Edge detection using directional filter.

[Sujata Mourya]

I have made a diamond filter of 29*29 and then sampled it by 512. here is the code,

close all
clear all
clc
k=0.35;


for n1=0:28
for n2=0:28
   

   z1= (n1^2)-((n2^2)*(k^2));
   
   if n1==0 && n2==0
        h(n1+1,n2+1)=k/2;
        
 elseif n1~=0 && n2==0
        h(n1+1,n2+1)=(k*(cos(n1*pi)-1))/((n1^2)*(pi^2));
        
 elseif n2~=0 && z1==0
        h(n1+1,n2+1)=0;
        
 else
   A= k/(((n2^2)*(k^2)-n1^2)*pi^2);
   B= 1/(2*n2*pi^2);
   C= (cos(((n2*k)-n1)*pi))/((n2*k)+n1);
   D= (cos(((n2*k)+n1)*pi))/((n2*k)+n1);
    
         h(n1+1,n2+1)= A-(B*(C+D));
    end
end
end
hf=fft2(h,512,512);
hfn=max(max(abs(hf)));
hflog=20*log10((abs(hf))/hfn);
figure
mesh(hflog)
surf(hflog(1:end,1:end))


%window function

n1=28
 N= n1+1
 t=1:N
 w1=kaiser(N,4)
 w1f=fft(w1,512);

%filter
A=fwind1(hf,w1);
freqz2(A)
Af=fft2(A,512,512);
figure
Afa=abs(Af);
surf(Afa(1:end,1:end))
figure

%image data
I = imread ('LEENA.bmp');
imshow(I)
figure
If=fft2(I);
Ifa=abs(If);
%operation

U=imfilter(Ifa,Afa);
Ui=ifft2(U);
Uia=abs(Ui);
imshow(Ui)

i have taken a standard image of LEENA, and applied the filter 'A' , but am unable to get the result. Uia results in white image.