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DCB DEMOSAICING

This website provides information about DCB demosaicing algorithm


 

Read first!

Please remember that I am not a pro and DCB is only my hobby project. I don't take any money for my work, I don't claim that DCB outperforms any other algorithm. I am very happy to hear that some people find the results usable - nothing more.

How can I test DCB?

The algorithm is implemented in my command line tool dcb_dcraw. Just download the source code and compile it, or better install RawTherapee (always check out the latest development version) where it was implemented (with many speed improvements).

Is it good for noisy images?

The noise rendering (without -E option) gives acceptable results. To see ISO 3200 image rendered with default DCB settings visit this comparison and scroll down.

Is it a modification of other algorithm?

I don't know about any other algorithm working like DCB. It is not a modificaion of VNG, PPG, VCD, AHD or NL.

Does DCB perform some kind of post processing?

No, there is no noise reduction, sharpening, CA correction etc.

What are its weak points?

DCB is confused when it comes to render areas with high chromatic aberration (use -C option from dcraw to fix that) or when the white balance is set incorrectly. It is quite slow too (solved in RawTerapee implementation). High contrast, black and white edges may be jagged.

What are its strong points?

Nyquist resolution is rendered with small number of artifacts and the the overall image look is attractive. Image is sharp and artifacts are not annoying.

How does it compare to other algorithms?

Image below shows the result of DCB demosaicing, hover the mouse over names of other algorithms to see how they compare. Just remember that differences in color, brightness and white balance are not the result of demosaicing but different color engine. Look at the number, visibility and color of artifacts, not at the brightness and overall colors of the image. First comparison was upscaled 200% using -scale command from Image Magick. Second and third image are sharpened using -sharpen 1 and then upscaled using -scale 200% command from Image Magick. The default view shows the result of DCB with specific options.
 
dcb_dcraw -w -W -q 4 -Q 2

DCRaw bilinear

DCRaw VNG

DCRaw PPG

DCRaw AHD

Bibble

RT HPHD

RT EAHD

RT 4 color VNG

LightZone

aperture

Capture1

Lightroom

DXO

Photo Studio

SilkyPix


 
dcb_dcraw -w -W -q 4 -Q 2 -E

Bibble 4

RT EAHD

RT HPHD

Lightzone

DCRAW AHD

DCRAW PPG

C1

Lightroom


 
dcb_dcraw -w -W -q 4 -Q 2

Bibble 4

RT EAHD

RT HPHD

Lightzone

DCRAW AHD

DCRAW PPG

C1

Lightroom


 

Copyright 2009, Jacek Góźdź
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