A combined fine-tuning camera calibration target

Abstract

The present invention discloses a combined fine-tuning camera calibration target, comprising a first calibration plate, a second calibration plate, a third calibration plate, an outer frame and a light-emitting plate, wherein the first calibration plate, the second calibration plate and the third calibration plate have the same structure and are provided with a plurality of black and white grids, wherein the white grids are light-transmissive and the black grids are light-impermeable, a light source is installed on the light-emitting plate, the first calibration plate is embedded in the front position of the outer frame, the light-emitting plate is embedded in the rear position of the outer frame, the second calibration plate can be slid left and right inside the outer frame and is located at the rear position of the first calibration plate, and the beneficial effects are as follows: during the calibration process, it is not necessary to frequently change the position of the calibration target, a controller is connected to a lead screw to enable precise fine-tuning of the calibration target, the size of the target image can be changed, and the calibration result can be made more accurate; the calibration plate can be supplemented with light through an LED light source board on a back plate, and the calibration accuracy can be improved in an environment with insufficient light conditions to achieve basic calibration tasks.

Description

Technical Field

[0001] The invention belongs to the technical field of robots, and in particular relates to a combined fine-tuning camera calibration target. Background Art

[0002] Calibration targets are used in machine vision, image measurement, photogrammetry, 3D reconstruction and other applications to correct camera lens distortion and determine the conversion relationship between physical size and pixels. By shooting a flat plate with a fixed-pitch pattern array with a camera, the geometric model of the camera can be obtained through calculation of the calibration algorithm, thereby obtaining high-precision measurement and reconstruction results. The flat plate with a fixed-pitch pattern array is the calibration target.

[0003] In the image measurement process and machine vision applications, in order to determine the relationship between the three-dimensional geometric position of a point on the surface of a spatial object and its corresponding point in the image, it is necessary to establish a geometric model of camera imaging. These geometric model parameters are camera parameters. Under most conditions, these parameters must be obtained through experiments and calculations. The process of solving the parameters is called camera calibration or camera calibration. Whether in image measurement or machine vision applications, the calibration of camera parameters is a very critical link. The accuracy of the calibration results and the stability of the algorithm directly affect the accuracy of the results produced by the camera. Therefore, improving the accuracy of camera calibration is the current focus of camera calibration.

[0004] The currently widely used calibration targets of chess black and white square patterns or solid circle array patterns usually use one target to move multiple times or arrange multiple targets to obtain multiple sets of experimental data. On the one hand, this calibration target increases the workload of the experimenter and cannot meet the basic calibration tasks at night with poor visibility and in dusty weather. Although the calibration accuracy can be improved by adding light sources for supplementary lighting, the light requirements for supplementary lighting are very high, which will increase manpower and financial costs and cause unnecessary waste. On the other hand, there are defects in calibration speed and accuracy, and it cannot meet the application scenarios of fast calibration and high calibration accuracy. Summary of the invention

[0005] In view of the problems in the prior art, a combined fine-tuning camera calibration target is provided.

[0006] A combined fine-tuning camera calibration target comprises a first calibration plate, a second calibration plate, a third calibration plate, an outer frame and a light-emitting plate, wherein the first calibration plate, the second calibration plate and the third calibration plate have the same structure and have a plurality of black and white grids, wherein the white grids are light-permeable and the black grids are light-impermeable, a light source is mounted on the light-emitting plate, the first calibration plate is embedded in the front position of the outer frame, the light-emitting plate is embedded in the rear position of the outer frame, the second calibration plate is slidably arranged inside the outer frame left and right and is located at the rear position of the first calibration plate, and the third calibration plate is slidably arranged inside the outer frame up and down and is located in the middle position of the second calibration plate and the light-emitting plate.

[0007] On the basis of the above scheme, the combined fine-tuning camera calibration target has a left and right adjustment screw rotatably arranged horizontally inside the outer frame, the left and right adjustment screw is driven to rotate by a first motor installed on the outer frame, and the second calibration plate is equipped with left and right adjustment nuts, which are meshed and transmission-connected with the left and right adjustment screw.

[0008] On the basis of the above scheme, the combined fine-tuning camera calibration target has an up and down adjustment screw rotatably arranged vertically inside the outer frame, the up and down adjustment screw is driven to rotate by a second motor installed on the outer frame, and an up and down adjustment nut is installed on the third calibration plate, and the up and down adjustment nut is meshed and transmission-connected with the up and down adjustment screw.

[0009] Preferably, the first motor and the second motor are stepper motors, which are electrically connected to a remote controller to achieve remote control.

[0010] Preferably, the target for calibration of the combined fine-tuning camera has a magnetic strip installed inside the outer frame, which fixes the first calibration plate and the light-emitting plate by magnets, making replacement and maintenance convenient.

[0011] Preferably, the combined fine-tuning camera calibration target has a light-emitting diode installed on the light-emitting board, which can adjust the brightness of the light.

[0012] Beneficial effects of the present invention:

[0013] 1. During the calibration experiment, there is no need to frequently change the position of the calibration target. The controller is connected to the lead screw to make precise fine adjustments to the calibration target, which can change the size of the target image and make the calibration result more accurate.

[0014] 2. The calibration board can be supplemented with light through the LED light source board on the back panel, which can improve the calibration accuracy in an environment with insufficient light conditions to achieve basic calibration tasks;

[0015] 3. The translation and vertical movement of the calibration plate and the control of the diode light source can be controlled by the remote controller, which can improve work efficiency and reduce work costs;

[0016] 4. The inner wall of the calibration target outer frame is a magnetic inner wall, which is easy to disassemble the calibration target and the diode light-emitting board.

[0017] Figure 1 A schematic diagram of a calibration plate according to an embodiment of the present invention;

[0018] Figure 2 It is a schematic diagram of the outer frame of an embodiment of the present invention;

[0019] Figure 3 FIG. 1 is a schematic diagram of a light-emitting panel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0021] like Figure 1 , 2 As shown in , 3, a combined fine-tuning camera calibration target includes a first calibration plate 1, a second calibration plate, a third calibration plate, an outer frame 2 and a light-emitting plate 3,

[0022] The first calibration plate 1, the second calibration plate and the third calibration plate have the same structure, and have black and white grids like a chessboard, wherein the white grids are light-transmissive and the black grids are light-impermeable.

[0023] The light emitting board 3 is provided with a light emitting diode, and the brightness of the light can be adjusted;

[0024] The first calibration plate 1 is embedded in the front side of the outer frame 2, and the light-emitting plate 3 is embedded in the rear side of the outer frame 2.

[0025] The second calibration plate is slidably disposed inside the outer frame 2 and is located at the rear side of the first calibration plate 1.

[0026] The third calibration plate is slidably disposed inside the outer frame 2 and is located in the middle of the second calibration plate and the light-emitting plate 3 .

[0027] A left and right adjusting screw is rotatably arranged horizontally inside the outer frame 2, and the left and right adjusting screw is driven to rotate by a first motor installed on the outer frame 2. A left and right adjusting nut is installed on the second calibration plate, and the left and right adjusting nut is meshed and transmission-connected with the left and right adjusting screw.

[0028] An up and down adjusting screw is rotatably arranged vertically inside the outer frame 2, and the up and down adjusting screw is driven to rotate by a second motor installed on the outer frame 2. An up and down adjusting nut is installed on the third calibration plate, and the up and down adjusting nut is meshed and transmission-connected with the up and down adjusting screw.

[0029] The first motor and the second motor are stepper motors, which are electrically connected to the remote controller to achieve remote control.

[0030] A magnetic strip is installed inside the outer frame 2 to fix the first calibration board 1 and the light-emitting board 3 by magnets, so as to facilitate replacement and maintenance.

[0031] Principle description: The first calibration plate 1 is fixed, the light-emitting plate 3 can be controlled by a remote controller to emit light of different brightness, and the second and third calibration plates are driven by precise lead screws to adjust left and right or up and down. Through the principle of projection, the opaque black areas of the second and third calibration plates block the translucent white areas of the first calibration plate 1, adjust the size of the controllable target image, and form a target of a new size, thereby improving the accuracy of camera calibration.

[0032] The size of the black and white grid image on the calibration board can be adjusted by the remote controller, thereby improving the camera calibration accuracy. The back layer of the calibration board is a diode light-emitting board 3 with adjustable brightness, which can be manually adjusted to cope with various complex environments. Fine-tuning is performed through a precise screw mechanism, and the screw is adjusted by a remote controller, with high operating accuracy and remote adjustment. The outer frame of the calibration target is a magnetic inner wall, which is easy to disassemble the calibration target and the diode light-emitting board.

[0033] It is to be understood that although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A combined fine-tuning camera calibration target, characterized in that: It comprises a first calibration plate (1), a second calibration plate, Three calibration plates, outer frame (2) and light-emitting plate (3), The first calibration plate (1), the second calibration plate and the third calibration plate have the same structure and have a plurality of black and white grids, wherein the white grids are light-transmissive and the black grids are light-impermeable. A light source is mounted on the light emitting panel (3). The first calibration plate (1) is embedded in the front side of the outer frame (2), and the light-emitting plate (3) is embedded in the rear side of the outer frame (2). The second calibration plate is slidably arranged inside the outer frame (2) and is located at the rear side of the first calibration plate (1). The third calibration plate is slidably arranged inside the outer frame (2) and is located in the middle of the second calibration plate and the light-emitting plate (3); A left and right adjustment screw is rotatably arranged horizontally inside the outer frame (2), the left and right adjustment screw is driven to rotate by a first motor installed on the outer frame (2), and a left and right adjustment nut is installed on the second calibration plate, and the left and right adjustment nut is meshed and transmission-connected with the left and right adjustment screw; An up-and-down adjusting screw is rotatably arranged vertically inside the outer frame (2), the up-and-down adjusting screw is driven to rotate by a second motor installed on the outer frame (2), an up-and-down adjusting nut is installed on the third calibration plate, and the up-and-down adjusting nut is meshed and transmission-connected with the up-and-down adjusting screw; The first motor and the second motor are stepper motors, which are electrically connected to the remote controller to achieve remote control.

2. The combined fine-tuning camera calibration target according to claim 1, characterized in that: A magnetic strip is installed inside the outer frame (2) to fix the first calibration plate (1) and the light-emitting plate (3) by magnetic attraction, so as to facilitate replacement and maintenance.

3. The combined fine-tuning camera calibration target according to claim 1, characterized in that: The light source on the light-emitting panel (3) is a light-emitting diode, and the brightness of the light can be adjusted.

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