Research On The High Precision Calibration Of Zoom Camera And Mapping Accuracy

At present, loading cameras of all rovers including the lunar rover are fixed focus camera in the field of deep space exploration. Adopting fixed focus camera is unable to dynamically adjust or focus on a object, besides, the mapping accuracy, the range and resolution of generated orthoimage are all limited. Zoom camera has unparalleled advantage of dynamically zooming view and focusing on specific goals compared with fixed focus camera. Additionally, it can extremely obtain large amounts of elaborate image data and 3D information. However, there are few applications of zoom camera in the fields of photogrammetry and deep space exploration, due to the difficulty of high precision calibration of zoom camera. Therefore, implementing the high precision calibration of zoom camera has important scientific significance, which is both frontier topic in the field of photogrammetry and computer vision fields and the needs of future application of new generation of deep space detection technology.This paper mainly focused on the geometric model of zoom camera. We completed the high precision calibration of zoom camera and analyzed the application of zoom camera in the fields of 3D reconstruction and mapping. The main contents include:(1)Zoom camera high precision calibration method is studied in this paper. The change of zoom camera principal distance can be simplified into the combined effect of zoom change and focus change. The change of principal distance can cause the change of interior orientation elements. It is very difficult and unrealistic to calibrate at every time change of interior orientation elements In order to obtain interior orientation elements of zoom camera at arbitrary principal distance quickly and real-timely, This paper carries on geometric modeling of zoom camera. The dynamic calibration of zoom camera under arbitrary principal distance is realized.In addition,the relative position modeling and calibration of fixed-zoom stereo camera is finished.(2)This paper conducted a feasibility study of 3D reconstruction for monocular zoom camera,concluding that 3D reconstruction base on monocular zoom camera is infeasible,but research on ultra high precision matching method will implement the application of target depth estimation base on monocular zoom camera.(3) The paper analyzed the mapping accuracy of fixed-zoom stereo camera. The paper deduced the mapping error formula for stereo camera with different focal lengths.This paper experimentally and theoretically compared the mapping accuracy of fixed-focus stereo camera and fixed-zoom stereo camera, concluding that in most ranges when the principal distance of zoom camera is greater than that of fixed-focus camera, the mapping accuracy of fixed focus-zoom stereo camera is higher. The results could make a contribution to the mapping accuracy and scientific exploration for a new generation of deep space rover.