OpenCV  4.0.1 Open Source Computer Vision
Fourier descriptors

## Classes

class  cv::ximgproc::ContourFitting
Class for ContourFitting algorithms. ContourFitting match two contours $$z_a$$ and $$z_b$$ minimizing distance

$d(z_a,z_b)=\sum (a_n - s b_n e^{j(n \alpha +\phi )})^2$

where $$a_n$$ and $$b_n$$ are Fourier descriptors of $$z_a$$ and $$z_b$$ and s is a scaling factor and $$\phi$$ is angle rotation and $$\alpha$$ is starting point factor adjustement. More...

## Functions

void cv::ximgproc::contourSampling (InputArray src, OutputArray out, int nbElt)
Contour sampling . More...

Ptr< ContourFittingcv::ximgproc::createContourFitting (int ctr=1024, int fd=16)
create ContourFitting algorithm object More...

void cv::ximgproc::fourierDescriptor (InputArray src, OutputArray dst, int nbElt=-1, int nbFD=-1)
Fourier descriptors for planed closed curves. More...

void cv::ximgproc::transformFD (InputArray src, InputArray t, OutputArray dst, bool fdContour=true)
transform a contour More...

## § contourSampling()

 void cv::ximgproc::contourSampling ( InputArray src, OutputArray out, int nbElt )
Python:
out=cv.ximgproc.contourSampling(src, nbElt[, out])

Contour sampling .

Parameters
 src contour type vector , vector or vector out Mat of type CV_64FC2 and nbElt rows nbElt number of points in out contour

## § createContourFitting()

 Ptr cv::ximgproc::createContourFitting ( int ctr = 1024, int fd = 16 )
Python:
retval=cv.ximgproc.createContourFitting([, ctr[, fd]])

create ContourFitting algorithm object

Parameters
 ctr number of Fourier descriptors equal to number of contour points after resampling. fd Contour defining second shape (Target).

## § fourierDescriptor()

 void cv::ximgproc::fourierDescriptor ( InputArray src, OutputArray dst, int nbElt = -1, int nbFD = -1 )
Python:
dst=cv.ximgproc.fourierDescriptor(src[, dst[, nbElt[, nbFD]]])

Fourier descriptors for planed closed curves.

For more details about this implementation, please see [161]

Parameters
 src contour type vector , vector or vector dst Mat of type CV_64FC2 and nbElt rows A VERIFIER nbElt number of rows in dst or getOptimalDFTSize rows if nbElt=-1 nbFD number of FD return in dst dst = [FD(1...nbFD/2) FD(nbFD/2-nbElt+1...:nbElt)]

## § transformFD()

 void cv::ximgproc::transformFD ( InputArray src, InputArray t, OutputArray dst, bool fdContour = true )
Python:
dst=cv.ximgproc.transformFD(src, t[, dst[, fdContour]])

transform a contour

Parameters
 src contour or Fourier Descriptors if fd is true t transform Mat given by estimateTransformation dst Mat of type CV_64FC2 and nbElt rows fdContour true src are Fourier Descriptors. fdContour false src is a contour