JPH0650731A - Three-dimensional shape measuring device with tip-positioning function for object to be measured - Google Patents

Abstract

PURPOSE:To perform tip-positioning work of an object to be measured which is required before measuring a three-dimensional shape automatically, efficiently, and accurately by efficiently utilizing a configuration part which this type of device is originally provided with. CONSTITUTION:The title device is provided with a light-point detection part 14 for detecting a reflection light from an object 3 to be measured where light is applied out of a video signal generated by the image pick-up of a specific region and a movement mechanism 17 for transferring the object 3 to be measured and a laser light source 1 relatively, thus actuating the movement mechanism 17 speedily in forward direction until the reflection light is detected by the light-point detection part 14. Then, a control means for controlling the light-point detection part 14 and the movement mechanism 17 while they are related each other so that the movement mechanism 17 is speedily actuated in a reverse direction from that point to a point when the reflection light cannot be detected and then the movement mechanism 17 is actuated at a low speed in forward direction until the reflection light is detected again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a measuring object with spot light such as laser light or slit light, and picks up an optical image thereof by an image pickup section such as a CCD camera. The present invention relates to a three-dimensional shape measuring device that obtains the position of the object and measures its shape in a non-contact manner.Specifically, it relates to a three-dimensional shape measuring device that has the function of moving to the tip of the object to be measured prior to measurement. is there.

[0002]

2. Description of the Related Art As a non-contact type three-dimensional shape measuring device,
In what is known in the art, the spot light such as laser light is projected onto the object to be measured and the reflected light is captured by the line sensor, or what is called a light-section method, laser slit light is applied to the object to be measured. By projecting and capturing the slit light image with a surface sensor such as a CCD camera,
It is common to adopt a method of calculating the position and shape of the measuring object based on the principle of triangulation.

In the three-dimensional shape measuring apparatus using the reflected light as described above, the measurement time is shortened by accurately measuring the origin and by measuring only the range in which the object to be measured exists. In order to save memory, it is necessary to start the measurement from the position where the irradiation light such as laser light is irradiated to the tip of the measurement target. Therefore, prior to the start of measurement, a so-called tip-out operation of the measurement object is required, in which the light source section and the measurement object in the measurement device are relatively moved to adjust the position. In performing such a tip-out operation, conventionally, a worker operates a drive mechanism such as a motor through a key input from a computer while the operator visually observes before the irradiation light hits the tip of the object to be measured.

[0004]

However, the above-described conventional tip-end work is a manual operation, and not only a great deal of labor and time are required for the predetermined tip-end operation, but also key input and irradiation. Since it is necessary to visually check the light position at the same time, the leading-out accuracy is low. Since industrial products are usually processed by designating the dimensions with the ends as reference planes, for example, when comparing the processing dimensions of a plurality of industrial products processed based on the same design drawing, If the origin precision when aligning the origin on the measurement with the end of the product is low, the reproducibility of the generated data is lost and the reliability of the measurement is impaired. Further, since an ON / OFF command signal is frequently input to a drive mechanism such as a motor, an overload is applied, which adversely affects the life of the drive.

The present invention has been made in view of the above circumstances, and automatically and automatically makes use of the structure originally provided in this type of device for the work of setting the tip of the measured object prior to the start of measurement. It is an object of the present invention to provide a three-dimensional shape measuring apparatus that can be efficiently performed and that can improve the accuracy of leading out.

[0006]

In order to achieve the above object, a three-dimensional shape measuring apparatus having a function of projecting a tip of a measured object according to the present invention comprises a light source section for irradiating a predetermined area with light,
An image pickup unit that picks up the predetermined area to generate a video signal, a light spot detection unit that detects reflected light from the measurement target object irradiated with light from the video signal, and a measurement target object and a light source unit. A moving mechanism that moves at least one relative to the other and scans the object to be measured by irradiation of light, and from the measurement start time to the first time when the reflected light is detected by the light spot detection unit. A first mechanism for operating the moving mechanism at a high speed in a forward direction to put an object to be measured in the predetermined area.
Control means for operating the moving mechanism in the reverse direction at high speed until the reflected light is no longer detected by the light spot detection unit from the first time point, and the light point detection from the second time point. The third part where reflected light is detected again
The third moving mechanism operates the moving mechanism at low speed in the forward direction up to the time point.
And the control means of.

[0007]

According to the present invention, the light source section irradiates light toward a predetermined area, the predetermined area is imaged to generate a video signal, and the measurement object irradiated with light from the video signal. The moving mechanism is operated at high speed in the forward direction until the first time point when the light reflected from the object is detected by the light spot detection unit. Due to the high speed movement in the forward direction, the light emitted from the light source unit slightly overruns the tip of the measurement target. Next, the moving mechanism is operated in the reverse direction at a high speed from the first time point to the second time point when the detection of the reflected light by the light spot detection unit disappears. As a result, the light emitted from the light source unit is located at a position close to the tip of the object to be measured, and a position slightly overrun in the opposite direction from the tip.

Finally, the moving mechanism is operated at a low speed in the forward direction from the second time point to the third time point when the reflected light is detected again by the light spot detecting section. Due to this low speed movement in the forward direction, the light emitted from the light source unit matches the tip of the object to be measured, and the predetermined tip end is completed.

As described above, even if the position of the irradiated light is largely deviated from the tip of the object to be measured by the high speed movement in the forward direction and the high speed movement in the reverse direction, the position of the light and the measurement are measured. The amount of deviation from the tip of the object can be quickly and automatically adjusted to a minute amount. Then, finally, by moving at a low speed in the forward direction, it is possible to converge a minute amount of deviation and accurately perform a predetermined leading end.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of a three-dimensional shape measuring apparatus having a tip-out function of a measured object according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a laser light source forming a light source unit, and a polygon mirror. By rotating (not shown), the slit light is applied to a predetermined region including the measurement object 3. Reference numeral 2 denotes an image pickup unit that picks up a slit light image to generate a video signal. In the present embodiment, two CCD cameras 2A are installed to reduce the blind spots, but the number may be one.

The measuring object 3 is fixed to a rotary table 4A provided at one end of the table 4 via a rotary shaft 4B. Then, while moving the table 4 in the X direction, the slit light is scanned (scanned) with respect to the measuring object 3. When measuring the back surface of the object 3 to be measured, or when a portion of the object 3 which is not exposed to the laser light is generated, a command is issued from the table driver (driving circuit) 15 to the rotary table 4A for measurement. The object 3 is rotated.

A drive system control unit 5 outputs a forward / reverse signal to the table driver 15 so as to move the table 4 by a unit amount in the forward and reverse directions. The drive system controller 5, the driver 15 and the motor 18 constitute a moving mechanism 17 for moving the measuring object 3 relative to the laser light source 1 to scan the measuring object 3 with slit light. ing. A light source controller 6 controls ON / OFF of the laser light source 1. An image pickup system control unit 7 controls the shutter speed of the CCD camera 2A. A video input unit 8 inputs a video signal of the slit light image captured by the CCD camera 2A.

Reference numeral 9 denotes an A / D converter, which is the video input unit 8
The video signal output from is binarized. Reference numeral 10 denotes a peak value detection unit that detects the highest luminance point of the video signal binarized by the A / D conversion unit 9 as a coordinate point on camera coordinates for each scanning line of a plurality of camera screens. Therefore, in order to improve the measurement accuracy, the true maximum luminance point is obtained by using the camera pixel position (address) actually sampled as the peak value and the sampling values at both positions adjacent thereto. Reference numeral 11 denotes a sync signal generator, which is a sync separator 11 for separating a horizontal sync signal and a vertical sync signal from the video signal.
A and an image clock generator 11B that generates a sampling clock on each scanning line.

An address generator 12 generates a Y-direction address based on the horizontal sync signal separated by the sync separator 11A of the sync signal generator 11. Reference numeral 13 denotes a data generation unit that obtains the height (Z coordinate) on the object coordinates, which is the space in which the measurement target 3 is placed, from the highest luminance address on the camera coordinates obtained by the peak value detection unit 10, The three-dimensional position coordinate (X, Y, Z) data of the same image pickup portion is created, and in this system, it exists mainly in the form of software that functions on a personal computer.
The above A / D converter 9, peak value detector 10, synchronization signal generator 11, address generator 12, and data generator 1
The light spot detector 14 detects the reflected light from the measuring object 3 irradiated with the slit light from the video signal.

Reference numeral 16 is a data discriminating means, which discriminates the three-dimensional position coordinate data created by the data generating section 13,
The determination result is input to the drive system control unit 5, and in the present embodiment, the maximum brightness point obtained by exceeding the threshold level when the measurement object 3 enters the slit light irradiation range. However, if there are 10 points or more, it is determined that there is data, and if there are 5 points or less, it is determined that there is no data.

The drive system controller 5 includes the light spot detector 1
The first, second and third control of the operation of the driver 15 in the moving mechanism 17 based on the detection result of 4 and the data determination result of the data determination means 16.
Control means 5A, 5B and 5C.
Among them, the first control means 5A, as shown in A of FIG. 2, extends from the measurement start time t0 to the first time t1 at which the reflected light is detected by the light spot detection unit 14 and then the measurement object 3 Sends a signal in the positive direction to the driver 15 of the moving mechanism 17 so as to enter the slit light irradiation range to operate the motor 18 at high speed in the forward direction. As shown in FIG. 2B, the second control means 5B controls the movement mechanism 17 from the first time point t1 to the second time point t2 when the reflected light is not detected by the light spot detection unit 14. A reverse signal is sent to the driver 15 to operate the motor 18 at high speed in the reverse direction. Also, the third control means 5C
As shown in FIG. 2C, a forward signal is sent to the driver 15 of the moving mechanism 17 from the second time point t2 to the third time point t3 when the reflected light is detected again by the light spot detection unit 14. Then, the motor 18 is operated at a low speed in the forward direction.

FIG. 3 shows a processing flow in the drive system control section 5. When the laser light source 1 is ON-controlled by the light source controller 6 and a predetermined area is irradiated with spot light to start the measurement (time t0 in FIG. 2), the data discriminating means 16 outputs a signal indicating no data to the drive system controller. Enter in 5. Based on this, a signal in the forward direction is sent from the first control means 5A to the driver 15 and the motor 18 is operated at high speed in the forward direction (steps S1 to S3).

When the reflected light from the object 3 to be measured is detected by the light spot detector 14 in accordance with the high speed operation of the motor 18 in the forward direction (time point t1 in FIG. 2),
The data discriminating means 16 inputs a signal with data to the drive system control section 5, and the operation of the motor 18 is stopped (steps S4, S5). Subsequently, a signal in the reverse direction is sent from the second control means 5A to the driver 15, and the motor 18 operates at a high speed in the reverse direction. Along with this operation, the reflected light from the measuring object 3 causes the optical inspection. When it is no longer detected by the output unit 14 (time point t2 in FIG. 2), the data discriminating means 1
6 inputs a signal with no data to the drive system control unit 5, and the operation of the motor 18 is stopped (steps S6 to S9).

Then, a signal in the forward direction is sent from the third control means 5C to the driver 15 so that the motor 18 operates in the forward direction at a low speed. Along with this operation, when the light spot detector 14 again detects the reflected light from the measurement object 3 (time point t3 in FIG. 2), the operation of the motor 18 is stopped (steps S10 to S13).

Through the above-described step processing, the spot light emitted from the laser source 1 matches the tip of the object 3 to be measured, and the predetermined tip exposure is completed. As described above, even if the position of the spot light to be irradiated is largely deviated from the tip of the measurement object 3 due to the high speed movement in the forward direction and the high speed movement in the reverse direction, the position of the light and the measurement object are measured. The amount of deviation from the tip of 3 can be quickly and automatically adjusted to a very small amount.
Then, finally, by moving at a low speed in the forward direction, it is possible to converge a minute amount of deviation and accurately perform a predetermined leading end.

Actually, in the conventional manual work by visual inspection, the precision of the tip of the measuring object was about 2 to 3 mm, but in the present invention, the feed pitch of the table 4 at the time of low speed movement is 0.02 mm, for example. By setting to, it is possible to increase the tip extension accuracy to 0.02 mm.

Further, by making the upper surface of the table 4 black so that the laser reflected light is less likely to be generated and the laser reflected light from the table 4 is prevented from entering the visual field range of the CCD camera 2A, a more accurate tip is obtained. It goes without saying that you can put it out.

In the above embodiment, the measurement object 3 side is moved via the table 4, but it may be moved on the laser light source 1 side. Both 3 and the laser light source 1 may be moved. Furthermore, the present invention can also be applied to a three-dimensional shape side device that projects spot light onto the measurement target 3 and captures the reflected light with a line sensor.

[0024]

As described above, according to the present invention, before the measurement of a predetermined three-dimensional shape, the light source unit irradiates a predetermined area with light, and the predetermined area is imaged and video-recorded. By simply generating a signal, the light source unit is automatically positioned at the tip of the object to be measured by effectively utilizing the detection function of the reflected light by the light spot detection unit originally provided in the three-dimensional shape measuring apparatus. Therefore, it is possible to save labor and improve the efficiency of the predetermined tip-out work.

Moreover, since the automatic leading-out operation is performed by a combination of high-speed movement in the forward direction and high-speed movement in the reverse direction and subsequent low-speed movement in the forward direction,
The initial relative position between the light source and the object to be measured is rough,
Even if the position of the radiated light is largely deviated from the tip of the object to be measured, the amount of deviation can be quickly and automatically adjusted to a very small amount, and the subsequent slow movement in the forward direction makes it possible to make a fine adjustment. A small amount of deviation can be converged to perform a predetermined tip end with extremely high accuracy, and thus an accurate origin of measurement can be obtained.

Since the origin of measurement can be accurately matched to the tip of the object to be measured in this manner, the object to be measured can be compared with the conventional case where the origin is before the tip of the object to be measured. Since you can measure only the range where an object exists,
It is possible to reduce the measurement time and the amount of data generated.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a three-dimensional shape measuring apparatus having a tip-out function of a measured object according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a tip-out operation process of a measurement object.

FIG. 3 is a diagram illustrating a processing flow of a main part of FIG.

[Explanation of symbols]

1 ... Laser light source (light source section), 2 ... Imaging section, 2A ... CCD
Camera, 3 ... Object to be measured, 5 ... Drive system controller, 5A ... First controller, 5B ... Second controller, 5C ... Third controller, 10 ... Peak value detector, 14 ... Optical inspection Debu, 17 ...
Moving mechanism, 18 ... Motor.

Claims (1)

[Claims] 1. A light source unit for irradiating a predetermined region with light, an image capturing unit for capturing an image of the predetermined region to generate a video signal, and reflected light from a measurement object irradiated with light from the video signal. A light spot detection unit for detecting, at least one of the measurement target and the light source unit is relatively moved with respect to the other, and a moving mechanism for scanning the measurement target by irradiation of light,
From a measurement start time point to a first time point when the reflected light is detected by the light spot detection unit, first control means for operating the moving mechanism at a high speed in a forward direction to put an object to be measured into the predetermined area, and the first control means. Second control means for operating the moving mechanism in the reverse direction at high speed until the reflected light is no longer detected by the light spot detector from one time point, and the reflected light is detected again by the light spot detector from the second time point. A three-dimensional shape measuring apparatus having a tip-out function for measuring an object to be measured, which comprises a third control means for operating the moving mechanism at a low speed in a forward direction until a third time point.