opencv：读取图像中每一点像素的RGB/HSV值

痛定思痛。 2022-12-11 01:29 224阅读 0赞

#include "opencv2/core.hpp"
    #include "opencv2/imgproc.hpp"
    #include "opencv2/video.hpp"
    #include "opencv2/videoio.hpp"
    #include "opencv2/highgui.hpp"
    #include "opencv2/imgproc/imgproc_c.h"
    #include <iostream>
    #include <fstream>
    #include<iomanip>
    
    
    using namespace std;
    using namespace cv;
    
    
    int main(int argc, const char** argv)
    {
        
        // 加载图像到内存
        Mat myImg = imread("/home/oceanstar/桌面/1.jpg");
    
        // 判断图像是否存在
        if (myImg.empty())
        {
        
            cout << "could not find image..." << endl;
            return -1;
        }
    
        Mat hsvImg;
        Mat outputhsvImg;
        // 将RGB图像myImg转化为HSV图像hsvImg
        cvtColor(myImg, hsvImg, COLOR_BGR2HSV);
    
        // 定义一个与hsvImg图像一样大小的像素值都是（255,255,255,）的空白图像outputhsvImg，用于实时显示，可忽略
        outputhsvImg = Mat(hsvImg.rows, hsvImg.cols, CV_8UC3, cv::Scalar(255, 255, 255));
    
        // 显示原图
        imshow("origin", myImg);
        waitKey(1);
        double H = 0.0, S = 0.0, V = 0.0;
    
        // 建立输出文件流
        ofstream ofile;
        ofile.open("3_jpg.txt");
        ofile << "图像3.jpg每一像素的HSV值：" << endl;
        ofile << "序号\t坐标\tH\tS\tV" << endl;
    
        for (int i = 0; i < hsvImg.rows; i++)
        {
        
            for (int j = 0; j < hsvImg.cols; j++)
            {
        
                // 读取每一点HSV值，存在H,S,V变量中。
                H = hsvImg.at<Vec3b>(i, j)[0];
                S = hsvImg.at<Vec3b>(i, j)[1];
                V = hsvImg.at<Vec3b>(i, j)[2];
    
                // 将当前H,S,V值更新到空白图像中，用于显示，便于观察
                outputhsvImg.at<Vec3b>(i, j)[0] = H;
                outputhsvImg.at<Vec3b>(i, j)[1] = S;
                outputhsvImg.at<Vec3b>(i, j)[2] = V;
    
                // 显示新的实时图像
                imshow("outputhsvImage", outputhsvImg);
                char key = (char)waitKey(1);
                if (key == 27)
                    return 0;
    
                // 输出当前像素点坐标及对应H,S,V值。
                cout << "第" << i*hsvImg.rows + j << "个像素点(" << i << "," << j << ")的HSV值为："
                     << " H: " << H << " S: " << S << " V: " << V<<endl;
    
                // 将图片的HSV值写入文件
                ofile << i*hsvImg.rows + j <<"\t"<<"(" <<i<<","<<j <<")"<<"\t"<< H <<"\t"
                      << S << "\t"<< V << endl;
            }
        }
    
        //关闭文件流
        ofile.close();
    
        return 0;
    }

如果想得到RGB值，只需删除转换函数cvtColor()即可。

*  某一区域的hsv并且判断颜色

#include <opencv2/imgproc/imgproc.hpp> //头文件
    #include <opencv2/highgui/highgui.hpp>
    #include <opencv2/core/core.hpp>
    #include <iostream>
    #include <opencv2/core/types_c.h>
    
    using namespace cv; //包含cv命名空间
    using namespace std;
    
    void avg_hsv(const Mat& imagePart, int *meanH, int *meanS, int *meanV){
        
        Mat hsvImage;
        cvtColor(imagePart, hsvImage, COLOR_BGR2HSV); //将RGB转成HSV
        int rowNumber = hsvImage.rows;   //行数
        int colNumber = hsvImage.cols;   //列数
    
        CvPoint pointVal;
        int hValues = 0,sValues = 0,vValues = 0;
        for(int i = 0; i < rowNumber; i++)  //行循环，可根据需要换成rowNumber
        {
        
            for(int j = 0; j < colNumber; j++)  //列循环，同理
            {
        
                pointVal.x=j;
                pointVal.y=i;
    
                hValues +=  static_cast<int>(hsvImage.at<Vec3b>(Point(pointVal))[0]); //H通道灰度值
                sValues +=  static_cast<int>(hsvImage.at<Vec3b>(Point(pointVal))[1]); //S通道灰度值
                vValues +=  static_cast<int>(hsvImage.at<Vec3b>(Point(pointVal))[2]); //V通道灰度值
            }
        }
    
        *meanH=hValues/(rowNumber*colNumber); //区域图像的平均H值
        *meanS=sValues/(rowNumber*colNumber); //区域图像的平均S值
        *meanV=vValues/(rowNumber*colNumber); //区域图像的平均V值
    }
    
    int main()
    {
        
        // 【1】读入一张图片
        Mat srcImage = imread("/home/oceanstar/workspace/cpp/a.png"),dstImage,imagePart,hsvImage;
        resize(srcImage, srcImage, Size(srcImage.cols / 2, srcImage.rows / 2), 0, 0, INTER_LINEAR_EXACT);
        dstImage = srcImage.clone();
    
    
        while(true){
        
            Rect rect;
            rect=selectROI("aaaa", srcImage);
    
            imagePart=srcImage(rect);//抠图
    
            int meanH = 0, meanS = 0, meanV = 0;
            avg_hsv(imagePart, &meanH, &meanS, &meanV);
    
    
            std::cout << meanH << ";" << meanS << "; " << meanV << "\n";
            if ((meanH >= 0 && meanH <= 180) && (meanS>= 0 && meanS <= 255) && (meanV >= 0 && meanV <= 46)){
        
                cout << "黑" << endl;
            }else if ((meanH >= 0 && meanH <= 180) && (meanS >= 0 && meanS <= 43) && (meanV >= 46 && meanV <= 220)){
        
                cout << "灰" << endl;
            }else if ((meanH >= 0 && meanH <= 180) && (meanS >= 0 && meanS <= 30) && (meanV >= 221 && meanV <= 255)){
        
                cout << "白" << endl;
            }else if (((meanH >= 0 && meanH <= 10) || (meanH >= 156 && meanH <= 180)) && (meanV >= 43 && meanV <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "红" << endl;
            }else if ((meanH >= 11 && meanH <= 25) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "橙" << endl;
            }else if ((meanH >= 26 && meanH <= 34) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "黄" << endl;
            }else if ((meanH >= 35 && meanH <= 77) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "绿" << endl;
            }else if ((meanH >= 78 && meanH <= 99) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "青" << endl;
            }else if ((meanH >= 100 && meanH <= 124) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 &&meanV  <= 255)){
        
                cout << "蓝" << endl;
            }else if ((meanH >= 125 && meanH <= 155) && (meanS >= 43 && meanS <= 255) && (meanV >= 46 && meanV <= 255)){
        
                cout << "紫" << endl;
            }else{
        
                cout << "未知" << endl;
            }
    
            //cvtColor(srcImage,dstImage,CV_BGR2GRAY);
            // 【2】在窗口中显示载入的图片
            // imshow("效果图",dstImage);
            // 【3】等待按任意键窗口自动关闭
            waitKey(0);
        }
    
        return 0;
    }