Low-Complexity Approximations of the WECS Method for SAR Change Detection

This letter introduces low-complexity approximations for the Wavelet Energy Correlation Screening (WECS) method, which aims at change detection in multitemporal SAR images. The WECS method relies on the non-decimated discrete wavelet transform (ND-DWT) to compute approximation coefficients employed in a feature screening process based on the Pearson correlation. Although effective, WECS presents a high computational cost due to its repeated wavelet filtering stage. To overcome this drawback, we propose two approximations for the wavelet filter coefficients, obtained by truncating their canonical signed digit (CSD) representation, which significantly reduces the number of arithmetic operations. Numerical experiments using both simulated and real-world datasets demonstrate that the proposed methods not only maintain the performance of the original WECS but also achieve computational gains, even outperforming it in certain scenarios.