Research On Image Mosaic Of CE-3Panoramic Camera

The second phase of lunar exploration project will achieve landing of China’sfirst extraterrestrial objects. As one of landing detectors, panoramic camera willcomplete survey of lunar topography and geological structure. An important missionis to get panoramic images of the lunar surface. We carry out research on imagemosaic of CE-3camera. The main contents include: elements of interior orientationcalibration of panoramic camera, image distortion correction, image mosaictechnology of panoramic camera.To begin with, the ideal imaging model and interior parameters model areintroduced, moreover, linear calibration method of non-linear model is analyzed.According to the requirement of calibration method, we design the experiment ofcamera calibration. Combined with the target images, the interior parameters anddistortion parameters are obtained by programming. Simultaneously, we also verifythe interior parameters of CE-3camera.Second, we introduce the camera distortion model, also the amount of distortiondiagram of panoramic camera is given. Combined with image distortion correctionmethod based on the interior parameters, we correct the image distortion. Due to thesmall amount of distortion of panoramic camera, validation of distortion correctionmethod is only for discussion.In the end, we select the method of image mosaic based on Scale InvariantFeature Transform (SIFT) algorithm as the image mosaic algorithm. The method ofextracting SIFT feature points is described in detail. To resolve the mismatchingproblem in image registration，an improved feature matching principle based onvector similarity is proposed and it is compared with the conventional matchingmethod. Also, we explain the reason for improvement of matching accuracy. Theinitial image transformation matrix is solved by RANSAC algorithm and the initialmatrix is refined by L-M algorithm. In the part of image fusion, we improve the gray difference between two images by using the curve fitting method and the seambetween two images is eliminated by adopting the weighted fusion method. Frame tomosaic image synthesis method is applied for image mosaic. We get panoramicimages based on image acquisition experiment. It can be say that the CE-3panoramiccamera is equipped with the capability of panoramic imaging.