predictive grayscale image coding scheme using vq and btc
DESCRIPTION
Predictive Grayscale Image Coding Scheme Using VQ and BTC. Author: Yu-Chen Hu Source: Fundamenta Informaticae 78 (2007) 239–255 Speaker: Meng -Jing Tsai Date: 2011.12.29. Outline. Introduction The proposed scheme Block prediction technique Vector quantization (VQ) - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/1.jpg)
Predictive Grayscale Image Coding Scheme Using VQ and BTC
Author: Yu-Chen HuSource: Fundamenta Informaticae 78 (2007) 239–255
Speaker: Meng-Jing TsaiDate: 2011.12.29
![Page 2: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/2.jpg)
2
Outline• Introduction• The proposed scheme– Block prediction technique– Vector quantization (VQ)– Block truncation coding (BTC)
• Conclusion
![Page 3: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/3.jpg)
3
Introduction• A predictive image compression scheme that
combines the advantages of vector quantization and moment preserving block truncation coding to provide good image quality at a low bit rate.
![Page 4: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/4.jpg)
4
• VQ is widely used because it has a simple decoding structure and requires a low bit rate. However, a lot of computational costs are needed in the codebook design procedure and the image coding procedure.
• BTC has the advantages of requiring very low computational cost and providing good
• reconstructed image quality. However, a high bitrate is needed in BTC.
![Page 5: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/5.jpg)
5
• To reduce the bit rate
![Page 6: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/6.jpg)
6
Vector quantization (VQ)image vector :x=(x1,x2,…,xk)
…
…
Codebook
Original image
d(x,y1)
d(x,y2)
d(x,yN)
NiiyY 1
),...,,( 111 11 kyyy
),...,,( 222 11 kyyy
),...,,(11 kNNN yyy
),(min,...,2,1
min iNi
yxdd
index of ymin
![Page 7: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/7.jpg)
7
VQ encoding procedure• Find Closest codeword
Codebook012
255254253
IndexImage vector(21,44,45,78) 2
(24,45,47,76)
(33,32,97,98)(78,22,77,20)
(20,55,53,26)
(20,25,17,11)(12,14,13,16)
![Page 8: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/8.jpg)
8
VQ encoding procedure
ImageIndex table
w
Index table
h
![Page 9: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/9.jpg)
9
VQ decoding procedure
ImageIndex table
wh
Index table
![Page 10: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/10.jpg)
10
Block truncation coding (BTC)• 區塊臨界值 =區塊平均值
11
qqmxb
qmqxa
mx
m
iix
個數大於等於臨界值的像素 : q
sizeblock :m
![Page 11: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/11.jpg)
11
≤
![Page 12: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/12.jpg)
12
Block prediction technique
![Page 13: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/13.jpg)
13
≤
![Page 14: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/14.jpg)
14
≤≤
![Page 15: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/15.jpg)
15
BTC
251 7 5 43 169 12 0 16 255 247 200 37 47 56 114 121
98.75
block 44 aConsider
th
x
xx
x
204 17 17 17 204 17 17 17
204 204 204 17 17 17 204 204
: isblock tedReconstruc
1 0 0 01 0 0 01 1 1 00 0 1 1
: is map-Bit
2042.204177.16
795.92
baq
![Page 16: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/16.jpg)
16
≤
![Page 17: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/17.jpg)
17
![Page 18: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/18.jpg)
18
![Page 19: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/19.jpg)
19
• Experimental results of image quality of related BTC scheme and VQ with different codebook sizes
![Page 20: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/20.jpg)
20
• Results of block prediction technique for BTC and VQ with different search range sr
![Page 21: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/21.jpg)
21
![Page 22: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/22.jpg)
22
![Page 23: Predictive Grayscale Image Coding Scheme Using VQ and BTC](https://reader036.vdocument.in/reader036/viewer/2022062410/56816295550346895dd30c88/html5/thumbnails/23.jpg)
23
Conclusion• This scheme exploits the block similarities
among neighboring image blocks to improve the bit rate of traditional hybrid methods based on VQ and BTC.
• By choosing adequate controlling thresholds, the proposed scheme provides good image quality at a low bit rate.