FPGAs allow you to program logic into a chip for use in an embedded system. Maybe you have an interesting program that would benefit from the additional speed that hardware offers. Wavelet Processing - Wavelets are a fairly new concept, and applications using the wavelet transform are still in early development. One outstanding area is compression, and video compression using wavelets promises to have a significant impact. Other Ideas - You don't need to have a thesis topic fully planned out on the first day.
Many students start with one idea and evolve it over the course of their study.
Others know what interests them, and narrow down their topic after some initial investigation. I think it is important that you find something you enjoy . If you have an idea for a topic or are interested in one of my research areas, feel free to come by and talk to me. Please be as specific as possible.