Pseudo-color processing of forward looking sonar image: An adaptive hot metal coding algorithm

摘要

According to the features of forward looking sonar image, an adaptive hot metal coding algorithm with maximum entropy threshold (AH-M) is proposed to complete pseudo-color processing in forward looking sonar image. Specifically, the parabolic eight-point interpolation is used to interpolate the beams and the sampling points. Meanwhile, the backward mapping coordinate transformation is adopted to generate forward looking sonar image. On this basis, a new hot metal coding algorithm is proposed to complete pseudo-color processing. In order to perform pseudo-color processing according to the features of forward looking sonar image, the node values of the hot metal coding are selected adaptively by the maximum entropy threshold method. The experimental results demonstrate that the proposed AH-M can eliminate mosaic phenomenon and get detail-prominent sonar images. And it can get rich and distinct colors in generated sonar images with relatively fast speed.