JPH01277705A - Method and apparatus for detecting reference position - Google Patents

Abstract

PURPOSE:To detect the position of a reference hole even when there is no brightness difference between the reference hole and the periphery thereof, in a reference position detecting method for taking out the reference hole from the image containing the reference hole provided to an object to be detected, by using an infrared imaging means in photographing. CONSTITUTION:The color of a car is judged on the basis of the signal from a color detection sensor 7 and, when a body color is other than black, the lighting of a white lamp and the photographing by a white and black camera 4 are performed. When the body color is judged to be black, an infrared lamp 5 is allowed to light and the periphery of a reference hole 2 is heated by the infrared lamp 5 and, thereafter, the photographing due to an infrared camera 3 is performed in a step S5. The image from the above mentioned white and black camera 4 or the image from the infrared camera 3 is taken in to be subjected to binarization processing and the reference hole 2 is selected from the image. When the selection of the reference hole 2 is improper, photographing is again performed by a camera different from that used in the preceding photographing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a J&quasi position detection method and apparatus for extracting a reference hole from a captured image and detecting the position of the reference hole.

(Prior Art) As seen in Japanese Utility Model Application Laid-Open No. 58-16998, there is known a device in which a camera is used to detect the position of an object. In this case, the position of the reference hole is detected by providing a reference hole in the object and representing the reference hole in a coordinate system. Therefore, in such a position detection method, it is required to accurately extract the reference hole from the captured image.

(Problem to be Solved by the Invention) However, when detecting a reference hole provided in the body of a car, for example, when the car body is a bright color such as white, there is a large difference in brightness from the reference hole, so the imaging It is easy to distinguish between the reference hole and the car body from the image. However, when the vehicle body is a dark color such as black, there is almost no difference in brightness from the reference hole, so there is a problem in that it is difficult to distinguish between the reference hole and the vehicle body.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reference position detection method that can accurately extract a reference hole from a captured image even when there is almost no difference in brightness between the reference hole and its surroundings. and to provide such equipment.

(Means and actions for solving the problem) Conventionally, images were taken using visible light]; Based on the recognition that the problem of recording contrast has occurred, the present invention uses infrared light. .

More specifically, on the premise of a reference position detection method or device for extracting a reference hole from an image including a reference hole provided in a target object and detecting the position of the reference hole, the method for imaging the reference hole is performed. It is characterized by using infrared imaging means.

That is, when creating an image using infrared rays emitted by an object, the difference in brightness between the reference hole and its surroundings is no longer a problem. Rather, since the image is formed by the heat of the object, it is more preferable to heat the area around the reference hole.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings. This embodiment shows an example in which the present invention is applied to determining a reference position when installing a suspension or a pension in the assembly of an automobile.

In FIG. 2, four reference holes 2 are provided on the lower surface of an automobile body 1, and an infrared camera 3 and a black-and-white camera 4 are installed at each half hole 2, facing these reference holes 2 from below. In addition, an infrared lamp 5 and a white lamp 6 are provided for each camera 3.4, and these lamps 5.6 are provided facing the reference hole 2.

The cameras 3 and 4 have a body l as shown in FIG.
The color detection sensor 7 or the manual changeover switch 8 detects the color of the image sensor 7, which is selectively switched based on a signal from the host computer 9, and the imaging signal from the camera 3 or 4 is input to the image processing unit 10. In the image processing unit) 10, a reference hole 2 is detected by image binarization processing, and this reference hole 2 is detected by the position detection control unit) 11.
The position of the reference hole 2 is input to the system control unit 12, expressed in a coordinate system at . The system control unit 12 generates control signals for the various suspension mounting robots based on the detected position of the reference hole 2, and corrects the positions of the suspension mounting robots as appropriate. .

Since the processing after the binarization processing is the same as the conventional one, the processing before that will be explained in detail based on the flowchart shown in FIG.

First, in step S1, the color of the car is determined based on signals from the color detection sensor 7, etc., and if the body color is out of color, the process proceeds to step S2, where the white lamp 6 is turned on, and in step S3, an image is taken by the monochrome camera 4. will be done. On the other hand, when it is determined that the body color is black in step S1, the process moves to step S4, where the infrared lamp 5 is turned on, and the area around the reference hole 2 is heated by the infrared lamp 5, and then in step S5. ,
An image is taken by an infrared camera 3.

The image from the monochrome camera 4 or the image from the infrared camera 3 is captured in step S6, and then in step S
Binarization processing is performed in step 7, and the reference hole 2 is selected from the image. If the selection of the reference hole 2 is inappropriate, the process proceeds from step S8 to step S9, and the image is captured again using a camera different from the one used for the previous image capture.

With the above configuration, as shown in FIG. 5, when a black member is imaged with the monochrome camera 4, there is no difference in brightness between the reference hole 2 and its surroundings, making it difficult to select the reference hole 2 by binarization processing. This problem can be solved by taking an image with an infrared camera 3, as shown in FIG.

In this embodiment, since the area around the reference hole 2 is heated by the infrared lamp 5, the gap G between the reference hole 2 and its surroundings becomes large. Therefore, there is an advantage that there is no need to prepare a high-precision infrared camera 3. Furthermore, in cases other than Bad Son, the black and white camera 4 is used because, as shown in Figure 5, for example, when the body color is white, the difference in brightness between the reference holes 2 and 2 is sufficiently large. Therefore, the reference hole 2 can be sufficiently selected using the monochrome camera 4. Of course, it is also possible to use an infrared camera in all cases, regardless of the body color of the car. Further, when the camera is a high-precision infrared camera, the heating means 5 is not necessarily required.

(Effects of the Invention) As is clear from the following description, the present invention has the advantage that the position of the reference hole can be detected even if there is no difference in brightness between the reference hole and the surrounding area.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the output level of the reference hole and its surroundings when imaged with an infrared camera, and Figure 2 is the arrangement of the reference hole provided in the car body as a target object and the camera that images it. Fig. 3 is a system configuration diagram according to the embodiment; Fig. 4 is a two-chart showing an example of camera switching control; Fig. 5 is a diagram showing the relationship between the reference hole and its surroundings when imaged with a black and white camera. A diagram showing output levels. l2 car body 22 reference hole 3: infrared camera 5: infrared lamp lO: image processing unit

Claims (2)

[Claims] (1) In a reference position detection method in which a reference hole is extracted from an image including a reference hole provided in a target object and the position of the reference hole is detected, an infrared imaging means is used to image the reference hole. A reference position detection method characterized by: (2) In a reference position detection device that extracts a reference hole from an image including a reference hole provided in a target object and detects the position of the reference hole, an infrared imaging means is used to image the reference hole. A reference position detection device characterized by: