mathematical operation on each element of gpuArray

How can i do mathematical operation on each element of gpuArray with the equation below? s = 2r(i, j) − r(i, j +1) + r(i, j −1). here r is the image matrix. I've written the code below:
im = imread('(HTC-1-M7)1.jpg');
tic
img = gpuArray(im);
for j =2: size(im,2) -1
A(:,:,:) = 2*img(:, :,:) -img(:,j+1,:) + img(:, j-1,:);
end
B = gather(A);
toc
Is there anyway to apply equation on each element of gpuarray with function like arrayfun without using loop? Thanks in advance.

2 个评论

Are you certain that it is not a 2nd order differencing filter that you want:
s = 2r(i, j) r(i, j +1) - r(i, j 1)
actually I found it from a research paper from IEEE. They derive this equation for row wise(x-axis) second order differentiation. But i have come to know about imgradientxy function, not sure this function does the same stuff like this equation or not.

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回答(1 个)

B=gather( imfilter(gpuArray(img), [+1,2,-1]) );

4 个评论

actually I found it on a research paper from IEEE. They derive this equation for row wise(x-axis) second order differentiation. But i have come to know about imgradientxy function, not sure this function does the same stuff like this equation or not.
if you don't mind could you explain the code how does it works? I'm newbie in matlab.
Is there any builin function in matlab to determine the second order derivative of image like the equation above?
B=gather( diff(gpuArray(img),2,2) );

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2018-1-22

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