Adaptive patch projection for the generation of orthophotos from satellite images

In this paper, we describe an "Adaptive Patch Projection" scheme that can accelerate the orthorectification for satellite images without losing accuracy. The proposed scheme is comprised of two major components: (a) orbit modeling, and (b) image orthorectification. In orbit modeling, we provide a collocation procedure to determine the precise orbits. In image orthorectification, the area of interest is sequentially subdivided into four quadrate tiles until a specified threshold for terrain variations is met. The threshold of maximum terrain variation in a tile will be optimized according to the computational efficiency and the accuracy requirements. Once the ground tiles are determined, we perform adaptive patch projection to the corresponding image pixels. Test images from SPOT5 Supermode and QuickBird satellites are included. The experimental results show that this algorithm can minimize the orthorectification computation time, while the modeling error is insignificant.