A measurement system for scattered target points of special-shaped springs based on a single camera

Abstract

The present invention provides a measurement system for scattered target points of shaped springs based on a single camera, comprising a measured shaped spring, a light source, a reflector, a microscope lens and an industrial camera; the measurement light propagation path of the system is that the light source emits the measurement light, the measured shaped spring reflects the measurement light, the measurement light passes through the reflector and then passes through the microscope lens, and then enters the industrial camera. The present invention can economically and effectively perform accurate visual measurement of the geometric dimensions of scattered target points of shaped springs. On the one hand, it overcomes the disadvantage that the pixels of the image are not fully utilized in the measurement scheme of a single telecentric lens camera, and also solves the mechanical interference problem of the measurement scheme using only multiple microscope lens cameras; on the other hand, compared with a single microscope lens plus a precise motion platform, the present invention can significantly reduce costs while ensuring measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of machine vision, and more particularly to a measurement system for scattered target points of special-shaped springs based on a single camera. Background Art

[0002] The machine vision system includes light source, lens, camera, image processing unit, image processing software, monitor, communication / input and output unit, etc. In the image acquisition stage, the image acquisition scheme composed of the type of camera and light source and their installation position has an important impact on the difficulty of implementing the subsequent stage of image acquisition and the accuracy of the measurement results of the measured object.

[0003] For the geometric measurement of scattered target points of special-shaped springs, one solution is to use a single high-resolution camera equipped with a telecentric lens to complete the measurement by taking an image in one shot. However, the area of ​​the target area of ​​interest in the image accounts for too small a proportion of the total image area, and the image pixel resources are not fully utilized to achieve greater measurement accuracy. Another solution is to use only multiple microscope lens cameras to measure the multiple scattered target points of the special-shaped spring separately. However, when the size between the target points on the spring is smaller than the size that the camera can be placed side by side, there will be mechanical interference in the hardware part of the camera, and the camera cannot be placed normally, resulting in the inability to complete the measurement task. Another solution is to use a single microscope lens camera in conjunction with a precise motion platform to gradually obtain images of the spring target points, and then combine the camera motion parameters to complete the geometric measurement of the target points. However, this solution will increase the cost due to the precise motion platform.

[0004] At present, the precise geometric measurement of scattered target points of special-shaped springs mostly adopts the measurement method of a single telecentric lens camera. Since the special-shaped spring itself is small in size, and the area where the target point is located (such as the target point is the center of a circular arc) is also small relative to the size of the spring itself, the use of a single camera for measurement will make the area where the target point is located in the image occupy a very small proportion of the entire image area. At the same time, as the measurement accuracy requirements increase, the camera resolution needs to be improved to improve the measurement accuracy, which will increase the camera cost and more image pixels in the camera image are not fully utilized. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a measurement system for scattered target points of special-shaped springs based on a single camera.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] A single-camera-based measurement system for scattered target points of a special-shaped spring, comprising a special-shaped spring to be measured, a light source, a reflector, a microscope lens and an industrial camera;

[0008] The measuring light propagation path of this system is that the light source emits the measuring light, the measured special-shaped spring reflects the measuring light, the measuring light passes through the reflector and then the microscope lens, and then enters the industrial camera.

[0009] In a preferred embodiment, the light source is an annular light source, and the annular light source is placed directly above the special-shaped spring to be tested.

[0010] In a preferred solution, the opening diameter of the annular light source should be larger than the maximum size of the special-shaped spring to be tested.

[0011] In a preferred solution, the reflector includes N surfaces, including a first reflector, a second reflector, and a third reflector fixed at a certain angle, the first reflector is parallel to the second reflector and the third reflector, the first reflector is placed above the special-shaped spring to be measured and the annular light source, and reflects all the light irradiated on the special-shaped spring to be measured; the reflector is placed on one side of the first reflector, and the light reflected by the first reflector is partially reflected to the microscope lens and then enters the industrial camera for imaging; the third reflector is located on one side of the first reflector, and the light reflected by the first reflector is partially reflected to the microscope lens and then enters the industrial camera for imaging. The reflector is a plane reflector.

[0012] In a preferred embodiment, the angle between the reflector surface and the horizontal plane is 45 degrees.

[0013] In a preferred embodiment, the optical axis of the microscope lens is 45 degrees to the reflector and 90 degrees to the plane where the tested shaped spring is placed. The tested shaped spring is placed flat on the plane, and the placement plane is parallel to the horizontal plane.

[0014] In a preferred embodiment, the relative positions and sizes of the second and third reflectors are within the field of view and depth of field of the microscope lens, so that objects reflected by the second and third reflectors can be fully and clearly imaged in the camera.

[0015] In a preferred embodiment, the object to be measured is not limited to a special-shaped spring, and the number of dispersed target points to be measured is not limited to two.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] The present invention can economically and effectively perform accurate visual measurement of the geometric dimensions of the scattered target points of the special-shaped spring. On the one hand, it overcomes the disadvantage that the pixels of the image are not fully utilized in the measurement scheme of a single telecentric lens camera, and also solves the mechanical interference problem of the measurement scheme using only multiple microscope lens cameras; on the other hand, compared with a single microscope lens plus a precise motion platform, the present invention can significantly reduce the cost, especially the expensive motion platform cost, while ensuring the measurement accuracy. This improves the accuracy of the geometric measurement of the scattered target points of the special-shaped spring, while making more full use of the image pixels, and can appropriately reduce the camera resolution to reduce the camera cost to achieve better economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a measurement system for scattered target points of a special-shaped spring based on a single camera provided by the present invention;

[0019] Figure 2 is a schematic diagram of the front structure of the tested special-shaped spring in Example 2;

[0020] Figure 3 is a schematic diagram of the side structure of the tested special-shaped spring in Example 2;

[0021] Wherein: 1. spring to be tested, 1a. circular end surface, 2b. inner circular ring; 2. annular light source; 3 is a reflector (marked in the figure) including: 3a. a first reflector, 3b. a second reflector, 3c. a third reflector; 4. a microscope lens; 5. an industrial camera. DETAILED DESCRIPTION

[0022] The drawings are for illustrative purposes only and should not be construed as limiting the present patent;

[0023] In order to better illustrate the present embodiment, some parts in the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product;

[0024] It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Example 1

[0027] A single camera-based measurement system for scattered target points of special-shaped springs. Figure 1 As shown, it includes a tested special-shaped spring 1, a light source 2, a reflector 3, a microscope lens 4 and an industrial camera 5;

[0028] The measuring light propagation path of the system is that the light source emits the measuring light, the measured special-shaped spring 1 reflects the measuring light, the measuring light passes through the reflector 3, then passes through the microscope lens 4, and then enters the industrial camera 5.

[0029] In a preferred embodiment, the light source 2 is an annular light source, and the annular light source 2 is placed directly above the special-shaped spring 1 to be tested.

[0030] In a preferred solution, the opening diameter of the annular light source 2 should be larger than the maximum size of the special-shaped spring 1 to be tested.

[0031] In a preferred embodiment, the reflector 3 includes N surfaces, including a first reflector 3a, a second reflector 3b, and a third reflector 3c fixed at a certain angle. The first reflector 3a is parallel to the second reflector 3b and the third reflector 3c. The first reflector 3a is placed above the special-shaped spring 1 to be measured and the annular light source 2 to reflect all light irradiated on the special-shaped spring 1 to be measured; the second reflector 3b is placed on one side of the first reflector 3a to reflect part of the light reflected by the first reflector 3a to the microscope lens 4 and then enter the industrial camera 5 for imaging; the third reflector 3c is located on one side of the first reflector 3a to reflect part of the light reflected by the first reflector 3a to the microscope lens 4 and then enter the industrial camera 5 for imaging.

[0032] In a preferred embodiment, the angle between the reflector 3 and the horizontal plane is 45 degrees.

[0033] In a preferred embodiment, the optical axis of the microscope lens 4 is 45 degrees to the reflector 3 and 90 degrees to the plane where the special-shaped spring to be measured is placed.

[0034] In a preferred embodiment, the relative positions and sizes of the second reflector 3b and the third reflector 3c are within the field of view and depth of field of the microscope lens 4, so that the objects reflected by the second reflector and the third reflector can be completely and clearly imaged in the camera.

[0035] In a preferred embodiment, the object to be measured is not limited to a special-shaped spring, and the number of dispersed target points to be measured is not limited to two.

[0036] Example 2

[0037] The system provided in this embodiment is consistent with the embodiment, a measurement system for scattered target points of a special-shaped spring based on a single camera, comprising a special-shaped spring to be measured 1, a ring light source 2, a reflector 3, a microscope lens 4 and an industrial camera 5; wherein the structure of the special-shaped spring to be measured is as follows Figure 2 , Figure 3 As shown;

[0038] The measuring light propagation path of each dispersed target point to be measured is that the annular light source 2 emits the measuring light, the measured special-shaped spring 1 reflects the measuring light, the measuring light passes through the reflector 3 and then the microscope lens 4, and then enters the industrial camera 5.

[0039] The reflector 3 includes three surfaces, which are parallel to each other and fixed at 45 degrees to the horizontal plane. The first reflector 3a is placed above the special-shaped spring 1 to be measured and the annular light source 2, and reflects all the light irradiated on the special-shaped spring 1 to be measured. The size should be slightly larger than the maximum size of the special-shaped spring 1 to be measured; the second reflector 3b is placed on one side of the first reflector 3a, and reflects part of the light reflected by the first reflector 3a to the microscope lens 4 and then enters the industrial camera 5 for imaging, wherein the light reflected by the second reflector 3b should only include the light of the circular end surface 1a of the measuring part of the special-shaped spring 1 to be measured reflected in the first reflector 3a, but not the light of the inner ring 1b of another measuring part. The imaging area of ​​the circular end surface 1a in the industrial camera 5 should be in a certain part of the image plane in the industrial camera 5, such as imaging in the left half of the image plane; the third reflector 3c is located on the same side of the first reflector 3a, and reflects part of the light reflected by the first reflector 3a to the industrial camera 5a for imaging, wherein the light reflected by the third reflector 3c should only include the light of the inner ring 1b part of the measuring part of the measured special-shaped spring 1 reflected in the first reflector 3a, but not include the light of the circular end surface 1a part of another measuring part, and the imaging area of ​​the inner ring 1b part in the industrial camera 5 should be in a certain part of the image plane in the industrial camera 5, such as imaging in the right half of the image plane. The opening diameter of the annular light source 2 should be larger than the maximum size of the measured special-shaped spring, and it should be located above the measured special-shaped spring 1. The optical axis direction of the microscope lens 4 is 45 degrees to the vertical mirror direction of the reflector 3.

[0040] During the working process, the annular light source 2 first evenly illuminates the measured special-shaped spring 1, and the second reflector 3b and the third reflector 3c respectively reflect the light reflected by the first reflector 3a to the microscope lens 4 and then enter the two parts of the imaging plane in the industrial camera 5 to form images respectively; then, by calibrating the two parts of the image formed by the industrial camera 5, such as the left and right parts, the camera is calibrated respectively, and the actual center distance of the two measurement targets in the image of the industrial camera 5 in the real world is calculated, such as the center distance between the circular end face 1a and the inner ring 1b of the measured special-shaped spring 1.

[0041] The terms used in the drawings to describe positional relationships are only used for illustrative purposes and should not be construed as limiting this patent;

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A measurement system for scattered target points of special-shaped springs based on a single camera, characterized in that: It includes a light source (2), a reflector (3), a microscope lens (4) and an industrial camera (5); The measuring light propagation path of the system is that the light source emits the measuring light, the measured special-shaped spring (1) reflects the measuring light, the measuring light passes through the reflector (3), then passes through the microscope lens (4), and then enters the industrial camera (5); The reflector (3) includes three surfaces, which are parallel to each other and fixed at 45 degrees to the horizontal plane. The first reflector (3a) is placed above the measured shaped spring (1) and the annular light source (2) to reflect all the light irradiated on the measured shaped spring (1). The size should be slightly larger than the maximum size of the measured shaped spring (1). The second reflector (3b) is placed on one side of the first reflector (3a) to reflect part of the light reflected by the first reflector (3a) to the microscope lens (4) and then enter the industrial camera (5) for imaging. The light reflected by the second reflector (3b) should only include the light reflected by the first reflector (3a) of the measuring part of the circular end surface (1a) of the measured shaped spring (1) but not the light reflected by the inner ring (1b) of another measuring part. The imaging area of ​​the circular end surface (1a) in the industrial camera (5) should be within A portion of an image plane in an industrial camera (5); a third reflector (3c) is located on the same side as the first reflector (3a) and reflects part of the light reflected by the first reflector (3a) to form an image in the industrial camera (5a), wherein the light reflected by the third reflector (3c) should only include the light of the inner ring (1b) portion of the measuring part of the measured special-shaped spring (1) reflected in the first reflector (3a) and does not include the light of the circular end surface (1a) portion of another measuring part, and the imaging area of ​​the inner ring (1b) portion in the industrial camera (5) should be in a portion of the image plane in the industrial camera (5), the opening diameter of the light source (2) should be larger than the maximum size of the measured special-shaped spring and be located above the measured special-shaped spring (1); the optical axis direction of the microscope lens (4) is 45 degrees to the vertical mirror surface direction of the reflector (3).

2. The measurement system for scattered target points of special-shaped springs based on a single camera according to claim 1, characterized in that: The light source (2) is an annular light source, and the annular light source (2) is placed directly above the special-shaped spring (1) to be tested.

3. The measurement system for scattered target points of special-shaped springs based on a single camera according to claim 2, characterized in that: The opening diameter of the annular light source (2) is larger than the maximum size of the special-shaped spring (1) to be tested.

4. The measurement system for scattered target points of special-shaped springs based on a single camera according to claim 1, characterized in that: The angle between the reflector (3) and the horizontal plane is 45 degrees.

5. The measurement system for scattered target points of special-shaped springs based on a single camera according to claim 1, characterized in that: The optical axis of the microscope lens (4) is 45 degrees to the mirror surface of the reflector (3), and 90 degrees to the plane on which the special-shaped spring to be measured is placed.

6. The measurement system for scattered target points of special-shaped springs based on a single camera according to claim 1, characterized in that: The relative positions and sizes of the second reflector (3b) and the third reflector (3c) are both within the field of view and depth of field of the microscope lens (4).

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