Image deformation calibration method irrespective with shooting apparatus

Abstract

The invention discloses an image distortion standardization method which is not related to a photo equipment. The method has following steps as: a straight goal line is selected in the image of a photo to be standardized; a starting point A, a midpoint B and an end-point C are respectively selected out on the goal line; the photo coordinates of three pixels (xA, yA), (xB, yB), (xC, yC) are measured, by which a distortion type is calculated. An enough large radius vector delta rb is given to the midpoint B to make the three corrected points A', B' and C' have the opposite distortion type. An assumed image distortion factor is calculated according to the assumed distortion radius vector. According to the assumed image distortion factor, the radius vectors of the three positions A', B' and C' of the three points A, B and C after the distortion is eliminated are calculated. The pixel coordinates of the three positions A', B' and C' after the assumed image distortion is eliminated are calculated. By utilizing a split-middle method, an iterative approach computation is made to get the image distortion factor k1. The method of the invention takes a digital image as a standardization target, breaks away from a camera to calibrate the distortion factor of the digital image (including the historical image and the image in a network transmission, etc.) obtained in various channels.

Description

technical field [0001] The invention relates to an image distortion calibration method, in particular, an image distortion calibration method independent of photographic equipment. This method does not take photographic equipment as the calibration object, but digital images as the calibration object, and is applicable to digital images acquired through any means. It is widely used in computer vision, photogrammetry and other fields. Background technique [0002] Ordinary digital cameras and video cameras are non-measuring cameras. When performing image measurement on ordinary digital images, the distortion of the objective lens directly affects the accuracy of image measurement. The determination of the distortion coefficient of the objective lens becomes the main content of camera calibration. Therefore, in image processing and image measurement, the camera must be calibrated. [0003] At present, camera calibration methods can be divided into two categories. One is opt...

AI Technical Summary

Problems solved by technology

Its disadvantages are: (1) multiple images need to be taken at multiple positions and angles, and the calibration process is relatively complicated; (2) it can only be calibrated separately before or after use, and cannot achieve real-time calibration in the true sense; (3) ) It is impossible to calibrate the objective lens distortion for images without a camera

[0004] It can be seen that the calibration of objective lens distortion must be carried out for the photographic equipment itself. For the diversified images of unknown photographic equipment, it is often impossible to calibrate the distortion of the image due to the inability to understand the photographic equipment, which affects the accuracy of image measurement.

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