Design of Linear Phase Cosine Modulated Filter Banks for 
                 Subband Image Compression
       J. E. Odegard, R. A. Gopinath, C. S. Burrus

  Department of Electrical and Computer Engineering -- MS 366
             Rice University, Houston, TX-77251

		        CML-TR94-06
		         Nov 1993


		         ABSTRACT


This paper proposes to investigate a new class of $M$-band linear
phase modulated filter banks. In particular we propose to investigate
different methods for designing the prototype filter based on
perceptual measures such as reduced image artifacts as well as more
traditional measures such as coding gain and mean square
difference. Image compression at low bit rates typically introduces
image artifacts annoying to the human observer. One can classify the
various types of compression artifacts in to three categories:
blurring, blocking and ringing. Each of these artifacts will have a
different visual impression on the observer and typically blurring
will be the most acceptable distortion; blocking and ringing artifacts
tends to cause more visual interference to the observer. Blocking is
typically found in transform coding based algorithms (e.g., the JPEG
standard which is based on the DCT) while ringing is typically found
in subband image coders and is due to the coarse quantization of the
high frequency bins.