CN111198190A

CN111198190A - Optical detection system

Info

Publication number: CN111198190A
Application number: CN201911025844.0A
Authority: CN
Inventors: 林伯聪; 李岳龙
Original assignee: Utechzone Co Ltd
Current assignee: Utechzone Co Ltd
Priority date: 2018-11-16
Filing date: 2019-10-25
Publication date: 2020-05-26
Also published as: TW202020418A

Abstract

The invention discloses an optical detection system, which comprises a detection platform, an image capturing device, an optical lens and an image processor. The detection platform is provided with a shooting surface for placing an object to be detected. The image capturing device is arranged on one side of the detection platform. The image capturing device comprises a photosensitive chip, and the photosensitive chip is provided with an imaging surface. The optical lens is arranged between the image capturing device and the detection platform. The optical lens has a lens surface. The extension of the image capture surface, the image plane and the lens surface intersect at the same linear position. The image processor is connected to the image capturing device, and the image of the object to be detected is obtained by the image capturing device for automatic optical detection.

Description

Optical detection system

Technical Field

The present invention relates to an optical inspection system, and more particularly to an optical inspection system capable of increasing the depth of field of image capture.

Background

Automatic Optical Inspection (AOI) is a research and development technique commonly applied to various high-tech industries, has the advantages of high speed, high precision and the like, mainly uses machine vision as a detection standard technology, uses an Optical instrument to perform non-contact Inspection to obtain an image of a finished product or a semi-finished product, and then uses image processing to identify foreign matters or other defects in the image. Automatic optical inspection can improve and use optical instrument to detect through personnel in the past and lead to consuming time hard or personnel's deletions such as erroneous judgement, effectively promotes detection efficiency and detection precision.

The camera is used to focus on a subject to obtain a clear image of the subject, and the imaging range of the camera relative to the focus is called Depth of Field (DOF), and the image within the DOF is relatively clear compared to the image before or after the DOF. However, the lens plane and the imaging plane of a general camera are parallel to each other, and it is difficult to simultaneously obtain a sharp image in which both near and far subjects are in focus when performing optical inspection.

In view of the above, the present inventors have determined that an optical inspection technique capable of effectively simplifying the inspection time and improving the inspection efficiency is required to be devised because the conventional camera is limited in its own specifications and structure and cannot acquire a wide range of clear images of the object.

Disclosure of Invention

The present invention is directed to an optical inspection system capable of effectively simplifying the inspection time and improving the inspection efficiency.

To achieve the above objective, the present invention provides an optical inspection system, which includes an inspection platform, an image capturing device, an optical lens and an image processor. The detection platform is provided with a shooting surface for placing an object to be detected. The image capturing device is arranged on one side of the detection platform. The image capturing device comprises a photosensitive chip, and the photosensitive chip is provided with an imaging surface. The optical lens is arranged between the image capturing device and the detection platform. The optical lens has a lens surface. The extension of the image capture surface, the image plane and the lens surface intersect at the same linear position. The image processor is connected to the image capturing device, and the image of the object to be detected is obtained by the image capturing device for automatic optical detection.

Optionally, a first inclination angle is formed between the imaging surface of the image capturing device and the lens surface of the optical lens. A second inclination angle is formed between the lens surface of the optical lens and the shooting surface of the detection platform. The first inclination angle and the second inclination angle are in a linear relation or a proportional relation.

Optionally, the second inclination angle is between 10 and 70 degrees.

Optionally, a sum of the first inclination angle and the second inclination angle is less than or equal to 90 degrees.

Optionally, a first image capturing distance is provided between the imaging surface of the image capturing device and the lens surface of the optical lens.

Optionally, a second image capturing distance is provided between the lens surface of the optical lens and the shooting surface of the detection platform.

Optionally, the apparatus further comprises a transfer device for carrying the image capturing device and the optical lens. The transfer device comprises a controller, and the controller controls and drives the transfer device to respectively adjust the setting angle and the setting position of the image capture equipment and the optical lens relative to the detection platform.

Optionally, the viewing angle of the optical lens is between 60 and 120 degrees.

Optionally, the device further comprises an illuminating device arranged on one side of the detection platform.

Optionally, the lighting device is a side light source arranged at the side of the shooting surface and/or a back light source arranged at the back side of the object to be measured.

Compared with the prior art, the invention has the following advantages:

the optical detection system provided by the invention adjusts the arrangement of the imaging surface of the image capture equipment and the lens surface of the optical lens relative to the shooting surface of the detection platform so as to improve the range of the depth of field, to take images of an object to be detected in a large range, to simplify the detection time and to improve the detection efficiency.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic structural diagram of an optical inspection system according to the present invention.

FIG. 2 is a side view of the optical inspection system of the present invention.

FIG. 3 is a block diagram of an optical inspection system according to the present invention.

Detailed Description

The detailed description and technical contents of the present invention will be described below with reference to the accompanying drawings. For convenience of explanation, the drawings are not necessarily to scale, and the drawings and the scale are not intended to limit the scope of the present invention.

Referring to fig. 1 to 3, there are shown a structure, a side view and a block diagram of an optical inspection system according to the present invention, as shown in the drawings:

the present invention provides an optical inspection system 100, which includes an inspection platform 10, an image capturing device 20, an optical lens 30 and an image processor 40, so as to obtain a large-range and clear image of an object P to be inspected on the inspection platform 10, which is helpful to simplify the inspection process and improve the inspection efficiency.

The testing platform 10 has a shooting surface 11 for placing the object P to be tested on the shooting surface 11 for shooting. The object P to be measured may be placed on the shooting surface 11 by manual placement, conveying by a conveyor belt, or grabbing by a robot arm, which is not limited in the present invention.

The image capturing device 20 is disposed at one side of the inspection platform 10. The image capturing device 20 includes a photosensitive chip 21, and the photosensitive chip 21 has an imaging surface 22 for imaging the object P on the imaging surface 11.

The optical lens 30 is disposed between the image capturing device 20 and the inspection platform 10. The optical lens 30 has a lens surface 31. In a preferred embodiment, the angle of view a of the optical lens 30 is between 60 degrees and 120 degrees. The extensions of the imaging surface 11, the imaging surface 22, and the lens surface 31 substantially intersect at the same straight line position I. The approximate intersection may be, for example: the method comprises the steps of firstly obtaining an intersection point of two surfaces (such as an imaging surface and a lens surface) on a coordinate plane, then obtaining a coordinate point of a third surface (such as an imaging surface) on the coordinate plane, and indicating that the three surfaces approximately intersect at the same straight line position I when the distance between the intersection point and the coordinate point meets an allowable range. The allowable range depends on the image capturing accuracy of the optical inspection system 100, which is not limited by the invention. As shown in fig. 2, the intersection of the three planes at the same straight line position I is shown in a side view, and since the parameters in the Z-axis direction need not be discussed, only the case of the common point of the three lines needs to be discussed by the XY plane. The extension lines of the three planes are defined on an XY coordinate plane, where L1 is defined as a1x + b1y + c1, L2 is defined as a2x + b2y + c2, and L3 is defined as a3x + b3y + c3, respectively, for the imaging plane 22. When L1, L2, and L3 are three completely unparallel and different straight lines and satisfy the following equation, it means that the extension intersections of the image capturing plane 11, the image plane 22, and the lens plane 31 are at the same straight line position I, i.e. the range of depth of field can be increased to capture images of the object P in a wide range.

The imaging surface 22 of the image capturing device 20 and the lens surface 31 of the optical lens 30 have a first inclination angle θ 1 therebetween. The lens surface 31 of the optical lens 30 and the shooting surface 11 of the detection platform 10 have a second inclination angle θ 2. The first inclination angle and the second inclination angle are in a linear relation or a proportional relation. When the second inclination angle θ 2 is a small angle (e.g., 10 degrees), the first inclination angle θ 1 is also a small angle (e.g., between 2-3 degrees), and conversely, when the second inclination angle θ 2 is a large angle (e.g., 70 degrees), the first inclination angle θ 1 is also a large angle (e.g., between 15-20 degrees), thereby increasing the depth of field of the image captured by the image capturing apparatus 20. The second inclination angle θ 2 is between 10 degrees and 70 degrees, and the sum of the first inclination angle θ 1 and the second inclination angle θ 2 is less than or equal to 90 degrees, so as to avoid the problem that the sum of the angles of the two inclination angles is too large, which causes serious distortion of the image or too large difference of brightness and darkness of the image.

The image capturing device 20 has a first image capturing distance S1 between the image plane 22 and the lens plane 31 of the optical lens 30. The first image-taking distance S1 is the distance from the central axis of the image capturing device 20 to the central axis of the optical lens 30. A second image capturing distance S2 is provided between the lens surface 31 of the optical lens 30 and the image capturing surface 11 of the detecting platform 10. The second image-capturing distance S2 is a distance from the central axis of the optical lens 30 to the detecting platform 10. The depth of field of the image captured by the image capturing device 20 is determined by the above-mentioned inclination angle and the image capturing distance, and the extension intersection or the approximate intersection of the shooting surface 11, the imaging surface 22 and the lens surface 31 is at the same straight line position I, so as to obtain a wide-range and clear image of the object P.

The image processor 40 is connected to the image capturing device 20, and the image of the object P is obtained by the image capturing device 20 for automatic optical inspection. In one embodiment, the image processor 40 performs, for example, binarization processing, sharpening processing, contrast enhancement processing, back reduction processing, image segmentation processing or other similar image processing procedures according to the acquired image of the object P. And identifying the positions of foreign matters, concave-convex or other flaws on the surface or the inner layer of the object P to be detected through the image after the image processing. In another embodiment, the image processor 40 compares the acquired image of the object P with a pre-stored default image after passing through an image processing procedure to identify the defect and the position of the object P. The above illustration is merely an illustration of two preferred embodiments of the image processing of the present invention, and the embodiments of the present invention are not limited to the above embodiments.

The optical inspection system 100 further includes a transfer device 50 for carrying the image capturing apparatus 20 and the optical lens 30. The transferring device 50 includes a controller 51 for controlling and driving the transferring device 50, so that the transferring device 50 can adjust the setting angle and the setting position of the image capturing apparatus 20 and the optical lens 30 relative to the inspection platform 10, respectively, to focus and capture an image of the object P. The transfer device 50 may be a robot, a movable stage, or any other device or apparatus capable of carrying and adjusting the arrangement of the image capturing device 20 and the optical lens 30, which is not limited in the present invention.

The optical inspection system 100 further includes an illumination device 60 disposed on one side of the inspection platform 10. The illumination device 60 can provide uniform illumination for the side light source 61 disposed at the side of the photographing surface 11 and/or the back light source 62 disposed at the back side of the object P, so that the image capturing apparatus 20 can obtain a clear image of the object P.

Before the optical inspection system 100 of the present invention performs inspection, first, the optical lens 30 is set and positioned to fix the angle (the second inclination angle θ 2) and the distance (the second image capturing distance S2) between the lens surface 31 of the optical lens 30 and the shooting surface 11 of the inspection platform 10; then, the object P to be detected is set on the shooting surface 11 of the detection platform 10, and the depth of field range to be captured by the image capturing device 20 is determined based on the area size of the object P to be captured, where the depth of field range is determined by the angle (the first inclination angle θ 1) and the distance (the first image capturing distance S1) between the imaging surface 22 of the image capturing device 20 and the lens surface 31 of the optical lens 30, so that the object P imaged in the depth of field range is a clear and undistorted image, thereby facilitating detection of the object image.

In summary, the optical inspection system of the present invention adjusts the arrangement relationship of the image capturing device and the optical lens relative to the inspection platform, so that the image plane, the lens plane and the image plane are approximately intersected on a straight line, and the inclination angle relationship among the three planes is linear or proportional, thereby increasing the depth of field of the image, and facilitating the improvement of the overall optical inspection efficiency.

Although the present invention has been described in detail, it should be understood that the foregoing is only a preferred embodiment of the invention, and not as an attempt to limit the application of the invention to the particular forms disclosed.

Claims

1. an optical detection system, is characterized in that, comprises:

a detection platform, the detection platform has a photographing surface for placing an object to be tested;

an image capture device disposed on one side of the detection platform, the image capture device includes a photosensitive chip, and the photosensitive chip has an imaging surface;

an optical lens, disposed between the image capture device and the detection platform, the optical lens has a lens surface, wherein, the extension and intersection of the shooting surface, the imaging surface and the lens surface are at the same straight line position; and

An image processor is connected to the image capture device, and the image capture device obtains the image of the object to be tested for automatic optical detection.

2 . The optical detection system of claim 1 , wherein a first inclination angle exists between the imaging surface of the image capturing device and the lens surface of the optical lens, and the lens surface of the optical lens and the lens surface of the optical lens have a first inclination angle. There is a second inclination angle between the shooting surfaces of the detection platform, and the first inclination angle and the second inclination angle are in a linear relationship or a proportional relationship.

3 . The optical detection system of claim 2 , wherein the second inclination angle is between 10 degrees and 70 degrees. 4 .

4 . The optical detection system of claim 2 , wherein the sum of the first inclination angle and the second inclination angle is less than or equal to 90 degrees. 5 .

5 . The optical detection system of claim 1 , wherein there is a first image capturing distance between the imaging surface of the image capturing device and the lens surface of the optical lens. 6 .

6 . The optical detection system of claim 1 , wherein a second imaging distance exists between the lens surface of the optical lens and the photographing surface of the detection platform. 7 .

7. The optical detection system of claim 1, further comprising a transfer device for carrying the image capture device and the optical lens, the transfer device comprising a controller, the controller controls and drives the The transfer device adjusts the setting angle and setting position of the image capturing device and the optical lens relative to the detection platform respectively.

8 . The optical detection system of claim 1 , wherein the viewing angle of the optical lens is between 60 degrees and 120 degrees. 9 .

9 . The optical detection system of claim 1 , further comprising an illumination device disposed on one side of the detection platform. 10 .

10 . The optical detection system according to claim 9 , wherein the illumination device is a side light source disposed on the side of the photographing surface and/or a back light source disposed on the back side of the object to be measured. 11 .