1. CHEN Guowang FANG Wei HUANG Baihan
JPEG Coding
CHEN Guowang
FANG Wei
HUANG Baihan

2. Adding Redundancy to Ensure Correctness
General Coding
Source Data
Source Coding
Channel Coding
Transmission
Reducing Redundancy
Adding Redundancy to Ensure Correctness

3. JPEG Compression Source Image Color Space Transformation Down Sample
Break into 8x8 Blocks
Compressing each 8x8 block
2-D DCT
Quantization
Lossless Coding
Compressed Image

4. Color Space Transformation
Y: brightness
Cb & Cr: blue-difference and red-difference

5. Original
Down-sample all components
Preserve Y component

6. JPEG Compression Source Image Color Space Transformation: RGB to YCbCr
Down Sample Cb, Cr Components
Break into 8x8 Blocks
Compressing each 8x8 block
2-D DCT
Quantization
Lossless Coding
Compressed Image

7. 2-D Basis Images

8. 2-D DCT
Input image block After 2-D DCT

9. Quantization
Coefficient Matrix ÷ Quantization Matrix = Result = ÷

10. Zigzag Scan & Run-length Coding
Numbers of Zeros Before
Value 1 -2 -1 2
End of Block

11. Q & A