Title: Wavelet Based Color Compression
1Wavelet Based Color Compression
2Background
- WDR
- Significance Pass
- With threshold T and T2 find item where
T2gtItemgtT - Encode the Address
- Encode Plus or Minus
- Repeat
- Refinement Pass
- If Item gtT2
- Write Refinement
- Repeat
3WDR
4Color WDR
- Significance Pass
- Three Passes
- Red Pass
- Green Pass
- Blue Pass
- Refinement
- Three Passes
- Red
- Green
- Blue
5Color WDR
6Issues Color WDR
- Progressive nature
- Cannot stop anywhere (missing color component)
- Speed
- 3 Passes
- 3 Scan orders
- 3 data matrices
- Accounting
7Resolution To Color WDR Issues
- Color Correlation (lack of correlation)
- Ability to predict significant values
- Encode more data with one color and get a very
close color when decoding - Simplify scan order
8Color Space
- Primitive Color Spaces
- RGB
- Additive color space
- Tells how much light is needed to make a specific
color - CYM K
- Subtractive color space
- Tell what quantity of pigment is needed to make a
specific color - Other Color Spaces
- YUV
- YPbPr (YCbCr)
- Video and Image Compression Schemes, Analog
(Digital) - YCoCg
- Integer to Integer Color space similar to YPbPr
9Transform Matrix RGB to YCoCg
- Forward - RGB -gt YCoCg
- Reverse - YCoCg -gt RGB
10Back To Color WDR
- We now have the ability to
- Predict significant color values
- Simplify to one scan order
- Retain some RGB color information when we stop
encoding anywhere
11Color WDR
12Optimizations
- Encoder optimizations
- ASWDR
- Lossy Color Space
13How good is this compared to JPEG 2000?
PSNR from Color Compression of Lena PSNR from Color Compression of Lena PSNR from Color Compression of Lena
1bpp (241) 0.5bpp (481)
JPEG2000 34.320604 32.239947
Color WDR 33.414003 31.180589
PSNR from Color Compression of Parrots (kodim23) PSNR from Color Compression of Parrots (kodim23) PSNR from Color Compression of Parrots (kodim23)
1bpp (241) 0.5bpp (481)
JPEG2000 40.553139 37.526301
Color WDR 38.60774 34.599361
PSNR from Color Compression of Hats (kodim03) PSNR from Color Compression of Hats (kodim03) PSNR from Color Compression of Hats (kodim03)
1bpp (241) 0.5bpp (481)
JPEG2000 39.946701 35.951137
Color WDR 34.542265 32.215072
14Pictures Lena
Left Original (Cropped) Top Right
Color WDR 1 bpp Bottom Right JPEG 2000
1 bpp
15Pictures Hats
Left Original (Cropped) Top Right
Color WDR 1 bpp Bottom Right JPEG 2000
1 bpp
16Pictures Parrots
Left Original (Cropped) Top Right
Color WDR 1 bpp Bottom Right JPEG 2000
1 bpp
17Questions?