The invention discloses a polarization SAR
image compression method based on multi-direction
dictionary learning. The method mainly solves the problem that the quality of an image compressed and reconstructed through the existing technology is low. The method includes the implementation steps of firstly, inputting a set of polarization SAR four-channel images, and conducting asymmetrical three-dimensional
wavelet transform; secondly, conducting sparse representation on coefficient matrixes, in different directions, of high-frequency sub-bands under different scales of all the channels after the
discrete wavelet transform is conducted so as to obtain all sparse matrixes; thirdly, conducting quantizing and coding on the coefficient matrixes of all low-frequency sub-bands after the
discrete wavelet transform is conducted to obtain low-
frequency code streams; fourthly, conducting unified quantizing and coding on the sparse matrixes in different scales and different directions so as to obtain high-
frequency code streams; fifthly, forming final code streams through the low-
frequency code streams and the high-frequency code streams. By means of the method, redundancy between the channels can be effectively eliminated, the marginal information and contour information of images are better preserved, the quality of a compressed and reconstructed image is improved, and the method can be used for transmitting and storing polarization SAR images.