JPH07190773A - Optical three-dimensional position detecting device - Google Patents

Abstract

PURPOSE:To simplify a structure and reduce production cost by computing the vertical elevation angle of a measurement object on the basis of the photographed image of converged return light, a rectilinear distance on the basis a return time and the horizontal deflection angle of the object on the basis of timing to receive the return light, respectively. CONSTITUTION:Projection light 1 emitted from an LED 2 through a projector lens 4 is reversibly reflected from the reflecting prism 101 of a position indicator 100, and the return light 7 is converged at a position 6. The light 7 is received with the image pick-up element 9 of an elevation angle detecting section, and an elevation angle operation means performs an image analysis for the picked up image, thereby computing a vertical elevation angle. Also, a distance detecting section has each means for modulation, comparison and distance calculation, and modulates the projection light 1 in terms of a time, on the basis of the prescribed reference signal. Thereafter, the light 7 is received with a light receiving element 11, and a comparison is made between an outputted electrical signal and a reference signal in terms of a phase, thereby finding a return time. A rectilinear distance is calculated on the basis of the return time. Also, the scanning means of a deflection angle detecting section, or a stepping motor 12 angularly scans the light 1 along a horizontal direction in such state as crossing the prism 101, and calculates a horizontal deflection angle on the basis of timing for receiving the light 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical three-dimensional position detecting device for surveying, which is mainly used in civil engineering sites and construction sites, and an optical three-dimensional position detecting device used for robot control. In particular, the present invention relates to a method for automatically detecting the three-dimensional position of a measured object without manual intervention.

[0002]

2. Description of the Related Art A tracking type total station is conventionally known as an optical position detecting device capable of three-dimensional measurement. The total station basically has a structure in which a light-wave rangefinder and a transit are integrated together.
The optical distance measuring device optically measures a linear distance by using a reflecting mirror provided on a position indicator such as a pole arranged at a remote measuring point as a target. Transit also measures the vertical elevation and horizontal declination of the pointing device. Three-dimensional position information of the measurement point is obtained from the linear distance, vertical elevation angle, and horizontal declination. The tracking total station also has a built-in scanner and motor. The scanner two-dimensionally scans the beam from the laser light source incorporated in the main body of the total station along the vertical direction and the horizontal direction, and automatically detects the reflector of the position indicator. Based on this detection result, the pair of elevation angle motors and declination motors are driven to perform the tracking operation for the position indicator.

[0003]

Since the conventional tracking type total station includes a laser scanning mechanism and a pair of horizontal deflection and vertical deflection motors, it has a very complicated and expensive structure and is extremely convenient for position detection. Although it is a device, it is currently not widely used. or,
The tracking type total station has a problem that it takes a long search time when a target is lost or a new target is set. Since the scanning of the target using the laser beam is performed two-dimensionally along the horizontal direction and the vertical direction, the search takes a multiplicative time and requires a long time. Furthermore, the conventional tracking type total station has a fundamental problem that it cannot measure a plurality of position indicators at the same time because the position measurement is performed while tracking a single position indicator.

In view of the above-mentioned problems of the conventional technique, a first object of the present invention is to provide an optical three-dimensional position detecting device having a simple structure and a general price range.
A second object of the present invention is to provide an optical three-dimensional position detecting device that enables high-speed search for a target that has been set arbitrarily, and can thereby realize robot control and the like. A third object of the present invention is to provide an optical three-dimensional position detecting device capable of simultaneously measuring a plurality of position pointing devices, so that a single operator can simultaneously measure different locations or detect the positions of a plurality of robots. Is to be possible.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art and achieve the object of the present invention, the following means were taken. That is, the optical three-dimensional position detecting device according to the present invention includes the light emitting means and the lens means. The light emitting means emits light to the object to be measured having a reflecting surface, while the lens means collects the return light reflected backward from the reflecting surface. or,
The elevation angle detection unit, the declination angle detection unit, and the distance detection unit are provided, and the vertical elevation angle, the horizontal declination angle, and the linear distance of the measured object are obtained based on the collected return light. As a feature of the present invention, the elevation angle detecting section includes an image pickup element having a multi-divided image pickup surface for receiving the condensed return light, and an elevation angle calculation means for image-analyzing the obtained image pickup to calculate a vertical elevation angle. Includes and. Further, the distance detecting unit modulates the projected light with time based on a predetermined reference signal, a light receiving element that receives the collected return light and outputs a corresponding electric signal, and the reference signal. And a comparison means for phase-comparing the electric signals to obtain a return time, and a distance calculation means for calculating a linear distance based on the return time. Further, the declination detector detects a horizontal deviation based on scanning means for angularly scanning the projected light in a horizontal direction so as to traverse the reflection surface of the object to be measured, and the light reception timing of the return light reflected backward during the angular scanning. And a declination calculation means for calculating the angle.

The optical three-dimensional position detecting apparatus according to the present invention preferably includes a beam splitting means, and the return light condensed by the lens means is divided into two parts, that is, both the image pickup element and the light receiving element. Distribute to. Further, the deviation angle calculation means detects the light reception timing of the return light in accordance with the electric signal output from the light receiving element, and reads the angular scanning amount of the light projection at the light reception timing to obtain the horizontal deviation angle. There is. The deviation angle calculating means can calculate the horizontal deviation angle of each of the measured objects based on the light reception timing of the return light that is sequentially backward-reflected from the plurality of measured objects during the angular scanning of the projection. According to one aspect of the present invention, the declination detection unit selectively directs the light projection to the object to be measured based on the horizontal declination obtained by angular scanning, while the elevation angle detection unit and the distance detection unit select. The vertical elevation angle and the linear distance of the object to be measured are detected during pointing. In this case, the elevation angle calculation means, the distance calculation means, and the declination angle calculation means are constituted by a microcomputer, and it becomes possible to execute three-dimensional position measurement according to a predetermined sequence program. In some cases, a position indicator having a reflecting surface is additionally provided, and the object to be measured is set at a desired measurement point. However, the present invention is not limited to this, and it is possible to perform three-dimensional position detection by using any kind of object having a reflecting surface as the measured object.

[0007]

According to the present invention, vertical elevation angle detection is performed electronically using an image pickup device such as a CCD having a multi-divided image pickup surface, and vertical scanning is unnecessary.
In addition, for linear distance detection, a light receiving element such as a photodiode is prepared separately from an image pickup element such as a CCD. C
While a CD or the like is a storage type and has a slow response speed, a light receiving element such as a photodiode is excellent in high-speed response and thus is used for linear distance detection. The image pickup element and the light receiving element are optically arranged at the same position by using, for example, a beam splitter or the like, and the condensing lens and the light receiving path are shared.
By taking these two measures, the structure is simplified and the product cost is reduced. At the same time, the conventional two-dimensional scanning is replaced by one-dimensional scanning only in the horizontal direction, which realizes high-speed search. For horizontal declination detection, light projection is angularly scanned along the horizontal direction, and the light reception timing of return light at that time is detected by the light receiving element having a short response time. By repeating this detection operation in order during angular scanning, it is possible to simultaneously measure a plurality of position indicators.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of an optical three-dimensional position detecting device according to the present invention. This device is for detecting the three-dimensional position of the object to be measured. Here, the position indicator 10 having a pole shape as the measured object is used.
0 is targeted. This position indicator 100 is preliminarily set at a desired measurement point or a plurality of points at the time of surveying. The position indicator 100 has a reflecting surface, and in this example, the reflecting prism 101 is embedded.

On the other hand, the main body of this apparatus is provided with a light emitting means, and emits a light projection 1 to the position indicator 100. In this example, the light emitting means is composed of the light emitting diode 2 and is housed in the upper barrel 3 of the main body. The light projection 1 emitted from the light emitting diode 2 via the light projection lens 4 has a vertically long spot shape elongated in the vertical direction. This spot shape is preset so as to cover the measurement range in the vertical direction, and a part of the projected light 1 is always reflected backward by the reflection prism 101. In this example, since the light projection 1 having a vertically long spot shape is emitted, the light emitting diode 2 uses a linear array arranged in the vertical direction. Instead of this, a cylindrical lens may be combined with the light projecting lens 4 to obtain a vertically long spot shape.

A condenser lens 6 is incorporated in the lower lens barrel 5, and constitutes a lens means for condensing the return light 7 backward-reflected from the reflection prism 101. A filter 8 is attached to the entire surface of the condenser lens 6.

The present apparatus further comprises an elevation angle detection unit, a declination angle detection unit, and a distance detection unit. The vertical elevation angle, the horizontal declination angle, and the straight line distance of the position indicator 100 can be obtained respectively, and the three-dimensional position is optically detected. Can be done. The elevation angle detection unit includes an image sensor 9 that receives the collected return light 7, and an elevation angle calculator that analyzes the obtained image to calculate a vertical elevation angle. The elevation angle calculating means is included in the controller 10. The image pickup element 9 has a multi-divided image pickup surface at least along the vertical direction, and in this example, a CCD linear image sensor is used. Further, the distance detecting section is a modulation means for time-modulating the light projection 1 based on a predetermined reference signal, and a light receiving element 1 for receiving the condensed return light 7 and outputting a corresponding electric signal.
1, a comparison means for phase-comparing the reference signal and the electric signal to obtain a return time, and a distance calculation means for calculating a linear distance based on the return time. In this example, the light receiving element 1
1 uses a photodiode excellent in high-speed response. The above-mentioned modulation means, comparison means, and distance calculation means are included in the controller 10. Further, the deviation angle detection unit is based on the scanning means for angularly scanning the light projection 1 in the horizontal direction so as to traverse the reflection prism 101 of the position indicator 100, and the light reception timing of the return light 7 reflected backward during the angular scanning. And a declination calculation means for calculating a horizontal declination. In this example, this scanning means comprises a stepping motor 12 and is housed in a turntable 13. This turntable is rotatably mounted on the tripod base 14. The stepping motor 12 integrally drives the above-described upper lens barrel 3 and lower lens barrel 5 about the vertical axis 15 to scan the light projection 1 angularly along the horizontal direction. This makes it possible to receive the return light 7 at the same time. In this example, the stepping motor 12 is used to mechanically scan the light projection 1, but the present invention is not limited to this.
For example, the projection 1 can be scanned at high speed by using a galvanometer mirror or the like. In the present invention, it is not necessary to scan the light projection 1 two-dimensionally along the vertical direction and the horizontal direction, and it suffices to scan only the horizontal direction by using one stepping motor 12. Thereby, the search time of the position indicator 100 can be shortened. The declination calculation means is included in the controller 10.

In this embodiment, a beam splitter 16 is incorporated in the lower lens barrel 5, and the return light 7 condensed by the lens 6 is divided into two and divided into both the image pickup element 9 and the light receiving element 11. is doing. Further, a slit plate 17 is interposed between the beam splitter 16 and the light receiving element 11. By using the beam splitter 16, the distance detection unit and the elevation angle detection unit can share the condenser lens 6 and the lower lens barrel 5, which leads to a reduction in the number of parts. Further, the declination calculation means included in the controller 10 detects the light reception timing of the return light 7 according to the electric signal output from the light receiving element 11, and the angular scanning amount of the light projection 1 at the light reception timing (of the stepping motor 12). Rotation amount) is read to obtain the horizontal declination. This declination calculation means is used for a plurality of position indicators 100 during angular scanning of the light projection 1.
It is possible to calculate the horizontal deflection angle of each position indicator 100 based on the light reception timing of the return light 7 that is sequentially reflected backward. In this case, the declination detection unit selectively directs the light projection 1 to the position indicator 100 based on the horizontal declination obtained by angular scanning, while the elevation angle detection unit and the distance detection unit indicate the position during the selective pointing. The vertical elevation angle and the straight line distance of the vessel 100 can be detected. In this way, it becomes possible to successively detect the three-dimensional position for the plurality of position indicators 100.

FIG. 2 is a schematic diagram showing an optical configuration of the optical three-dimensional position detecting device shown in FIG. The state where the lower lens barrel 5 is viewed from the direction of the entrance is shown. The image pickup device 9 is arranged behind the beam splitter 16 and has a multi-divided image pickup surface 31 arranged in the vertical direction. The return light 7 condensed through the lens 6 forms a spot image on the multi-division image pickup surface 31. The vertical declination of the position indicator 100 can be detected by image-analyzing this spot image and determining its position. That is, the coordinate position of the spot image along the vertical direction and the vertical elevation angle are in a proportional relationship. As the image pickup device 9, the CCD linear image sensor is used as described above. Since the vertical elevation angle range is generally narrower than the horizontal declination angle range, it is possible to measure the vertical elevation angle with a practically sufficient resolution by a CCD linear image sensor.

A light receiving element 11 is arranged below the beam splitter 16 via a slit plate 17. The slit 32 formed in the slit plate 17 is aligned with the multi-division image pickup surface 31 in the horizontal direction. When the projected light 1 is angularly scanned in the horizontal direction, the spot image of the collected return light 7 moves so as to cross the multi-division image pickup surface 31. When the spot image is exactly aligned with the multi-division image pickup surface 31, the amount of the split return light passing through the slit 32 reaches a peak. The light receiving element 11 is composed of a photodiode or the like having a high-speed response, can detect the peak of return light in real time, and can specify the light reception timing of the return light during angular scanning. The horizontal deflection angle is obtained by reading the angular scanning amount according to the light receiving timing. The light receiving element 11 is also used for linear distance detection. As described above, in the present invention, three-dimensional position measurement is possible with a simple configuration by skillfully using the image pickup device 9 having the storage effect and the light receiving device 11 having the high-speed response.

FIG. 3 is a block diagram showing the electrical construction of the optical three-dimensional position detecting apparatus shown in FIG. 1, and particularly shows the concrete construction of the controller 10. A microcomputer 51 is provided, and the distance calculation means 52, the deflection angle calculation means 53, and the elevation angle calculation means 54 described above are configured by software. The data of the straight line distance, the horizontal declination angle, and the vertical elevation angle calculated by the computing means 52 to 54 are transferred to an external computer system via the computer interface 55.

The image pickup device 9 has a multi-divided image pickup surface for receiving the condensed return light, and supplies the obtained image pickup to the microcomputer 51 via the image input circuit 56 and the A / D converter 57. The elevation angle calculation means 54 analyzes the image of the input image and calculates the vertical elevation angle.

The controller 10 includes a reference oscillator 58 and generates a predetermined reference signal STD. The light emitting diode 2 is connected to a reference oscillator 58 via a drive amplifier 59, and emits time-modulated light projection based on the reference signal STD. That is, the reference oscillator 58 and the drive amplifier 59
Constitute the modulation means. On the other hand, the light receiving element 11 receives the collected return light and amplifies the corresponding electric signal ELC by the amplifier 60.
Output via. The phase comparator 61 constitutes a comparison means, and compares the reference signal STD and the electric signal ELC in phase to obtain a return time. This return time is input to the microcomputer 51, and the distance calculation means 52 calculates the linear distance based on the input return time. That is, the return time and the linear distance are in a proportional relationship.

Further, the electric signal ELC output from the light receiving element 11 is input to the microcomputer 51 via the A / D converter 62. The declination calculation means 53 detects the light reception timing of the return light according to the input electric signal ELC, reads the angular scanning amount of the light projection at the light reception timing, and obtains the horizontal declination. At this time, the microcomputer 51 drives the stepping motor 12 via the motor controller 63 to angularly scan the projected light. The microcomputer 51 stores the rotation amount of the stepping motor, and the declination calculation means 53 reads the stored rotation amount according to the detected light receiving timing to obtain the horizontal declination.

Finally, referring to the flow chart of FIG.
The operation of the microcomputer 51 shown in FIG. 3 will be described in detail. After starting the device, first of all, step S1
The stepping motor is rotated at high speed, and the light projection is angularly scanned in the horizontal direction. Next, in step S2, it is determined whether or not the peak value of the electric signal output from the photodiode has been detected. This judgment is continuously made until the peak value is detected. When the peak value is detected, the process proceeds to step S3. In this step, the rotation angle θ of the stepping motor at the time when the peak value is detected is read and stored as a horizontal deviation angle. Next, in step S4, the rotation of the stepping motor is stopped immediately after the peak value is detected. At this time, the stop position slightly overshoots the stored horizontal declination angle due to the inertia of the mechanical section and the like. Therefore, the process proceeds to step S5, in which the stepping motor is reversely rotated to direct the light projection to the horizontal deflection angle θ. Next, in step S6, the image of the CCD linear image sensor is read, and the vertical elevation angle φ to the reflecting prism is calculated from the position of the imaged spot. Further, in step S7, the output of the phase comparator is processed to obtain the linear distance D. Finally step S
At 8, the calculated horizontal declination θ, vertical elevation φ, and linear distance D are sent to the computer system via the computer interface. After this, again step S1
Return to and re-execute the angular scanning of light projection. The three-dimensional position detecting operation described above is executed according to the sequence program loaded in the microcomputer 51. It is possible to measure the three-dimensional position in a desired procedure by appropriately selecting the sequence program. For example, the horizontal deflection angle of each position indicator can be sequentially calculated based on the light reception timing of the return light that is sequentially back-reflected from the plurality of position indicators during the angular scanning of light projection. in this case,
After the horizontal deflection angles of the plurality of position indicators are all obtained first, the light projection can be selectively directed to each position indicator to detect the distance and the elevation angle.

[0020]

As described above, according to the present invention, C
Electronically detecting the elevation angle using an image pickup device such as a CD linear image sensor has the effects of simplifying the structure of the optical three-dimensional position detecting device and increasing the search speed. The beam splitter is used to split the returned light into two parts, which are distributed to both the image pickup device for elevation angle detection and the light receiving device for distance detection. As a result, the condensing lens and the optical barrel can be shared, the structure is simplified, and the manufacturing cost can be reduced. By increasing the search speed, there is an effect that it can be applied to position detection such as robot control in addition to the field of surveying. By angularly scanning the light emission in the horizontal direction, detecting the peak of the return light generated at that time with a light receiving element with a short response time, and repeating this in order in the rotation direction enables continuous measurement of multiple position indicators. The effect of becoming

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an optical three-dimensional position detection device according to the present invention.

FIG. 2 is a block diagram showing an optical configuration of the optical three-dimensional position detecting device shown in FIG.

FIG. 3 is a block diagram showing an electrical configuration of the optical three-dimensional position detection device shown in FIG.

4 is a flowchart for explaining the operation of the optical three-dimensional position detecting device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light projection 2 Light emitting diode 3 Upper lens barrel 5 Lower lens barrel 6 Condensing lens 7 Return light 9 Imaging device 10 Controller 11 Light receiving device 12 Stepping motor 13 Turntable 16 Beam splitter 17 Slit plate 31 Multi-division imaging surface 32 Slit 51 Microcomputer 52 Distance calculating means 53 Declination calculating means 54 Elevation angle calculating means 58 Reference oscillator 61 Phase comparator 63 Motor controller

Claims (7)

[Claims] 1. A light emitting means for emitting light to an object to be measured having a reflecting surface, a lens means for collecting return light backwardly reflected from the reflecting surface, and a base for the returning light collected. And an optical three-dimensional position detection device including an elevation angle detection unit, a declination detection unit, and a distance detection unit that respectively obtain a vertical elevation angle, a horizontal declination angle, and a linear distance of a measured object, wherein the elevation angle detection unit is An image pickup device having a multi-divided image pickup surface for receiving the collected return light, and an elevation angle calculation means for image-analyzing the obtained image pickup to calculate a vertical elevation angle, the distance detecting section, Modulation means for time-modulating the light projection based on a predetermined reference signal, a light receiving element for receiving the collected return light and outputting a corresponding electric signal, and a phase comparison between the reference signal and the electric signal And a comparison means to obtain the return time,
A deviation calculating unit that calculates a linear distance based on the return time, the deviation angle detecting unit includes a scanning unit that horizontally scans the light projection so as to traverse the reflection surface of the measured object. An optical three-dimensional position detecting device comprising: a deviation angle calculating means for calculating a horizontal deviation angle based on the light reception timing of the return light reflected backward during the angular scanning. 2. A beam splitting means is included, and the return light condensed by the lens means is divided into two and is divided into both the image pickup element and the light receiving element. The described optical three-dimensional position detection device. 3. The horizontal deviation angle detecting means detects the light reception timing of return light in accordance with an electric signal output from the light receiving element, reads the angular scanning amount of the light projection at the light reception timing, The optical three-dimensional position detecting device according to claim 1, wherein 4. The declination calculation means calculates the horizontal declination of each of the measured objects based on the light reception timing of the return light that is sequentially back-reflected from the plurality of measured objects during the angular scanning of the projection. The optical three-dimensional position detecting device according to claim 1, wherein 5. The deflection angle detection unit selectively directs the light projection to the object to be measured based on the horizontal deflection angle obtained by angular scanning, while the elevation angle detection unit and the distance detection unit are selectively directed. The optical three-dimensional position detecting device according to claim 1 or 4, which detects a vertical elevation angle and a linear distance of the object to be measured. 6. The optical three-dimensional position detecting device according to claim 1, wherein the elevation angle calculating means, the distance calculating means and the declination calculating means are constituted by a microcomputer. 7. The optical three-dimensional position detecting device according to claim 1, further comprising a position indicator having a reflecting surface, which is set at a desired measuring point as the object to be measured.