OpenCV计算卫星云图大致面积及周长

一、概述

  案例:使用OpenCV实现卫星云图的周长面积计算

  实现步骤:

    1.输入图像

    2.对图像进行高斯模糊,主要是为了降噪

    3.图像灰度化

    4.图像二值分割

    5.执行形态学操作去除小点并使对象黏连

    6.轮廓发现,并过滤目标轮廓

    7.计算轮廓周长及面积

    8.输出目标图像,并在目标图像上显示周长及面积

二、代码示例

 //【1】载入图像
    Mat src = imread(filePath);
    if(src.empty()){
        qDebug()<<"图片为空";
        return;
    }
    imshow("src",src);
    //【2】高斯模糊去除噪声
    GaussianBlur(src,src,Size(15,15),0,0);
    //【3】图像灰度化
    Mat gray;
    cvtColor(src,gray,COLOR_BGR2GRAY);
    //【4】二值分割
    threshold(gray,gray,0,255,THRESH_BINARY|THRESH_TRIANGLE);
    imshow("threshold",gray);
    //【5】执行形态学开操作
    Mat kernel = getStructuringElement(MORPH_RECT,Size(3,3),Point(-1,-1));
    morphologyEx(gray,gray,MORPH_OPEN,kernel,Point(-1,-1),2);
    imshow("morphologyEX",gray);

    //【6】发现轮廓
    vector<vector<Point>> contours;
    vector<Vec4i> hier;
    findContours(gray,contours,hier,RETR_TREE,CHAIN_APPROX_SIMPLE);
    RNG rng(123456);
    Mat resultImage = Mat::zeros(src.size(),CV_8UC3);
    for(size_t i = 0;i<contours.size();i++){
        Rect rect = boundingRect(contours[i]);
        if(rect.width>src.cols/2&&rect.height>src.rows/3){
            Scalar scalar = Scalar(rng.uniform(0,255),rng.uniform(0,255),rng.uniform(0,255));
            drawContours(resultImage,contours,i,scalar,-1,LINE_8);
            //【7】计算面积,周长
            double area = contourArea(contours[i],false);
            double length = arcLength(contours[i],false);
            QString str;
            str = QString("area:%1,length:%2").arg(area).arg(length);
            putText(resultImage,str.toStdString(),Point(src.cols/3,src.rows/2),FONT_HERSHEY_PLAIN,1,Scalar(255,255,255));
            qDebug()<<"面积:"<<area;
            qDebug()<<"周长:"<<length;
        }

    }
    //【输出目标图像】
    imshow("resultImage",resultImage);  

 

三、示例图片

 

posted on 2022-03-18 09:40  飘杨......  阅读(293)  评论(0编辑  收藏  举报