dct.rar_图像进行DCT

#define EXTRA_NAME "@dcttransform." #include "loadbmp.h" #define Point(x,y) lpPoints[(x)+(y)*nWidth] void FFT(COMPLEX * TD, COMPLEX * FD, int power) { int count; int i,j,k,bfsize,p; double angle; COMPLEX *W,*X1,*X2,*X; count=1<<power; W=(COMPLEX *)malloc(sizeof(COMPLEX)*count/2); X1=(COMPLEX *)malloc(sizeof(COMPLEX)*count); X2=(COMPLEX *)malloc(sizeof(COMPLEX)*count); for(i=0;i<count/2;i++) { angle=-i*pi*2/count; W[i].re=cos(angle); W[i].im=sin(angle); } memcpy(X1,TD,sizeof(COMPLEX)*count); for(k=0;k<power;k++) { for(j=0;j<1<<k;j++) { bfsize=1<<(power-k); for(i=0;i<bfsize/2;i++) { p=j*bfsize; X2[i+p]=Add(X1[i+p],X1[i+p+bfsize/2]); X2[i+p+bfsize/2]=Mul(Sub(X1[i+p],X1[i+p+bfsize/2]),W[i*(1<<k)]); } } X=X1; X1=X2; X2=X; } for(j=0;j<count;j++) { p=0; for(i=0;i<power;i++) { if (j&(1<<i)) p+=1<<(power-i-1); } FD[j]=X1[p]; } free(W); free(X1); free(X2); } void DCT_Pre(double *f, double *F, int power) { int i,count; COMPLEX *X; double s; count=1<<power; X=(COMPLEX *)malloc(sizeof(COMPLEX)*count*2); memset(X,0,sizeof(COMPLEX)*count*2); for(i=0;i<count;i++) { X[i].re=f[i]; } FFT(X,X,power+1); s=1/sqrt(count); F[0]=X[0].re*s; s*=sqrt(2); for(i=1;i<count;i++) { F[i]=(X[i].re*cos(i*pi/(count*2))+X[i].im*sin(i*pi/(count*2)))*s; } free(X); } void Dct() { int w=1,h=1,wp=0,hp=0; while(w*2<=nWidth) { w*=2; wp++; } while(h*2<=nHeight) { h*=2; hp++; } int x,y; BYTE *lpPoints=new BYTE[nWidth*nHeight]; GetPoints(lpPoints); double *f=new double[w*h]; double *W=new double[w*h]; for(y=0;y<h;y++) { for(x=0;x<w;x++) { f[x+y*w]=Point(x,y); } } for(y=0;y<h;y++) { DCT_Pre(&f[w*y],&W[w*y],wp); } for(y=0;y<h;y++) { for(x=0;x<w;x++) { f[x*h+y]=W[x+w*y]; } } for(x=0;x<w;x++) { DCT_Pre(&f[x*h],&W[x*h],hp); } double a; memset(lpPoints,0,nWidth*nHeight); for(y=0;y<h;y++) { for(x=0;x<w;x++) { a=fabs(W[x*h+y]); if (a>255) a=255; Point(x,nHeight-y-1)=(BYTE)(a); } } delete f; delete W; PutPoints(lpPoints); delete lpPoints; } void main(int argc, char *argv[]) { if(argc==2) FileName=argv[1]; else return; OpenFile(); Dct(); SaveAs(); }