//參數說明:
//LPSTR lpDIBBits    - 指向源DIB圖像指針
//LONG  lWidth       - 源圖像寬度（象素數，必須是4的倍數）
//LONG  lHeight      - 源圖像高度（象素數）
/
//函數說明:
//該函數用來對BlurDIB()生成的DIB圖像進行復原操作。
BOOL WINAPI RestoreDIB (LPSTR lpDIBBits, LONG lWidth, LONG lHeight)
{
	// 指向源圖像的指針
	LPSTR	lpSrc;
	//循環變量
	long i;
	long j;
	//像素值
	unsigned char pixel;
	// 圖像每行的字節數
	LONG lLineBytes;
	//用于做FFT的數組
	double *fftSrc,*fftKernel;
	double a,b,c,d;
	//二維FFT的長度和寬度
	unsigned long nn[3];
	//圖像歸一化因子
	double MaxNum;
	// 計算圖像每行的字節數
	lLineBytes = WIDTHBYTES(lWidth * 8);
	double dPower = log((double)lLineBytes)/log(2.0);
	if(dPower != (int) dPower)
	{
		return false;
	}
	dPower = log((double)lHeight)/log(2.0);
	if(dPower != (int) dPower)
	{
		return false;
	}
	fftSrc = new double [lHeight*lLineBytes*2+1];
	fftKernel = new double [lHeight*lLineBytes*2+1];
	nn[1] = lHeight;
	nn[2] = lLineBytes;
	for (j = 0;j < lHeight ;j++)
	{
		for(i = 0;i < lLineBytes ;i++)
		{
			// 指向源圖像倒數第j行，第i個象素的指針			
			lpSrc = (char *)lpDIBBits + lLineBytes * j + i;
			
			pixel = (unsigned char)*lpSrc;
			
			fftSrc[(2*lLineBytes)*j + 2*i + 1] = (double)pixel;
			fftSrc[(2*lLineBytes)*j + 2*i + 2] = 0.0;
			
			if(i < 5 && j == 0)
			{
				fftKernel[(2*lLineBytes)*j + 2*i + 1] = 1/5.0;
			}
			else
			{
				fftKernel[(2*lLineBytes)*j + 2*i + 1] = 0.0;
			}
			fftKernel[(2*lLineBytes)*j + 2*i + 2] = 0.0;
		}
	}
	
	//對源圖像進行FFT
	fourn(fftSrc,nn,2,1);
	//對卷積核圖像進行FFT
	fourn(fftKernel,nn,2,1);
	for (j = 0;j < lHeight ;j++)
	{
		for(i = 0;i < lLineBytes ;i++)
		{
			a = fftSrc[(2*lLineBytes)*j + 2*i + 1];
			b = fftSrc[(2*lLineBytes)*j + 2*i + 2];
			c = fftKernel[(2*lLineBytes)*j + 2*i + 1];
			d = fftKernel[(2*lLineBytes)*j + 2*i + 2];
			if (c*c + d*d > 1e-3)
			{
				fftSrc[(2*lLineBytes)*j + 2*i + 1] = ( a*c + b*d ) / ( c*c + d*d );
				fftSrc[(2*lLineBytes)*j + 2*i + 2] = ( b*c - a*d ) / ( c*c + d*d );
			}
		}
	}
	//對結果圖像進行反FFT
	fourn(fftSrc,nn,2,-1);
	
	//確定歸一化因子
	MaxNum = 0.0;
	for (j = 0;j < lHeight ;j++)
	{
		for(i = 0;i < lLineBytes ;i++)
		{
			fftSrc[(2*lLineBytes)*j + 2*i + 1] = 
				sqrt(fftSrc[(2*lLineBytes)*j + 2*i + 1] * fftSrc[(2*lLineBytes)*j + 2*i + 1]\
				+fftSrc[(2*lLineBytes)*j + 2*i + 2] * fftSrc[(2*lLineBytes)*j + 2*i + 2]);
			if( MaxNum < fftSrc[(2*lLineBytes)*j + 2*i + 1])
				MaxNum = fftSrc[(2*lLineBytes)*j + 2*i + 1];
		}
	}
	
	//轉換為圖像
	for (j = 0;j < lHeight ;j++)
	{
		for(i = 0;i < lLineBytes ;i++)
		{
			// 指向源圖像倒數第j行，第i個象素的指針			
			lpSrc = (char *)lpDIBBits + lLineBytes * j + i;
			
			*lpSrc = (unsigned char) (fftSrc[(2*lLineBytes)*j + 2*i + 1]*255.0/MaxNum);
		}
	}
	delete fftSrc;
	delete fftKernel;
	// 返回
	return true;
}