Sampling Theory for Optimal Signal Reconstruction and Application to White-Light Interferometry

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• Dr Akira Hirabayashi, Department of Information Science and Engineering, Yamaguchi University, Japan
• Monday 09 November 2009, 14:00-15:00
• Gabor Seminar Room, 611.

If you have a question about this talk, please contact Danilo Mandic.

Sampling theory is at the interface of analog/digital conversion and therefore universal in modern technology. Its goal is to perfectly reconstruct an underlying signal. Since the perfect reconstruction is possible only in certain situations, however, to reconstruct an optimal approximation under some criteria has been considered as a relaxed goal. A popular criterion is consistency: if the reconstruction is measured using the same sampling functions, then the measurements will be equal to the original ones. This criterion has been discussed for critical or over-sampling situations. In this talk, however, we will focus on how to deal with under-sampling situations, which we may encounter in real applications such as image magnification. Multi-channel sampling with unknown offsets will also be discussed from the approximation point of view. As an application of sampling theory, we will talk about white-light interferometry, which is an elegant technique to measure surface topology of objects such as semiconductors or liquid crystal displays (LCDs). The main task in this technique is to detect the peak of a white-light interferogram from its sampled values. We proposed the world fastest profiling algorithm using the so-called quadrature sampling technique. We will briefly review the algorithm and discuss possibilities of even faster algorithms.

Dr. Akira Hirabayashi received the B.E., M.E., and D.E. degrees in Computer Science in 1993, 1995, and 1999, respectively, from the Tokyo Institute of Technology, Tokyo, Japan. From 1995 to 2000, he was a research associate of the Graduate School of Information Science and Engineering, Tokyo Institute of Technology. He is now an associate professor of the Department of Information Science and Engineering, Yamaguchi University, Japan. From 2004 to 2005, he was a visiting scholar at the Biomedical Imaging Group, EPFL , Switzerland. He is now staying at the CSP group in Imperial College London for collaboration with Dr. Pier Luigi Dragotti until February 2010. His research interests include sampling theory, image processing, and optical measurement. Dr. Hirabayashi is a member of IEEE , the Institute of Electrical, Information, and Communication Engineers(IEICE) Japan, and the Society of Instrument and Control Engineers (SICE) Japan.

This talk is part of the COMMSP Seminar series.

This talk is included in these lists:

• COMMSP & CP list
• COMMSP Seminar
• Gabor Seminar Room, 611
• SAP Talks

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