Optimization and Systems Theory Seminar
Tuesday, September 16, 2003, 11.00-12.00, Room 3721, Lindstedtsv. 25

Professor Yutaka Yamamoto
Department of Applied Analysis and Complex Dynamical Systems
Graduate School of Informatics
Kyoto University
Kyoto 606-8501

Signal processing via sampled-data control theory

There has been remarkable progress in sampled-data control theory in the last decade. The main accomplishment here is that there exists a digital (discrete-time) control law that takes the intersampling behavior into account and makes the overall analog (continuous-time) performance optimal, in the sense of H-infinity norm. It has been also recognized that the new method can give rise to a substantial improvement in analog performance. The crux of this theory is in incorporating an analog model for the design of digital controllers.

Digital signal processing also aims at designing a digital controller (filter) for an optimal processing of analog signals. While this has much in common with sampled-data control theory, the primary analog model employed thus far is based on Shannon perfect band-limited assmption.

We observe that this can often lead to a fairly undesirable result, e.g., harsh ringing in CD processing, block and mosquito noise in digital images, and show that sampled-data theory can provide an optimal platform to circumvent such defects. We will give a new design method based on H-infinity sampled-data control theory not based on the perfect band-limited hypothesis. Examples of sound/image processing will be presented to illustrate the advantage of the proposed theory.

Calendar of seminars
Last update: September 1, 2003 by Anders Forsgren, anders.forsgren@math.kth.se.