Underwater De-scattering Range-Gated Imaging Based on Numerical Fitting and Frequency Domain Filtering

Abstract

One of the major challenges of underwater imaging is its sensitivity to water scattering. In this paper, a method of underwater de-scattering range-gated imaging based on numerical fitting and frequency domain filtering is developed to suppress scatter effect and improve image quality. The backscatter noise is eliminated by using its numerical fitting value after measuring a sequence of water scattering maps. The Jaffe-McGlamery computer model and the light propagation property in water are introduced, and forward-scatter noise is reduced by filtering process in the frequency domain. After removing the backscatter and forward-scatter noise, the resolution and contrast of gated images are improved. A range-gated imaging system is established, and experiments are conducted in pools to prove the effectiveness and superiority of the proposed method. Compared with traditional range-gated imaging, the results demonstrate that the proposed method increases the image entropy by about 69%. The research is beneficial for enhancing underwater range-gated active imaging.