CN214622375U - Workpiece side circumference imaging system - Google Patents

Abstract

The present disclosure provides a workpiece perimeter imaging system comprising: a glass stage; the super-telecentric lens is positioned on one side of the glass table, and the angle range of a first acute angle formed by the optical axis of the super-telecentric lens and the surface of the glass table is between 45 and 80 degrees; the light source is positioned on the other side, away from the ultratelecentric lens, of the glass platform; the light source is a plane plate light source or a point light source, and the glass table is a glass disc.

Description

Workpiece side circumference imaging system

Technical Field

The disclosure relates to the technical field of workpiece defect detection, in particular to a workpiece side circumference imaging system.

Background

At present, when the side periphery and the edge of a workpiece are imaged simultaneously, a plurality of cameras are generally needed to be adopted to image the workpiece respectively, and the mode causes the system to be too complex and high in cost. Or, use the super telecentric lens to form images to make the optical axis of super telecentric lens be on a parallel with the side of the work piece week when forming images, but this mode is poor to the formation of image quality of the edge of keeping away from super telecentric lens one side, leads to having the defect on this edge, even has and to collide with the edge and fall the angle and also difficult to detect out when being great.

It is to be noted that the information disclosed in the above background section is only for enhancement of understanding of the background of the present disclosure, and thus may include information that does not constitute prior art known to those of ordinary skill in the art.

SUMMERY OF THE UTILITY MODEL

It is an object of the present disclosure to provide a workpiece side imaging system.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows, or in part will be obvious from the description, or may be learned by practice of the disclosure.

According to one aspect of the present disclosure, there is provided a workpiece perimeter imaging system comprising: a glass stage; the super-telecentric lens is positioned on one side of the glass table, and the angle range of a first acute angle formed by the optical axis of the super-telecentric lens and the surface of the glass table is between 45 and 80 degrees; the light source is positioned on the other side, away from the ultratelecentric lens, of the glass platform; the light source is a plane plate light source or a point light source, and the glass table is a glass disc.

According to an embodiment of the present disclosure, the first acute angle ranges between 55 degrees and 75 degrees.

According to an embodiment of the present disclosure, when the light source is a flat panel light source, a light emitting surface of the light source faces the glass stage.

According to an embodiment of the present disclosure, the flat plate light source and the glass stage are parallel to each other, or a second acute angle formed between a plane where a light emitting surface of the flat plate light source is located and a plane where the glass stage is located is less than 30 degrees.

According to an embodiment of the present disclosure, when the light source is a point light source, a first connection line is formed between a center of a surface of the hyper-telecentric lens and a center of a field of view formed by the hyper-telecentric lens on the glass stage, a second connection line is formed between the center of the field of view and the center of the light source, and an included angle between the first connection line and the second connection line is less than 170 degrees.

According to an embodiment of the present disclosure, an included angle between the first line and the second line is smaller than a difference between 170 degrees and the first acute angle degree.

According to the workpiece periphery imaging system provided by the embodiment of the disclosure, when the super-telecentric lens is used for imaging the workpiece periphery, the optical axis of the super-telecentric lens is inclined to the surface of the glass table, the angle range of an acute angle formed between the optical axis of the super-telecentric lens and the surface of the glass table is limited, and in addition, a plane plate light source or a point light source is arranged on the other side of the glass table far away from the super-telecentric lens, so that a light source is provided for the super-telecentric lens during imaging. Due to the fact that the super-far-center lens is arranged obliquely to the glass table, the imaging range of the super-far-center lens is changed, and therefore a clearer image can be presented for the edge of the workpiece to be imaged, which is far away from the super-far-center lens, and imaging display force of defects on the periphery of the side of the workpiece is remarkably improved. Furthermore, when the workpiece side periphery defect detection is carried out based on the workpiece side periphery image, the probability of missed detection is greatly reduced, and particularly the probability of defects on missed detection edges is reduced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty.

Fig. 1 is an imaging schematic diagram of an ultratelecentric lens shown according to an example.

Fig. 2 is a schematic diagram illustrating a defect in an edge of a subject away from a lens according to an example.

FIG. 3A is a perspective schematic view of a workpiece perimeter imaging system according to one exemplary embodiment.

FIG. 3B is a side view of a workpiece perimeter imaging system shown in accordance with an exemplary embodiment.

FIG. 4 is a schematic diagram illustrating an arrangement of a flat panel light source intersecting a glass table in accordance with an exemplary embodiment.

FIG. 5 is a schematic diagram illustrating a light source as a point source according to an exemplary embodiment.

FIG. 6 is a schematic diagram of a hyper-telecentric lens view shown according to an example.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Furthermore, the drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repetitive description will be omitted. Some of the block diagrams shown in the figures are functional entities and do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor devices and/or microcontroller devices.

In the description of the present disclosure, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the present disclosure.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise the first and second features being in direct contact, or may comprise the first and second features being in contact, not directly, but via another feature in between. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Furthermore, in the description of the present disclosure, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

Common lenses (including the human eye) image objects at divergent angles of view, and telecentric lenses image objects at parallel angles of view. And hyper-telephoto lenses (hyper-telephoto lenses/hyper-telephoto lenses) provide a convergent view of the subject, i.e., the captured images are convergent. Unlike other lenses, the hyper-telephoto lens can image an object surface parallel to the optical axis, that is, the top and side of a subject can be seen in an image at the same time.

Fig. 1 is an imaging schematic diagram of an ultratelecentric lens shown according to an example. As shown in fig. 1, when imaging a subject 2 (for example, a bottle cap in the figure) using an ultratelecentric lens 1, a captured image 3 includes not only a top image 301 corresponding to a top 201 of the subject 2 but also a side periphery image 302 corresponding to a side periphery 202 of the subject 2. The side periphery 202 of the subject 2 is parallel to the optical axis 4.

The function of the super-telecentric lens avoids the need of using a plurality of cameras or a plurality of reflectors in the machine vision detection or identification application, and can effectively reduce the complexity of the workpiece detection system.

As an emerging technology, the super-telecentric lens is beginning to be applied in a workpiece lateral periphery imaging or defect detection system. However, although the super-telecentric lens has the above advantages when applied to the defect detection of the workpiece side circumference, in practical application, the inventor of the present disclosure finds that if the optical axis of the super-telecentric lens 1 is parallel to the side circumference of the workpiece 2 to be imaged as shown in fig. 2 during imaging, the image of the edge far from the lens side in the captured image is not clear, which results in that the edge has defects and is difficult to detect even when a large broken edge drop angle (as shown in fig. 2) exists.

Therefore, a workpiece imaging system needs to be designed, so that the advantages of the super-far-center lens are effectively utilized, and the high-quality images of the side periphery and the edge of the workpiece are provided by adjusting the direction between the optical axis of the super-far-center lens and the side periphery of the workpiece to be imaged.

The workpiece lateral periphery imaging system provided by the embodiment of the disclosure is described below with reference to the accompanying drawings.

FIG. 3A is a perspective schematic view of a workpiece perimeter imaging system according to one exemplary embodiment. FIG. 3B is a side view of a workpiece perimeter imaging system shown in accordance with an exemplary embodiment.

Referring to fig. 3A and 3B, the workpiece imaging system 30 includes: an ultra-far-center lens 31, a glass stage 32 and a light source 33.

The super-telephoto lens 31 is located on one side of the glass stage 32, and an acute angle α formed between the optical axis L31 of the super-telephoto lens 31 and the surface S32 of the glass stage 32 is between a first angle threshold and a second angle threshold, the first angle threshold being set to be between 30 degrees and 55 degrees, for example, and the second angle threshold being set to be between 70 degrees and 85 degrees, for example. The disclosure is not so limited. For example, the first angle threshold is set to 45 degrees and the second angle threshold is set to 80 degrees.

In some embodiments, the first angle threshold may also be set to 55 degrees, and the second angle threshold may be set to 75 degrees, so as to reduce the compression degree of the side surface imaging, and the imaging area of the side surface on the target surface of the camera is larger, which is more favorable for the imaging quality of the edge of the workpiece to be imaged far away from the side of the super-telecentric lens 31, and improves the defect detection accuracy.

The glass table 32 is a glass disk that is transparent to allow sufficient transmission of light provided by the light source 33 during imaging. In addition, the glass table 32 may be a rotatable glass table that facilitates adjustment of the position of a workpiece to be imaged placed thereon. L32 is the centerline of glass table 32.

The light source 33 is located on the other side of the glass stage 32 from the hyper-telecentric lens 31, and may be, for example, a flat panel light source as shown in fig. 3A to 3B or fig. 4. Alternatively, the light source 33 may be a point light source as shown in fig. 5.

In the scheme, the point light source is a surface-shaped light source with a small light emitting area, for example, the light emitting area is less than 5 square centimeters, even less than 3 square centimeters, even less than 1 square centimeter, and the outline of the light emitting area can be circular, square, polygonal and the like.

In some embodiments, as shown in fig. 3B, the light-emitting surface of the flat panel light source 33 faces the glass stage 32, and the flat panel light source 33 and the glass stage 32 are arranged parallel to each other.

According to the workpiece periphery imaging system provided by the embodiment of the disclosure, when the super-telecentric lens is used for imaging the workpiece periphery, the optical axis of the super-telecentric lens is inclined to the surface of the glass table, the angle range of an acute angle formed between the optical axis of the super-telecentric lens and the surface of the glass table is limited, and in addition, a plane plate light source or a point light source is arranged on the other side of the glass table far away from the super-telecentric lens, so that a light source is provided for the super-telecentric lens during imaging. Due to the fact that the super-far-center lens is arranged obliquely to the glass table, the imaging range of the super-far-center lens is changed, and therefore a clearer image can be presented for the edge of the workpiece to be imaged, which is far away from the super-far-center lens, and imaging display force of defects on the periphery of the side of the workpiece is remarkably improved. Furthermore, when the workpiece side periphery defect detection is carried out based on the workpiece side periphery image, the probability of missed detection is greatly reduced, and particularly the probability of defects on missed detection edges is reduced.

FIG. 4 is a schematic diagram illustrating an arrangement of a flat panel light source intersecting a glass table in accordance with an exemplary embodiment. As shown in fig. 4, an acute angle β is formed between a plane where the light emitting surface S33 of the flat plate light source 33 is located and a plane where the surface S32 of the glass bench 32 is located, the acute angle β is set to be less than or equal to a third angle threshold, and the range of the third angle threshold may be set to be between 15 degrees and 45 degrees, for example, but the disclosure is not limited thereto, and the third angle threshold may be set according to actual requirements in actual applications. For example, in some embodiments, the third angle threshold may be set to 30 degrees.

FIG. 5 is a schematic diagram illustrating a light source as a point source according to an exemplary embodiment. As shown in fig. 5, when the light source 33 is a point light source, a first line L1 (coinciding with the optical axis L31) is formed between the center of the lens surface S31 of the extra-center lens 31 and the center of the field of view Vf formed by the extra-center lens 31 on the glass stage 32. A second line L2 is formed between the center of the field Vf and the center of the point light source 33. The angle θ between the first line L1 and the second line L2 is smaller than a fourth angle threshold, which may be set to be in a range of 150 degrees to 175 degrees, for example. However, the disclosure is not limited thereto, and the fourth angle threshold may be set according to actual requirements in actual applications. For example, in some embodiments, the fourth angle threshold may be set to 170 degrees.

In some embodiments, the fourth angle threshold may also be set to the difference between 170 degrees and the acute angle α, for example, as described above.

A field of view Vf formed by the super-telecentric lens 31 on the glass stage 32, i.e., a range that the super-telecentric lens 31 can see on the glass stage 32, i.e., an imaging area of the super-telecentric lens 31, can be observed by a camera connected to the lens 31 to observe a boundary of the field of view.

FIG. 6 is a schematic diagram of a hyper-telecentric lens view shown according to an example. Fig. 6 is a side view, and as shown in fig. 6, the field of view Vf of the hyper-telecentric lens 31 is located between the center Cp of the entrance pupil of the hyper-telecentric lens 31 and the lens lower end plane (i.e., the lens surface) S31 of the hyper-telecentric lens 31. The area of the glass stage 32 visible through the hyper-telecentric lens 31 at this time is the field of view Vf of the current hyper-telecentric lens 31.

The current view Vf of the extra-far-center lens 31 can be determined by an experimental method, such as replacing the CCD target surface of the extra-far-center lens 31 with a flat plate light, where the lens is a light-emitting structure. A piece of white paper is placed on the glass table 32, and a spot of light is present on the white paper, which spot of light includes the current field of view Vf of the area, i.e., the hyper-telecentric lens 31. The area of the field of view Vf (or the distance between the field of view Vf and the lower surface S31 of the hyper-telecentric lens 31) can be adjusted according to the parameters of the hyper-telecentric lens 31.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims (4)

1. A workpiece perimeter imaging system, comprising:

a glass stage;

the super-telecentric lens is positioned on one side of the glass table, and the angle range of a first acute angle formed by the optical axis of the super-telecentric lens and the surface of the glass table is between 45 and 80 degrees;

the light source is positioned on the other side, away from the ultratelecentric lens, of the glass platform;

the light source is a plane plate light source or a point light source, and the glass table is a glass disc;

when the light source is a plane plate light source, the plane plate light source and the glass table are parallel to each other, or a second acute angle formed between a plane where a light emitting surface of the plane plate light source is located and a plane where the glass table is located is smaller than 30 degrees;

when the light source is a point light source, a first connecting line is formed between the center of the surface of the super-telecentric lens and the center of a visual field formed by the super-telecentric lens on the glass table, a second connecting line is formed between the center of the visual field and the center of the light source, and an included angle between the first connecting line and the second connecting line is smaller than 170 degrees.

2. The workpiece lateral imaging system of claim 1, wherein the first acute angle ranges between 55 degrees and 75 degrees.

3. A workpiece lateral periphery imaging system according to claim 1 or 2, wherein a light emitting face of the planar plate light source faces the glass stage.

4. The workpiece lateral imaging system of claim 1 or 2, wherein an angle between the first line and the second line is less than a difference between 170 degrees and the first acute angle degree.

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