This volume contains the proceedings of ICAOS '96 the 12th International Conference on Analysis and Optimization of Systems. This conference was co-organized by INRIA and the CEREMADE and was dedicated to Images, Wavelets and PDE's. The aim of the conference was to discuss the impact on image analysis of recent mathematical developments in multiscale analysis, partial differential equations, variational methods and so on. ICAOS '96 provided a forum for image processing researchers and mathematicians to interact and to exchange their technical knowledge and experience, theoretical or practical, in this emerging and exciting domain. The selected papers have been organized according to the following sessions, each session corresponding to a section of the book: 1. Active Contours; 2. Image Enhancement and Restoration, Scale-Spaces; 3. Wavelets; 4. Image Segmentation; 5. Image Restoration; 6. Coding; 7. Applications.