Design And Algorithm Research Of Binocular Passive Ranging System

Binocular passive ranging technique can be used to calculate the distance of the target according to the parallax in the left and right images,which is based on the principle of stereo vision.It has been widely used in many fields such as intelligent obstacle avoidance,industrial measurement,and aerospace due to non-contact and high concealment.Based on the military field,this thesis designed a long-distance binocular passive ranging system with high precision for the special needs of individual reconnaissance.In addition,the optical axis correction,camera calibration algorithm and image stereo matching algorithm were also investigated.This thesis firstly designs binocular passive ranging system on the whole.It utilized the error propagation law to work out the ranging index and the system parameters that meet the requirements of the index for completing the structural design of the prototype.Secondly,based on analysis of traditional optical axis correction methods and classical camera calibration algorithms,we proposed a novel image-based optical axis correction method.The camera system was calibrated by self-designed calibration plate with large size.Experimental results show that the original information of the target images can be reserved effectively by firstly correction and subsequently calibration.Thirdly,based on the analysis of the advantages and disadvantages of image stereo matching algorithm,we designed Sub-pixel stereo matching algorithm based on multi-scale.Rough matching was firstly achieved by utilizing the region matching algorithm based on optimized search strategy and the matching points of the target are mapped to the pixel level.Then the fine matching was obtained by SURF feature matching algorithm based on PROSAC and the target was mapped to Sub-pixel.It was indicated that the accuracy and speed of stereo matching were improved effectively by the tough to fine matching strategy.Finally,ranging experiment was carried out by binocular passive ranging system with short baseline and error analysis of corresponding experimental results was also performed.It had been verified that binocular passive ranging system designed in this thesis can achieve the range measurement within 2000 meters,and the ranging accuracy can up to 4%,which completely meets the special index of long distance,high precision and real-time speed in the field of military investigation.