Image from RGB to another one

I have two Questions :

•1. Read the RGB image?

•2. Convert RGB color image into CMYK color image?

I solve the first one

             figure 
             image_mat = imread('color.jpg');
             imshow(image_mat)

but How can i solve the second one ?

Answer 1

[Image Analyst]

Did you even try the function in the link KSSV gave you? Because I did, and the attached code worked just fine.

[Nour George]

Can the colors of the CMYK be combined into a single image?

[Walter Roberson]

The output of rgb2cmyk() is a single image.

... It just isn't all that meaningful of an image. You cannot get a meaningful CMYK image without a device profile.

[Nour George]

I don't understand , Can you explain me

[Image Analyst]

cmyk() is a single 3-D image with 4 planes (C, Y, M, and K) in the 3rd dimension. What are you going to do with it? If you plan on visualizing it as a 3D RGB image, I and Walter don't seen any use in that. What's the point? Even if you just viewed CMY as RGB with C being in red, M being green, and Y being as blue, how are you going to interpret that? What's the point? It's a completely different color space. In my mind the only real way to visualize the 4 CMYK channels is by looking at each one, one at a time, in grayscale.

[Nour George]

I have this question to convert from RGB color to CMYK color

when i execute the Code I get this result

ans =

'RGB'

This means that no conversion occurred and the image did not appear to me, what can i do ?

folder = iccroot;

disp(folder)

profiles = iccfind(folder)

size(profiles)

currentProfile = profiles{1}

currentProfile.Description

ProfileName = currentProfile.Description.String

[~,descriptions] = iccfind(folder)

descriptions

[profiles,descriptions] = iccfind(folder,'rgb')

descriptions

currentProfile.Description

P = iccread('sRGB.icm');

P_new = iccwrite(P,'my_profile.icm');

I_rgb = imread('Pepper.png');

inprof = iccread('sRGB.icm');

outprof = iccread('EV2456 User 5000K G2.2.icc');

C = makecform('icc',inprof,outprof)

I_cmyk = applycform(I_rgb,C);

imwrite(I_cmyk,'pep_cmyk.tif','tif')

info = imfinfo('pep_cmyk.tif');

info.PhotometricInterpretation

[Walter Roberson]

The Enzo ev2456 is not a CMYK device.

[Nour George]

My problem was solved , the last Question is How can i display cmyk image , what is the instruction

[Image Analyst]

As I showed you, you can use imshow() to show the component channels. And as Walter and I have both said, displaying 3 or 4 of the cmyk channels as an RGB image makes little sense but if you want, you can obtain that gibberish by extracting the three channels you want into an rows-by-columns-by3 image and using imshow(). For more sophisticated ways of converting a multi-channel color image into a 3-channel RGB image, see the attached paper.

Answer 2

[KSSV]

https://in.mathworks.com/matlabcentral/answers/499387-how-can-i-calculate-cmyk-values-from-rgb-in-matlab

http://mooring.ucsd.edu/software/matlab/doc/toolbox/graphics/color/rgb2cmyk.html

[Nour George]

I want a solution to my question because the links did not help me anything

[Walter Roberson]

%this code is about as good as any other in constructing CMYK from
%RGB without a color profile.

ind = rgb2ind(image_mat, 256);
cmap = randi([0 255], 4, 'uint8');
image_cmyk = reshape( cmap(ind, :), size(image_mat,1), size(image_mat,2), 4 );

[Nour George]

I get this Error :

Error in HomeworkQQQQ (line 9)

image_cmyk = reshape( cmap(ind, :), size(image_mat,1), size(image_mat,2), 4 );

How can i solve it ?

[Walter Roberson]

 %this code is about as good as any other in constructing CMYK from
%RGB without a color profile.

 ind = rgb2ind(image_mat, 256);
cmap = randi([0 255], 256, 4, 'uint8');
image_cmyk = reshape( cmap(ind, :), size(image_mat,1), size(image_mat,2), 4 );

[Nour George]

I still have the same Error

[Walter Roberson]

 %this code is about as good as any other in constructing CMYK from
%RGB without a color profile.

 ind = rgb2ind(image_mat, 256);
cmap = randi([0 255], 256, 4, 'uint8');
image_cmyk = reshape( cmap(ind+1, :), size(image_mat,1), size(image_mat,2), 4 );

[Nour George]

Can you make it for color profile ?

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/499387-how-can-i-calculate-cmyk-values-from-rgb-in-matlab#answer_409544 already shows the code with color profile, but you rejected that.

[Nour George]

Excuse me , Can you make it for me ? because i don't understand How can i take .icc from the link

Can you solve the Question by the link that you refers to <because I don't understand

[Walter Roberson]

image_mat = imread('baby.jpg');

inprof = iccread('srgb.icm');  outprof = iccread('USSheetfedCoated.icc');
cform = makecform('icc', inprof, outprof);  %conversion from SRGB of a CRT to CMYK of a particular device

image_cmyk = applycform(image_mat, cform);

imshow(image_cmyk(:,:,1:3))