Optical Implementation For The Wavelet Transform Of Image

The widely application of traditional wavelet transform in the image data compression is limited due to its high computation amount. Optical wavelet transform combines the advantage of both optical information processing and wavelet transform, so it is an effective approach to implement image data compression with its advantages in physical nature, such as parallelism, high-speed and high-capacity, etc.. But the precision of optical wavelet transform system is not high enough till now. The high resolution image data compression can be implemented in optical way only if the precision can be improved greatly.The main obstacle for the application of the optical wavelet transform to image data compression is the processing precision of the optical system. In this paper, the fundamental theory and trend of the development of the optical information processing and the wavelet transform are introduced in detail. Based on the previous work of the team, the configuration of the optical wavlet transform system is presented. The factors that lead to the lowering of the precision of the system are analyzed and the corresponding high-precision locating methods are proposed accordingly. Then the optimized experiment system is built and experiments are done based on the proposed integrated adjusting process for the system. The experiment results illustrated the good performace of the system. Taking peak-to-peak signal to noise ratio (PSNR) as the criterion for imaging quality, the average PSNR reached 24dB with 10 common images revolved in the experiments. The systematic experiment results have been applied to image data compression successfully by other team members. On the other hand, the multi-channel optical wavelet transform system is also studied in this thesis. Verification experiments are designed based on the experiment equipments in the laboratory. Then the experiment results which demonstrated the feasibility of the design are presented.Both the single-scale system and the multi-channel system are coherent light proceesing system illuminated by monochromatic light. They are interfered by the problem of coherent noise significantly. So the way to suppress the coherent optical noise deserves studying to improve the precision of the system.