Tit

1
Design of Large ICs (5kk53)
The application Image compression G. de Haan
2
Image matrix of brightness values

• More pixels per image ? better resolution ? more
  storage capacity

3
JPEG principle

• Multiply pixel matrix with invertible matrix
• Result matrix has properties that some entries
  are more important for image quality than others
• Quantize entries that are less important more
  coarsely

Divide image into blocks
4
JPEG compression
Data reduced to 20
Data reduced to 10
5
But if you drive it too far.
Quality with compression factor 100, worse than
100 times less pixels
6
Video compression
.bmp
.jpg
JPEG decoder
JPEG encoder
.bmp
quality
7
Different qualities of up-scaling
Simple bi-linear
Advanced content adaptive
8
Design issues

• What is the cost of the various coding options?
• Which option gives the best performance?
• Define a good price performance point and
  identify what the choices depend upon

9
Tools

• PaintshopPro
• for bmp to jpg with variable compression
• Jpgdrc
• to convert jpg to bmp
• To down-scale images
• To linearly up-scale
• To up-scale with content adaptive filter (DRC)