JP2001311612A - Shape input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape input device that can simultaneously inputting a two-dimensional image and a distance information while being able to prevent an occlusion. SOLUTION: In the shape input device for measuring the time up to the reception of reflected reference light from the transmission of reference light at a plurality of positions P on an object 9, an image pickup means 70 is provided to input two-dimensional image information of the object 9, and an optical path separation means 75 to separate light with a specified wavelength range containing the emission wavelength of the reference light and the light with other wavelength ranges. The image pickup means 70 and the optical path separation means 75 are so arranged that out of the optical path V10 of the reflected reference light received by a photo detector being reflected at an arbitrary position P on the object 9, the portion to the optical path separation means 75 from the position P substantially coincides with the line of sight V70 as aimed at the position P by the image pickup means 70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape input device for projecting reference light so as to perform two-dimensional or one-dimensional scanning on an object and measuring round-trip propagation time of light at a plurality of positions on the object. Related to the device.

[0002]

2. Description of the Related Art Time of flight (TOF) from transmission of a light pulse to reception of a pulse reflected back from an object.
ight), it is possible to determine the inter-object distance by applying a known light propagation velocity. By incorporating a scanning mechanism that deflects pulsed light into a distance measuring device using this technique, distance measurement in multiple directions (multi-point measurement) is required compared to repeating distance measurement by changing the position and orientation of the distance measuring device itself. Measurement) can be performed quickly. If the scanning mechanism is driven to perform two-dimensional scanning, it is possible to measure the undulation of the object surface (three-dimensional input). Even in one-dimensional scanning, shape information in a corresponding range can be obtained.

Conventionally, in order to facilitate confirmation of a scanning position on an object, an image pickup means is arranged side by side with an optical system for distance measurement, and an object is photographed and displayed. JP-A-8-21878 discloses that a laser spot position on an object is detected by separating light condensed by an imaging lens into visible light and laser light, and a laser spot position is displayed when a captured image of the object is displayed. An apparatus for marking is described.

[0004]

It is conceivable that image data obtained by photographing an object is used not only for checking the situation during a distance measuring operation but also for data processing on shape data obtained by measurement. For example, reference information for data correction and thinning,
It can be a texture to be attached to the shape model. In such a use form, image data covering all measurement points on the object is required.

However, conventionally, there is a parallax between the optical system for measuring the position of the object and the optical system for photographing the object, and so-called occlusion may occur depending on the positional relationship between the object to be measured and the device for performing the measurement. There was a problem that occurred.

An object of the present invention is to prevent the occurrence of this occlusion.

[0007]

According to the present invention, there is provided an image pickup optical system for inputting an image of an object in an optical path between a scanning optical system for distance measurement by a time-of-flight method and an object to be measured, and a measuring object. An optical element (for example, a dichroic mirror) for separating the measurement light and the imaging light is provided in an optical path between the object and the object, so that the direction line of the distance measurement and the line of sight of the imaging coincide in the range between the object and the optical element. , A scanning optical system, an imaging optical system, and an optical element are arranged.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a block diagram showing the overall configuration of a shape input distance measuring apparatus according to the present invention, and FIG. 2 is a conceptual diagram of distance measurement.

The shape input device 1 includes an optical scanning system 10 for transmitting and receiving light pulses, a controller 60, an imaging system 70 for inputting a color image or a monochrome image of the object 9, and an optical path separating means 75. Although the arrangement relationship of the optical scanning system 10, the imaging system 70, and the optical path separating means 75 is fixed, these need not be integrated with the controller 60. A personal computer may be used as the controller 60. A video camera or an electronic still camera can be used as the imaging system 70.

The optical scanning system 10 includes a scanning mechanism 30 having a light source and a photodetector for multipoint measurement, a light emitting circuit 40 for driving the light source, and a receiving circuit 50.
The receiving circuit 50 sends reception data indicating the reception time point t2 of the reflected pulse light to the controller 60 according to the photoelectric conversion signal from the photodetector. The controller 60 calculates the light propagation time (flight time) Ta from the transmission time t1 to the reception time t2, with the time when a certain time has elapsed from the output of the light emission instruction signal as the transmission time t1. Further, the controller 60
Is the light propagation time Ta and the known light propagation speed (3 × 10 ⁸ m /
s) and the distance L to the object 9 is calculated.

FIG. 3 is a diagram showing an optical path configuration of the first embodiment. The imaging system 70 is arranged so that its field of view β intersects the scanning range α of the optical scanning system 10. In the figure, the intersection angle between the two optical axes is 90 degrees, but the present invention is not limited to this.

At a position where the visual field β of the imaging system 70 and the scanning range α of the optical scanning system 10 intersect, a separation mirror 75 as an optical path separating means is disposed. The separation mirror 75 is
The optical scanning system 10 has a characteristic of selectively transmitting light in a specific wavelength range including the wavelength of the measurement light emitted from the optical scanning system 10 and reflecting light in other wavelength ranges. As the separating mirror 75, a dichroic mirror is preferable. When the measurement light is infrared light, a cold mirror can be used.

The field of view β is deflected by the reflection at the separating mirror 75 as shown by the broken line in the figure. On the other hand, the scanning range α of the optical scanning system 10 is hardly affected as shown by the solid line in the drawing, except for a very slight refraction corresponding to the glass thickness of the separation mirror 75. Here, for an arbitrary point P on the surface of the object existing in the scanning range α and the field of view β, the deflected portion of the line of sight V70 of the imaging system 70 toward the point P, and the measurement light The optical scanning system 10 and the imaging system 7 so that the optical path V10 substantially matches each other.
The relative posture relationship between the three mirrors 0 and 75 is set. In FIG. 3, the line of sight V70 and the optical path V10 reaching P are shown.
Are drawn shifted from each other in order to distinguish them from each other.

Such a posture relationship can be realized, for example, by setting the following conditions. That is, the imaging system 70 and the optical scanning system 10 are arranged such that their optical axes face each other at an angle of 90 degrees. At the position where the optical axis intersects, the separation mirror 75 is moved to the imaging system 70 and the optical scanning system 1.
It is arranged so as to take a 45-degree inclined posture with respect to both of 0. Then, from an arbitrary point P on the object surface, the optical scanning system 1
The arrangement position is determined so that the distance (d0 + d1) to the scanning center R of 0 is equal to the distance (d0 + d1) from the point P to the optical principal point Q of the imaging system 70, that is, d1 = d2.

With the above configuration, the input of the shape information of the object 9 and the input of the two-dimensional image information can be performed simultaneously from substantially the same viewpoint with the same line of sight and without substantially affecting each other. Become. Since the “appearance” between the input shape information and the two-dimensional image information coincides and occlusion does not occur, it is easy to compare and correlate both information.

Further, in the example, the field of view β of the imaging and the scanning range α of the distance measurement are set such that the spread angles substantially coincide with each other. This not only has no parallax,
It is possible to input information in which the input area is matched between the shape (three-dimensional) and the image (two-dimensional). However, the field of view β
And the scanning range α do not need to coincide with each other, and one may be included in a part of the other, or both may partially overlap each other.

An apparatus configuration for performing two-dimensional scanning will be described below. FIG. 4 is a schematic diagram of a first example of the optical scanning system. The optical scanning system 10 in FIG.
35 and actuators 32 and 36 for rotating them. Pulse light emitted from a semiconductor laser 11 as a light source passes through a light projecting lens 12 for adjusting a divergence angle, and enters a first scanning mirror 31 via a prism 13.
The scanning mirror 31 rotates about the axis A1, and deflects the pulse light in a direction corresponding to the angular position. The pulse light deflected by the scanning mirror 31 is reflected by the second scanning mirror 35 and travels to the external object 9. The scanning mirror 35 rotates about an axis A2 that is crossed or twisted with respect to the axis A1.

As long as the surface of the object 9 is not a mirror surface, the pulse light P1 reflects diffusely. Therefore, even if the incidence on the object surface is not perpendicular incidence, at least a part of the reflected pulse light P <b> 2 goes to the optical scanning system 10. The pulse light P2 returned to the optical scanning system 10 is reflected by the scanning mirror 35 and the scanning mirror 31, and proceeds to the light receiving lens 21. Light receiving lens 21
Focuses the pulse light P2 on the light receiving surface of the photodetector 22. In the shape input device 1, by changing the angular positions of the scanning mirrors 31 and 35, it is possible to measure the distance to a plurality of locations of the object 9 without changing the installation position or posture of the device itself.

In this configuration, one of the two axes of rotation corresponds to the main scanning and the other corresponds to the sub-scanning.
An operation is performed in which the sub-scan advances by one resolution each time the main scan of the line is performed. The main scanning is repeated a plurality of times, during which the sub-scanning has progressed from the start to the end, and a series of multipoint measurements, that is, shape input is completed. Which of the scanning mirrors 31 and 35 is mainly used is arbitrary.
For example, assuming that the deflection around the axis A1 is main scanning and the deflection around the axis A2 is sub-scanning, while the scanning mirror 35 rotates from the start point to the end point of the rotation angle range, the scanning mirror 31 moves a plurality of times in the rotation angle range. Make a reciprocating rotation. Scanning mirrors 31, 3
The rotation angle of 5 is always grasped by the controller 60. As a general method of angle detection, there are a method of attaching an encoder to a rotating shaft, and a method of using a stepping motor whose rotation follows a command value as an actuator. From the rotation angles of the scanning mirrors 31 and 35 and the measured distance L, the three-dimensional coordinates of a point on the object 9 can be calculated. The calculation may be performed inside the shape input device 1 or an external device. In the latter case, the shape input device 1 outputs data in which the rotation angle is associated with the distance L.

FIG. 5 is a schematic view of a second example of the optical scanning system, and FIG.
FIG. 4 is a schematic diagram of a third example of the optical scanning system. In these figures, the same components as in the example of FIG. 4 are denoted by the same reference numerals as in FIG.

The optical scanning system 10b of FIG. 5 performs two-dimensional scanning with one scanning mirror 31. The scanning mirror 31 is rotationally driven by a second actuator 36 together with an actuator 32 for rotating the scanning mirror 31.

The optical scanning system 10c shown in FIG.
Do not have one. In this example, two-dimensional scanning is realized by supporting a structure 39 to which optical components necessary for transmission and reception of a laser pulse are attached in a biaxial gimbal format and connecting actuators 32 and 36 to both axes.

[Second Embodiment] FIG. 7 is a diagram showing an optical path configuration of a second embodiment. The optical scanning system 10 is arranged so that the scanning range α intersects the visual field β of the imaging system 70. In the figure, the crossing angle of both optical axes is 90 degrees,
It is not limited to this.

At a position where the visual field β and the scanning range α intersect, a separating mirror 76 as an optical path separating means is disposed. The separation mirror 76 has a characteristic of selectively reflecting light in a specific wavelength range including the wavelength of the measurement light emitted from the optical scanning system 10 and transmitting light in other wavelength ranges. Separation mirror 76
A dichroic mirror is preferable. When the measurement light is infrared light, a hot mirror can be used.

The scanning range α is deflected by the reflection at the separation mirror 76 as shown by a solid line in the drawing. On the other hand, the field of view β of the imaging system 70 is hardly affected as shown by the broken line in the drawing, except for a very slight refraction corresponding to the glass thickness of the separation mirror 76. Here, for an arbitrary point P on the object surface existing in the scanning range α and the visual field β,
The optical scanning system 10, the imaging system 70, and the separation mirror so that the deflected portion of the optical path V10 of the measurement light toward the point P and the line of sight V70 of the imaging system 70 toward the point P substantially coincide with each other. A relative posture relationship between the three is set. Such a posture relationship can be realized by setting conditions similar to those in the configuration of FIG.

Also in the second embodiment, the input of the shape information of the object 9 and the input of the two-dimensional image information can be performed simultaneously from substantially the same viewpoint with the same line of sight and without substantially affecting each other. It becomes possible. Further, by setting the field of view β of the imaging and the scanning range α of the distance measurement so that the spread angles substantially coincide with each other, it is possible to input information in which the input area is matched between the shape and the image.

According to the above-described embodiment, a two-dimensional image including information on all measurement points on an object can be input simultaneously with distance measurement, regardless of the positional relationship between the object and the device.

The present invention is not limited to the method of irradiating pulsed light and measuring its reception timing. For example, the intensity of the illuminated light is modulated so as to periodically fluctuate like a sine wave, and the phase of the transmitted light and the reception output are modulated. The present invention can also be applied to a method for measuring a phase shift.

[0029]

According to the first to fourth aspects of the present invention,
It is possible to input a two-dimensional image including the information of the measurement points on the object simultaneously with the measurement of the distance, and to prevent occlusion between the input shape information and the two-dimensional image information.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a shape input device according to the present invention.

FIG. 2 is a conceptual diagram of distance measurement.

FIG. 3 is a diagram illustrating an optical path configuration according to the first embodiment.

FIG. 4 is a schematic diagram of a first example of an optical scanning system.

FIG. 5 is a schematic diagram of a second example of the optical scanning system.

FIG. 6 is a schematic diagram of a third example of the optical scanning system.

FIG. 7 is a diagram illustrating an optical path configuration according to a second embodiment.

[Explanation of symbols]

 Reference Signs List 1 shape input device 11 semiconductor laser (light source) P1 pulse light P2 pulse light (reflection pulse light) 22 photodetector Ta time 9 target object 30 scanning mechanism P arbitrary point (position on object) 70 imaging system (imaging means) 75, 76 Separating mirror (optical path separating means) V10 Optical path V70 Line of sight α Scanning range (scanning angle range) β visual field (viewing angle range)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Sukebe 2-13-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2F065 AA06 AA53 BB05 FF04 FF11 FF33 GG06 GG08 JJ03 JJ15 JJ26 LL13 LL20 LL62 MM16 PP22 2F112 AD01 BA02 CA08 DA32 DA40 EA03 5J084 AA05 AD01 BA04 BA11 BB11 BB24 CA03 EA04

Claims (4)

[Claims] A light source for emitting reference light; a photodetector for receiving reflected reference light reflected by a target object; and a scanning mechanism for changing a measurement direction, and a plurality of positions on the target object. A shape input device for measuring a time from transmission of the reference light to reception of the reflected reference light, wherein: an imaging unit that inputs two-dimensional image information of the target object; and a specific wavelength including an emission wavelength of the reference light. Optical path separating means for separating the light of the wavelength range and the light of the other wavelength range, and among the optical paths of the reflected reference light that is reflected at an arbitrary position on the target object and received by the photodetector, The image pickup unit and the optical path separation unit are arranged such that a portion from an arbitrary position to the optical path separation unit substantially coincides with a line of sight of the image pickup unit at the arbitrary position. Shape input device. 2. The shape input device according to claim 1, wherein said optical path separating means has an optical characteristic of selectively reflecting light of said specific wavelength range and transmitting light of another wavelength range. 3. The shape input device according to claim 1, wherein said optical path separating means has an optical characteristic of selectively transmitting light of said specific wavelength range and reflecting light of another wavelength range. 4. The shape input device according to claim 1, wherein a scanning angle range of said scanning mechanism is substantially equal to a viewing angle range of said imaging means.