1. Image coding/compression
EE5364 DSP Project
Pradeep Suthram, David Hemmert, Tammo Heeren
All Mathcad files [MCD/PDF] can be found on:

2. Overview Quantization Compression Linear quantization
Adaptive quantization
Compression
DCT
JPEG
Wavelet

3. Linear Quantization
Image intensities are quantized into equidistant quantization steps [Mathcad 2001 File]

4. Linear Quantization results
1 Bit
8 Bit

5. Linear Quantization error

6. Linear Quantization SNR
6.2dB per grayscale bit

7. Adaptive Quantization
Quantization steps are scaled by the characteristic image probability density function [Mathcad 2001 File]

8. Adaptive Quantization results
Linear quantization

9. Adaptive Quantization error (adaptive vs. linear)

10. Adaptive Quantization SNR
5.6dB per grayscale bit for adaptive quantization [red]
6.2dB per grayscale bit for linear quantization [blue]

11. JPEG Algorithm Lenna BMP file used
8x8 pixel block
DCT
Level-shift
Quantizer
Encoder
Data
Lenna BMP file used
Gray scale image level-shifted by –128
for n = 8, 2^(n-1) = 128

12. using a typical normalization matrix
JPEG Algorithm
Quantization
using a typical normalization matrix [ ]
Encoding
Zig-Zag Pattern
Huffman Coding
Run-length Coding
Tables DC
Size | Amplitude AC
Run/Size | Amplitude

13. To come:
Compression
DCT
JPEG decompression
Wavelet

14. References:
Rafael C. Gonzalez, Richard E. Wood, “Digital Image Processing”, Addison Wesley, 1993
Geoffrey M. Davis, Aria Nosratinia, “Wavelet-based Image Coding: An Overview”,
Subhasis, Saha, “Image Compression - from DCT to Wavelets : A Review”,
Weidong Kou, “Digital Image Compression Algorithms and Standards,” Kluwer Academic Publishers, 1995.
“Selected Papers on Image Coding and Compression,” Majid Rabbani, Ed., Brian J. Thompson, Gen. Ed., SPIE Milestone Series, Vol MS-48, SPIE Optical Engineering Press, 1992.
“Fractal Image Compression Theory and Application,” Yuval Fisher, Ed., Springer-Verlag New York, 1995.
Bernd Jaehne, “Digital Image Processing”, Third Edition, Springer-Verlag, New York 1995