Mapping colored image on grayscale
19 views (last 30 days)
I have a gray scale image of brain and a colored tumor image. i want to map the tumor colored image on the gray scale image, can i do this???
i have used for loop for mapping but the result is http://imgur.com/UoYBK, but this is not correct i guess, how can this be corrected
Image Analyst on 23 Jul 2012
Edited: Image Analyst on 23 Jul 2012
Segment the image, say, by thresholding the intensity to get a binary image of where the tumor is. Then multiply it by the original image to get an image of only the tumor. Then apply a colormap with the colormap() function. Something like (untested)
binaryImage = grayImage > thresholdValue; % You decide what thresholdValue is
maskedImage = uint8(binaryImage) .* grayImage;
With this case, binary image can be more general and sophisticated than the simple thresholding I showed here.
Or, you can simply do it with a colormap, like this:
thresholdValue = 130; % gray level where the colors start.
numberOfColorValues = 256 - thresholdValue + 1;
myColorMap = gray(256);
myColorMap(thresholdValue:end, :) = flipud(autumn(numberOfColorValues));
Matt Kindig on 23 Jul 2012
What do you want the resulting image to look like? Do you want the brain to render as gray, with the tumor shown in the flame-like colors? If so, you can follow this general approach:
1. Convert the brain image to RGB, using ind2rgb() with the original (gray) colormap.
2. Convert the tumor image to RGB, using ind2rgb() with the color (hot?) colormap.
3. Use logical indexing to identify all parts of the tumor image that are black (zeros).
4. Replace the brain image with the tumor image for those given pixels.
Walter Roberson on 23 Jul 2012
You need scaling and alignment information, which it is not clear that you have. Is the assumption that the tumor and brain image are already scaled to the same size and are positioned at the same place in their images?
Once they are scaled and aligned, image() or imagesc() the two images into place. On the top image (the one with the tumor), set the AlphaData to 0 for each pixel where the grayscale image is to show through.