CPLremFFT
by Alexandra Mercader, SG-Lib Toolbox: SolidGeometry 5.6 - CPL/Closed Polygon Lists
, Creation date: 2019-01-16, Last change: 2025-09-14
removes points from a CPL by removing high frequencies
Description
This function removes high frequencies of x and y coordinates of contours. The FFT is the method that is used for selecting the low frequencies and deleting high frequencies of the point list.
Remark: in fftshift matlab tutorial, for even number of elements there is one frequence more in the negative part of the transformated vector
In contrast to CPLfft this function does not insert auxiliary points into the shape and therefor the fourier analysis considers the points as minimum equidistant number of points(!). Therefor CPLremFFT removes redundant auxiliary points of a shape. BE SURE that you know the number of relevant points before using this function.
See Also: CPLfft
, CPLremstraightAmin
, CVLremstraight
Example Illustration
Syntax
CPLout=CPLremFFT(CPLin,percent)
Input Parameter
CPLin: | | Close point list |
percent: | | Percentage <0..100> of the number of points that remain |
Output Parameter
CPLout: | | CPL with reduced number of points |
Examples
CPLremFFT(PLcircle(5),50)
CPL=PLcircle(5); whos CPL, CPLremFFT(CPL,50); CPLN=ans; whos CPLN
CPL=PLcircle(5); whos CPL, CPLremFFT(CPL,50); CPLN=ans; whos CPLN
CPL=PLcircle(5); whos CPL, CPLremFFT(CPL,100); CPLN=ans; whos CPLN
CPL=PLsquare(5); whos CPL, CPLremFFT(CPL,50); CPLN=ans; whos CPLN
This software may be used free of charge for academic research and teaching purposes only. Commercial use, redistribution, modification, or reverse engineering is strictly prohibited. Access to source code is restricted and granted only under specific agreements. For licensing inquiries or commercial use, please contact: Tim C. Lueth
Last html export of this page out of FM database by TL: 2025-09-21