Thursday, November 15, Volen 101, 2:00-3.00 pm
Grayscale signals can be represented as sequences of integer-valued symbols. If such a symbol has alphabet {0,1,...,2^B-1} it can be represented by B binary digits. To embed information in these sequences, we are allowed to distort the symbols. The distortion measure that we consider here is squared error. The embedded message must be recoverable with error probability zero.
In this setup there is a so-called "rate-distortion function" that tells
us what the largest embedding rate is, given a certain distortion
level. First we determine this rate-distortion function. Then
embedding codes are proposed based on
(i) ternary Hamming codes and on the
(ii) ternary Golay code.
We show that all these codes are optimal in the sense that they
achieve the largest rate at a given distortion level for fixed
blocklength.
This is joint work with Frans Willems (Eindhoven University of Technology and Philips Research).
Host: Marty Cohn