JPS62214307A - Shape measuring instrument for object - Google Patents

Abstract

PURPOSE:To process efficiently recognition of an object by controlling the projecting direction of an optical cutting plane and an angle of rotation of the optical cutting plane with respect to the axial circumference. CONSTITUTION:Beams emitted from a laser light source 1 are projected in the direction of an object 11 by a scanner 3 which polarizes the beams independently in the vertical and horizontal directions. The scanner 3 is driven by a signal from a scanner controller 5. Then, a signal generator 7 produces a periodic signal to scan the laser beams periodically and form the optical cutting plane. The output and the output of a D/A converter 9 controlled by a computer 10 are synthesized by a signal synthesizer 6 and inputted to the controller 5. Further, a TV camera 4 picks up a sight including the object 11 on image and its video signal is taken in an image processor 8 and positional information of a part where the optical cutting plane intersects the object 11 is abstracted. Then, the computer 10 computes the distance to the material body based on a principle of triangulation from the geometrical relation with the positional information of a picture element, the camera 4 and the optical cutting plane.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to measurement and inspection of product shapes in automatic production processes, or for autonomously manipulating three-dimensional objects using visual information in industrial robots. The present invention relates to a device that measures the position of an object and performs object recognition.

[Prior Art] As an object position measuring device related to the present invention, there is a body position measuring device which has already been registered as Patent No. 815590%. In the front device,
By combining the projection of linear light onto an object and the use of a television camera, the position of the linear light projected onto the object surface of the television image H and the geometric arrangement relationship between the linear light projection device and the television camera are determined. The distance to an object is determined using the principle of triangulation.

[Problems to be Solved by the Invention] The plane through which linear light or beam-shaped light scanned to draw a linear trajectory is used to project onto an object is hereinafter referred to as a light cutting plane. In the technique, a light cutting surface for projection is used in which the rotation angle around the axis of the projection direction is fixed, such as horizontally or vertically with respect to the substrate surface. When the rotation angle of the optical cutting plane is limited as described above, the following problems occur.

In order to know the overall size and shape of the object, it is necessary to scan the light section in the section where the intersection of the light V5 section and the object is expected to occur and input the entire data.
There is a problem with the processing time.

In addition, when the difference between the slope of the light section and the slope of the object's first line becomes smaller, the intersection of the light section and the object becomes parallel to the ridgeline of the object. In this case, it becomes difficult to obtain a clear image of the above-mentioned intersection, and as a result, the distance l
There is a problem that the accuracy of 111 measurement decreases.

[Means for Solving the Problem] The present invention has been made to solve this problem, and is an object shape meter Il [using the principle of measuring the distance to a target object using an optical cutting plane]. 11 device generates a light cutting plane suitable for the shape or posture of the target object,
The gist of the device is an object shape measuring device that measures the distance to the object and recognizes the object based on the results.It also controls the projection direction of the light section and rotates the light section around the axis of the projection direction. Its special feature is that it has a mechanism to control the angle.

According to an object shape measuring device equipped with a mechanism such as r'', when the approximate position and orientation of the target object are known,
By projecting a cutting light plane with an inclination most suitable for recognizing the object or performing the required measurements on the object, it is possible to collect data with high speed and precision. In addition, when the position and orientation of the target object are unknown, a cutting light plane with a predetermined inclination is generated to collect outstanding data, and the position, orientation, and type of the object can be determined from partial information. Based on the estimation, the inclination of the cutting light surface and the projection direction of the cutting light are controlled, the next data is collected, and this is reflected back to efficiently recognize and measure the target object. becomes possible.

[Example] One method of generating a light section is to use a linear light source or a combination of a light source and a linear gap. In these cases, the light cutting plane can be rotated by rotating the light source or the H gap itself, or by passing linear light through a trapezoidal prism and rotating the trapezoidal prism around the optical axis. ,
-, the control in the throw 2i direction changes the rotated light section to
The rotation angle around J can be controlled from the outside.It can be realized by reflecting with a reflecting mirror. In the following, an embodiment will be described in which a beam-like light such as a laser beam is scanned using a beam scanner to simultaneously control both the rotation angle and the projection direction.

FIG. 1 shows the configuration of an embodiment of the present invention. A beam emitted from a laser light source 1 is projected toward an object 11 by a scanner 3 that deflects the beam independently in vertical and horizontal directions.

In this example, two uniaxial mirror scanners using galvanometers are used as the scanners, and the scanners are arranged so that their rotation axes are perpendicular to each other. Scanner 3
is driven by a signal from the scanner control device 5. The signal generator 7 is a device for generating a periodic signal for periodically scanning the laser beam to generate a light section.

The output of the signal generator 7 and the output of the DA converter 9 controlled by the computer 10 are combined by a signal synthesizer 6 and inputted to the scanner U4 device 5.

Reference numeral 4 is a television power unit for capturing an image of a scene including an object. The video signal from the television camera is taken into the image processing device 8, and position information of pixels at the intersection of the light section and the target object is extracted. In calculation #110, the distance to the object is calculated from the position information of the pixel and the geometrical relationship between the television camera and the light section using the principle of triangular 1w amount. The computer 10 is also used to recognize the target object based on the measured distance and to control the light section via the DA converter 9.

Next, a method for controlling the direction and rotation angle of the light cutting plane will be specifically explained. The scanner 3 provides a deflection angle proportional to the input voltage value applied to the scanner controller 5. Therefore, the signals expressed by the following equations are respectively input to the scanner.

v+ -AI-FD) + 81
(1) V2- A21F(t) + 82
(2) Here, Vl and v2 are input voltages for giving deflection angles around the vertical axis and horizontal axis, respectively, and AI, A2. B1 and B2 are the output voltages of the IJA converter 9, and F(t) is a periodic voltage signal output from the signal generator 7, which has a sawtooth shape;

Figure 2 shows the relationship between the rotation angle of the mirror rotation axis of the mirror scanner used as a scanner and the beam trajectory on a plane perpendicular to the coordinate axis of the beam projection direction, only in one-dimensional direction (X direction). This is what is displayed. the deflection angle is proportional to the input signal, and.

If it can be assumed that tanO=θ, the coordinate values of the beam trajectory in the X direction are as shown in equation (3).

X -CI-(At#F(t)+81) 苧d(3
) Here, d is the distance from the center of the scanner to the plane P shown in FIG. 2, and C1 is the conversion coefficient from the input voltage to the signal synthesizer 6 in FIG. 1 to the deflection angle by the scanner. It is.

Similarly, the beam trajectory coordinate in the Y direction perpendicular to the X direction is (4
) is as follows.

Y-C2=(A2-F(t)+82)-d
(4) C2 represents a conversion coefficient similarly to equation (3).

When F(t) is eliminated from equations (3) and (4), the relationship between X and Y becomes equation (5).

C2-A21X-C1,AICY=
(5) 2CImC2 (A2l81- AI#B2
)ld represents the line of intersection between the plane P and the light section. So A1, B1, A2. By specifying an appropriate value for B2, an arbitrary light section passing through the center of the scanner can be generated.

The signal expressed by equation (1) is created by the signal synthesizer shown in FIG. 1, but the @ signal synthesizer can be realized by having an analog multiplication circuit, for example.

In addition, in a scanner using a mirror scanner, when a 9JA toothed wave is used as a drive signal, when the beam returns.

The beam may trace a non-linear trajectory due to differences in the mechanical properties of the two mirror scanners or a phase shift in the drive signals. In such a case, as shown in FIG. 1, it is possible to obtain a stable light section by synchronizing the optical path shutter 2 with the sawtooth wave and blocking the return beam.

[Effect of the invention] As shown above, when the device according to the present invention is used,
By rotating and moving the optical cutting plane, the optical cutting plane most suitable for measuring or recognizing the object is selected, and efficient object recognition processing becomes possible. For example, if the object is columnar, the slope of the side surface or the direction of the long sleeve can be determined by using two cut planes perpendicular to the long axis direction and calculating the coordinates of two points on one edge on both sides. It can be calculated by asking for each. The length in the long-sleeve direction and the coordinates of the end points can be determined by one projection of the light-cut plane by applying the cut plane in the long-sleeve direction. Furthermore, even if the posture in the environment cannot be predicted, if a model of the object is given, the optimal cutting direction can be estimated by projecting a light cutting plane on a trial basis. As described above, the present invention greatly contributes to the technical field of product shape inspection in automatic production processes and visual processing for robots that handle three-dimensional objects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of the object shape measuring device of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the rotation angle of the mirror scanner and the beam trajectory. In the figure, l is the laser light source and 2 is the optical path shutter. 3 is the scanner. 4 is a television camera, 5 is a scanner control device, 6 is a signal synthesizer, 7 is a signal generator, and 8 is an image processing device. 9 is a DA converter, 10 is a computer, 11 is a target object, 12 is a mirror of a mirror scanner, and l3 is a laser beam. iI1 figure

Claims (1)

[Claims] Linear light or a beam of light whose scanning trajectory is linear is projected onto the target object, a scene including the target object is imaged with a television camera, and an image is formed on the imaging surface from the image data. In an object shape measuring device whose principle is to extract position information corresponding to a bright part of the light projected onto an object and use that information to calculate the distance to the object surface, the linear light or the scanned What is claimed is: 1. An object shape measuring device comprising: a mechanism for controlling a projection direction of a beam-like light; and a mechanism for controlling a rotation angle of a passing surface of the projected light around an axis in the projection direction.