逆滤波的实现
#define SWAP(a,b) tempr=(a);(a)=(b);(b)=tempr
//参数说明:
//LPSTR lpDIBBits - 指向源DIB图像指针
//LONG lWidth - 源图像宽度（象素数，必须是4的倍数）
//LONG lHeight - 源图像高度（象素数）
/
//函数说明:
//该函数用来对BlurDIB()生成的DIB图像进行复原操作。
BOOL WINAPI RestoreDIB (LPSTR lpDIBBits, LONG lWidth, LONG lHeight)
{
// 指向源图像的指针
LPSTR lpSrc;
//循环变量
long i;
long j;
//像素值
unsigned char pixel;
// 图像每行的字节数
LONG lLineBytes;
//用于做FFT的数组
double *fftSrc,*fftKernel;
double a,b,c,d;
//二维FFT的长度和宽度
unsigned long nn[3];
//图像归一化因子
double MaxNum;
// 计算图像每行的字节数
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++)
{
// 指向源图像倒数第j行，第i个象素的指针
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;
}
}
//对源图像进行FFT
fourn(fftSrc,nn,2,1);
//对卷积核图像进行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 );
}
}
}
//对结果图像进行反FFT
fourn(fftSrc,nn,2,-1);
//确定归一化因子
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];
}
}
//转换为图像
for (j = 0;j < lHeight ;j++)
{
for(i = 0;i < lLineBytes ;i++)
{
// 指向源图像倒数第j行，第i个象素的指针
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;
}
BOOL fourn(double * data/*psrc*/, unsigned long nn[]/*w*/, int ndim/*2*/, int isign)
{
int idim;
unsigned long i1,i2,i3,i2rev,i3rev,ip1,ip2,ip3,ifp1,ifp2;
unsigned long ibit,k1,k2,n,nprev,nrem,ntot;
double tempi,tempr;
double theta,wi,wpi,wpr,wr,wtemp;
for (ntot=1,idim=1;idim<=ndim;idim++)
ntot *= nn[idim];
nprev=1;
for (idim=ndim;idim>=1;idim--) {
n=nn[idim];
nrem=ntot/(n*nprev);
ip1=nprev << 1;
ip2=ip1*n;
ip3=ip2*nrem;
i2rev=1;
for (i2=1;i2<=ip2;i2+=ip1) {
if (i2 < i2rev) {
for (i1=i2;i1<=i2+ip1-2;i1+=2) {
for (i3=i1;i3<=ip3;i3+=ip2) {
i3rev=i2rev+i3-i2;
SWAP(data[i3],data[i3rev]);
SWAP(data[i3+1],data[i3rev+1]);
}
}
}
ibit=ip2 >> 1;
while (ibit >= ip1 && i2rev > ibit) {
i2rev -= ibit;
ibit >>= 1;
}
i2rev += ibit;
}
ifp1=ip1;
while (ifp1 < ip2) {
ifp2=ifp1 << 1;
theta=isign*6.28318530717959/(ifp2/ip1);
wtemp=sin(0.5*theta);
wpr = -2.0*wtemp*wtemp;
wpi=sin(theta);
wr=1.0;
wi=0.0;
for (i3=1;i3<=ifp1;i3+=ip1) {
for (i1=i3;i1<=i3+ip1-2;i1+=2) {
for (i2=i1;i2<=ip3;i2+=ifp2) {
k1=i2;
k2=k1+ifp1;
tempr=wr*data[k2]-wi*data[k2+1];
tempi=wr*data[k2+1]+wi*data[k2];
data[k2]=data[k1]-tempr;
data[k2+1]=data[k1+1]-tempi;
data[k1] += tempr;
data[k1+1] += tempi;
}
}
wr=(wtemp=wr)*wpr-wi*wpi+wr;
wi=wi*wpr+wtemp*wpi+wi;
}
ifp1=ifp2;
}
nprev *= n;
}
return true;
}