A Calculation Method of Homography Matrix h for Single Line Array Camera

Abstract

A homography matrix H computing method of a single line array camera applies a cross-ratio invariance principle and given four line calibration plates, wherein four lines meet the following rules (shown in the description), a (x, y, z) coordinate on a D4 line is calculated according to a line array camera imaging characteristic, the cross ratio of four collinear points in an image plane and application of the cross-ratio invariance, and a homography matrix H is further calculated.

Description

technical field [0001] The invention belongs to the field of camera calibration and relates to a calculation method of a homography matrix H from a target point to an imaging point of a single line array camera. Background technique [0002] Camera calibration is to determine the relationship between the three-dimensional geometric position of a point on the surface of a space object and its corresponding point in the image. Based on the established geometric model of camera imaging, the parameter model of the camera is solved from the image coordinates and world coordinates of known feature points. Camera calibration is a very critical link, the accuracy of the calibration results and the stability of the algorithm will directly affect the accuracy of the camera work results. Therefore, improving the camera calibration accuracy is the focus of camera calibration. [0003] An important step is the homography matrix H from the target point to the imaging point. To obtain t...

AI Technical Summary

Problems solved by technology

The checkerboard calibration board can easily obtain the coordinates of the target point. To obtain the accurate coordinates of the imaging point, a relatively uniform motion between the single line array camera and the calibration board is required, which increases the complexity of the system.

Using a circular calibration plate, if the speed of the relative uniform motion between the single-line array camera and the calibration plate is not set properly, the circle on the imaging plane obtained will be deformed, and the center of the circle cannot be effectively calculated, and thus the exact coordinates of the imaging point cannot be obtained

The equidistant fringe calibration plate can quickly get the x-axis or y-axis value of the target point and imaging point, but cannot get the value of the other coordinate axis

[0004] In summary, the current calculation method of the homography matrix H from the target point to the imaging point of the single-line array camera still has some shortcomings: the relatively uniform motion between the single-line array camera and the calibration plate makes it difficult to set the speed.

The relative non-uniform motion between the camera and the calibration plate makes it impossible to calculate the homography matrix H

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