image enhancement by modified Gaussian high-pass filter

Question

haider alnaqeeb 2016-3-1

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/270901-image-enhancement-by-modified-gaussian-high-pass-filter

回答： amal abbbes 2018-4-10

Dear Gen. I need your kind support in my issue, in my project i have to use a symmetrical modified Gaussian high-pass filter for image enhancement as in below two image,

the image in top is the gray input image and the image down is the filtered image.

the symmetrical modified Gaussian high-pass filter used the formula :

H(x,y)=a*(1-e^(-(distance^2)/(2*d^2)))+b
where : distance=sqrt((x-p)^2+(y-q)^2) , a=12.5 , b=-4 and d=12.
but when i coding the above formula and test it with a gray image there is no any change between the  input and output image.
my code as below:
[m, n]=size(grayimage);
f_transform=fft2(croppedImage);
f_shift=fftshift(f_transform);
p=m/2;
q=n/2;
d0=12;
for i=1:m
for j=1:n
distance=sqrt((i-p)^2+(j-q)^2);
x(i,j)=12.5*(1-exp(-(distance^2)/(2*(d0^2))))-4 ;
end
end
filter_apply=f_shift.*x;
image_orignal=ifftshift(filter_apply);
image_filter_apply=abs(ifft2(image_orignal));
figure(5)
imshow(image_filter_apply,[])

please any kind support

Kind Regards

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Image Analyst 2016-3-1

Exactly what is the question? Is there anything wrong with your code? Tell me first so I don't have to run it. Also, attach the original image, not a screenshot.

haider alnaqeeb 2016-3-1

编辑：haider alnaqeeb 2016-3-2

Dear Image Analyst, Good Day, my question is that symmetrical modified Gaussian high-pass filter must enhance the input image as in above screenshot but when i test my code the filtered image is the same as input image. if there any missing in my coding? the input image is below: you must first resize the below image to 200*64 pixels before filtering.

Kind regards

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