Re: Fusing Images: Color?

Posted by Nicholas Verge on Jun 24, 2007; 10:35am
URL: http://imagej.273.s1.nabble.com/Fusing-Images-Color-tp3699031p3699034.html

Abhishek,

There are literally dozens of algorithms for fusing greyscale  
single-channel images with multichannel colour iamges. It is a very  
important image processing procedure in remote sensing. There they are  
used to to produce a high resolution multispectral image, by fusing a wide  
spectral band, high resolution greyscale image with a colour-multispectral  
image of lower resolution. The wide variety of available methods reflects  
attempts to insert the high frequency information of the greuscale image  
into minimise into the nelarged colour image, and minimising the problem  
of colour distortion in high resolution colour product.

Note. The resolution enhancement aspect of these algorithms, is only a  
conventional resampling of the the colour image to the resolution of the  
greyscale image. So if your images are have both the same height and width  
as measured in pixels, ignore.

Try searching google using the terms "pan-sharpening" or "image fusion" or  
"resolution enhancment"

Common methods in use are:

Additive (alpha transparency merge)
HSI/HSL intensity/lightness substitution - replace the intsnsity/lightness  
componet of the enlarged low resolution colour image with the greyscale  
image (histogram matched)
PCA substitution - replace PC1 of the enlarged colour image with the  
greyscale image, then perform inverse PCA transform
Smoothed frequency intensity modulation
Various wavelet-transform-based fusion methods
High-pass filter method
Multi-resolution analysis intensity modulation.(MRAIM)
Pixel block intensity modulation
Brovey (chromaticity transform) method

Hope this may help.



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Nicholas J. Verge BSc. FGS