lowpass filter added

digital_image_processing/lab/lab2/lowpass.m

@@ -0,0 +1,29 @@
+input_image = imread('download.jfif'); 
+ image = rgb2gray(input_image);
+[M, N] = size(image); 
+ 
+FT_img = fft2(double(image)); 
+
+D0 = 30;  
+
+u = 0:(M-1); 
+idx = find(u>M/2); 
+u(idx) = u(idx)-M; 
+v = 0:(N-1); 
+idy = find(v>N/2); 
+v(idy) = v(idy)-N; 
+ 
+[V, U] = meshgrid(v, u); 
+
+D = sqrt(U.^2+V.^2); 
+
+
+H = double(D <= D0); 
+
+G = H.*FT_img; 
+
+
+output_image = real(ifft2(double(G))); 
+
+subplot(2, 1, 1), imshow(input_image), 
+subplot(2, 1, 2), imshow(output_image, [ ]);