Currently I am trying to convolve an image with a Gaussian function and am getting a white screen.

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Levi Stevens 2022-2-15

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https://ww2.mathworks.cn/matlabcentral/answers/1650635-currently-i-am-trying-to-convolve-an-image-with-a-gaussian-function-and-am-getting-a-white-screen

评论： Levi Stevens 2022-2-15

When I am trying to get the convolution I am getting blank screen. The code I have for this is given by:

p = imread('barphantom.png');
gp = rgb2gray(p)
figure, imshow(p) %shows the image
n = 1132;
m = 755;
sigma = 5 
h = zeros(n,m);
for x=1:n
    for y=1:m
        h(x,y) = exp(-((x-n/2)^2+(y-m/2)^2)/(2*sigma^2));  
    end
end
figure, imshow(h) % shows the gaussian figure
k = conv2(gp, h,'same')
figure, imshow(k)

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Answer 1

DGM 2022-2-15

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https://ww2.mathworks.cn/matlabcentral/answers/1650635-currently-i-am-trying-to-convolve-an-image-with-a-gaussian-function-and-am-getting-a-white-screen#answer_896980

编辑：DGM 2022-2-15

在 MATLAB Online 中打开

Sum-normalize the filter kernel

gp = imread('cameraman.tif');

n = 1132;

m = 755;

sigma = 5;

h = zeros(n,m);

for x=1:n

for y=1:m

h(x,y) = exp(-((x-n/2)^2+(y-m/2)^2)/(2*sigma^2));

end

h = h/sum(h(:)); % normalize the filter

%imshow(h) % shows the gaussian figure

k = conv2(im2double(gp), h,'same');

imshow(k)

Your filter also is wayyyy bigger than it needs to be. That only slows down the convolution. Depending on how much support you want, you can make it quite small. For comparison, imgaussfilt() creates the filter such that its width and height are 2*ceil(2*sigma)+1. You might want more support, so pick 2*ceil(3*sigma)+1 or 2*ceil(4*sigma)+1.