sir i have the code for my project color filtering method for CFA image based on gradient but iam not getting exact result, so please explain me the code has gone wrong.

sir please explain me that where the code has gone wrong,instead of applying noise to the image the result is showing that there is no noise and even it showing that there is no edges in the image.

 clc;
 clear all;
 close all;
 i = imread('mandi.tif');
 imshow(i);

%demosaic of image

 rgb = demosaic(i,'bggr');
 figure,imshow(rgb);

%noise addition

 for i=500:1:1000
    for j=500:1:1000
        rgb(i,j)=imnoise(rgb(i,j),'gaussian',9);
    end
 end
 figure,imshow(rgb);

%SNR calculation of image with noise

 m1=mean2(rgb);
 SD1=mean2(stdfilt(rgb));
 snr1=(m1/SD1)

 r=rgb;g=rgb;b=rgb;
 r(:,:,2)=0;
 r(:,:,3)=0;  
 g(:,:,1)=0;
 g(:,:,3)=0;
 b(:,:,1)=0;
 b(:,:,2)=0;
 m = size(rgb,1) 
 n = size(rgb,2)

%determination of enumeration variable TH for knowing the existence of noise and edges in a color image

 for i=2:1:m-1
     for j=2:1:n-1
 A1=abs(r(i-1,j-1)-r(i+1,j+1));
 B1=abs(r(i-1,j+1)-r(i+1,j-1));
     end
 end
 for i=3:1:m-2
     for j=3:1:n-2
        A2=abs(2*g(i,j)-g(i-1,j-2)-g(i+1,j+2));
        B2=abs(2*g(i,j)-g(i-2,j-1)-g(i+2,j+1));
     end
 end
 for k=2:2:m-1
     for l=3:2:n-1
        x=[k-1,k+1];
        y=[l-1,l+1];
 up=(A1<B1) & (eq(A2,B2)) & eq(max(abs(2*r(k,y)-r(k-1,l)-r(k+1,l))),l-1);
*%up says that g(i,j-1) is the noise*

 down=(A1<B1) & (eq(A2,B2)) & eq(max(abs(2*r(k,y)-r(k-1,l)-r(k+1,l))),l+1); *%down says that g(i,j+1) is the noise*

 left=(A1>B1) & (eq(A2,B2)) & eq(max(abs(2*r(x,l)-r(k,l-1)-r(k,l+1))),k-1); *%left says that g(i-1,j) is the noise*

 right=(A1>B1) & (eq(A2,B2)) & eq(max(abs(2*r(x,l)-r(k,l-1)-r(k,l+1))),k+1); *%right says that g(i+1,j) is the noise*

 no=(eq(A1,B1)) & (eq(A2,B2));                                           
*%no says that there is no noise and also no edge *

 level=(A1>B1) & (A2>B2);
*%level says that there is a edge in vertical direction*

 erect=(A1>B1) & (A2<B2);
*%erect says that there is a edge in horizontal direction*

     end
 end

 p=[1 2 3 4 5 6 7]
 TH=[up down left right no level erect]

 p_TH=p(TH==1)
 for i=2:1:m-1
     for j=2:1:n-1
 switch p_TH
    case 1
        r(i,j)=(r(i-1,j)+r(i+1,j)+r(i,j+1))/3;
        r(i,j-1)=r(i,j);
    case 2
        r(i,j)=(r(i-1,j)+r(i+1,j)+r(i,j-1))/3;
        r(i,j+1)=r(i,j);
    case 3
        r(i,j)=(r(i+1,j)+r(i,j-1)+r(i,j+1))/3;
        r(i-1,j)=r(i,j);
    case 4
        r(i,j)=(r(i-1,j)+r(i,j-1)+r(i,j+1))/3;
        r(i+1,j)=r(i,j);
    case 5
        r(i,j)=(r(i-1,j)+r(i+1,j)+r(i,j-1)+r(i,j+1))/4;
    case 6
        r(i,j)=(r(i-1,j)+r(i+1,j))/2;
    case 7
        r(i,j)=(r(i,j-1)+r(i,j+1))/2;
 end
     end
 end
 s=r+g+b;
 figure,imshow(s);

%SNR calculation of image after processing

 m2=mean2(s);
 SD2=mean2(stdfilt(s));
 snr2=(m2/SD2)

Answer 1

[Image Analyst]

I already gave some things to try when you posted this same question under your alternate identity: http://www.mathworks.com/matlabcentral/answers/76726-can-any-one-suggest-any-corrections-or-changes-for-the-code-witten-by-me. Things like giving indexes to A1, etc. Why have you not tried any of my suggestions?

[KAS]

sorry but it cannot make any changes in my result. whether the noise applied is not enough to be identified as a noise in the code.what should i do.