#include "stdafx.h"
#include "DCT.h"
#define PI 3.14159265
#define Tri 5//左上角三角形大小，用于逆变换，压缩
#define N 8
#define NN 240//图片调整后的大小
DCT::DCT()
{
}
DCT::~DCT()
{
}
//DCT变换
void DCT::Fxy2Fuv(IplImage* SRC, IplImage* DST){//DST是单通道图片
int H = NN, W = NN;
IplImage *srcimage = cvCreateImage(cvSize(W, H), IPL_DEPTH_8U, 3);
IplImage *gray = cvCreateImage(cvSize(W, H), IPL_DEPTH_8U, 1);
IplImage *dct = cvCreateImage(cvSize(W, H), IPL_DEPTH_8U, 1);
cvResize(SRC, srcimage, CV_INTER_LINEAR);//改变大小
cvCvtColor(srcimage, gray, CV_BGR2GRAY);//灰度化
double sum;
CvScalar pixel;
//遍历每个8x8小块循环
for (int dw = 0; dw < W / N; dw++){
for (int dh = 0; dh < H / N; dh++){
//对每个小块内部循环，元素对应图片像素
for (int w = dw*N; w <dw*N + N; w++){
for (int h = dh*N; h < dh*N + N; h++){
sum = 0.0;
for (int i = 0; i < N; i++){
for (int j = 0; j < N; j++){
pixel = cvGet2D(gray,dh*N+j,dw*N+i);
sum = sum + (pixel.val[0] - 128.0)*cos((2.0*i + 1.0)*(h - N*dh)*PI / (2.0*N))*cos((2.0*j + 1.0)*(w - N*dw)*PI / (2.0*N));
}
}
//end 计算变换和
sum = 2.0 * sum / N;
if (0 == (h % N)){
sum = sum / (sqrt(2.0));
}
if (0 == (w % N)){
sum = sum / (sqrt(2.0));
}
if ((h - dh*N) + (w - dw*N)<Tri){//只放入三角形中
pix[w][h] = sum;
}else{
pix[w][h] = 0.0;
}
pixel = cvScalar(sum);
cvSet2D(dct, h, w, pixel);
}
}
//end 小块内部循环
}
}
cvCopy(dct, DST, NULL);
cvReleaseImage(&srcimage);
cvReleaseImage(&gray);
cvReleaseImage(&dct);
dctflag = 1;
}
//DCT逆变换
void DCT::Fuv2Fxy(IplImage* SRC, IplImage* DST){
int H = NN, W = NN;
IplImage *dst = cvCreateImage(cvSize(W, H), IPL_DEPTH_8U, 1);
double sum,sum1;
CvScalar pixel;
//遍历每个8x8小块循环
for (int dw = 0; dw < W / N; dw++){
for (int dh = 0; dh < H / N; dh++){
//对每个小块内部循环，元素对应图片像素
for (int w = dw*N; w <dw*N + N; w++){
for (int h = dh*N; h < dh*N + N; h++){
sum = 0.0;
sum1 = 0.0;
for (int i = 0; i < N; i++){
for (int j = 0; j < N; j++){
sum1 = pix[dw*N+i][dh*N+j] * cos((2.0*(h - N*dh) + 1.0)*i*PI / (2.0*N))*cos((2.0*(w - N*dw) + 1.0)*j*PI / (2.0*N));
if (0 == i){
sum1 = sum1 / (sqrt(2.0));
}
if (0 == j){
sum1 = sum1 / (sqrt(2.0));
}
sum = sum + sum1;
}
}
//end 计算变换和
sum = 2.0 * sum / N;
pixel = cvScalar(sum + 128.0);
cvSet2D(dst, h, w, pixel);
}
}
//end 小块内部循环
}
}
cvCopy(dst, DST, NULL);
cvReleaseImage(&dst);
}
