JPH0311401B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an object detection device, and more particularly to an object detection device that recognizes the uneven surface of an object by measuring the distance between the object and the object detection device.

Various types of object detection devices have been proposed for detecting the surface of an object, and certain efforts have been made especially for recognizing objects with uneven surfaces.

The most common object surface detection device uses multiple television cameras to capture images of an object from two slightly different directions, and then combines these images to detect the object surface using the principle of binocular stereoscopic vision. Attempts have been made to recognize the unevenness of the surface.

Still another method, as shown in FIG. 1, is to apply a spot from a light projector 2 to a rotating mirror 1, scan the surface of an object 3 with the spot projected light, and detect the spot projected light with a photodetector 4. It is something to do.

FIG. 2 shows another conventional method in which a lamp 5a is passed through a slit 5b provided in a light source 5 to an object 3.
By projecting the slit-passing light 6, a projection 6a corresponding to the slit-passing light 6 is performed on the object, and the television camera 7 captures an image of the object 3 on which the slit-passing light is projected. The aim is to more clearly recognize the unevenness of the surface.

Conventional object detection devices as described above have the drawback of not being able to accurately detect irregularities on the surface of an object.

The present invention provides an object detection device that eliminates the above-mentioned drawbacks, and is characterized by scanning the surface of an object to be measured with a light beam, and forming a triangle between an observation point and a light beam scanning device. The position of the surface of the object is detected by forming the object and measuring the distance to the object.

Hereinafter, the present invention will be specifically explained based on FIGS. 3 and 4.

FIG. 3 shows the basic configuration of the present invention, in which laser light emitted from a laser source 8 is deflected by a scanning mirror 9. As shown in FIG.

The scanning mirror 9 has a fulcrum 9a in the direction of the arrow.
If the object to be measured 3A is located at position A by swinging around , the deflected laser beam scans the surface of the object to be measured at position A.

The reflected light reflected from the surface of the object to be measured 3A is reflected by a 90° reflecting mirror 10 and formed into an image by an imaging lens 11.

A prism mirror 12 is disposed on the imaging surface of the imaging lens 11.

Since the surface of the prism mirror is a mirror surface, when an image is formed exactly at the center of the prism mirror, the light image is divided equally on the left and right by the inclined surfaces 12 _L and 12 _R with the top of the prism mirror as the border. Therefore, the outputs of the left and right photodetectors 13a and 13b are equal to each other, and the difference therebetween is zero. on the other hand,
If the image plane shifts to the right or left, prism mirror 1
The light is reflected by the two inclined surfaces 12 _L and 12 _R , and outputs corresponding to the amount of reflected light are sent out from the photodetectors 13a and 13b.

The outputs from both photodetectors are compared by a comparison circuit 14 and outputted to a terminal 15.

Furthermore, even if the surface of the object to be measured has irregularities or the like and retreats to position B shown by 3B, the laser beam from the laser source 8 is reflected by the scanning mirror 9, as shown by the dotted line. Measured object 3B
The reflected light passes through a reflecting mirror 10 and is imaged by an imaging lens 11 and then onto a prism mirror 12.

That is, in the above configuration, the observation line 16, which is a straight line extending from the surface of the object to be measured in its displacement direction (if a mirror is interposed in the middle of the straight line, a straight line extending in the reflection direction via this mirror), and the object to be measured are connected to each other. When the reflected light from the measurement object matches the position,
The outputs of the two photodetectors 13a and 13b become equal to each other, and the output of the comparator 14 becomes zero. Therefore, in the present invention, first, the scanning mirror 9 is scanned while checking the output of the comparator 14, and when the output of the comparator 14 becomes zero (that is, the reflected light from the surface of the object to be measured is The scanning angle θ of the scanning mirror 9 (here, the angle formed by the horizontal line 9b in the x-axis direction passing through the center of the scanning mirror 9 and the reflected light of the scanning mirror 9 is defined as θ). ).

Then, _in the above configuration, since the distances _D By knowing this, the distances A _X and B _X from the objects to be measured 3A and 3B to the center position of the reflecting mirror 10 can be easily calculated using trigonometric functions. In the manner described above, it is possible to accurately measure the position of the surface of the object to be measured.

FIG. 4 is a specific configuration diagram of the object detection device of the present invention, and the same parts as in FIG. 3 are given the same reference numerals and redundant explanation will be omitted. The laser beam from the laser source 8 passes through an x-direction scanning mirror 9x and a y-direction scanning mirror 9y, and reflected light is projected onto the object to be measured 3A or 3B.

In addition, since the scanner scans one line in the x direction, moves in the y direction, and performs the next line in the x direction, the scanning period T _Y of the x direction scanning mirror 9y is The scanning period T _X of the scanning mirror 9x needs to be selected such that T _X <<T _Y.

Moreover, the x and y direction scanning mirror 9
The rotations of x and 9y are controlled by control signals from the computer 20 through scanning controllers 18 and 19.

On the other hand, the reflected light from the object to be measured is reflected by the y-direction scanning mirror 9y, further reflected by the first and second reflecting mirrors 10b and 10a, and is imaged on the prism mirror 12 through the imaging lens 11. .

The detection power from the photodetectors 13a and 13b is amplified by intensifiers 17a and 17b, and the outputs compared by a comparison circuit 14 are inputted to the computer 20, and the output of the comparison circuit 14 becomes zero. By knowing the scanning angles θ of the scanning mirrors 9x and _9y in the _x and y directions at The position of the object surface can be measured.

Since the present invention is configured as described above, the distance from the object to be measured to the reference position of the object detection device can be detected extremely accurately, so even if the object has unevenness, it can be recognized accurately. It has the characteristics of being able to

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the detection method of a conventional object detection device, FIG. 2 is a perspective view illustrating the detection method of another conventional object detection device, and FIG. 3 is a diagram of the object detection device of the present invention. FIG. 4 is a perspective view of an optical path system and a system diagram of an electrical system showing a specific configuration of the present invention. 3, 3A, 3B...Object to be measured, 8...Laser source, 9, 9X, 9Y...Scanning mirror, 1
0, 10a, 10b... Reflecting mirror, 11... Imaging lens, 12... Prism mirror, 13a, 13b
...Photodetector, 14...Comparison circuit, 20...Computer.

Claims (1)

[Claims] 1. A light source that outputs a laser beam; a first scanning device that scans the laser beam output from the light source within one plane; and a device scanned by the first scanning device. a second scanning means for scanning a laser beam in a plane orthogonal to the plane and irradiating the surface of the object to be measured; an imaging means for forming an image of the reflected light from the surface of the object to be measured guided through a second scanning means; and an optical image formed at the imaging position, which is disposed at an imaging position by the imaging means. a light splitting means for splitting the light into two directions; a pair of light detection means for detecting the respective lights split by the light splitting means; and a light detection means for detecting the respective lights split by the light splitting means; scanning angle control means for controlling each scanning angle of the first and second scanning means so that the reflected light passes on the observation line; and controlling the position of the surface of the object to be measured based on the controlled scanning angles. An object detection device comprising: a position calculation means for calculating a position.