Smoothing/splining data with a limit to the slope of the smooth fit
조회 수: 2 (최근 30일)
이전 댓글 표시
I have noisy data with erroneous measurements which I'm trying to smooth and remove outliers to better approximate the underlying "true" value that the data represent. I have a priori knowledge that the magnitude of the slope of the underlying true values cannot be more than a given value, i.e.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1123175/image.png)
In the attached example, there's a series of measurements which are erroneous around 16:25 which violate this condition. I want a way to automatically remove those points before using pchip to smooth and interpolate the data. Is there a MATLAB function already in existence which can do something like this?
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1123180/image.jpeg)
댓글 수: 2
John D'Errico
2022년 9월 13일
Be careful, as it is not always perfectly clear what is an outlier from merely the data, when viewed by an automatic scheme. It can be especially difficult when you have blocks of points that you perceive as outliers. It would help if you add a .mat file with some sample data, attached to a comment or to your original question, please.
답변 (1개)
Bruno Luong
2022년 9월 13일
편집: Bruno Luong
2022년 9월 13일
Using this File Exchange, its is not easy to find a combination of parameters to make it "works". I think it is difficult and the fit is fragile.
load('C:\Users\bruno\Downloads\example.mat')
ti=linspace(min(t),max(t),500);
pp=BSFK(t,x,3,200,[],struct('KnotRemoval','none','sigma',0,'lambda',1e-10));
plot(ti,ppval(pp,ti),'k',t,x,'.r')
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1123340/image.png)
댓글 수: 0
참고 항목
카테고리
Help Center 및 File Exchange에서 Creating and Concatenating Matrices에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!