Research On Underwater Target 3-D Imaging Method Based On Range-gated Laser Imaging Technology

Range-gated laser imaging has great advantages in underwater three-dimensional imaging, because of the mature theory, high engineering degree and good ability to adapt to environments.In this paper, we will reseach on the underwater three-dimensional imaging method based on range-gated laser imaging technology.Underwater imaging methods on an underwater range-gated laser imaging technique for are studied.First of all, laser echo intensity distribution in the imaging scope of range-gated imaging system is simulated and characteristics of the range-gated imaging are analyzed. A new underwater three dimensional imaging method,image matrix division, has been presented. Using the laser echo intensity distribution in the imaging scope,the curve about the distance and the value of elements in new matrix which is the result of image matrix division is simulated. Three-dimension imaging experiments in the air and in the water are designed.Different range-gate parameters have been selected to get the original image, and the original image is analyzed and processed.The three dimensional images of target are obtained by using image matrix division method.The error between three-dimensional images and actual target size is calculated and analyzed.And sources of errors in underwater three-dimensional imaging are discussed, which provides direction to improve the accuracy of underwater three-dimensional imaging.The results of experiments proves that:image matrix division three-dimensional imaging method effectively inhibits adverse impacts caused by differences of target surface materials, water attenuation,the change of the angle between the direction of incident laser pulse and the normal direction of target surface.This method don't need to change the direction of observation,reduces the number of required image acquisition,and simplifies the three-dimensional imaging process.