gfourier.h

来自「一个由Mike Gashler完成的机器学习方面的includes neural」· C头文件 代码 · 共 60 行

/*
	Copyright (C) 2006, Mike Gashler

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	see http://www.gnu.org/copyleft/lesser.html
*/

#ifndef __GFOURIER_H__
#define __GFOURIER_H__

class GImage;


struct ComplexNumber
{
	double real;
	double imag;

	void Multiply(struct ComplexNumber* pOther)
	{
		double t = real * pOther->real - imag * pOther->imag;
		imag = real * pOther->imag + imag * pOther->real;
		real = t;
	}
};


// Fourier transform
class GFourier
{
public:
	// This will do a Fast Forier Transform.  nArraySize must be a power of 2. If bForward is
	// false, it will perform the reverse transform
	static bool FFT(int nArraySize, struct ComplexNumber* pComplexNumberArray, bool bForward);

	// 2D Fast Forier Transform.  nArrayWidth must be a power of 2. nArrayHeight must be a power of 2. If bForward
	// is false, it will perform the reverse transform.
	static bool FFT2D(int nArrayWidth, int nArrayHeight, struct ComplexNumber* p2DComplexNumberArray, bool bForward);

	// pArrayWidth returns the width of the array and pOneThirdHeight returns one third the height of the array
	// (in other words, the height used by each of the three RGB channels)
	static struct ComplexNumber* ImageToFFTArray(GImage* pImage, int* pArrayWidth, int* pOneThirdHeight);

	// nArrayWidth is the width of the array. nOneThirdHeight is one third the height of the array. pImage is assumed
	// to already be allocated and set to the size of the image embedded in the array. normalize specifies whether or
	// not to ajust the pixel values to use their full range.
	static void FFTArrayToImage(struct ComplexNumber* pArray, int nArrayWidth, int nOneThirdHeight, GImage* pImage, bool normalize);

#ifndef NO_TEST_CODE
	static void Test();
#endif // NO_TEST_CODE
};


#endif // __GFOURIER_H__