Apply a colored filter on grayscale image?

I have two grayscale images and i need to merge as an anaglyph image without shifting. The purpose is to watch this image with red-green glasses thereby having a red filtered image only visible with one lens and a green filtered image only visible with the other.

I've found the function

imfuse()

But i need to apply a red and green filter. It is possible on grayscale images? how can i do?

Thanks

Answer 1

[Naman Chaturvedi]

You grayscale image (say iRed) is a m*n*1 matrix. (m, n are x and y dimensions). To make the grayscale image iRed to redscale image, do the following computations:

>> iRedMonochrome=cat(3,iRed,zeros(size(iRed)),zeros(size(iRed))); % for red filter [R 0 0]
>> iGreenMonochrome=cat(3,zeros(size(iGreen)),iGreen,zeros(size(iGreen))); % for green filter [0 G 0]
>> iBlueMonochrome=cat(3,zeros(size(iBlue)),zeros(size(iBlue)),iBlue); % for blue filter [0 0 B]

You can then simply add the images:

>> iRGB=iRedMonochrome+iGreenMonochrome+iBlueMonochrome;

[Filippo Gambarota]

Thanks! I've just tried an it works fine! However i'm trying to ask another question.

Now i have the grayscale image in red and the other in green. However i think that green and red have different luminance. Is there any way to match the green and red luminance?

[Image Analyst]

If the gray is the ref

meanGreen = mean2(greenImage);
meanRed = mean2(redImage);
redImage = double(redImage) * meanGreen / meanRed;

Or use imhistmatch().

[Filippo Gambarota]

Unfortunately the output is a flat red image...

F1_red=cat(3,SHINEd_F1,zeros(size(SHINEd_F1)),zeros(size(SHINEd_F1))); 
N1_green=cat(3,zeros(size(SHINEd_N1)),SHINEd_N1,zeros(size(SHINEd_N1)));
final = imhistmatch(N1_green,F1_red)
imshow(final)