Multi-view camera and grain appearance defect detection method using the same

Abstract

The present application relates to the technical field of grain detection, and provides a multi-view camera and a grain kernel appearance defect detection method using the same.S1: placing the grain kernel at the center position of a material placement area, forming different side images of the grain kernel on an imaging plane through a first total reflection prism, a second total reflection prism, a third total reflection prism and a fourth total reflection prism; meanwhile, forming a main image of the grain kernel in the center area of the imaging plane;S2: dynamically adjusting the relative positions of the first total reflection prism, the second total reflection prism, the third total reflection prism and the fourth total reflection prism and each side of the grain kernel according to the external contour of the grain kernel, and obtaining the maximum area projection of each side of the grain kernel.The beneficial effect lies in that the single camera can realize image acquisition at five angles simultaneously, greatly reducing the hardware cost, the space required for installation and the control difficulty of image acquisition.

Description

Technical Field

[0001] This invention relates to the field of grain inspection technology, specifically to a multi-view camera and a method for detecting appearance defects in grain kernels using the same. Background Technology

[0002] Currently, grain appearance inspection mainly involves superimposing multiple cameras to capture images of the same grain from different angles, obtaining a 360-degree view of a single grain. This is typically achieved using two cameras on the front and back, or four cameras at 90° angles to each other. However, when the grain has a certain thickness, it is difficult for the front and back cameras to capture images along the thickness direction. Using more than two cameras, such as four cameras, presents problems such as increased hardware costs, the need for a large space to arrange multiple cameras, and a large computational load (simultaneously acquiring images from four cameras).

[0003] Therefore, this invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-view camera and a method for detecting appearance defects in grains using the same, so as to solve the technical problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a multi-view camera, comprising: a camera body, wherein an imaging plane is disposed inside the camera body, and a plurality of total internal reflection prisms with the same structural size are disposed on one side of the imaging plane;

[0006] The first total reflection prism, the second total reflection prism, the third total reflection prism, and the fourth total reflection prism are arranged to surround the material placement area, and the first mirror surfaces of the first total reflection prism, the second total reflection prism, the third total reflection prism, and the fourth total reflection prism all face the material placement area.

[0007] In the initial state, the first total internal reflection prism and the third total internal reflection prism are set as mirror images of the center of the material placement area, and the second total internal reflection prism and the fourth total internal reflection prism are set as mirror images of the center of the material placement area.

[0008] The material placement area places the material, and the material forms different side images of the material on the imaging plane through the first total reflection prism, the second total reflection prism, the third total reflection prism and the fourth total reflection prism; at the same time, the central area of ​​the imaging plane also forms the main image of the material.

[0009] In an optional embodiment, the angle between the first mirror surface and the second mirror surface of the first total internal reflection prism, the second total internal reflection prism, the third total internal reflection prism and the fourth total internal reflection prism is α, where 60° < α ≤ 130°.

[0010] In an optional embodiment, the first total internal reflection prism, the second total internal reflection prism, the third total internal reflection prism, and the fourth total internal reflection prism can all rotate, and the rotation axes of the first total internal reflection prism, the second total internal reflection prism, the third total internal reflection prism, and the fourth total internal reflection prism are parallel to the horizontal line of the second prism of their own second mirror surface.

[0011] In an optional embodiment, the side image of the material enters through the first mirror surfaces of the first, second, third, and fourth total internal reflection prisms, and after being reflected inside each of the total internal reflection prisms, is projected onto the imaging plane through the second mirror surfaces of the first, second, third, and fourth total internal reflection prisms.

[0012] In an optional embodiment, multiple total internal reflection prisms of the same structural size are located below the imaging plane, and the central region of the imaging plane forms the main image of the material, which is the projection of the top view of the material onto the imaging plane.

[0013] On the other hand, the present invention also provides a method for detecting appearance defects in grain kernels, using a multi-view camera as described above, including:

[0014] S1: Place the grains at the center of the material placement area, and form different side images of the grains on the imaging plane through the first total reflection prism, the second total reflection prism, the third total reflection prism and the fourth total reflection prism;

[0015] Simultaneously, a main image of the grain is formed in the central region of the imaging plane;

[0016] S2: Based on the outer contour of the grain, dynamically adjust the relative positions of the first total reflection prism, the second total reflection prism, the third total reflection prism, and the fourth total reflection prism with each side of the grain to obtain the maximum area projection of each side of the grain, so as to obtain the maximum projection of each side of the grain on the imaging plane.

[0017] In an optional embodiment, the first total internal reflection prism, the second total internal reflection prism, the third total internal reflection prism, and the fourth total internal reflection prism are adjusted, with the upper and lower limits of the rotation angle adjustment for each total internal reflection prism being Rmax and Rmin, respectively, and the rotation step angle being rdelta.

[0018] In an optional embodiment, each total internal reflection prism is rotated to traverse Rmin to Rmax in increments of angle rdelta, and all projected areas of each total internal reflection prism are recorded to obtain the maximum projected area or the desired projection of each total internal reflection prism.

[0019] The beneficial effects of this invention are as follows:

[0020] (1) The multi-view camera of the present invention is equipped with multiple total reflection prisms. The material in the material placement area forms different side images of the material on the imaging plane of the camera through the multiple total reflection prisms surrounding it; at the same time, the top view of the material is projected into the central area of ​​the imaging plane to form the main image; by using a single camera to simultaneously acquire images of grains from 5 angles, the hardware cost, installation space required, and the difficulty of controlling image acquisition are greatly reduced.

[0021] (2) In the multi-view camera of the present invention, the angle between the first and second mirror surfaces of each total internal reflection prism is α, and 60° < α ≤ 130°. This allows for the concentration of the projection reflected onto the imaging plane within the camera's field of view, resulting in a larger seed area under the same camera field of view and thus a higher resolution projected image. Furthermore, using total internal reflection prisms reduces light loss and absorption compared to plane mirrors, leading to clearer imaging. It should also be noted that the rotation angle of each total internal reflection prism is adjustable. Each total internal reflection prism rotates in steps of angle rdelta, traversing from Rmin to Rmax, and recording all projected areas of each total internal reflection prism to obtain the maximum projected area or the desired projection area of ​​each prism to meet usage requirements. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the total internal reflection prism used inside a multi-view camera according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the arrangement of multiple total internal reflection prisms in a multi-view camera provided in an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram showing the relative state of a single total internal reflection prism in a multi-view camera before adjustment, according to an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram showing the relative state of a single total internal reflection prism in a multi-view camera after adjustment with an object, according to an embodiment of the present invention. Detailed Implementation

[0027] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] It should be noted that when a component is referred to as being "fixed to" or "attached" to another component, it can be located directly or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate orientations or positions based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "Multiple" means two or more, and "several" means any number including one, unless otherwise explicitly specified.

[0029] Please see the appendix Figure 1-4 The purpose of this embodiment is to provide a multi-view camera, including: a camera body, an imaging plane 5 disposed inside the camera body, and a plurality of total internal reflection prisms of the same structural size disposed on one side of the imaging plane 5; the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3 and the fourth total internal reflection prism 4 are arranged to surround a material placement area, and the first mirror surface a1 of the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3 and the fourth total internal reflection prism 4 all face the material placement area; in the initial state, the first total internal reflection prism 1 and the third total internal reflection prism 3 are mirror images of the center of the material placement area, and the second total internal reflection prism 2 and the fourth total internal reflection prism 4 are mirror images of the center of the material placement area; material is placed in the material placement area, and the material forms different side images of the material on the imaging plane 5 through the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3 and the fourth total internal reflection prism 4; at the same time, the central area of ​​the imaging plane 5 also forms the main image of the material.

[0030] The multi-view camera is equipped with multiple total reflection prisms. The material in the material placement area forms different side images of the material on the imaging plane 5 of the camera through the multiple total reflection prisms surrounding it. At the same time, the top view of the material is projected into the central area of ​​the imaging plane 5 to form the main image. By using a single camera to simultaneously acquire images of grains from 5 angles, the hardware cost, installation space required, and the difficulty of controlling image acquisition are greatly reduced.

[0031] The structure of the total internal reflection prism is shown in the attached figure. Figure 1As shown, the reference horizontal line oa1 is a straight line passing through the reference horizontal plane where the total internal reflection prism is installed; the prism vertical line oa3 is a straight line passing through the first mirror surface a1 of the total internal reflection prism; the first prism horizontal line oa2 is a straight line passing through the second mirror surface a2 of the total internal reflection prism; the second prism horizontal line oa4 is another straight line passing through the second mirror surface a2 of the total internal reflection prism; α is the angle between the first prism horizontal line oa2 and the prism vertical line oa3; and β is the angle between the first prism horizontal line oa2 and the reference horizontal line oa1. The side image of the material enters through the first mirror surface a1 of the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4. After reflection inside each total internal reflection prism, it is projected onto the imaging plane 5 through the second mirror surface a2 of the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4.

[0032] In this embodiment, the angle between the first mirror surface a1 and the second mirror surface a2 of the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4 is α, where 60° < α ≤ 130°. This angle setting allows for the concentration of the projection reflected on the imaging plane 5 within the camera's field of view, resulting in a larger seed area within the same camera field of view and thus a higher resolution projected image.

[0033] Furthermore, the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4 are all rotatable. The rotation axes of the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4 are parallel to the horizontal line oa4 of their own second mirror surface a2. The rotation angle of each total internal reflection prism is adjustable. Each total internal reflection prism rotates in increments of angle rdelta, traversing from Rmin to Rmax, and recording all projected areas of each total internal reflection prism to obtain the maximum projected area or the required projection of each total internal reflection prism to meet the usage requirements.

[0034] This invention also provides a method for detecting appearance defects in grain kernels, using a multi-view camera as described in the above embodiments, including:

[0035] S1: Place the grains in the center of the material placement area, and form different side images of the grains on the imaging plane 5 through the first total reflection prism 1, the second total reflection prism 2, the third total reflection prism 3 and the fourth total reflection prism 4; at the same time, form the main image of the grains in the central area of ​​the imaging plane 5.

[0036] S2: Based on the outer contour of the grain, dynamically adjust the relative positions of the first total reflection prism 1, the second total reflection prism 2, the third total reflection prism 3 and the fourth total reflection prism 4 with each side of the grain to obtain the maximum area projection of each side of the grain, so as to obtain the maximum projection of each side of the grain on the imaging plane 5.

[0037] S21: Adjust the first total internal reflection prism 1, the second total internal reflection prism 2, the third total internal reflection prism 3, and the fourth total internal reflection prism 4. The upper and lower limits of the rotation angle adjustment for each total internal reflection prism are Rmax and Rmin, respectively, and the rotation step angle is rdelta. In step angle rdelta, each total internal reflection prism rotates through Rmin to Rmax, and records all the projected areas of each total internal reflection prism to obtain the maximum projected area or the required projection of each total internal reflection prism.

[0038] See appendix Figure 3-4 Taking the outer contour of the current material (grain) as a triangular prism as an example, the angle β between the first prism horizontal line oa2 and the reference horizontal line oa1 of each total internal reflection prism is dynamically adjusted according to the outer contour of the material to obtain the projection of the maximum area of ​​the side of the material, and to obtain the maximum projection in the imaging plane 5.

[0039] The current material's outer contour is a triangular prism shape, and the current total internal reflection prism is... Figure 3 In the neutral orientation, the projection of the material interface b1 onto the total internal reflection prism is b1'. At this point, the area of ​​b1' is less than the actual area of ​​the material's projected surface. The total internal reflection prism module is controlled to rotate at an angular velocity r1 to adjust the prism's orientation, i.e., to adjust the β angle. The upper and lower limits Rmax and Rmin are set according to the material contour and the mechanical dimensions of the motion unit, with a rotation step angle rdelta. Rotation is performed in steps of rdelta, iterating from Rmin to Rmax, recording all projected areas b1', and selecting the largest b1'. (See attached diagram.) Figure 4 At the position shown, the first mirror a1 of the total internal reflection prism is completely parallel to the interface b1 of the material. All the information of the interface b1 is projected into the total internal reflection prism. At this time, b1' is the maximum projected area, and the recorded term is the angle rfind.

[0040] In an optional embodiment, grains fall parabolically into the material placement area above the intersection of two adjacent total reflection prisms (below the imaging plane 5). When the grains do not fall completely vertically as they pass through multiple total reflection prisms, the tilt angles of the multiple total reflection prisms are adjusted in real time according to the tilt state of each grain. Each total reflection prism adjusts its tilt angle individually in real time according to the tilt state of the grain. By traversing and obtaining the maximum projected area of ​​each interface of the grain, the image of the grain can be obtained more clearly and comprehensively.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-view camera, characterized by, Comprise: The camera body is internally provided with an imaging plane (5), one side of the imaging plane (5) is provided with a plurality of full reflection prisms with the same structure size; The first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) in the plurality of full reflection prisms are integrally arranged around the material placement area, and the first mirror surface (a1) of the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) all face the material placement area; In the initial state, the first full reflection prism (1) and the third full reflection prism (3) are mirror arranged about the center of the material placement area, and the second full reflection prism (2) and the fourth full reflection prism (4) are mirror arranged about the center of the material placement area; The material placement area places the material, and the material forms different side images of the material on the imaging plane (5) through the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4); At the same time, the central area of the imaging plane (5) also forms the main image of the material; The included angle between the first mirror surface (a1) and the second mirror surface (a2) of the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) is α, and α=130°; The first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) can rotate, and the rotation axis of the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) is parallel to the second prism horizontal line (oa4) of its own second mirror surface (a2); The side image of the material is entered by the first mirror surface (a1) of the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4), and is projected onto the imaging plane (5) by the second mirror surface (a2) of the first full reflection prism (1), the second full reflection prism (2), the third full reflection prism (3) and the fourth full reflection prism (4) after internal reflection of each full reflection prism; The grain kernel falls into the material placement area through the intersection of the adjacent two full reflection prisms in a parabolic shape, and when the grain kernel falls vertically through the plurality of full reflection prisms, the plurality of full reflection prisms adjust the inclination angle in real time according to the inclination state of each grain kernel, and each full reflection prism adjusts the inclination angle in real time according to the inclination state of the grain kernel, and the maximum projection area of each interface of the grain kernel is obtained through traversal.

2. The multi-view camera of claim 1, wherein, The plurality of full reflection prisms with the same structure size are located below the imaging plane (5), and the central area of the imaging plane (5) forms the main image of the material as the projection of the top view of the material on the imaging plane (5).

3. A method for detecting appearance defects of grain kernels using the multi-view camera according to any one of claims 1-2, characterized in that, Comprise: S1: placing the grain kernel at the center of the material placement area, forming different side images of the grain kernel on the imaging plane (5) through the first total reflection prism (1), the second total reflection prism (2), the third total reflection prism (3) and the fourth total reflection prism (4); Meanwhile, forming the main image of the grain kernel in the central area of the imaging plane (5); S2: dynamically adjusting the relative positions of the first total reflection prism (1), the second total reflection prism (2), the third total reflection prism (3) and the fourth total reflection prism (4) and each side of the grain kernel according to the external contour of the grain kernel, obtaining the maximum area projection of each side of the grain kernel, so as to obtain the maximum projection of each side of the grain kernel on the imaging plane (5).

4. The method of detecting appearance defects of grain kernels according to claim 3, wherein Adjusting the first total reflection prism (1), the second total reflection prism (2), the third total reflection prism (3) and the fourth total reflection prism (4), the upper and lower limits of the rotation angle of each total reflection prism are Rmax and Rmin respectively, and the rotation step angle is rdelta.

5. The method of detecting appearance defects of grain kernels according to claim 4, wherein Stepping by the angle rdelta, each total reflection prism rotates through Rmin to Rmax, and all projection areas of each total reflection prism are recorded to obtain the maximum projection area of each total reflection prism.

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