JPH1146359A - Visual field dislocation adjusting object for image-pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quantitatively grasp the dislocation of visual field of an image-pickup device with respect to its reference position by forming two mutually symmetrical square regions, linear boundaries and slanting line boundaries of a pattern which is centered on a vertical axis passing through a reference visual field. SOLUTION: An adjustment pattern 11 includes two small regions 11a and two right-angled triangular regions which are symmetrical to each other centering on a Y-axis. These two triangular regions include the linear boundary regions 11b crossing almost vertically to an X-axis an the slanting line boundaries 11c crossing the X-axis at about 45 degrees. The pattern 11 has a reflection factor different from that of the surface of its peripheral object 10. In this case, the intermediate point set between two intersecting points set between a visual field 20 and regions 11b is always located on the Y-axis since both regions 11b are symmetrical to each other centering on the Y-axis. Therefore, the position of the Y-axis is identical with a position, where the outputs A and D are divided equally. Thus, the difference between the Y-axis and the center of the field 20 is identical with the dislocation amount of the field 20 in the X-axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object suitable for use in adjusting the field of view of an image pickup device to a reference position in a visual inspection or the like for inspecting the surface of an object to be inspected.

[0002]

2. Description of the Related Art As an appearance inspection system having an image pickup device for forming an image of a subject on a linear image pickup device, for example, there is one shown in FIG. In the figure, reference numeral 10 denotes a subject, 20 denotes a visual field, 30 denotes an image pickup device such as a television camera including a lens 31 and an image pickup device 32. The image pickup device 30 picks up an image of the subject 10. When it is necessary to adjust the field of view of the imaging device 30 to a predetermined position with such an apparatus, an image of a subject on which a specific pattern is formed is taken, and the position of the field of view is obtained from the pattern image.

FIG. 4A shows an example of such an object for adjusting the visual field position. In FIG. 4A, the field of view 2 when the adjustment pattern 19 is at a predetermined position is shown.
It has the same shape as 0, but has a different reflectance from the other parts of the subject 10. Here, it is assumed that the reflectance is high. In the illustrated XY coordinate system, it is assumed that the reference position of the visual field 20 has its center at the origin of the coordinate system and its longitudinal direction on the X axis. When the position of the visual field 20 is not at the reference position as shown by the dotted line in FIG. 4A, only a part of the adjustment pattern 19 is imaged, and the output from the imaging device is as shown in FIG. 4B. When the position of the visual field 20 is at the reference position as shown by the dotted line in FIG. 4C, the entire adjustment pattern 19 is imaged, and the output from the imaging device is as shown in FIG.

[0004]

As described above, conventionally, it was possible to know that the field of view of the imaging device was not at the reference position, but it was not possible to know how much the displacement was.
Therefore, there is a problem in that it is not possible to determine how to move the field of view to adjust the field of view to the reference position. Therefore, an object of the present invention is to make it possible to quantitatively know the deviation of the visual field of the imaging device from the reference position.

[0005]

In order to solve such a problem, according to the first aspect of the present invention, an adjustment for adjusting a visual field position of an image pickup apparatus for forming a subject image on a linear image pickup surface to a reference position. In order to perform the above, in the field-of-view position adjustment subject of the imaging apparatus in which a predetermined pattern is formed, the pattern has a reflectance different from that of other portions, and is provided near both ends of a reference field of view serving as a reference and has substantially the same width as the field of view. And two linear boundaries that intersect approximately perpendicularly to the longitudinal axis of the reference field of view, and two linear areas that intersect at an angle of approximately 45 degrees to the longitudinal axis of the reference field of view. And a hatched boundary. This claim 1
In the present invention, each of the two rectangular regions, the linear boundary and the diagonal boundary of the pattern can be formed so as to be symmetric with respect to a vertical axis passing through the center of the reference visual field (the invention according to claim 2). ).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram for explaining an embodiment of the present invention. This explains the relationship between a pattern for adjusting the visual field position formed on the subject 10 (hereinafter also referred to as an adjustment pattern) and a signal output when the pattern is imaged.
It is formed of two small regions 11a and two right-angled triangle regions symmetric with respect to the Y axis. These two right-angled triangular regions include a linear boundary region 11b that intersects with the longitudinal direction of the visual field, that is, a direction that is substantially perpendicular to the X axis, and a region that is approximately 4 in the X axis.
And a hatched boundary region 11c that intersects at 5 degrees. In addition, the adjustment pattern 11 is formed so as to have a different reflectance from the surface of the subject 10 around the adjustment pattern 11. For example, if the subject 10 is a polished surface of Al (aluminum), the adjustment pattern 11 is formed by evaporating Cr (chromium).

FIG. 1A shows a case where the field of view 20 is shifted from a reference position as indicated by a dotted line, and FIG. 1B shows an output of an imaging device (not shown) at that time. That is, FIG.
The symbols A and D in FIG.
b indicates the position where the image was captured, but since the boundary 11b is symmetrically arranged with respect to the Y axis, the field of view 20 and the boundary 1
The midpoint between the two intersections with 1b is always on the Y axis. Therefore, the position at which the outputs A and D are bisected is the Y-axis position, and the difference between this and the center of the field of view indicates the amount of displacement of the field of view in the X-axis direction.

On the other hand, reference numerals B and C in FIG.
0 indicates the position where the oblique line-shaped boundary area 11c is imaged, but since the boundary 11c is arranged symmetrically with respect to the Y axis together with the boundary 11b, A, B and C are used when the visual field is at the reference position. The intervals of D both have a predetermined length. Therefore, the difference between the average value of the interval between A and B, the interval between C and D, and the reference length thereof indicates the shift amount of the visual field in the Y direction. When the distance between A and B is different from the distance between C and D, it indicates that the field of view is rotating, and FIG.
When the interval between A and B is larger than the interval between C and D as shown in FIG.

From the above, the amount of deviation from the predetermined position of the field of view of the imaging device can be quantitatively known from the imaging output signal, so that a target for adjusting the position of the field of view can be obtained. Further, in a state where there is almost no shift amount from the predetermined position of the visual field, as shown in FIG. 1C, two small-area regions provided at both ends of the visual field are imaged. It is shown as E and F in 1 (d). These two areas are chosen to be as wide as the field of view,
When the visual field is correctly located at a predetermined position, the signals E and F have a maximum and tend to decrease as the position deviates from the reference position. By providing such an area, the amount of deviation of the field of view of the imaging device from the reference position can be known with high sensitivity, and position adjustment can be performed with high accuracy.

FIG. 2 shows a modification of the pattern. These have different shapes from those shown in FIGS. 1 (a) and (c), but have two small areas 12a, 13a, 14a provided near both ends of the visual field, and in the longitudinal direction of the visual field. Linear boundaries 12b, 13b, 14b substantially orthogonal to this;
It is common in that it has diagonal borders 12c, 13c, and 14c that intersect with the longitudinal direction of the visual field at an angle of approximately 45 degrees. The present invention is not limited to the case where the number of imaging devices is one as shown in FIG. 3, but can be applied to a case where a plurality of imaging devices are provided and the visual field positions of the imaging devices are made to coincide with each other. It is.

[0011]

According to the present invention, it is possible to quantitatively know the deviation from the reference visual field position of the imaging apparatus for forming an image of a subject on a linear imaging surface having a predetermined width and length.
The target value for the visual field position adjustment is obtained, and the advantage is obtained that the adjustment can be performed easily and accurately.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for describing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a modification of an adjustment pattern.

FIG. 3 is a schematic diagram showing a conventional visual inspection system.

FIG. 4 is an explanatory diagram of a conventional displacement measurement method.

[Explanation of symbols]

10 subject, 11, 12, 13, 14, 19 adjustment pattern, 20 field of view, 30 imaging device (television camera), 31 lens, 32 imaging device.

Claims (2)

[Claims] 1. An object for field-of-view position adjustment of an image pickup apparatus having a predetermined pattern formed in order to adjust the field of view of the image pickup apparatus for forming a subject image on a linear image pickup surface to a reference position. As the pattern, the reflectance is different from that of the other portions, and two rectangular regions provided near both ends of the reference visual field serving as the reference and having substantially the same width as the visual field, and substantially perpendicular to the longitudinal axis of the reference visual field. A field position adjusting device for an image pickup apparatus, comprising: two intersecting linear boundaries; and two oblique line boundaries intersecting at an angle of approximately 45 degrees with respect to the longitudinal axis of the reference visual field. subject. 2. The method according to claim 1, wherein each of the two rectangular areas, the linear boundary and the diagonal boundary of the pattern are formed so as to be symmetric with respect to a vertical axis passing through the center of the reference visual field. An object for adjusting a visual field position shift of the imaging device according to the above.