i'm trying to enhanced image by gaussian high pass filter but it can't work... can you help me to repair my program? thangkyou before

% function GaussianHighPass [m n]=size(image.jpg); f_transform=fft2(image.jpg); f_shift=fftshift(f_transform); x0=m/2; y0=n/2; D0=70; a=12.53; b=-4; for x=1:m; for y=1:n; D=sqrt((x-x0)^2+(y-y0)^2); hpf(x,y)=a*(1-exp(-(D^2)/(2*(D0^2))))+b; end end filter_apply=conv2(image.jpg,hpf,'same'); figure,imshow(filter_apply) image_orignal=ifftshift(filter_apply); image_filter_apply=abs(ifft2(image_orignal)); figure,imshow(image_filter_apply,[])

Answer 1

[Jan]

As you are using imshow I'm guessing you have the image processing toolbox installed. In that case you might as well use the imfilter() function. The function

 fspecial('Gaussian', hsize, sigma )

will generate a Gaussian lowpass filter.

High pass filtering can be achieved by subtracting the low pass filtered from the original image, e.g.

 I = imread( 'peppers.png' );
 I_filtered = I - imfilter( I, fspecial('Gaussian', 5, 1 ) ); 
 imtool( I_filtered );

If you want to do the filtering explicitly, create the convolution matrix, e.g.

 hp_filter_matrix = fspecial('Gaussian', 5, 1);

This gives you a 5 x 5 double matrix that you can convolve with your image to low pass filter it. As before, the high pass filtered representation can be obtained by subtraction.

[elfrida]

thangkyou sir!

[Jan]

You are welcome! If that helped, you might want to mark it as 'Accepted Answer'.