1. JPEG implementation and improvement
Regular scan, Huffman :
Zigzag scan, Huffman:
Zigzag scan, Huffman_greedy:
Zigzag scan, adaptive Arithmetic coding(AAC):
R 林俊宏

4. Follow JPEG standard published in 1992 Input : Lena color image
Size = 512 * 512
Lena512c.bmp
Environment : matlab
1972年Lena圖

5. Coarse block diagram of Compression
Source data
(Text, Image, Video….)
Preprocessing
Entropy encoder
Compressed data (Bit Stream 0101….)
PSNR（Peak Signal to Noise Ratio）
SSIM （structural similarity）
Reconstruction data
(Text, Image, Video….)
Bit per pixel (b.p.p)
Bit per character (b.p.c.)
Compression ratio (CR)
Postprocessing
Entropy decoder

6. Evaluation, B.p.p. & PSNR Reduce↓ Keep the same
Lena 512*512 Color image
Reduce↓
Keep the same

7. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

8. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

9. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr)
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
64*64 cell
1*4096 cell
512*512
Stream_Y
Chrominance channel
(Cb & Cr)
64*64
1*4096
Huffman decoder
fun1Dto2D
Inverse Quantization
Inverse DCT Up
sampling
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
frequency domain DCT
Ac Run length coding 利用DCT後的特性做紀錄的小技巧
Dc 差分編碼 space domain
space domain 4:2:0
Stream_Cb
256*256
Stream_Cr

10. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

11. 左上數值小的Q table

12. DCT & Quantization

13. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

14. AC, Run length coding 999 = End of block(EOB) Input : 8*8 block
→[ZRL]→
output : 1*1cell

15. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

16. base code -- table

17. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

18. Inside Huffman.m : 4 TableDC
(Category 0~11) AC
(Run/Size = 0~F/0~A)
Luminance
(Y channel)
12 elements
16*10+2
(EOB & ZRL)
= 162 elements
Chrominance
(Cb & Cr channel)
依照資料數值大小可以用多少bits表示來分類

19. How to categorize？ Range DC difference Category (from 0 to 11)
Size of AC
(from 1 to A)
EOB || ZRL
-1,1 1
-3,-2,2,3 2
-7~-4, 4~7 3
-15~-8, 8~15 4
…..
-1023~-512, 512~1023 10 A

20. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

21. Stream structure Include 5 parts : Category DC base code Content DC
Run/Size AC base code
Content AC
………………repeat
End of Block(EOB)
Take the first block of luminance channel for example :
DC & AC:
16, [ ]
After encoding :
DC : Category 5 , need 5 bits to represent content DC

22. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

23. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

24. Proposed method 1.「之」字形紀錄
The scanning style from Regular-scan to Zigzag-scan. 1 2 3 …… 63 64 65 66 67
127
128
4033
4034
4035
4095
4096 1 2 3 …… 63 64
128
127
126 66 65
4096
4095
4094
4034
4033

25. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Future work
Conclusion

26. Proposed method 2. apply greedy algorithm on luminance DC.
Create own luminance DC table.
Why I want to create own table ？
To realize the core concept of Huffman :
less bits for symbol with high frequency.

27. Calculate each Category appears frequency.
Does not make sense !!!
Category 2 should have the shortest Code length in Lena image
→but it did not.

28. greedy algorithm luminance DC

29. tree{2}{1}{2}{2}{2}{2}{2}{2}{2} = 12 ← stages nine
How to implement?
tree{1}{1} = 3 ← stages two
tree{1}{2} = 4 ← stages two
tree{2}{1}{2}{2}{2}{2}{2}{2}{2} = 12 ← stages nine
Cell的結構，分1/0 = tree的左邊右邊
Category2, Codelength = 2

30. How about apply Greedy algorithm on chrominance DC?

31. Calculate each Category appears frequency.
The table is already fit the distribution of datas!!!
We cannot get benefit, from greedy algorithm.

32. Conclusion of Proposed method 2.
only apply greedy method on luminance DC (Y channel).
Future work :
To apply on AC channel maybe can further improve.

33. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

34. (Symbol-based) v.s. (Stream-based)
An optional alternative to Huffman coding in several video coding standards (ex. H.263, MPEG-4, H.26L)

35. Example of Arithmetic coding
To encode “aaabaa”
[Lower,upper] = ,
Use b bits to represent C
b = 5, C = 14
‘aaabaa’→ ‘01110’
重點提及：
事前機率0.8 , 0.2
Lower和upper調整

36. adaptive arithmetic coding (A.A.C.)
Add two mechanisms to fit the application on JPEG :
1. adapt the frequency table dynamically during the coding process.
2. adapt for long data length
直接套進來是行不通 : 1.不知道每個值發生的機率 2. 無法跑很長long Length
[講稿1]
the frequency table can truely fit the data distribution property.
Beneifit from a larger numerical interval compared to fix frequency table.
Consequently, we use less bit and make a good compression.
[講稿2]
剛剛的資料很短aaabaa，要適應道很長資料上，電腦的數值沒辦法紀錄這麼細 微
所以我設0.5為threshold，如果越界了就必須輸出0或1來標記，這樣在解碼端才 解的回來，penalty就是Stream length會上升

37. adaptive arithmetic coding (A.A.C.)
Stream structure
In A.A.C.
After encoding :
……01010
long data length + Range encode
Take the first block of luminance channel for example :
DC & AC:
16, [ ]
In huffman
After encoding :

38. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
Huffman encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

39. Lena Image Luminance channel (Y) Chrominance channel (Cb & Cr) 88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
AAC encoder
AAC
encoder
fun2Dto1D
Table L, AC
Table L, DC
Luminance channel (Y)
Stream_Y
Chrominance channel
(Cb & Cr)
Down
Sampling
88 DCT
Quantization
8*8 Qtable AC
Run length coding DC
differential
coding
AAC encoder
fun2Dto1D
Table C, AC
Table C, DC
Stream_Cb
Stream_Cr

40. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

41. Conclusion Implement the lossy compression standard JPEG.
modified the model to reduce b.p.p:
Regular scan, Huffman :
Zigzag scan, Huffman:
Zigzag scan, Huffman_greedy:
Zigzag scan, adaptive Arithmetic coding(AAC):

42. Outline JPEG overview proposed method 1 - scanning style
proposed method 2 – Huffman greedy algorithm
proposed method 3 – adaptive arithmetic coding
Conclusion
Future work

43. Future work shape adaptive : the block size is not always 8*8.
Coarse area : large block ; Fine area : small block
edge detection
image segmentation

44. Reference http://djj.ee.ntu.edu.tw/ADSP.htm
matlab.html
/proj1_jpeg_introduction.pdf