JP2529070B2 - Photoelectric conversion camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion camera,
In particular, the present invention relates to a photoelectric conversion camera for capturing an image of a predetermined subject surface of a subject.

[0002]

2. Description of the Related Art In recent years, when inspecting the external shape, surface condition, and indications on the surface of various products, photoelectric conversion cameras such as CCD (Charge Coupled Device) cameras are used for products. An inspection method is used in which an image of the surface of an image is observed and the image is observed.

A conventional method for inspecting the surface of a product using a CCD camera will be described with reference to FIGS. Here, FIG. 4A is a schematic view showing the arrangement of a CCD camera,
Fig. 4 (b) shows the surface of the product to be inspected (hereinafter referred to as "inspection surface").
Fig. 4 (c) is a view showing the display described in
It is a figure which shows the image | video of the inspection surface imaged by the D camera.

A light source 54 for irradiation is provided on the inspection surface 52 of the product 50.
Is irradiated with predetermined light. And this irradiation light is product 5
The light is reflected by the inspection surface 52 of 0, and the reflected light is incident on the imaging lens 58 of the CCD camera 56. This imaging lens 5
The light passing through 8 forms an image on a CCD plate 60 which is provided on the focal plane of the imaging lens 58 perpendicularly to the optical axis. Therefore, the points A, B, and C on the inspection surface 52 are imaged and imaged as the points A ″, B ″, and C ″ on the CCD plate 60. Here, the point A is the inspection surface of the product 50. The uppermost point of 52,
Point B is the lower end of the inspection surface 52, and point C is the intersection of the inspection surface 52 and the optical axis of the imaging lens 58.

The image of the inspection surface 52 of the product 50 imaged by the CCD camera 56 in this manner is, for example, a CCD.
It is observed using a monitor TV or VTR connected to the camera 56.

[0006]

In the inspection method using the conventional CCD camera 56, as shown in FIG. 5A, the inspection surface 52 of the product 50 is aligned with the optical axis of the imaging lens 58. When it is vertical, naturally the CCD plate 60 is also vertical to the optical axis, so that the inspection surface 52 and the CCD plate 6 are
It is parallel to 0. Therefore, the center of the imaging lens 58 is set to O
Then, ΔAOC and ΔA ″ OC ″, ΔBOC and ΔB ″
OC "Since the respective similarity, AC: A" C "= C O: C" O = CB: C "B" is established, therefore, AC: CB = A "C ": C "B" is satisfied To do. That is, the display of the inspection surface 52 of the product 50 without distortion is imaged on the CCD board 60, no distortion occurs in the image captured <br/> Te by the CCD camera 56.

However, when the CCD camera 56 and the like are arranged as shown in FIG. 4A, it is difficult to arrange the irradiation light source 54, the product 50, and the CCD camera 56 in a straight line because of the arrangement. is there. Therefore, product 5
The irradiation light source 54 must be arranged so that the irradiation light is obliquely incident on the inspection surface 52 of 0, and the CCD camera 56 must be arranged on the extension of the reflected light obliquely reflected from the inspection surface 52.

In such a case, as shown in FIG. 5B, the inspection surface 52 of the product 50 is not perpendicular to the optical axis of the imaging lens 58, and the angle θ (here, θ <π / 2)
Make Therefore, not parallel to the test surface 52 and the CCD plate 60, therefore, AC: A "C" = C O: C "O = CB: C" B " is not satisfied, AC: CB ≠ A" C ″: C ″ B ″ That is, with respect to the display of the inspection surface 52 of the product 50,
The optical image formed on the CCD plate 60 has B ″ to A ″.
Distortion that reduces in the direction of
Therefore a similar distortion in the captured image to the CD camera 56 occurs.

[0009] Therefore, the display of the inspection surface 52 of the product 50, for example, when a 123 numbers as shown in FIG. 4 (b), images that are thus imaged on the CCD camera 56 in FIG. 4 (c) The resulting number is distorted 123 and the image is distorted. Although the distortion generated in one direction is illustrated in FIG. 4C, the distortion may actually occur in the direction orthogonal to the one direction.

Accordingly, by this distortion in the images that are thus imaged on the CCD camera 56, the product 50
However, there is a problem that it is difficult to accurately inspect the external shape, surface condition, display, etc. of the inspection surface 52. Therefore, it is an object of the present invention to provide a photoelectric conversion camera capable of capturing an image without causing distortion even when the subject surface of the subject is not perpendicular to the optical axis of the image forming unit.

[0011]

FIG. 1 is a schematic sectional view showing a photoelectric conversion camera for explaining the principle of the present invention. The photoelectric conversion camera 10 has an image forming optical system 12 and an image pickup plate 14 provided on the focal plane of the image forming optical system 12. Then, the imaging optical system 12 focuses the light from the object surface 18 of the object 16 and forms an optical image of the object surface 18 on the image pickup plate 14, and the image pickup plate 14 makes the imaged object surface 18. The optical image of.

Here, when the object surface 18 of the object 16 is not perpendicular to the optical axis of the imaging optical system 12 of the photoelectric conversion camera 10 and forms an angle θ (where θ ≠ π / 2). Similarly, the image pickup plate 14 of the photoelectric conversion camera 10 also forms an angle θ with respect to the optical axis of the imaging optical system 12, that is, the image pickup plate 14 is installed substantially parallel to the object plane 18. There is a feature of the present invention.

If the angle θ between the subject surface 18 of the subject 16 and the optical axis of the image forming optical system 12 of the photoelectric conversion camera 10 is always constant, the image pickup plate 14 is set to the optical axis of the image forming optical system 12. It may be fixed so as to form an angle θ. Further, when the angle θ formed by the object plane 18 and the optical axis of the imaging optical system 12 changes depending on the type of the object 16, an angle changing means 20 for changing the angle of the image pickup plate 14 is provided. The angle θ formed by the imaging plate 14 and the optical axis of the imaging optical system 12 may be adjusted by using.

The image pickup plate 14 may be a chip on which a charge coupled device is mounted or a substrate on which such a chip is incorporated.

[0015]

The operation of the present invention will be described with reference to FIGS. Here, FIG. 2A is a conceptual diagram for explaining the operation of the photoelectric conversion camera of FIG. 1, and FIG. 2B is a diagram showing a display displayed on the subject surface 18 of the subject 16.
FIG. 7C is a diagram showing an image of the object surface 18 formed on the image pickup plate 14. Note that the imaging optical system 12 is illustrated as an imaging lens for ease of explanation.

In the present invention, the object surface 18 of the object 16 is not perpendicular to the optical axis of the imaging optical system 12 and forms an angle θ (where θ ≠ π / 2), and the image pickup plate 14 is also included. The subject plane 18 and the imaging plate 14 are parallel to each other because they are not perpendicular to the optical axis of the imaging optical system 12 and form an angle θ. Therefore, assuming that point A is the upper end point of the subject surface 18 of the subject 16, point B is the lower end point of the subject surface 18, and point C is the intersection of the subject surface 18 and the optical axis of the imaging optical system 12, the subject surface The points A, B, and C on 18 are imaged as points A ', B', and C'on the imaging plate 14 parallel to the object plane 18. Then, with respect to the center O of the imaging optical system 12, ΔAOC and ΔA′O
C ', ΔBOC and ΔB'OC' ΔAOB and ΔA'OB '
Since and are point-symmetrical, AC: A'C '= C0: C'O = CB: C'B' holds, and thus AC: CB = A'C ': C'B' holds.

That is, the display of the object surface 18 of the object 16 is imaged on the image pickup plate 14 without distortion. Therefore, the display of the object plane 18 is 123 as shown in FIG.
If the numbers, and forms an image on the imaging plate 14, the image is thus captured to the photoelectric conversion camera 10 also, as shown in FIG. 2 (c), longitudinal and skew in any direction transverse There is no number of 123, and the image is not distorted.

[0018]

EXAMPLES The present invention will be specifically described below based on examples. FIG. 3A is a schematic view showing the arrangement of a CCD camera and the like according to an embodiment of the present invention, and FIG. 3B is a sectional view showing the angle varying means of the CCD plate of the CCD camera. For example, a product 30 conveyed by a belt conveyor or the like
To irradiate the inspection surface 32 of with a predetermined light obliquely,
An irradiation light source 34 is installed. A CCD camera 36 is installed in the traveling direction of the reflected light reflected from the inspection surface 32 of the product 30 by the irradiation light from the irradiation light source 34.

The CCD camera 36 is provided on the focal plane of the imaging lens 38, on which the reflected light from the inspection surface 32 of the product 30 is incident, and the light passing through the imaging lens 38 is combined. And a CCD plate 40 for imaging. Further, the CCD plate 40 has a photosensitive section in which pixels for converting received light energy into electric charges are arranged in a two-dimensional matrix, and a transfer section for scanning photoelectrically converted electric charges. Specifically, it may be a chip on which a CCD is mounted or a substrate on which such a CCD chip is incorporated.

Further, this CCD plate 40 is used for the CCD camera 3
The angle varying means 44 is capable of adjusting the angle θ formed with respect to the optical axis of the imaging lens 38. The angle varying means 44 is configured as shown in FIG. 3 (b), for example. That is, the fixed block 46 is provided near the CCD plate 40 that is swingably installed in the housing 46 of the CCD camera 36.
Is provided, and the screw for slide 48 is screwed into the screw hole opened in the fixed block 46, and the screw for slide 48
The tip of the contact plate is in contact with the CCD plate 40. At least three sets of such sliding screws 48 are installed, and each set of sliding screws 48 is rotationally slid so that the CCD plate 40 with respect to the optical axis of the imaging lens 38 is rotated.
It is possible to adjust the angle θ formed by. That is, the angle θ formed by the CCD plate 40 can be corrected in both the vertical direction and the horizontal direction.

Therefore, when the inspection surface 32 of the product 30 is actually imaged by the CCD camera 36, the angle varying means 44 is used so that the CCD plate 40 of the CCD camera 36 is parallel to the inspection surface 32. adjust. That is, when the inspection surface 32 makes an angle θ with the optical axis of the imaging lens 38, the CCD plate 40 also makes an angle θ with the optical axis of the imaging lens 38.

Although not shown, the CCD camera 36
A monitor TV, a VTR, etc. are connected to the monitor TV, the VTR, etc. can be used to observe the image of the inspection surface 32 of the product 30 imaged by the CCD camera 36. . As described above, according to this embodiment, the CCD plate 40 of the CCD camera 36 can be adjusted to be parallel to the inspection surface 32 of the product 30 by using the angle varying means 44. A, B, and C are points A ′, B ′ on the CCD plate 40 without distortion,
An image is formed and imaged as C '. Therefore, it becomes possible to accurately inspect the external shape, surface condition, display, etc. of the inspection surface 32 of the product 30.

In the above-described embodiment, the case where the three sets of sliding screws 48 that come into contact with the swingably installed CCD plate 40 are used as the angle changing means 44, but the present invention is not limited to this. Needless to say, various methods can be used. Further, the angle varying means may be automated. When the inspection surface 32 of the product 30 is always constant, that is, the inspection surface 32 is the imaging lens 3
When the angle θ formed with respect to the optical axis of 8 is always constant, C
The CD plate 40 may be fixed so as to form an angle θ with the optical axis of the imaging lens 38.

Further, in the above embodiment, the light source 34 for irradiation and the CCD camera 36 are applied to the inspection surface 32 of the product 30.
Are provided on the same side, and the reflected light from the inspection surface 32 is incident on the CCD camera 36. However, when the product 30 is a transparent glass plate or the like, the irradiation light source 34 and the CCD camera 36 are on the opposite side. And the transmitted light that has passed through the inspection surface 32 is
It may be incident on the CD camera 36.

[0025]

As described above, according to the present invention, in the photoelectric conversion camera provided with the image forming means for forming the optical image of the subject and the image pickup plate for taking the optical image of the formed subject, Since the imaging plate is installed parallel to the subject surface of the subject, even if the subject surface of the subject is not perpendicular to the optical axis of the image forming unit, the subject surface is imaged without distortion. can do.

This makes it possible to accurately inspect the external shape of the subject surface, the surface condition, the display on the surface, and the like.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a photoelectric conversion camera for explaining the principle of the present invention.

FIG. 2 is a diagram for explaining the operation of the photoelectric conversion camera according to the present invention.

FIG. 3 is a diagram illustrating an inspection method using a CCD camera according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining an inspection method using a conventional CCD camera.

FIG. 5 is a diagram for explaining the operation of a conventional CCD camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Photoelectric conversion camera 12 ... Imaging optical system 14 ... Imaging plate 16 ... Subject 18 ... Subject plane 20 ... Angle changing means 30 ... Product 32 ... Inspection surface 34 ... Irradiation light source 36 ... CCD camera 38 ... Imaging lens 40 ... CCD plate 42 ... CCD camera housing 44 ... Angle varying means 46 ... Fixed block 48 ... Sliding screw 50 ... Product 52 ... Inspection surface 54 ... Irradiation light source 56 ... CCD camera 58 ... Imaging lens 60 ... CCD plate

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-3-95538 (JP, A) JP-A-4-172436 (JP, A) JP-A-4-203915 (JP, A) JP-A-63- 179206 (JP, A) JP 59-3304 (JP, A) JP 4-50828 (JP, A) JP 4-366938 (JP, A) Actual development Sho 52-16936 (JP, U)

Claims (3)

(57) [Claims] 1. The optical axis is tilted with respect to the subject plane of the subject.
Cage, and focuses the light from the object, and an imaging means for imaging an optical image of the object on the focal plane, provided on the focal plane of the imaging means, the optical image of the said object The image pickup plate for taking an image and the image pickup plate are substantially parallel to the subject plane of the subject.
Angle formed by the imaging plate with respect to the optical axis of the image forming means.
A photoelectric conversion camera , comprising: an angle adjusting unit for adjusting a degree . 2. A direction oblique to the object plane of the object
Imaging the subject illuminated by the illumination means
A photoelectric conversion camera, wherein the irradiation light emitted by the irradiation means is reflected by the subject.
On the subject surface of the subject so that it receives the reflected light
The optical axis is tilted with respect to the image forming means for focusing the reflected light to form an optical image of the subject on a focal plane, and the image forming means provided on the focal plane of the image forming means. The imaging plate that captures the optical image of the subject and the imaging plate are substantially parallel to the subject surface of the subject.
As described above, the photoelectric conversion camera is provided with an angle adjusting unit that adjusts an angle formed by the imaging plate with respect to the optical axis of the image forming unit. 3. A direction oblique to the subject plane of the subject
Imaging the subject illuminated by the illumination means
A photoelectric conversion camera, wherein light emitted by the irradiation means is transmitted by the subject
The optical axis with respect to the subject plane of the subject to receive light
An image forming means for focusing the transmitted light to form an optical image of the subject on a focal plane; and an optical image of the subject formed on the focal plane of the image forming means. The image pickup plate that picks up the image of the object and the image pickup plate are substantially parallel to the subject surface of the subject.
As described above, the photoelectric conversion camera is provided with an angle adjusting unit that adjusts an angle formed by the imaging plate with respect to the optical axis of the image forming unit.