CPUTracker::FFT2D Class Reference

Class to facilitate 2D Fourier transforms. More...

#include <cpu_tracker.h>

Public Member Functions
	FFT2D (int w, int h)
	Initialize the class. More...
	~FFT2D ()
	Free memory and delete the instance. More...
void	Apply (float *d)
	Apply the 2D FFT. More...

Public Attributes
kissfft< float >	xfft
	Handle to FFT kissfft instance for x. More...
kissfft< float >	yfft
	Handle to FFT kissfft instance for y. More...
std::complex< float > *	cbuf
	Calculation buffer. More...

Detailed Description

Class to facilitate 2D Fourier transforms.

Definition at line 99 of file cpu_tracker.h.

Constructor & Destructor Documentation

FFT2D()

CPUTracker::FFT2D::FFT2D ( int  w, int  h  )

inline

Initialize the class.

Parameters

[in]	w	Image width.
[in]	h	Image height.

Definition at line 109 of file cpu_tracker.h.

: xfft(w,false), yfft(h,false) {cbuf=new std::complex<float>[w*h]; }

~FFT2D()

CPUTracker::FFT2D::~FFT2D ( )

inline

Free memory and delete the instance.

Definition at line 112 of file cpu_tracker.h.

{ delete[] cbuf; }

Member Function Documentation

Apply()

void CPUTracker::FFT2D::Apply

(

float *

d

)

Apply the 2D FFT.

Parameters

[in,out]

d

Input array of floats. Output will be put back in this array.

Definition at line 1026 of file cpu_tracker.cpp.

{
    int w = xfft.nfft();
    int h = yfft.nfft();

    std::complex<float>* tmpsrc = ALLOCA_ARRAY(std::complex<float>, h);
    std::complex<float>* tmpdst = ALLOCA_ARRAY(std::complex<float>, h);
    
    for(int y=0;y<h;y++) {
        for (int x=0;x<w;x++)
            tmpsrc[x]=d[y*w+x];
        xfft.transform(tmpsrc, &cbuf[y*w]);
    }
    for (int x=0;x<w;x++) {
        for (int y=0;y<h;y++)
            tmpsrc[y]=cbuf[y*w+x];
        yfft.transform(tmpsrc, tmpdst);
        for (int y=0;y<h;y++)
            cbuf[y*w+x]=tmpdst[y];
    }
    // copy and shift
    for (int y=0;y<h;y++) {
        for (int x=0;x<w;x++) {
            int dx=(x+w/2)%w;
            int dy=(y+h/2)%h;
            auto v=cbuf[x+y*w];
            d[dx+dy*w] = v.real()*v.real() + v.imag()*v.imag();
        }
    }

//  delete[] tmpsrc;
//  delete[] tmpdst;
}

Member Data Documentation

cbuf

std::complex<float>* CPUTracker::FFT2D::cbuf

Calculation buffer.

Definition at line 103 of file cpu_tracker.h.

xfft

kissfft<float> CPUTracker::FFT2D::xfft

Handle to FFT kissfft instance for x.

Definition at line 101 of file cpu_tracker.h.

yfft

kissfft<float> CPUTracker::FFT2D::yfft

Handle to FFT kissfft instance for y.

Definition at line 102 of file cpu_tracker.h.

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The documentation for this class was generated from the following files:

• cputrack/cpu_tracker.h
• cputrack/cpu_tracker.cpp