i am writing the matlab code for bi-histogram equalization for the color image...i am using the 'function' to extend to all three planes i.e, RG&B ...but i am getting error 'Function definitions are not permitted in this context.'.

clc;
 close all;
 clear all;

   function y = BBHE(x);

   sz = size(x);
   o_mean = round(mean(x(:)));

                                                                                 % HISTOGRAM
   h_l = zeros(256,1);
   h_u = zeros(256,1);

   for i = 1:sz(1)
       for j = 1:sz(2)
           g_val = x(i,j);
            if(g_val<=o_mean)
             h_l(g_val+1) = h_l(g_val+1) + 1;
           else
              h_u(g_val+1) = h_u(g_val+1) + 1;
           end

       end
   end
   disp(h_l)
   disp(h_u)

nh_l = zeros(256,1);

nh_u = zeros(256,1);

                                                                                % NORMALIZED HISTOGRAM OR PDF
   nh_l = h_l/sum(h_l);
   nh_u = h_u/sum(h_u);

% % CDF

   hist_l_cdf = double(zeros(256,1));
   hist_u_cdf = double(zeros(256,1));

   hist_l_cdf(1) = nh_l(1);
   hist_u_cdf(1) = nh_u(1);

   for k = 2:256
       hist_l_cdf(k) =  hist_l_cdf(k-1) + nh_l(k);
       hist_u_cdf(k) =  hist_u_cdf(k-1) + nh_u(k);
   end

                                                                                  % IMAGE REMAPPING 
   equalized_img = zeros(sz);

   range_l = [0 o_mean];
   range_u = [(o_mean+1) 255];

   for i =1:sz(1)
       for j =1:sz(2)
           g_val = x(i,j);

           if(g_val<=o_mean)
              equalized_img(i,j) = range_l(1) + round(((range_l(2)-range_l(1))*hist_l_cdf(g_val+1))); 
           else
              equalized_img(i,j) = range_u(1) + round(((range_u(2)-range_u(1))*hist_u_cdf(g_val+1))); 
           end

      end
   end
the above code is in one .m file  and following code is in another .m file 

a = imread('C:\Users\Public\Pictures\Sample Pictures\imageo1.jpg');
x = a(:,:,1);
y = BBHE(x);

figure,imshow(y);

[CSE]

please help me if you have run this code on color images..my code is not working on color images.please send me suggestion for code on [e-mail].

Answer 1

[Image Analyst]

Get rid of the

clc;
 close all;
 clear all;

and get rid of the semicolon after

function y = BBHE(x);

replace y with equalized_img:

function equalized_img = BBHE(x)

and it should work fine. I did (with a standard color demo image) and it worked fine.

[vishwas h s]

thanks for the solution sir....but now i am getting a new kind of error saying that "Output argument "equalized_image" (and maybe others) not assigned during call to "C:\Users\vishwas\Documents\MATLAB\BBHE.m>BBHE".

[Image Analyst]

Do you know how to use the debugger? http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

Just step through the code and find out why you're not stepping into the for loops. Like I said, I used it with peppers.png and it worked fine.