Side-scan sonar image gray scale equalization method and system

Abstract

The invention discloses a side-scan sonar image gray scale equalization method and system. The method comprises the following steps: geocoding track line data and a side-scan sonar waterfall plot to obtain a side-scan sonar image; dividing each side-scan sonar survey line image with geographic coordinates in the side-scan sonar images into a plurality of path buffer areas, wherein the pixel pointslocated in the same path buffer area are located on the same side of the track line, and the distance between the pixel points and the track line is within a preset range; extracting gray scale features of each path buffer area, and performing gray scale equalization on pixel points in the path buffer areas according to the gray scale features; and performing gap interpolation and image inlayingon all the equalized side-scan sonar survey line images with the geographic coordinates to obtain an equalized side-scan sonar image. According to the invention, gray scale equalization processing iscarried out on the side-scan sonar image after geocoding, the imaging quality of the side-scan sonar can be improved, and the subsequent image interpretation or automatic classification precision is further improved.

Description

technical field [0001] The invention relates to the technical field of underwater geomorphology measurement, in particular to a method and system for equalizing gray levels of side-scan sonar images. Background technique [0002] Side Scan Sonar (SSS), also known as "Side Scan Sonar", is a geophysical survey technology that realizes submarine landform imaging. The side-scan sonar emits a beam fan to the seabed through oblique incidence, and performs seabed imaging by recording the arrival time and intensity of the echo signal. [0003] The side-scan sonar transducer continuously emits acoustic signals and records the received acoustic signals in time sequence, and displays the received signal corresponding to each emission as a row of pixels according to a specific color mapping rule, which is called a "scan line". As the side-scan sonar moves along the course, these pixels are arranged row by row, and the resulting image is called a "waterfall image." Such as figure 1 As...

AI Technical Summary

Problems solved by technology

The gain correction method at the signal level is based on the physical model of sound wave propagation in water, which is the basis for gray level equalization correction, but the image forming effect is often difficult to meet expectations; the gray histogram normalization method at the waterfall level is based on a continuous measurement signal. Statistical features. Compared with the first method, this method has a certain improvement in the mapping effect, but because each pixel of the waterfall image does not directly contain spatial coordinate information, it is only suitable for grayscale correction of local images. The side-scan sonar Image quality still needs to be improved

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