how to convert gray images to rgb

Question

mohd akmal masud 2023-11-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2041351-how-to-convert-gray-images-to-rgb

回答： Walter Roberson 2023-11-1

采纳的回答： Walter Roberson

spect128x128.zip

在 MATLAB Online 中打开

Dear all,

Anyone can help me how to convert my gray images to rgb. (as attached)

I tried this below command but failed:

%% Read main set data
clc
clear all
close all
[spect map]=dicomread('spect128x128');
info = dicominfo('spect128x128');
%gp=info.SliceThickness;
spect=(squeeze(spect));%smooth3
map = hsv(256); % Or whatever colormap you want.
rgbImage = ind2rgb(spect, map); % im is a grayscale or indexed image.

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Shohei 2023-11-1

在 MATLAB Online 中打开

Hello,

Are you trying to convert "volume" to RGB data?

As far as I know, ind2rgb support "image" data.

You can get RGB image of specific slice as following.

rgbImage = ind2rgb(spect(:,:,slice), map);

If you want to view RGB volume, you can also use sliceViewer.

sliceViewer(spect);
colormap hsv

mohd akmal masud 2023-11-1

编辑：mohd akmal masud 2023-11-1

Dear @Shohei,

Yah, I want to convert volume to rgb

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Answer 1

Walter Roberson 2023-11-1

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2041351-how-to-convert-gray-images-to-rgb#answer_1344966

在 MATLAB Online 中打开

sc = round(rescale(spect,1, 256));
rgbBlock = permute(reshape(map(sc,:), size(sc,1), size(sc,2), [], 3), [1 2 4 3]);

rgbBlock is now 130 x 130 x 3 x 42 with each rgbBlock(:,:,:,K) being the rgb representation of slice #K according to the given colormap.

Note that the scalling done is overall not slice-by-slice. So for example slice 2 has an input maximum of 372 and slice 16 has a maximum value of 5540, so the second slice will take up only 372 / 5540 of the color space, which is less than 7%