reconstruction of a color

Hi suppose I have an image. It shows 2 colors visually.I need two know whether there is actually 2 colors or many different colors. I have used the following code.but perhaps Im not getting the right answer:

Here I seems to have two bars of two colors.

I1=rgb2hsv(I);

color=zeros([30,50,3],'double');

r=size(I1,1); for r=1:size(I1,1); for c=1:size(I1,2)

        h=num2str(I1(r,c,1));
        s=num2str(I1(r,c,2));
        v=num2str(I1(r,c,3));
        filename=strcat(path,num2str(r),'\',num2str(r),num2str(c),'h=',h,'s=',s,'v=',v,'.jpg');

        color(:,:,1)=I1(r,c,1);
        color(:,:,2)=I1(r,c,2);
        color(:,:,3)=I1(r,c,1);

        hsvcolor=hsv2rgb(double(color));

        imwrite(hsvcolor,filename,'jpg');
    end
end
am i doing the right process?If not what is necessary for correction?

Answer 1

[Walter Roberson]

T = reshape(I1,[],3);
U = unique(T,'rows');
if size(U,1) > 2
  disp('there were more than 2 colors');
end

Though this does depend upon what you mean by "color"; possibly you just want to compare hues?

[Mohammad Golam Kibria]

Yes, I want to compare hues and also want to know how much hue difference makes visible color difference in our eyes.So I need a program that will be of different hue but saturation and value will be same. But any file saved in takes array hue value as rgb value. can you suggest me how to write that type of program?

Answer 2

[Bjorn Gustavsson]

Maybe your problem can be trivially solved with any of these FEX contributions: http://www.mathworks.com/matlabcentral/fileexchange/20757-drawing-color-histograms-and-color-clouds http://www.mathworks.com/matlabcentral/fileexchange/28681-imhistogram http://www.mathworks.com/matlabcentral/fileexchange/4875-color-image-histogram

HTH, Bjeorn