Function after spline fitting
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Hello hello,
I have a question regarding spline fitting. I have the below curve which obtained by fitting a curve on my test data. (this is the roll angle of an IMU data) I used spline fitting and piecewise polynomial to have it smoothend by increasing the increment (time) 10 times.
I want to use this data in another program to create motion on a body.
Is it possible to obtain this curve az a sin/cos function? Or any kind of function?
Thank you for your answers:)
回答（2 个）
John D'Errico
2021-3-26
0 个投票
You cannot extract any "function" from a spline. At least, if you did, it would not be anything you could read or type without many, many coefficients, that you problably would not find useful.
In order to build an approximation using a sum of sin and cosine terms, you will usually use a tool like the curve fitting toolbox, but the optimization or stats toolbox can also do nicely. you can also do it without any such toolbox, but it wil take more effort. So knowing what you have would be important. Also, it would greatly help to have your data.
Star Strider
2021-3-26
0 个投票
The easiest way to fit it to a sin or cos function (or both) to it would be to take the Fourier transform of it using the fft function. It would then be possible to reconstruct it in the time domain from the real and imaginary coefficients at the frequencies you want to use for that. (It would likely require several terms to get a decent approximation to the data.)
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