1. Lecture 18
Figures from Gonzalez and Woods, Digital Image Processing, Second Edition, 2002.

2. Image Compression
Images contain lots of redundancy, so compression is important in
Teleconferencing
Remote sensing
Document and medical imaging
FAX transmissions
Anything that requires the transmission of an image requires a compression scheme

3. Image Compression (2) Two types
Information preserving—used in medical applications
Lossy—used in TV, FAX transmission,etc.
Types of redundancy
Coding redundancy
Interpixel redundancy
Psychovisual redundancy

4. Image Compression (3)

5. Coding Redundancy

6. Chapter 8
Image Compression

7. Chapter 8
Image Compression

8. Interpixel Redundancy

9. Chapter 8
Image Compression

10. Interpixel Redundancy

11. Chapter 8
Image Compression

12. Psychovisual Redundancy
The eye does not respond equally to all visual information. Information of less relative importance is psychovisually redundant.

13. Chapter 8
Image Compression

14. Chapter 8
Image Compression

15. Fidelity Measures RMS error and signal to noise ratio; quantifiable
Eyeball norms…Television rating scale

16. Chapter 8
Image Compression

17. Chapter 8
Image Compression

18. Chapter 8
Image Compression

19. Coding and Decoding
Hamming distance
Hamming code
Parity corrections