Research On Key Technology Of Underwater Laser Imaging

Underwater laser imaging technology is one of the new kind advanced detection technologies, which has great applicative anticipation in the domain of martial spy. exploration of sea resource and defense of key objects. Many developed countries attach importance to researching and developing this detection technology at present. But because it involves a lot of technologies such as high power and repetition rate miniaturization laser technique, gated imaging, noise reduction, graphics processing technique and so on, a lot of difficulty should be conquered on the correlative theory study and system design. In this paper, deeply theoretical and experimental research was done, and the mainly research work and achievement are as follows:1. A theoretical model of laser underwater imaging system was established. The analytical expressions of the target echo signal power and the back-scattering and forward-scattering power were given. And some important result for the system design was got.2. The sea wave’s effect on underwater imaging system was studied, and the recovery and evaluating model of target image distortion resulting from sea wave was prompted, which can realize the purpose of wiping off the image distortion.3. Using software, the simulation of underwater imaging system theory and image distortion resulting from sea wave were done, and the changing discipline of the target echo signal power, system signal noise ratio and the maximum system detectable water depth was got, also the recovery image distortion simulation was given.4. A laser underwater target range-gated imaging system was built along with other colleague in the group, and experimental study of attenuation coefficient of water, laser initial power, water depth, sea wave, and other factors’effect on the imaging system was carried out. Experimental results showed that the largest target recognition depth is six times water attenuation length and in eight times water attenuation length target can be found.5. The basic principle of the laser underwater streak tube scan imaging technology was initially studied, and a laser underwater streak tube imaging experimental system was built along with other colleague in the group. The experimental research results were similar to the range-gated imaging system.