Research On Optical Wavelet Filter Based On Lifting Scheme

Image compression has very crucial role in the multimedia information technique, the wavelet transform has proven to be a valuable tool in image compression application field during the last decade, and it attracted more and more researchers to study the new theory related to wavelet and its application in image compression.In 1995, Sweldens put forward lifting scheme providing the frame of constructing the second-generation wavelets, later, Daubechies factored the traditional wavelet transform into lifting steps. The advantage of constructing traditional wavelet by lifting scheme is it can generate custom wavelets according to specific requirement. Thus, this thesis constructs the wavelet filter satisfying the optical wavelet image compression system using lifting scheme.Optical wavelet transform perform wavelet transform in optics through spatial filter in frequency domain or projection in spatial domain. It has characteristics of parallelism and real-time. Applying optical wavelet transform into image compression field will improve the speed of compressing image data, which has important role in some application fields which need transmit abundant image data, such as sunspace remote sensing and forest fireproofing.Designing optical wavelet filter is a important part in optical image compression system. These thesis focuses on the research of optical wavelet filter including study the traditional requirements of wavelet filter and analyzing the specific requirements according to its application in optical image compression system.This thesis is Supported by Foundation for University Key Teacher by the Ministry of Education (GG-510-10611-1031) and Applied Basis Foundation?supported by Chongqing Science and Technology Committee (No.7344). The whole thesis consists of five parts:Firstly, the thesis introduces the wavelet theory and its application in image compression field, and discusses deeply the selection and optimization of wavelet bases appling in image compression. these description establish the bases of the following optimization of optical wavelet. The second part paies much importance to lifting scheme, including how to construct traditional wavelets, and reveals the reason of flexibility of using lifting scheme in constructing traditional wavelets. In third part, we construct new wavelet to satisfy the traditional requiremenets of optical wavelet filter, that is to say, we solve how to construct perfect constrcution, linear-phase and biorthogonal wavelets by lifting scheme. Meanwhile, the optimization of the filter is also solved. The specific requirements of optical wavelet filter applying into optical image compression system are discussed in the fourth part, we analyze deeply the aspects of real number representation in wavelet frequency domain and accuracy of optical wavelet filter. Finaly, we design the error measurement system to solve the error problem during fabricate of the optical wavelet filter.