Research On Calibration Technology For Multiple Camera Field Stitching Measuring System

Landing is a key link of flight safety, aircraft need exterior trajectory measurement equipment to assist it landing safely in the process of landing, and it is first to get the aircraft's location parameter. Vision-based measurement method is more and more applied in aerospace, weapon development and test recently. Because of high speed and long range capabilities, the visual field of vision-based measurement equipment should cover the aircraft's moving spaces, the traditional double CCD cameras system already can't meet the demands. Thus, use measuring system based on multiple camera by field stitching to observe the whole motion and measure the whole range of landing has important application value.Camera calibration is one of the important subject of Computer Vision, and it is also the basis and key step of kinds of vision-based measurement. This paper mainly studies calibration technology for multiple camera measuring system, a two step method combined with calibration in advance and in-situ is proposed. The experimental evidence obtained has shown that the method is correct and effective, which has high accuracy and satisfies the requirements of the measurement.The key work of the paper includes:1. The structural characteristics of multiple camera measuring system is researched, the model of vision-based measuring system is also build, and the accuracy influence factors are analyzed, which has some meaning for the structural arrangement of vision-based measuring system.2. Problem of camera focusing and depth of field is introduced, and characteristics of field depth of each camera which constitute the multiple camera measuring system is also researched.3. The dissertation mainly studies calibration technology for large field and long range imaging system, and give the experimental verification of single camera using suggested method. Also a camera calibration method based on angle is investigated and simulation experimental verification is given.4. Pose between cameras is derived in this paper, and reference camera coordinate system is established. The relationship between each camera and reference camera is calibrated in advance while the experimental environment is in a better situation, then the reference camera's external parameter is calibrated by proper cooperative markers in measuring field, furthermore all camera's external parameter is obtained, which effectively overcome the limitation of multiple cameras' calibration in field.5. According to each camera's physical parameters in measuring system, camera's field range is calculated, then calibration targets and calibration scheme are designed, and then the calibration work of measuring system is completed using the camera calibration method on the previous study and the solving method of multiple camera's relationship, the verification implementation in field proves that this method is feasible and meets request of precision.