference between the reference distance and the reference distance is smaller than the set value (± 10%) and is within the allowable range of the error, the three-dimensional coordinate value data (measurement point sequence data) obtained in step S3 is stored in the file 5
4 and the scanning vector is registered in a predetermined memory area in the CPU 51 (S8). Here, the scanning vector is a vector indicating in which direction the measuring head 30 is to be run next when performing so-called scanning measurement.
For example, referring to FIG. 14, at the measurement start position, the scan vector v1 is oriented in the horizontal direction, but when the measurement is performed at the second measurement point, the scan vector v2 is shifted from the measurement point to the measurement point. Changes to That is, from the path that has been passed so far (for example, in the direction from the immediately preceding measurement point to the current measurement point), the measurement head 3
Decide the direction to run 0. FIG. 14 shows scan vectors v1, v2,.
v3, v4, v5, and v6 are shown, respectively. In addition,
This scan vector is updated each time one point is measured.

Next, the measuring head 30 is moved in the direction of the scanning vector registered in step S8 by the distance of the measuring pitch P input in step S2 (S9). The point after the movement is the next measurement point.

If the total moving distance in the horizontal direction (that is, the horizontal axis) from the measurement start position is equal to or less than the scanning distance D input in step S2 (S10: N
O) Returning to step S3, the measurement at the next measurement point moved in step S9 is repeatedly executed.

On the other hand, the total moving distance is the scanning distance D.
Is exceeded (S10: YES), the scheduled 1
The measurement for the line is completed. Then, the processing shifts to the measurement for the next one line as necessary.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a distance measuring sensor used in a shape measuring device according to the present invention.

FIG. 2 is an overall configuration diagram of a shape measuring apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a control system of the shape measuring device of FIG. 2;

FIG. 4 is a block diagram showing a more detailed configuration of the control system of FIG. 3;

FIG. 5 is a drawing for explaining an angle error table;

FIG. 6 is a diagram illustrating an example of an angle error table.

FIG. 7 is a drawing for explaining a distance table.

FIG. 8 is a diagram illustrating an example of a distance table.

FIG. 9 is a drawing for explaining measurement point sequence data.

FIG. 10 is a drawing showing an example of measurement point sequence data.

FIG. 11 is a flowchart illustrating an example of a procedure of a three-dimensional shape measurement process performed by the shape measurement device in FIG. 2;

FIG. 12 is a diagram provided for describing an angle evaluation process in FIG. 11;

FIG. 13 is a diagram provided for explanation of a distance evaluation process in FIG. 11;

FIG. 14 is a diagram for explaining a scan vector.

[Explanation of symbols]

Reference numeral 10: distance measuring sensor, 11: laser light source, 12a, 12b: condenser lens, 13a, 13b: CCD camera (light receiving element, one-dimensional CC)
D image sensor), 20: positioning device, 21a: moving mechanism, 21b: rotating mechanism, 30: measuring head, 40: camera controller, 50: control computer (control means), 51: CPU, 52: angle error table ( Angle correction table), 53: distance table, 54: measurement point sequence data, 60a, 60b, 60c: axis driver.

Claims (6)

[Claims] 1. A shape measuring apparatus for measuring a surface shape of an object to be measured by triangulation using reflection of a laser beam, comprising: a laser light source; and a left and right position symmetrical to each other with respect to a laser light emitting direction of the laser light source. A distance measuring sensor having two array-type light receiving elements arranged; a rotation mechanism that relatively varies an inclination angle of the distance measuring sensor with respect to a measured surface; and a light receiving intensity of the two light receiving elements compared. And a control means for controlling the rotation mechanism so that they coincide with each other. 2. The shape measuring apparatus according to claim 1, wherein said light receiving element is a one-dimensional CCD image sensor. 3. The control means stores an angle correction table which is prepared in advance and indicates a relationship between a difference between light receiving intensities of the two light receiving elements and a correction amount of an inclination angle of the distance measuring sensor with respect to a surface to be measured. The light receiving intensity of the two light receiving elements is compared to obtain a difference between the two. Based on the obtained light receiving intensity difference and the angle correction table, the angle formed between the laser light emitting direction and the surface to be measured is a right angle. 2. The shape measuring apparatus according to claim 1, wherein a correction amount necessary for the correction is obtained and output to the rotation mechanism. 4. The shape measuring apparatus according to claim 3, wherein the control means outputs the correction amount to the rotating mechanism when the obtained absolute value of the correction amount is equal to or larger than a predetermined value. 5. A moving mechanism for relatively moving the distance measuring sensor in a vertical direction and a horizontal direction at a predetermined measuring pitch in accordance with the shape of the surface to be measured, and wherein the control means is provided in the distance measuring sensor. The distance between the distance measuring sensor and each measuring point is calculated based on a triangulation method from the change in the light receiving position on the light receiving element, and the obtained distance value is compared with a predetermined reference value to determine the difference between the two. 2. The shape measuring apparatus according to claim 1, wherein a correction position is calculated so as to eliminate the difference between the obtained distances, and the corrected position is output to the moving mechanism. 6. The shape measuring apparatus according to claim 5, wherein the control unit outputs the correction position to the moving mechanism when an obtained absolute value of the distance difference is equal to or more than a predetermined value.