Color space conversion xyz2srgb, using makecform function

Hi

I have an image and try to convert it from XYZ to sRGB in order to display the image on the screen and be able to draw a ROI. I used the makecform function but it seems that it doesn't work well as I get a black image instead!

RGB=zeros(size(XYZ2));    
cform=makecform('xyz2srgb');
RGB=applycform(XYZ2,cform);

Here are the max values of the XYZ and RGB matrices I get, respectively

   max(max(XYZ2))                       
  ans(:,:,1) = 31.6600,   ans(:,:,2) =33.5200,     ans(:,:,3) = 40.6900

   max(max(RGB))
  ans(:,:,1) = 1,     ans(:,:,2) = 1,    ans(:,:,3) = 1

Do you may have an idea? Did I use the cform function wrongly?

Many thanks in advance

Answer 1

[Radha Krishna Maddukuri]

This issue is happening because of scaling of the input data. The function 'xyz2srgb' expects input values in the range of 0 to 1.

Therefore, the input data can be scaled by dividing it with a standard value or the maximum value for the data.

clear
XYZ2 = [10 20 30; 40 50 60; 70 80 90; 100 110 120; 130 140 150; 160 170 180];
RGB=zeros(size(XYZ2));
cform=makecform('xyz2srgb');
RGB=applycform(XYZ2/180,cform);

I hope this helps you with the issue that you are facing.