Line structure cursor positioning method based on chessboard target

Abstract

The invention discloses a line structure cursor positioning method based on a chessboard target, which comprises the following steps: calibrating a camera to obtain a distortion coefficient D of an internal parameter matrix of the camera, a rotation matrix Rcw of external parameters of the camera and a translation vector Tcw; eliminating camera distortion of the obtained light bar image; extracting a characteristic point Q' of the light bar center on the image from which the camera distortion is removed, and obtaining a homogeneous coordinate (u,v,1)-1 of the point under a pixel coordinate system; calculating the coordinates of a projection point Q" of the Q projected on a normalized image plane under the camera coordinate system according to the coordinates (u,v,1)-1 of the characteristicpoint Q' under the pixel coordinate system; connecting two points between the projection point Q" and the original point into a straight line to obtain a straight line equation under the camera coordinate system; calculating the coordinates of the characteristic point Q under the camera coordinate system by using simultaneous plane equation and linear equation: obtaining coordinates of all characteristic points on the light bar under the camera coordinate system; and fitting the light plane equation by using the obtained characteristic point coordinates. According to the method, all the characteristic points on the light bar can be extracted at the same time, and all the characteristic points on the light bar are calibrated.

Description

technical field [0001] The invention belongs to the field of non-contact measurement, in particular to a line-structured cursor calibration method suitable for simple calibration on site. Background technique [0002] Non-contact measurement is an important research direction in the field of machine vision research. It is a sensor based on acoustics, optics, waves and other related principles to obtain three-dimensional information of the measured object. Its advantages are minimal impact on the measured object, ease of automation, less requirements on the working environment and shorter measurement cycles. Non-contact measurement mainly includes: infrared measurement, ultrasonic measurement, multi-camera measurement and structured light measurement. Structured light measurement has been widely used in the fields of 3D model reconstruction and object shape measurement due to its advantages of high measurement density, fast speed, high measurement accuracy and the ability to...

AI Technical Summary

Problems solved by technology

However, the calibration method based on the principle of cross-ratio invariance needs to intersect the light strip projected by the line structured light with the chessboard on the chessboard target, which is not conducive to extracting the corner points of the chessboard and the center point of the light strip, and at the same time extracts fewer feature points

while solving for the light plane The matrix calibration method needs to combine three plane equations to calculate the matrix, the calculation is more complicated

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