convert gray image back to rgb
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how to back grat to rgb gray2rgb function not found
3 commentaires
AliHdr
le 30 Oct 2021
I have done this but i can not use imwrite anymore
there is and error
<<Data with 9 components not supported for JPEG files.>>
how can I overwrite new rgb file with old gray file?
Image Analyst
le 31 Oct 2021
@AliHdr evidently JPG can't store multispectral or volumetric images. Either use a mat file or save each slice as its own image.
Réponse acceptée
Image Analyst
le 14 Mar 2013
If you have a color map - a mapping of what intensity should go to what color, like what imread() or rgb2ind() can give you - then you can use ind2rgb.
rgbImage = ind2rgb(grayImage, colormap);
Otherwise use
rgbImage = cat(3, grayImage, grayImage, grayImage);
grayImage needs to be in the range 0-255 uint8 if you want to display it.
3 commentaires
Alexandar
le 1 Juil 2022
What do you mean by create a colormap and how can you do it within the scales that you'd like?
Image Analyst
le 1 Juil 2022
@Alexandar There are a bunch of built-in colormap functions such as hsv, turbo, and jet. Or you can make up your own 256 by 3 matrix with values in the range 0-1.
Plus de réponses (3)
Shaun VanWeelden
le 14 Mar 2013
Alternatively
rgb=img(:,:,[1 1 1]); does the same thing as Jan's, but is a little shorter maybe and easier to remember. img is your image you want to convert to rgb obviously
4 commentaires
Image Analyst
le 18 Nov 2016
No, that throws an error if img is a gray scale image since there is no third dimension for gray scale images.
Jan
le 14 Mar 2013
Asking Google for "Matlab gray2rgb" would be a good idea.
But a general method is:
RGB = cat(3, Gray, Gray, Gray);
4 commentaires
Walter Roberson
le 2 Juil 2022
sample_logical_2d = rand(64,80) > 0.8;
imshow(sample_logical_2d)
sample_logical_3d = cat(3, sample_logical_2d, sample_logical_2d, sample_logical_2d );
try
imshow(sample_logical_3d)
catch ME
fprintf('oooo! imshow did not like 3D logical!')
disp(ME)
end
sample_double_3d = double(sample_logical_3d);
imshow(sample_double_3d)
shehbaz Ali
le 14 Mar 2013
This is not possible to to convert black and white image to gray image. Because you don't what will be colors of any pixel for rgb picture.
5 commentaires
Walter Roberson
le 14 Juin 2023
You cannot gain information when you convert black and white to grayscale, or grayscale to color -- but you can create the grayscale or color image with the same amount of information.
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