Abstract：Researchers generally consider that Ratio Of Exponentially Weighted Averages (ROEWA) can not calculate the edge directions of SAR images. Therefore, some directional filters are used to add directions to ROEWA. In this paper, an Enhanced ROEWA (EROEWA) algorithm is proposed. Through the further derivation of the ROEWA algorithm convolution process, the pixel-level observation formula of ROEWA algorithm is obtained. First, a new convolution strategy is used to decouple the ROEWA formula to obtain exponentially weighted averages over the four directions. Second, the SAR images are rotated by 45° and exponentially weighted averages of the four additional directions are calculated. Finally, exponentially weighted averages of eight directions are expressed as eight vectors, and edge intensity and direction are solved by vector synthesis. Experimental results show that the EROEWA has a significant enhancement effect on the edge intensity and the direction.
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