Interpolate a 3D-Matrix using interp1

Question

Matthias 2012-12-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/56055-interpolate-a-3d-matrix-using-interp1

编辑： Matt J 2014-1-16

I try to interpolate a 3D Matrix using interp1. I think it should be easy but i just don't get it.

I have a 3d-matrix and a vector in z direction. I wan't to get an interpolated 2d Matrix for any value in the z direction. For Example:

    matrix(1:3,1:3,1) = 1
    matrix(1:3,1:3,2) = 2
    z(1,1,1:2) = [10,20]
    interp1(z,matrix,15)

so I thought interp1 would return a 3x3 Matrix with the values 1.5 but i just get an error.

Thanks a lot!

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 2012-12-8

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/56055-interpolate-a-3d-matrix-using-interp1#answer_67907

编辑：Matt J 2012-12-8

在 MATLAB Online 中打开

    V=reshape(matrix,[],2).'; 
    VI = interp1(z,V,15);
    ans =  reshape(VI,3,3),

You could also use griddedInterpolant instead

 F=griddedInterpolant({1:3,1:3,z},matrix);
 ans= F({1:3,1:3,15});

It's hard to say which would be more efficient, in general. griddedInterpolant is a newer and better optimized function, but interp1 takes advantage of the 1D nature of the interpolation.

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

Glynn 2014-1-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/56055-interpolate-a-3d-matrix-using-interp1#answer_121023

Using the same example above, what if the xi in interp1(x,Y,xi), is a 2-d matrix the same size as the first two dimensions of 'matrix'? I keep getting OOM issues when trying to solve: x is a (1,3)array Y is a (2030,873,3) matrix xi is a (2030,873) matrix

3 个评论
显示 1更早的评论隐藏 1更早的评论

Glynn 2014-1-16

Okay got it, thanks, makes sense. So should I be using interp3 instead? I'm confused as how to set that up with my particular example. Any help is appreciated.

Matt J 2014-1-16

编辑：Matt J 2014-1-16

Yes, you could use interp3, though I think griddedInterpolant is easier to work with. I don't actually have a clear picture how your xi are supposed to be interpreted. If you are interpolating in a 3D array, like Y, then the locations at which you interpolate must consist of (xx,yy,zz) coordinate triplets.

请先登录，再进行评论。