how to convert gray scale image into rgb image?
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my project is on iridiology...and it requires to convert the gray scale image to an rgb image to find the basic color of the iris. am in need of the code to convert the gray scale image to rgb image.
2 Comments
TEJASWINI CHINAWALE
on 21 Sep 2017
you can use ind2rgb(grayscale image, colormap)...However that cannot convert your grayscale image totally into the coloured one as earlier.
Image Analyst
on 22 Sep 2017
You should put this in the "Answer" section. Right below my Answer that says the same thing you just did.
Answers (6)
Ahmed A. Selman
on 1 Apr 2013
Use colormap types, since you are interested with a colored region of interest, I think any colormap format suffices. Example:
close all
clear
clc % just to clear things up
I=imread('333.jpg');
R=rgb2gray(I); % It is gray now
y=colormap(hot(110));
imwrite(R,y,'rgb.jpg','jpg'); % Re-change it to colored one
imshow('rgb.jpg');
5 Comments
Image Analyst
on 1 Apr 2013
ug, if your starting image is monochrome, then you cannot determine the original color. You cannot. Not if all you have is the grayscale image. Period.
You can convert a grayscale image into an RGB image using cat():
rgbImage = cat(3, grayImage, grayImage, grayImage);
of course it will look all grayscale even though it is a "true color" RGB image - it's just that all the "colors" are gray. You can apply a pseudocolor lookup table to the gray values, where each gray value gets mapped into some color, to get a multi-colored image, like this:
rgbImage = ind2rgb(grayImage, jet(256));
however the colors are NOT the original colors of the iris as if you had snapped it with a color camera.
2 Comments
Image Analyst
on 2 Apr 2013
Like I said before see my new answer ( http://www.mathworks.com/matlabcentral/answers/69368#answer_80694). ind2rgb() doesn't apply anymore. You will not be using ind2rgb. Again, see my new answer above.
Image Analyst
on 2 Apr 2013
You ask: "i hav an image of the iris with all extra features like eye lashes n all..i hav to extract only the iris frm tis image. first i select the two circles of the iris..the resultant image is that the coloured part of the iris is converted to gray scale n the rest is blacked out... but i want to get the original colour....is there ne other method to get the colour of the iris?"
Here's how to do it.
% Make a mask from your circle using poly2mask
% xCircle, yCircle are the coordinates of your circle perimeter.
mask = poly2mask(xCircle, yCircle, rows, columns);
% Now mask the image so that only the original RGB part
% inside the circle remains, and outside the circle is set to black.
maskedRgbImage = bsxfun(@times, rgbImage, cast(mask,class(rgbImage)));
0 Comments
ug
on 1 Apr 2013
6 Comments
Image Analyst
on 2 Apr 2013
We're in agreement here. If all you want to do is to colorize it, you can pick whatever colormap you feel looks best or suits your needs - it's totally subjective.
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