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A Pixel-by-Pixel Calibration Method for Camera Distortion

A calibration method and camera technology, applied in the field of computer vision, can solve problems such as limited accuracy, and achieve the effect of improving accuracy and calibration accuracy

Active Publication Date: 2021-10-22
杭州先奥科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Because the commonly used distortion model is an approximation of the real distortion relationship of the camera, the accuracy that can be achieved by using this model for calibration is very limited.

Method used

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  • A Pixel-by-Pixel Calibration Method for Camera Distortion
  • A Pixel-by-Pixel Calibration Method for Camera Distortion
  • A Pixel-by-Pixel Calibration Method for Camera Distortion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0056] Such as Figure 6 It is a schematic flow sheet of the inventive method, and the specific method is as follows:

[0057] Prepare the image used for calibration and make a calibration plate from this image. The speckle pattern is generated by formula (4) as the image used for calibration. Set the size of the speckle image to 4000 × 4000 pixels, n=15000, D=60. This parameter setting is not the only solution and can be increased or decreased. The principle is that the areas of the black and white areas of the speckle image are roughly equal. After printing on the surface of the calibration plate and taking pictures with the camera, the details of the speckle can be clearly seen. A black border of 500 pixels width is left around the speckle area, such as figure 2 shown.

[0058] The physical size of the calibration board is determined by the focal length and field of view of the camera being calibrated. The principle of selecting the size of the calibration board is th...

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Abstract

The invention discloses a pixel-by-pixel calibration method for camera distortion. The method is as follows: carry out digital image correlation calculation on the photographed calibration plate picture, the standard calibration plate picture and its mask, and extract control points according to the calculation results, and perform internal and external parameters of the camera The initial estimation of the parameters; the virtual calibration plate and the virtual mask plate are projected onto the image, and the digital image correlation calculation is performed on the projection result and the calibration plate picture, and the mean square error of the non-zero values ​​in the calculated mapping matrix is ​​used as the objective function. The internal parameters and external parameters of the camera are used as optimization variables for optimization calculation; the virtual calibration plate and the virtual mask plate are projected onto the image by using the optimal values ​​of the internal and external parameters of the camera, and the digital image correlation calculation is performed on the projection result and the calibration plate picture, and the calculated The average of the non-zero values ​​of each element in the obtained mapping matrix in each group of mapping matrices is used as the distortion amount of each point to obtain a distortion matrix. This method can significantly improve the accuracy of camera distortion and internal parameter calibration.

Description

technical field [0001] The invention belongs to the technical field of computer vision and relates to a pixel-by-pixel calibration method for camera distortion. Background technique [0002] In binocular vision measurement and 3D reconstruction technology, the accuracy of camera calibration has a decisive impact on the accuracy of measurement, matching and reconstruction. At present, the pinhole imaging model is widely used to calibrate the internal parameters of the camera. For the calibration of distortion, radial and tangential distortion models or other distortion models are used. It is characterized by using high-order equations to approximately describe the distortion at different positions of the imaging plane. [0003] The reason for camera distortion is that a lens is added in front of the camera. The distortion caused by the shape of the lens is called radial distortion. The light is more curved when it is far away from the center of the lens than when it is close ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T7/80G06T5/00
CPCG06T7/80G06T5/80
Inventor 李稚雪程丹丹郑钦洪
Owner 杭州先奥科技有限公司