Visualize 4 band .tif image

I have tried several methods including imread, multibandread, imadjust to read and visualize the attached image with no success in showing its real colors. Looking forward for your support.

Answer 1

[Walter Roberson]

Tricky without guidance as to the expected output.

cmyk = imread('testPatch1.tif');
C = makecform('cmyk2srgb');
rgb = applycform(cmyk, C);
rescaled_rgb = mat2gray(rgb);
imshow(rescaled_rgb);

[Abedelkarim Jezzini]

Thank you Mr. Walter, Your code didn't give me RGB image, since rescaled_rgb is in double format not uint8, please see the attached result, any idea?

[Walter Roberson]

rescaled_image is an RGB image. MATLAB has multiple ways of representing images, and internally uses 0 to 1 in a number of places (for example, color maps are 0 to 1).

If you want a uint8 image, then

rescaled_8 = im2uint8(rescaled_rgb);

[Abedelkarim Jezzini]

i convert it to uint8, and still facing the same problem, the colors are not showing well as the original image, viewed by another software..

[Walter Roberson]

That image looks fine to me. It is exactly what I expect.

If my expectations do not match your expectations, it might be because you have not paid attention to my very first remark,

"Tricky without guidance as to the expected output."

[Abedelkarim Jezzini]

Thank you Mr.Roberson for your continuous support. Would it be possible to visualize the tif file in true colors the same way i see it in the attached file when opened in eCoginito software for instance?.

[Walter Roberson]

I have seen that image before, but I cannot find the Answers thread at the moment. Were we discussing it in email?

The answer for that image was NO, it was not possible, at least not with the tiff file that was available at that time. I ran a regression to calculate the proportions of each of the four channels that should be used to create the final image, and found that there were significant differences between the required final image and the best possible predicted image.

I am having difficulty locating my source code for that discussion :(

[Abedelkarim Jezzini]

Dear Walter, I do not think we discussed that issue via mail. The tif file is from a well known data set so I believe others might have the same concern. Can you please let me know why it is not possible to visualize in Matlab true colors as we can do in other software?

[Walter Roberson]

It turns out the image was only similar to what I dealt with before. See https://www.mathworks.com/matlabcentral/answers/346170-how-to-get-rgb-from-this-tiff-image-file#comment_464334 for the calculation technique.

[Abedelkarim Jezzini]

Dear Mr. Walter..

I have read your previous answer and successfully processed the tiff image, but i notice that its brightness is dark a little bit. I tried to apply histogram equalization to the image but it seems to be un acceptable solution, so my question is: How can i enhance the brightness of the RGB tiff image after reading it?. Thanks