JPH0545118A - Detecting method of surface position and shape of object - Google Patents

Abstract

PURPOSE:To detect the surface position and shape of a body to be detected, in a noncontact manner and on a real time basis. CONSTITUTION:A pan angle and a tilt angle of one pan head 2 on which a laser beam generating device 1 is mounted are controlled so that a spot light of a laser beam of the device 1 be applied onto the surface of a body to be detected, while the pan angle and the tilt angle of the other pan head 4 on which a video camera 3 is mounted are controlled so that a point (t) of application of the laser beam be led to the center of a screen of an image picked up by the camera 3, and the position of the point (t) of application is detected in three-dimensional coordinate values by computation of a triangulation method based on the pan angles and the tilt angles of the two pan heads 3 and 4. Besides, the pan angle and the tilt angle of the pan head 2 are controlled so that the spot light of the laser beam of the device 1 be made to sweep the surface of the body to be detected, while the pan angle and the tilt angle of the pan head 4 are controlled so that each point (t) of application of the laser beam be led to the center of the screen of the image picked up by the camera 3, and the position of each point (t) of application is detected in the three-dimensional coordinate values by the computation of the triangulation method based on the pan angle and the tilt angle of the two pan heads 2 and 4, whereby the shape of the body to be detected is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface position detecting method and a shape detecting method for an object which can be applied to a three-dimensional digitizer which detects the surface positions and shapes of various objects in a non-contact manner.

[0002]

2. Description of the Related Art Conventionally, in a three-dimensional digitizer such as a visual sensor device for position control of industrial robot equipment, non-contact detection of a three-dimensional position of an arbitrary point on the surface of an object to be detected such as a three-dimensional object. , For example, a high-intensity illuminant such as a high-intensity LED is provided at the arbitrary point, and the illuminant is tracked by two video cameras such as CCD cameras, and the pan angle of two pan heads to which both cameras are attached. , The arbitrary point is detected by a three-dimensional coordinate value by a triangulation calculation using a tilt angle.

Then, for example, if the light-emitting bodies are provided at a large number of points on the surface of the object to be detected and the lights are turned on in sequence, and the three-dimensional coordinate values of each point are detected, the shape of the object to be detected is determined from the detection results. It is also possible to detect.

[0004]

When the high-luminance light emitter is tracked by two video cameras and the surface position and shape of the object to be detected are detected in a non-contact manner as in the prior art, it is complicated to provide the high-luminance light emitter. However, since a large number of light emitters are provided for shape detection, the work becomes extremely complicated. Moreover, since the detection is performed after the high-luminance light emitter is provided,
The surface position and shape cannot be detected in real time.

Further, since two video cameras are simultaneously tracked, it is necessary to variably adjust the pan angle and tilt angle of the two pan heads to which both cameras are attached by extremely complicated tracking control. Therefore, there is a problem that the surface position and shape of the object to be detected cannot be detected easily and in real time by simple control.

The present invention simplifies tracking control by using only one video camera, and detects the surface position of an object to be detected without providing a high-luminance illuminant on the surface of the object to be detected, unlike the prior art. The purpose is to enable shape detection.

[0007]

In order to solve the above-mentioned problems, in the method for detecting the surface position of an object of the present invention, a laser beam generator and a video camera are provided with two variable pan and tilt angles. The pan angle and the tilt angle of one of the pan heads mounted on each pan head are controlled so that the spot light of the laser beam of the pan may irradiate the surface of the object to be detected. The pan angle and tilt angle of the other pan head to which the camera is attached are controlled so that the irradiation point of the laser beam of the object to be detected is drawn to the center of the shooting screen of the video camera. The position of the irradiation point is detected by a three-dimensional coordinate value by a triangulation calculation based on the tilt angle.

In the object shape detecting method of the present invention, the laser beam generator, the video camera, the pan angle,
The pan angle and the tilt angle of one of the pans on which the generator is mounted are attached to the two pans whose tilt angles are variable, and the spot light of the laser beam of the generator sets the surface of the object to be detected. The pan angle and tilt angle of the other platform with the video camera attached are controlled so that they sweep.
The irradiation points of the laser beam of the object to be detected are controlled so as to be drawn to the center of the image pickup screen of the video camera, and the calculation of the triangulation method based on the pan angle and the tilt angle of both pans causes the irradiation point The position is detected by three-dimensional coordinate values to detect the shape of the detected object.

[0009]

In the object position detecting method of the present invention constructed as described above, the irradiation point of the laser beam of the laser beam generator mounted on one pan head is used instead of the conventional high brightness illuminant. The pan angle and tilt angle of the other platform are adjusted by the tracking control so that this irradiation point is drawn into the center of the shooting screen of one video camera of the other platform.

Then, the position of the irradiation point is detected by the three-dimensional coordinate value by the calculation of the triangulation method based on the pan angle and the tilt angle of both pan heads, and the high-intensity luminous body is provided on the detected body as in the conventional case. In addition, the surface position of the object to be detected is detected in real time in real time only by tracking control of one video camera.

Further, in the case of the object shape detecting method of the present invention, the irradiation point of the laser beam of the laser beam generator mounted on one of the platform heads sweeps the surface of the object to be detected,
The pan angle and tilt angle of the other platform are adjusted by the tracking control so that each irradiation point that moves by this sweep is drawn to the center of the shooting screen of one video camera of the other platform.

Then, the position of each irradiation point is detected by three-dimensional coordinate values by the calculation of the triangulation method based on the pan angle and the tilt angle of both pans, and the shape of the object to be detected is detected from these coordinate values. The shape of the object to be detected can be detected in real time in real time without providing a large number of high-luminance light emitters on the object to be detected as in the prior art, and only by the tracking control of one video camera.

[0013]

EXAMPLES Examples will be described with reference to FIGS. 1 to 3. FIG. 1 shows an apparatus configuration, 1 is a laser beam generator (laser head) attached to one platform 2;
3 is, for example, a two-dimensional CCD having a structure of 256 × 196 pixels
Two video cameras having an image pickup body, which are attached to the other platform 4. The pans 2 and 4 have a pan (horizontal) angle range of ± 135 ° and a tilt (vertical) angle range of ± 45 °.

Reference numeral 5 is an RS232C standard communication interface provided between the camera 3 and the control processing unit 6 having a microcomputer configuration. Reference numerals 7 and 8 are provided between the camera platform 3 and 4 and the control processing unit 6. A 2-channel A / D converter, and 9 is an operation switch for instructing data acquisition.

Reference numeral 10 denotes a pan angle of each of the pan heads 2 and 4 formed by the sweep control and tracking correction of the control processing unit 6,
4-channel D for analog conversion of tilt angle data
/ A converters, 11 and 12 are two automatic / manual changeover switches provided between the converter 10 and an amplifier 13 for the driver of the camera platform 2, and 14 and 15 are converters 10 and the camera platform 4. Two automatic / manual changeover switches provided between the driver and the amplifier 16.

Reference numeral 17 denotes D / to which the data of the three-dimensional coordinate value obtained by the calculation of the triangulation method of the control processing unit 6 is supplied.
It is an A converter and outputs an analog signal for position and shape display to the monitor CRT. The switches 11 to 15 are turned on and off by automatic control and manual control of the pan heads 2 and 4.

Further, the amplifiers 13 and 16 are switches 11 to 11.
The pan drive signals Vα _A and Vα _B and the tilt drive signals Vβ _A and Vβ _B are output to the camera platform 2 and 4 by an analog signal for automatic control via 15 and an analog signal for manual control based on joystick operation and the like.

When detecting the surface position of the object to be detected, after the pedestals of both pans 2 and 4 are initially set horizontally, for example, the switches 11 and 12 are turned off, and the laser of the generator 1 is operated by joystick operation. The drive signal Vα is set so that the spot light of the beam irradiates a desired surface position of the detected object.
Adjust _A and Vβ _A to manually set the pan and tilt angles of the platform 2. At this time, the position of the irradiation point t becomes a brightness that is clearly distinguished from the surrounding environment by the irradiation of the high-intensity laser beam, as in the case of providing the conventional high-intensity light-emitting body.

On the other hand, the camera 3 for photographing the object to be detected has an image processing unit of a microcomputer configuration, and this processing unit instantaneously binarizes each pixel data of the photographing screen to obtain each point of the irradiation point t. Two-dimensional coordinate values (X, Y) on the shooting screen are obtained in real time.

The two-dimensional coordinate values (X, Y) are obtained, for example, with the center of the photographing screen as the origin (0, 0), and the irradiation point t
Shows the deviation from the target position (center of the screen).

Then, the data of the coordinate value (X, Y) is sent to the control processing unit 6 through the communication interface 5, and the tracking correction of the control processing unit 6 pulls the coordinate value (X, Y) to the center of the screen. The pan angle digital data and the tilt angle digital data of the camera platform 4 are formed.

Further, the pan angle of the platform 2 generated by the automatic irradiation control such as the sweep control described later of the control processing unit 6,
The digital data of the tilt angle and P _A, T _A, the pan angle of the camera platform 4 which is generated by the tracking control of the control unit 6, the digital data of the tilt angle P _B, When T _B, these data P _A , P _B , T _A , T _B are analog-converted by the D / A converter 10, and the analog signals of the data P _A , T _A are supplied to the amplifier 13 via the switches 11, 12.
The analog signals of the data P _B and T _B are switches 14 and 15
Is supplied to the amplifier 16 via.

Then, for example, tracking correction data P _B , T
_The drive signals Vα _B and Vβ _B based on _B are given by
It is shown by the formula.

[0024]

[Number 1] _{Vα B = Kα B · (0} -X) Vβ B = Kβ B · (0-Y)

Note that Kα _B and Kβ _B are control gain constants.

Then, the pan angle and tilt angle of the platform 4 are controlled by the drive signals Vα _B and Vβ _B , and the camera 3 variably controls the photographing state (posture) so that the position of the irradiation point t is pulled to the center of the screen. To be done.

At this time, as shown in FIG.
A horizontal line segment connecting (generator 1, camera 3) is defined as an x-axis, and the origin O (x, y, z) of the three-dimensional coordinates of this axis and the y-axis and the z-axis (height direction) = (0, (0, 0) is the central point of the interval L between the platform 2 and 4, and the angle (pan angle) in the xy horizontal plane when the irradiation point t is seen from each of the platform 2 and 4 is α _A , α
_{If B} and the angles in the z-axis plane (tilt angles) are β _A and β _B , the x-axis, y-axis, and z-axis components x _t , y _t , and z of the irradiation point t are shown.
_t has the relationship shown by the following two equations of the equation 2 and the equations of the equation 3 or the equation 4.

[0028]

Y _t / (x _t + L / 2) = tan (α _A ) y _t / (x _t −L / 2) = tan (α _B )

[0029]

## EQU00003 ## z _t / {y _t cosec (α _A )} = tan (β _A )

[0030]

## EQU00004 ## z _t / {y _t cosec (α _B )} = tan (β _B )

By the way, α _A and β _A are pan angles of the pan head 2,
This corresponds to the tilt angle, and α _B and β _B correspond to the pan angle and the tilt angle of the platform 4. Then, the pan heads 2 and 4 form voltage signals proportional to the pan angle and the tilt angle by the potentiometers and supply the voltage signals to the A / D converters 7 and 8. Based on this supply, the converters 7 and 8 generate α signals. Digital data of _A , β _A , α _B , and β _B is formed, and these data are sent to the control processing unit 6.

Further, in order to manually instruct the control processing unit 6 to take in data, after the adjustment of the platform 4 by the tracking control is completed, the switch 9 is pushed to turn on. At this time, the control processing unit 6 takes in the pan angle and tilt angle data of the converters 7 and 8 and takes in the detected object from the following equation 5 obtained from the equation 2 and the equation 3 or 4. Three-dimensional coordinate values (x _t , y _t , z _t ) of the irradiation point t on the surface are obtained and detected.

X _t / L = − {tan (α _A ) + tan (α _B )} / {tan (α _A ) -tan (α _B )} / 2 y _t / L = − {tan (α _A ). tan (α _B )} / {tan (α _A ) -tan (α _B )} z _t / L = −tan (β _A ) sin (α _B ) / sin {(α _A ) − (α _B )} = −tan (β _B ) sin (α _A ) / sin {(α _A ) − (α _B )}

Further, three-dimensional coordinate values (x _t , y _t ,
The data of z _t ) is supplied to the D / A converter 17, and digital data and analog signals of the position of the irradiation point t are obtained from the input side and the output side of this converter 17.

When the pan and tilt angles of the platform 2 are adjusted by the joystick operation to change the position of the irradiation point t, the pan and tilt angles of the platform 4 are tracked according to the change in the position of the irradiation point t. Changes, and switch 9
By pressing, the three-dimensional coordinate value (x
_t , y _t , z _t ) are determined and detected. by the way,
It is also possible to automatically set and detect the pan angle and tilt angle of the platform 2.

In this case, the position information of the irradiation point t is given to the control processing unit 6 in advance, and all the switches 11 to 15 are held on. Then, when the detection start is instructed, the control processing unit 6 forms the digital data P _A and T _A of the pan angle and the tilt angle of the platform 2 by the automatic irradiation control based on the given position information, and both data P The pan and tilt angles of the platform 2 are automatically set by the drive signals Vα _A and Vβ _A of the amplifier 13 based on _A and T _A , and the irradiation point t is automatically set to a desired position on the surface of the detected object.

At this time, the pan angle and tilt angle of the platform 4 are automatically adjusted according to the irradiation point t by the tracking correction of the control processing unit 6. Then, when the switch 9 is turned on, the three-dimensional coordinate value (x _t , y
_t , z _t ) are sought and detected.

The operation of the switch 9 is omitted, and the irradiation point t is converged to the center of the screen of the camera 3 by the tracking control so that the camera platform 4 can be controlled.
When the automatic control of T is finished, the control processing unit 6 automatically takes in the digital data of the converters 7 and 8, and the irradiation point t
The three-dimensional coordinate values (x _t , y _t , z _t ) may be automatically obtained. In this case, the surface position of the object to be detected can be detected by completely automatic control.

When the irradiation point t cannot be photographed by the camera 3 due to the unevenness of the object to be detected, for example, the turntable on which the object to be detected is rotated or the turntable on which the pan heads 2 and 4 are placed. The direction (range) of the detected object viewed from the generator 1 and the camera 3 may be shifted by the rotation around the detected object, and the irradiation point t may be detected by the camera 3.

At this time, for example, when the correction of the coordinate axis rotation corresponding to the above-mentioned direction is added to the obtained three-dimensional coordinate value (x _t , y _t , z _t ), the coordinate axis in the reference direction (reference coordinate axis) is obtained. The irradiation point t can be detected.

Next, the shape detection of the object to be detected will be described. First, when the irradiation point t is automatically set and detected,
A program for sweep control of the platform 2 is preset in the control processing unit 6, and the switches 11 to 15 are held on.

Then, when the detection start is instructed, the control processing unit 6 performs the horizontal swing motion and the vertical motion of the platform 2 based on the sweep control program so that the spot light of the laser beam of the generator 1 is generated. So as to sweep the surface of the object to be detected like a scanning line of a television, while continuously changing the digital data P _A and T _A of the pan and tilt angles of the platform 2. By continuously varying the pan angle and tilt angle of the platform 2 based on this continuous formation, the irradiation point t moves by sweeping the surface of the detected object.

At this time, by the tracking control of the control processing unit 6, the pan head 4 and the tilt angle are interlocked with the movement of the irradiation point t so that the irradiation point t is drawn to the center of the photographing screen of the camera 3. Is adjusted. Then, the control processing unit 6 takes in the pan angle and tilt angle data of the converters 7 and 8 at preset intervals, and the three-dimensional coordinate value (x
_The shape is detected by obtaining _t , y _t , z _t ).

In order to display the detected shape on the CRT or the like on the screen, for example, after the completion of the sweep control, the control processing unit 6 sets the three-dimensional coordinates based on the three-dimensional coordinate values (x _t , y _t , z _t ) of each irradiation point t. The three-dimensional graphic drawing program is executed, three-dimensional display data of the detected shape is formed and supplied to the converter 17.

When detecting the shape of the entire body to be detected, the body to be detected is placed on a turntable, for example.

Then, the table is rotated by a predetermined angle to change the orientation of the object to be detected little by little, and the three-dimensional coordinate value (x) of each irradiation point t based on the sweep control in each orientation (x
_t , y _t , z _t ) is obtained.

Furthermore, the three-dimensional coordinate values (x _t , y _t , z) of each irradiation point t in each direction according to the rotation angle of the tape.
_t ) is corrected, and the shape of the entire body to be detected is detected with a common coordinate axis. By the way, it is also possible to detect the irradiation point t while moving it manually. In this case, the switches 11 and 12 are held off as in the manual detection of the surface position.

Then, the pan angle and tilt angle of the platform 2 are manually variably set so that the irradiation point t sweeps the object to be detected by the joystick operation.

Further, each time the switch 9 is operated, the converter 7,
The pan angle and tilt angle data of No. 8 are taken into the control processing unit 6, three-dimensional coordinate values of each irradiation point t are obtained, and the shape is detected. An example of a display image based on the three-dimensional display data obtained by automatic or manual shape detection is shown in FIG.

[0050]

Since the present invention is configured as described above, it has the following effects. First, in the case of the object surface position detecting method of the present invention, the irradiation point t of the laser beam of the laser beam generator 1 mounted on one platform 2 is used in place of the conventional high-intensity illuminant, and this irradiation point is used. The pan angle and the tilt angle of the other platform 4 are adjusted by the tracking control so that t is drawn to the center of the shooting screen of one video camera 3 of the other platform 4, and the pans 2 and 4 of both platforms 2 and 4 are adjusted. Since the position of the irradiation point t is detected by the three-dimensional coordinate value by the triangulation based on the pan angle and the tilt angle, it is not necessary to provide a high-intensity light emitting body on the detected object as in the conventional case, and one video camera is used. By the simple tracking control of 3, the surface position of the detected object can be detected in non-contact in real time.

Further, in the case of the object shape detecting method of the present invention, the irradiation point of the laser beam of the laser beam generator 1 mounted on one platform 2 sweeps the surface of the object to be detected and moves by this sweep. The pan angle and tilt angle of the other pan head 4 are adjusted by the tracking control so that each irradiation point t is drawn into the center of the shooting screen of one video camera 3 of the other pan head 4. The position of each irradiation point t is detected by three-dimensional coordinate values by triangulation based on the pan angle and tilt angle of 2 and 4, and the shape of the detected object is detected from these coordinate values. The non-contact detection of the shape of the detected object can be performed in real time without providing the high-intensity light-emitting body of No. 1 on the detected object and only by the tracking control of one video camera 3.

[Brief description of drawings]

FIG. 1 is a device block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of position detection of an irradiation point by the device of FIG.

3 is a front view of an example of a display image based on shape detection of the apparatus of FIG.

[Explanation of symbols]

 1 Laser beam generator 2, 4 Pan head 3 Video camera t Irradiation point

Claims (2)

[Claims] 1. A laser beam generator and a video camera are mounted on each of two pans whose pan and tilt angles are variable, and the pan of one of the pans on which the generator is mounted,
The tilt angle is controlled so that the spot light of the laser beam of the generator irradiates the surface of the object to be detected, and the pan angle and tilt angle of the other platform on which the video camera is attached are detected as the object to be detected. The irradiation point of the laser beam on the body is controlled so as to be drawn into the center of the photographing screen of the video camera, and the position of the irradiation point is determined by calculation of the triangulation method based on the pan angle and the tilt angle of both pans. A surface position detection method for an object, which is characterized in that detection is performed by three-dimensional coordinate values. 2. A laser beam generator and a video camera are attached to each of two pans whose pan and tilt angles are variable, and the pan of one of the pans to which the generator is attached,
The tilt angle is controlled so that the spot light of the laser beam of the generator sweeps the surface of the object to be detected, and the pan angle and tilt angle of the other pan head to which the video camera is attached are detected as the object to be detected. The irradiation points of the laser beam on the body are controlled so as to be drawn to the center of the photographing screen of the video camera, and the irradiation points of the irradiation points of the respective irradiation points are calculated by the triangulation method based on the pan and tilt angles of the pan heads. A method for detecting the shape of an object, characterized in that the shape of the detected object is detected by detecting the position with a three-dimensional coordinate value.