High Precision Ranging Based On Binocular CCD

According to the status and characteristics of binocular CCD cameras ranging, the subject has been studied depth in this paper. Through analyzing the binocular parallax, the specific requirements of the CCD camera, lens, ranging platform, and other equipments'parameters are proposed for satisfying the requirement of distant range target measurement and high-precision. The binocular CCD camera ranging system has been determined and completed in this paper.Calibrating the camera is the precondition of high-precision binocular measurements, and the camera is calibrated perfectly in experiment. A completely linear approach for camera calibration is presented in this paper, and it improves the Tsai's calibration algorithm. Solving the other internal and external camera parameters based on Radial-Array-Constraints and first-order radial distortion model, which include focal length, first-order radial distortion parameter, rotation matrix and translation vector. Because of the problem in calibration experiments, the original algorithm has been improved. It calibrates the translation component tz, which eliminates the unstable effect for the result and makes the good convergence of the focal length. Experimental data show that the algorithm has high accuracy.The article also achieved high precision sub-pixel matching, and the matching algorithm is the core of high accuracy binocular ranging. By applying the correlative matching algorithm, the fast matching algorithm based on scale transform is presented for overcoming the shortcomings of more complex operations, and it significant saves in time. According to the correlative function obtained in matching, two fitting algorithm are proposed for improving the matching accuracy, so as to achieving sub-pixel level.Measurement results show that the binocular CCD camera ranging system has a high accuracy, and the measurement accuracy better than 0.28% within 3 km distance in the current.