Get derivatives of a noisy surface

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Zhenhui 2011-6-10

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/9195-get-derivatives-of-a-noisy-surface

Hi everyone,

I still have trouble in getting derivatives of a surface. Is there any method to do this as the data are noisy? For the data z=f(x,y), how can I do the smoothing/ regularization to get the reliable derivatives. Someone suggested that regularizing the differentiation process to avoid the noise amplification of finite-difference methods. Is there any way to do that in matlab?

I found some ways to smooth and get derivatives for a curve fitting like z=f(x), but I don’t know how to deal with the 3D data.

Any suggestion? Your answer will be greatly appreciated.

Cheers Hui

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Zhenhui 2011-6-10

yes, but i still didnt find ways to solve it...T-T

Zhenhui 2011-6-10

sure, thanks for linking this ;)

i am wondering whether neural network will work somehow. anyway, i dont know much about that...

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Answer 1

Sean de Wolski 2011-6-10

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https://ww2.mathworks.cn/matlabcentral/answers/9195-get-derivatives-of-a-noisy-surface#answer_12677

Perhaps a point-wise least squares method might be of interest to you?

This paper gives a fairly decent description of it for strain calculation in 2-dimensional images - numerical derivatives of a surface. http://www.sciencedirect.com/science/article/pii/S0143816609000189

It gave me good results for my work.