Resolution-fusion for LASAR based on DWT

This paper introduces a new resolution-fusion method for linear array 3-D imaging SAR (LASAR). The cross-track (CT) resolution of LASAR is often coarser than that in the along-track (AT) direction, limited by the length of the linear array. To overcome this limitation, we assume that there are two LASAR systems whose trajectories are orthogonal to each other. Thus, we obtain a row-coarse-resolution image and a column-coarse-resolution image of the same scene. According to the multi-resolution theory, we could fuse the row/column-coarse-resolution images into a quasi-fine-resolution image using the discrete wavelet transform. There are two types of distortions in the process of fusion. One distortion is caused by the missing of diagonal high frequency coefficient matrix, and it is unrecoverable. As the coefficient matrix contains the high frequency information, the distortion will increase along with the increase of high frequency component. The other distortion is caused by the difference of scaling functions, and this distortion can be reduced by selecting fitted wavelet basis.