Sangeun Han and Yi Liang

1
Comparison Study on the Performance of
Critically Sampled Pyramid vs. Over-Complete
Pyramid
2
Overview

• Introduction of multiresolution and pyramid
  coding
• Critically sampled and overcomplete pyramids
• Bit allocation and quantization
• Comparison and results

3
Multiresolution and Pyramid Coding

• Multiresolution offers excellent coding
  efficiency.
• Multiresolution supports scalability.

r0.09, 0.23, 0.60, 1.00 bpp
4
Critically Sampled Pyramid
H1
Q
G1
Q
H1
G1

Input
H0
Recon.
G0

Q
H0
G0
Channel
Octave subband coding
Original Image Decomp. Subbands
5
Oversampled Pyramid
6
Choosing the Filters
7
Bit Allocation

• Analytical form
• Critically sampled, open-loop oversampled
• The greedy algorithm

Close-loop oversampled
where
8
Comparison of Rate-distortion Performance
In general, critically sampled outperforms
oversampled in terms of rate-distortion. Reason
oversampling.
9
Scalability
Critically sampled Overcomplete
PSNR 28.4 dB
PSNR 28.4 dB
PSNR 27.2 dB
PSNR 27.2 dB
PSNR 23.8 dB
PSNR 20.9 dB
PSNR 25.8 dB
PSNR 22.8 dB
10
Number of Layers
Critically sampled Overcomplete
11
Conclusions

• Critically sampled pyramid outperforms the
  over-complete pyramid in terms of
  rate-distortion.
• Coarse images from overcomplete pyramids show
  better subjective quality.
• Other features of overcomplete pyramid lower
  complexity, freedom in choosing filters, control
  of quantization noise.