#include <iostream>
#include <opencv2/core.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
using namespace cv;
Mat RGB2HSI(Mat src){
int row = src.rows;
int col = src.cols;
Mat dsthsi(row, col, CV_64FC3);
Mat H = Mat(row, col, CV_64FC1);
Mat S = Mat(row, col, CV_64FC1);
Mat I = Mat(row, col, CV_64FC1);
for (int i = 0; i < row; i++){
for (int j = 0; j < col; j++){
double h, s, newi, th;
double B = (double)src.at<Vec3b>(i, j)[0] / 255.0;
double G = (double)src.at<Vec3b>(i, j)[1] / 255.0;
double R = (double)src.at<Vec3b>(i, j)[2] / 255.0;
double mi, mx;
if (R > G && R > B){
mx = R;
mi = min(G, B);
}
else{
if (G > B){
mx = G;
mi = min(R, B);
}
else{
mx = B;
mi = min(R, G);
}
}
newi = (R + G + B) / 3.0;
if (newi < 0) newi = 0;
else if (newi > 1) newi = 1.0;
if (newi == 0 || mx == mi){
s = 0;
h = 0;
}
else{
s = 1 - mi / newi;
th = (R - G) * (R - G) + (R - B) * (G - B);
th = sqrt(th) + 1e-5;
th = acos(((R - G + R - B)*0.5) / th);
if (G >= B) h = th;
else h = 2 * CV_PI - th;
}
h = h / (2 * CV_PI);
H.at<double>(i, j) = h;
S.at<double>(i, j) = s;
I.at<double>(i, j) = newi;
dsthsi.at<Vec3d>(i, j)[0] = h;
dsthsi.at<Vec3d>(i, j)[1] = s;
dsthsi.at<Vec3d>(i, j)[2] = newi;
}
}
return dsthsi;
}
Mat HSI2RGB(Mat src){
int row = src.rows;
int col = src.cols;
Mat dst(row, col, CV_64FC3);
for (int i = 0; i < row; i++){
for (int j = 0; j < col; j++){
double preh = src.at<Vec3d>(i, j)[0] * 2 * CV_PI;//H
double pres = src.at<Vec3d>(i, j)[1]; //S
double prei = src.at<Vec3d>(i, j)[2]; //I
double r = 0, g = 0, b = 0;
double t1, t2, t3;
t1 = (1.0 - pres) / 3.0;
if (preh >= 0 && preh < (CV_PI * 2 / 3)){
b = t1;
t2 = pres * cos(preh);
t3 = cos(CV_PI / 3 - preh);
r = (1 + t2 / t3) / 3;
r = 3 * prei * r;
b = 3 * prei * b;
g = 3 * prei - (r + b);
}
else if (preh >= (CV_PI * 2 / 3) && preh < (CV_PI * 4 / 3)){
r = t1;
t2 = pres * cos(preh - 2 * CV_PI / 3);
t3 = cos(CV_PI - preh);
g = (1 + t2 / t3) / 3;
r = 3 * prei * r;
g = 3 * g * prei;
b = 3 * prei - (r + g);
}
else if (preh >= (CV_PI * 4 / 3) && preh <= (CV_PI * 2)){
g = t1;
t2 = pres * cos(preh - 4 * CV_PI / 3);
t3 = cos(CV_PI * 5 / 3 - preh);
b = (1 + t2 / t3) / 3;
g = 3 * g * prei;
b = 3 * prei * b;
r = 3 * prei - (g + b);
}
dst.at<Vec3d>(i, j)[0] = b;
dst.at<Vec3d>(i, j)[1] = g;
dst.at<Vec3d>(i, j)[2] = r;
}
}
return dst;
}
int main(){
cv::Mat src = cv::imread("I:/Learning-and-Practice/2019Change/Image process algorithm/Img/002.jpg");
if (src.empty()){
return -1;
}
cv::Mat dst, dst2;
//////////RGB2HSI//////////
double t1 = (double)cv::getTickCount(); //测时间
dst = RGB2HSI(src); //RGB2HSI
dst2 = HSI2RGB(dst); //HSI2BGR
//std::cout << dst << std::endl;
t1 = (double)cv::getTickCount() - t1;
double time1 = (t1 *1000.) / ((double)cv::getTickFrequency());
std::cout << "My_RGB2HSI=" << time1 << " ms. " << std::endl << std::endl;
cv::namedWindow("src", CV_WINDOW_NORMAL);
imshow("src", src);
cv::namedWindow("My_RGB2HSI", CV_WINDOW_NORMAL);
imshow("My_RGB2HSI", dst);
cv::namedWindow("My_HSI2RGB", CV_WINDOW_NORMAL);
imshow("My_HSI2RGB", dst2);
cv::waitKey(0);
return 0;
}
