Study on Underwater Image Conversion Algorithm Based on Light Refraction Model

基于光线折射模型的水下图像转换算法研究

¹ School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an, 710072, China
² School of Electronic and Information, Northwestern Polytechnical University, Xi’an, 710072, China

Received: 7 May 2018

Abstract

Aiming at the problem of image distortion caused by light refraction during underwater imaging, and the conversion error caused by existing image conversion algorithms due to neglecting the secondary refraction of light, an underwater image conversion algorithm based on the light refraction model is proposed in this paper. The algorithm firstly obtains the pixel information of the underwater image, then calculates the corresponding coordinate information of the pixel points in the equivalent air image through the mapping relationship, and finally obtains the equivalent air image through image interpolation. Experimental results shows, compared with the existing image conversion algorithms, the proposed algorithm reduces the average error of u direction from 2.289 5 to 1.213 3, which is a decrease of 47.01%. The average error of v direction is reduced from 3.252 5 to 1.526 3, which is a decrease of 53.07%. At the same time, the mean value of ranging error was reduced from 58.83 mm to 28.88 mm, a decrease of 50.91%。

摘要

针对水下目标成像时光线折射所造成的图像失真问题，以及现有图像转换算法因忽略光线二次折射所造成的转换误差，提出一种基于光线折射模型的水下图像转换转算法。该算法首先获取水下图像的像素点信息，通过映射关系计算得到像素点在等效空气图像中的对应坐标信息，从而获得水下目标的等效空气图像。实验结果显示，文中所提算法较之现有图像转换算法，u方向图像转换误差均值由2.289 5降为1.213 3，降低47.01%，v方向图像转换误差均值由3.252 5降为1.526 3，降低53.07%。同时，测距误差均值由58.83 mm降为28.88 mm，降低50.91%。