A Parameter Calibration Method of the Optical Flow Catadioptric Camera Ranging System with Coaxial Center Distance

Abstract

The invention discloses a method for calibrating parameters of an identical-axis-distance equal-luminous-flux catadioptric camera distance measuring system. According to the method, a central symmetrical axis of a rotary body mirror face is collinear with an optical axis of a perspective camera, a to-be-measured object is arranged below the rotary body mirror face, incidence light is reflected by the mirror face to be imaged by the perspective camera, and the rotary body mirror face has a mirror face profile with equal-luminous-flux characteristic. The method comprises the following steps of establishing a plurality of different simulation environments by adopting the camera distance measuring system, gradually increasing the distance from a to-be-measured object spatial point in each simulation environment to the optical axis, respectively acquiring luminous flux of the to-be-measured object spatial point in each simulation environment on an acquisition image of the perspective camera, and re-fitting the relation between the axis distance and the luminous flux. According to the method, the system is subjected to the parameter calibration, the influence of the processing precision and installation precision on the characteristics of the mirror face can be alleviated under the non-ideal configuration situation of the system, and the distance measuring precision can be improved. Compared with the traditional external parameter calibration method, the method is simpler, more convenient and more effective.

Description

technical field [0001] The invention relates to a parameter calibration method of a ranging system. Specifically, it relates to a method for calibrating the parameters of a coaxial center distance equal optical flow catadioptric camera ranging system. Background technique [0002] At present, omnidirectional cameras commonly used in video surveillance, robot navigation, video conferencing and scene reconstruction are mostly camera ranging systems composed of traditional perspective cameras and reflective mirrors. The use of reflective mirrors makes omnidirectional cameras have large field of view imaging characteristics . According to whether it satisfies the single-viewpoint characteristic, omnidirectional cameras can be divided into single-viewpoint catadioptric cameras and non-single-viewpoint catadioptric cameras. Since the installation of the perspective camera and the mirror surface will be misaligned to a certain extent in practical applications, the non-single-view...

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Problems solved by technology

[0004] The traditional external parameter calibration is to estimate the rotation and translation between the mirror surface and the perspective camera by means of the calibration object; for the optical flow catadioptric camera ranging system with the coaxial center distance, the traditional external parameter calibration method has obvious disadvantages: first , the system is a highly nonlinear system, and the optical flow compensation for the angle installation error needs to be performed for each pixel one by one, and the optimization calculation is very heavy; secondly, the obtained compensation amount is only effective for a certain height, once the system is far from the experimental plane If the distance changes, a new optical flow compensation template is required

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