【OpenCV学习笔记】3.1 RGB图像转换为HSI图像

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由于发现OpenCV中cvtColor()函数中没有给定RGB颜色模型到HSI模型的变换类型，学习一下自己写这个函数。

颜色模型变换公式

这里写图片描述

代码

#include<opencv2/opencv.hpp>#include<math.h>#include<vector>using namespace std;using namespace cv;//-------------------------- RGB 模型 转换为 HSI 模型--------------------//int main(){    Mat LeafBGRImage = imread("……/yy2.bmp");    Mat LeafHSIImage = Mat(Size(LeafBGRImage.cols, LeafBGRImage.rows), CV_8UC3);    vector <Mat> channels;    split(LeafHSIImage, channels);    Mat Hvalue = channels.at(0);    Mat Svalue = channels.at(1);    Mat Ivalue = channels.at(2);    for (int i = 0; i < LeafBGRImage.rows; ++i)        for (int j = 0; j < LeafBGRImage.cols; ++j)        {            double H, S, I;            int Bvalue = LeafBGRImage.at<Vec3b>(i, j)(0);            int Gvalue = LeafBGRImage.at<Vec3b>(i, j)(1);            int Rvalue = LeafBGRImage.at<Vec3b>(i, j)(2);            //求Theta =acos((((Rvalue - Gvalue) + (Rvalue - Bvalue)) / 2) / sqrt(pow((Rvalue - Gvalue), 2) + (Rvalue - Bvalue)*(Gvalue - Bvalue)));            double numerator = ((Rvalue - Gvalue) + (Rvalue - Bvalue)) / 2;            double denominator = sqrt(pow((Rvalue - Gvalue), 2) + (Rvalue - Bvalue)*(Gvalue - Bvalue));            if (denominator == 0) H = 0;            else{                double Theta = acos(numerator / denominator) * 180 / 3.14;                if (Bvalue <= Gvalue)                     H = Theta;                else  H = 360 - Theta;            }                   Hvalue.at<uchar>(i, j) = (int)(H * 255 / 360); //为了显示将[0~360]映射到[0~255]            //求S = 1-3*min(Bvalue,Gvalue,Rvalue)/(Rvalue+Gvalue+Bvalue);            int minvalue = Bvalue;            if (minvalue > Gvalue) minvalue = Gvalue;            if (minvalue > Rvalue) minvalue = Rvalue;            numerator = 3 * minvalue;            denominator = Rvalue + Gvalue + Bvalue;            if (denominator == 0)  S = 0;            else{                S = 1 - numerator / denominator;            }            Svalue.at<uchar>(i, j) = (int)(S * 255);//为了显示将[0~1]映射到[0~255]            I= (Rvalue + Gvalue + Bvalue) / 3;                      Ivalue.at<uchar>(i, j) = (int)(I);        }    merge(channels, LeafHSIImage);    namedWindow("HSI");    imshow("HSI", LeafHSIImage);    waitKey(6000);    return 0;}

实例效果

这里写图片描述

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