Sum two matrices shifted by a non integer number?

Question

MementoMori 2023-3-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1935439-sum-two-matrices-shifted-by-a-non-integer-number

编辑： Matt J 2023-3-26

Suppose we have two matrices A and B, and I want to sum them shifted by a non-integer number of pixels. How can I do it?

For example for a 0.5 shift. We can enlarge them by a factor of 2, sum them shifted by 1 pixel and reduce it by a factor 2.

But this way can be very computational expensive, in particular for a low pixel shift.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Matt J 2023-3-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1935439-sum-two-matrices-shifted-by-a-non-integer-number#answer_1201274

编辑：Matt J 2023-3-26

在 MATLAB Online 中打开

Because of the linearity of interpolation, you should not interpolate each matrix. You should sum the matrices first, then interpolate the result, e.g,

C=imtranslate(A+B,[0.5,0]);

which will cut down the computation by half.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

John D'Errico 2023-3-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1935439-sum-two-matrices-shifted-by-a-non-integer-number#answer_1201134

There is no magic, whereby you can do things that take computational time, and do them instantly.

What you want to do is implicitly interpolate the images, at sub-pixel levels. You can use interp2 to interpolate one array at a shift of some fractional amount. Then add the results. But no matter what, you will need to perform an interpolation.