JPH1038522A - Three dimensional visual sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 3D visual sensor which provides accurate 3D space coordinates. SOLUTION: The sensor obtains a distance information based on an interference fringe caused by an object light wherein an object 4 is irradiated with laser light through a beam splitter 2 and a reference light incident in the direction of a CCD 8 through a lens 6, a mirror 7 and half-mirror 5 separated with the beam splitter 2, and in addition, the distance information is obtained by photo-detecting with the CCD 8 the light information wherein an object is irradiated with the slit light from another laser light source 9 and processing it with optical cutting method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a three-dimensional visual sensor.

[0002]

2. Description of the Related Art As a three-dimensional measurement technique, a light section method is known. Regarding the light-section method, IEICE Transactions 8
In May of May, there was a paper entitled "Real-Time Distance Detector Using Light-Section Method". For shape recognition, CCD and PS
As a document using D-elements, IEICE National Convention, Annual Meeting, Fall 1990, “One-Dimensional Measurement Method Using Two-Dimensional Photodetector Arrays”, IEICE Transactions, March 1985, “Distance by Spatial Coding” Image input ". In addition, accurate spatial coordinates can be obtained by using a plurality of cameras and slit light without being affected by the background scene. In addition, there is JP-A-1-100492 "Laser vision sensor" for synthesizing a three-dimensional image using intensity as luminance information and phase delay as distance information in order to detect a phase delay.

[0003]

However, the technique using a two-dimensional light receiving element array has a problem that a measurement area is limited, and a three-dimensional shape cannot be recognized over a wide range. When shape recognition is performed by the compound eye method, the blind spot can be reduced by measuring the three-dimensional shape by the compound eye method, but it is difficult to associate positions. High resolution cannot be obtained. Wide three-dimensional measurements are not possible with laser vision sensors.

An object of the present invention is to solve the above problems.
It is to provide a three-dimensional visual sensor.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an object light for irradiating an object with a laser beam through a beam splitter, and an object beam split by the beam splitter and passing through a lens, a mirror and a half mirror. The distance information is obtained by interference fringes generated by the reference light incident in the CCD direction, and the slit light from another laser light source irradiates the object with the CCD, and the light information is received by the CCD and processed using the light cutting method. A three-dimensional visual sensor was configured to obtain distance information.

[0006]

Embodiments of the present invention will be described below.

FIG. 4 is a diagram for explaining how to obtain spatial coordinates.

First, three-dimensional space coordinates are obtained as follows.

(X, y, z) = (dtanψ / tanψ)
+ Tanθ, dtanψ ・ tanθ / tanψ + tan
θ, dtanγ · tanθsecθ / tanψ + tan
θ) d indicates the distance between the laser light source and the light receiving surface. θ,
ψ and γ are shown in FIG. 4 and θ is an angle formed by the object with the XY plane.

The above are three-dimensional spatial coordinates by trigonometry. In the present invention, three-dimensional space coordinates are obtained by using this method and distance information based on the phase shift. The distance information is information perpendicular to the lens, that is, parallel to a line drawn in the normal direction from the lens, and can be measured between several μm and several tens.

FIG. 1 is a schematic diagram of the present invention. Light passing from the laser diode 1 and passing through the lens 3 through the beam splitter 2 irradiates the object 4 and enters the half mirror 5 as object light. On the other hand, from the beam splitter 2 to the lens 6
The light passes through the mirror 7 and is reflected by the mirror 7.
The reference light is incident in the direction. After passing through the half mirror 5, the object light and the reference light form interference fringes, and distance information is obtained by calculating the difference between the interference fringes and the reference interference fringes.
That is, in the figure, the left half is the part where distance measurement by phase shift is performed. Further, slit light is emitted from the laser light source 9 (right side in the figure) and scanned. The CCD 10 receives light information obtained by irradiating the object 4 with the slit light. CCD 8 and CCD 10 are converted by an optical switch or shutter 11. This is to cope with the fact that the information processing speed of the CCD is slow.

The information received by the CCD 10 is processed using a light-section method to provide three-dimensional spatial coordinates. However, in the light section method having a depth accuracy, a good result may not be obtained because a blind spot is formed depending on an irradiation angle.
For this purpose, the shape is supplemented by distance information based on the phase shift.

The light source unit 12 has a configuration as shown in FIG. 2, in which a laser beam from a laser diode 13 is collimated by a collimating lens 14 to generate a pseudo slit light by a polygon mirror 15, which is converted into a galvanomirror 1
6 and the like. However, if the slit light can be scanned, the components are not limited to those described above. Reference numeral 17 denotes an fθ lens, and reference numeral 18 denotes a CCD camera.

FIG. 3 shows an embodiment of the three-dimensional visual sensor according to the present invention. The outline is as described in FIG. 1
9 is a laser diode and a collimator lens, 20 is a beam splitter, 21 is a lens, 22 is a mirror, and 23 is C
CD device, 24 is a half mirror, 25 is a lens, 2
6 is a light source and 27 is a lens.

Alternatively, the blind spot can be reduced by using a plurality of CCD light receiving elements or by using two or more slit light sources.

With respect to the phase shift, the light interference technique is used as the basic technique, so that the wave equations of the object light and the reference light at the position of the half mirror are combined on the CCD light receiving surface based on the principle of superposition. The light intensity is input as projected light information. Distance information can be obtained by calculation with an interference fringe pattern on a reference plane stored in advance. Further, the phase shift can be obtained by using the information of the synchronization signal and the like by performing an inverse calculation from the equation of the light intensity on the light receiving surface.

[0017]

As described above, according to the present invention, in addition to the light-section method, phase information is taken as information, and the distance is measured. Therefore, the distance at an angle that cannot be measured by the light-section method can be accurately measured. Since the phase information is used for distance measurement, a blind spot which is a problem in the light section method can be reduced, and accurate three-dimensional space coordinates can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a light source unit.

FIG. 3 is an external view showing an embodiment of the three-dimensional visual sensor of the present invention.

FIG. 4 is a diagram for explaining how to obtain spatial coordinates.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser diode 2 Beam splitter 3 Lens 4 Object 5 Half mirror 6 Lens 7 Mirror 8 CCD 9 Laser light source 10 CCD 11 Shutter 12 Light source unit 13 Laser diode 14 Collimating lens 15 Polygon mirror 16 Galvanometer mirror 17 fθ lens 18 CCD camera 19 Laser diode And collimator lens 20 beam splitter 21 lens 22 mirror 23 CCD device 24 half mirror 25 lens 26 light source 27 lens

Claims (1)

[Claims] 1. Distance information based on interference fringes generated by object light that irradiates an object with a laser beam through a beam splitter and reference light that is separated by the beam splitter and enters the CCD direction through a lens, a mirror, and a half mirror. And a distance information is obtained by receiving, by a CCD, light information obtained by irradiating an object with slit light from another laser light source and using a light cutting method. .