JPS6136871A - Image input device - Google Patents

Abstract

PURPOSE:To prevent an input of a shadow of an object to an image pickup means by setting an illumination means at a place opposite to the visual axis of the image pickup means and at the same time setting a mirror having a light transmitting part at the center on the visual axis of the image pickup means so that the coincidence is obtained between said visual axis and the optical axis of the illumination means. CONSTITUTION:A mirror 6 having a light transmitting part 60 at the center is set on a visual axis 10 of a TV camera 1 with a tilt and the mirror surface set toward an object 5. A light source 2 is set opposite the axis 10. Thus the image of the light source 2 is formed on the axis 10 at the rear side of a half mirror 6 at the same position as a visual point 11 of the camera 1 or after the point 11. A shadow 51 produces at the back of the object 5 is hidden by the object 5 and does not enter the viewfield of the camera 1. Thus the shadow 51 is not recognized as a subjected of picture input. This avoids the misrecognition of the object 51 which is due to the shadow 51.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an image input device mainly used to image a three-dimensional object, for example in an object recognition device for an industrial robot.

<Background of the Invention> As shown in FIG. 8, a conventional image input device of this type has a television camera 1 and an illumination light source 2 arranged at a fixed angle such as a viewing axis 10 and an optical axis 20 with respect to an object 5 on a table 4. They are arranged at diagonally upper positions on opposite sides so as to form θ. However, in the case of this method, since the shadow 51 that appears behind the object 5 is input as an image to the television camera 1, there is a risk that this may be mistakenly recognized as part of the object 5, which poses a major obstacle in object recognition. There is.

Therefore, as an improvement to the above system, an image input device was proposed in which an illumination light source 2 is provided inside the table 4 to prevent the appearance of shadows on the table 4, as shown in FIG.

However, in the case of this method, the light source 2 is built into the table 4, which requires large-scale equipment, and since the heat of the light source 2 is transmitted to the table 4, objects with low heat resistance cannot be used as objects of interest. There is a problem.

<Objective of the Invention> The object of the present invention is to provide a compact image input device that can effectively utilize illumination light without inputting an image of the shadow of an object, thereby solving the above-mentioned conventional problems at once. shall be.

<Configuration and Effects of the Invention> In order to achieve the above object, an apparatus of the present invention includes an imaging means for obtaining an object image and an illumination means for irradiating light onto the object, and the illumination means is used as the imaging means. A mirror body having a transparent portion at the center is disposed on the visual axis so as to align the optical axis of the illumination means with the visual axis.

According to the present invention, since a single shadow force image of the object is not input to the imaging means, the object can be recognized correctly and the object recognition accuracy is improved. Further, unlike the conventional example shown in FIG. 9, there are no disadvantages such as the need for large-scale equipment or the recognition target being limited to heat-resistant objects, and it is easy to put into practical use. In addition, since a mirror body with a transparent part in the center is used, the light from the illumination means is reflected on the mirror surface around the mirror body and irradiated onto the object, and the amount of illumination light is used effectively, reducing the work of the illumination means. 'The number of throats can be reduced,
In addition, since the light from the object enters the imaging means through the transparent part at the center of the mirror body, the object can be properly imaged, which is a remarkable effect of achieving the object of the invention.

<Description of Embodiments> Figs. 1 to 3 show the basic configuration of an image input device according to the present invention, and include a television camera 1 that obtains an image of an object 5, and a light beam directed to the object 5 (indicated by an arrow in the figure). It consists of an illumination light source 2 and a retroreflector 3 placed on the back of the object 5.

The retroreflector 3 is an object that reflects light in the direction of incidence of the light, thereby obtaining a high contrast image. In the case of this embodiment, the retroreflector 3 is used by pasting a sheet-like material onto the table 4, and the object 5 is placed on it.

The television camera 1 is placed obliquely above the object 5 on the table 4, and the light source 2 is positioned so that its optical axis 20 coincides with the viewing axis 10 of the television camera 1.

In order to realize this coaxial illumination, in this embodiment, a mirror body 6 (shown in FIG. 7) having a transparent part 60 in the center is tilted on the visual axis 10 of the television camera, and the mirror surface is placed on the object side. At the same time, the light source 2 is positioned opposite to the visual axis 10, so that the image (apparent light source) 2' of the light source 2 is /%-
The rear viewing axis of the mirror 6 can be formed at the same rear position as the viewpoint 11 of the television camera 1. The light-transmitting portion 60 of the mirror body 6 can be formed into any shape such as circular or rectangular as long as it does not obstruct the field of view of the television camera 1. In addition, any other aspect may be adopted, such as doubling the hole with a transparent glass plate or the like.

4 and 5 show an embodiment in which a unit 7 incorporating a light beam 2 and a mirror body 6 is attached to a television camera 1 with a mounting bracket 71, and FIG.
The opening 80 of the cover unit 8 is partially fixed with the support fitting 81.
An embodiment in which a light source and a mirror body 6 are arranged is shown. In both examples, the optical axis 20 of the light source 2 and the cedar axis 10 of the television camera 1
The structure coincides with that of the object, and has a structure that allows coaxial illumination to the object.

However, when coaxial illumination is applied to the object 5 from the directional force of the television camera 1, the shadow 51 that appears behind the object 5 is
If the TV camera 1 is hidden behind the TV camera 1 (it enters the field of view, and therefore becomes the subject of image input), the light irradiated on the object 5 is diffusely reflected on the back surface of the object, and a part of the reflected light is transmitted through the mirror body 6. The light is incident on the television camera 1 through the transparent section 60.On the other hand, since the light irradiated on the retroreflector 3 is reflected in the direction of the television camera 1, most of it passes through the transparent section 60 and enters the television camera 1-. \Injected.

As a result, the object 5 is imaged dark and the background bright, resulting in a high-contrast image. In this way, the object is correctly recognized without the risk of misrecognition of the object due to the shadow 51 or confusion of the object with the background due to the low conotrust image.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic configuration of the image input device of the present invention, Figure 2 is a diagram showing the positional relationship between the light source and the television camera, Figure 3 is a diagram showing the principle of coaxial illumination, and Figure 4 is a diagram showing the positional relationship between the light source and the television camera. A side view of an example of the device according to the present invention, FIG. 5 is a front view thereof, FIG. 6 is a structural explanatory diagram showing another embodiment, FIG. 7 is a front view showing the structure of a mirror body, and FIG. 9 is a diagram showing a conventional method, and FIG. 9 is a diagram showing another conventional method. 1...TV camera 2...Light source 10.
...Visual axis 20...Optical axis 6...
Mirror body 60...transparent part patent applicant
Tateishi Electric Co., Ltd. Terrorism Figure square 7 Figure, j J

Claims (1)

[Scope of Claims] An imaging means for obtaining an image of an object, and an illumination means for irradiating light onto the object, the illumination means being positioned opposite to the visual axis of the imaging means and located on the visual axis. The image input device includes a mirror body having a light-transmitting portion in the center so that the optical axis of the illumination means coincides with the visual axis.