JP2006266952A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system which brings illumination light to reach only an object to be measured in a camera view of a photography site, and can realize a good operation of photographing the object to be measured, since a base or the like of the background is not illuminated with light. <P>SOLUTION: In the lighting system for photographing the object to be measured which is loaded on a conveying plane and moved thereby, by using a line camera, an optical fiber illuminating unit is disposed as a component of the lighting apparatus being used along with the line camera which has a view field in the direction perpendicular to that of the conveying plane and is disposed above the conveying plane so as to make the view field normal to the conveying plane. The optical fiber illuminating unit is arranged such that its light beam extending in the direction perpendicular to the conveying plane is directed so as to illuminate the upper surface of the object to be measured, when the object to be measured having a prescribed height enters the view field of the line camera, and such that the light beam extending in the direction perpendicular to the conveying plane is directed so as not to illuminate the region of the view field on the conveying plane, when the object to be measured is not positioned in the view field of the line camera. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lighting device, and more particularly, to a low background lighting device that creates a stable background in an image processing inspection.

  FIG. 3 is a layout diagram of a conventional line CCD camera and optical fiber illumination. In FIG. 3, the line CCD camera 1 is disposed above the belt conveyor 7 so that the field of view 5 extends at right angles to the transport direction and the field of view 5 is perpendicular to the surface 7 a of the belt conveyor 7. When the optical fiber illumination 2 enters the field of view 5 of the line CCD camera, the belt conveyor so that the light beam 6 extending perpendicular to the transport direction of the optical fiber illumination hits the upper surface of the optical measurement object 4. 7 is disposed obliquely above 7. Here, the diffused light from the optical fiber illumination 2 is converted into a parallel light beam 6 by the cylindrical lens 3. Assuming that the line intersecting the visual field 5 of the line CCD camera 1 and the surface 7a of the belt conveyor 7 is P, the light flux of the optical fiber illumination 2 irradiates the line P even when the measurement object 4 does not exist. become.

  In the image processing, it is necessary to clearly recognize the measurement object. However, when the measurement object is imaged by using the conventional illumination device shown in FIG. 3, the table supporting the measurement object is shown. Therefore, there may be a problem that it is difficult to distinguish from the measurement object. In addition, stains on the table and dust on the table may appear, which may adversely affect image processing.

  Therefore, an object of the present invention is to realize good imaging of an object to be measured because the illumination light reaches only the object to be measured within the field of view of the camera at the shooting location and the light does not hit the background table or the like. The object is to provide a lighting device.

  A line camera is effective in terms of speed and cost for imaging products moving on a production line. Since the line camera has a linear field of view, it does not affect the image even if illumination is applied to a place other than the line. The present invention utilizes this phenomenon.

  In the present invention, a line CCD camera having a field of view extending in a direction perpendicular to the direction in which the object to be measured is conveyed is disposed on the conveyance line, and the illumination light (light beam) extends in a line extending in the direction perpendicular to the direction of conveyance. Fiber optic lighting that emits).

  The field of view of the line CCD and the linear illumination are arranged so as to maintain a parallel relationship, and coincide with each other at a certain height on the transport line, and have a shifted positional relationship just above the transport line.

  Specifically, the illuminating device of the present invention is an illuminating device for picking up an image of an object to be measured that moves on a certain transport plane using a line camera, and has a field of view perpendicular to the transport direction. In an illuminating device used together with a line camera arranged above the conveyance plane so as to direct the field of view perpendicular to the conveyance plane, when the object to be measured reaches a position within the line camera's field of view, the measurement is performed. When a light beam extending perpendicular to the transport direction is directed so as to irradiate the upper surface of the object, and when the object to be measured is not in a position entering the field of view of the line camera, the field area on the transport plane is not irradiated. It has the optical fiber illumination arrange | positioned so that the light beam extended at right angles to a conveyance direction may be aimed.

  According to the present invention, a good background image can be obtained as follows.

  With the arrangement of the line CCD and the linear illumination according to the present invention, when there is no object to be measured (or no place), the illumination light does not reach the field of view of the line CCD immediately above the conveyance line. A black image can be obtained.

  When the object to be measured at a certain height is carried, where the line CCD field of view intersects with the linear illumination, the illumination light reaches the surface of the object to be measured within the line CCD field of view. An image corresponding to the surface of the object is picked up by the line CCD camera.

  Only the object to be measured is shown in the captured image, and the area around the object to be measured has a black background. Even if the transport line is not black, it appears black, so the color and shape of the transport line are not reflected, and image processing is easy. Further, even if the conveyance line is dirty, the image processing is not affected, and stable image processing is possible.

FIG. 1 is a layout diagram of a line CCD camera and optical fiber illumination according to the present invention. FIG. 2 is a perspective view in which the description of the optical fiber illumination and the cylindrical lens in FIG. 1 is omitted.
1 and 2, the line CCD camera 1 is arranged above the belt conveyor 7 so that the field of view 5 extends at right angles to the transport direction and the field of view 5 is perpendicular to the surface 7a of the belt conveyor 7. Yes. The two optical fiber illuminations 2 arranged symmetrically with respect to the field of view 2 convey the optical fiber illumination to the upper surface of the object to be measured 4 when the object to be measured 4 enters the field of view 5 of the line CCD camera. It arrange | positions diagonally above the belt conveyor 7 so that the light beam 6 extended at right angles to a direction may contact | win.

  Here, the diffused light from the optical fiber illumination 2 is converted into a parallel light beam 6 by the cylindrical lens 3. Assuming now that the line intersecting the visual field 5 of the line CCD camera 1 and the surface 7a of the belt conveyor 7 is P, the luminous flux of the optical fiber illumination 2 irradiates the area of the line P when the measurement object 4 does not exist. do not do. That is, the illumination angle, the width of the illumination light, and the spread angle of the illumination light are adjusted so that the illumination light does not strike the field of view of the CCD camera on the line P on the transport line plane.

  The height of a certain product (object to be measured) was in the range of 20 to 70 mm. The product is conveyed on a belt conveyor.

  A line CCD camera was arranged vertically on the belt conveyor so as to have a field of view perpendicular to the product conveyance direction.

  Optical fiber illuminations that emit illumination light in the shape of a line parallel to the field of view of the line CCD were arranged at two locations in the front-rear direction of the transport direction, and the illumination was inclined 45 degrees from the horizontal.

  The illumination light was adjusted to be parallel light using a cylindrical lens for optical fiber illumination. Considering the product height change range of 50 mm and the illumination angle of 45 degrees, the optical design was made so that the illumination would be slightly wider than 50 cos (45 degrees) = 35 mm.

  The angle and height of the illumination were adjusted so that the lower intersection height of the two illuminations having a width was slightly less than 20 mm, and the intersection position was placed on the line CCD camera field of view.

  By adopting parallel light, there is an advantage that it is easy not to illuminate the field of view of the CCD camera on the belt conveyor while making the lower crossing height below the minimum product height.

  By arranging illumination at two locations in the front-rear direction of the belt conveyor, there is an advantage that the influence of shadows caused by unevenness on the product surface can be reduced, and image processing becomes easy.

  According to the present invention, when there is no product, a black image is captured, so that there is no problem of image processing of the contamination of the belt conveyor even though there is no product.

  When image processing was performed on the product, the conveyor belt was no longer contaminated, so a stable image was obtained and inspection accuracy was improved.

  The effect of shadow caused by unevenness on the product surface was reduced, and stable inspection was realized.

  In the past, only a uniform and clean flat belt conveyor could be used to prepare a stable background. However, the present invention provides a degree of freedom for the conveyance platform and conveyance method, and broadens the application range of image processing. Became possible.

FIG. 1 is a layout view of a line CCD camera and optical fiber illumination according to the present invention. FIG. 2 is a perspective view in which the description of the optical fiber illumination and the cylindrical lens in FIG. 1 is omitted. FIG. 3 is a layout diagram of a conventional line CCD camera and optical fiber illumination.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Line CCD camera 2 Optical fiber illumination 3 Cylindrical lens 4 Object to be measured 5 Line CCD camera visual field 6 Optical fiber illumination light beam 7 Belt conveyor 8 Optical fiber illumination light beam reflected on the belt conveyor

Claims (3)

Illumination device for imaging an object to be measured that is placed on a certain transport plane using a line camera, and transports the field of view perpendicular to the transport direction and perpendicular to the transport plane. In the illumination device used together with the line camera arranged above the plane,
When the object to be measured having a predetermined height comes into the position of the line camera, the light beam extending perpendicular to the transport direction is directed so as to irradiate the upper surface of the object to be measured, and the object to be measured is An illuminating device comprising: an optical fiber illumination arranged so as to direct a light beam extending perpendicular to a conveyance direction so as not to irradiate a field area on a conveyance plane when the line camera is not in a position to enter the field of view of the line camera . The illumination device according to claim 1, wherein the optical fiber illumination generates parallel light. 2. The illumination device according to claim 1, wherein the optical fiber illumination is disposed on both sides of a visual field of a line camera.