modules/shape/samples/shape_example.cpp

一个使用形状距离算法的示例

/*
* shape_context.cpp -- 形状匹配的形状上下文演示
 */
 
#include "opencv2/shape.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"
#include <opencv2/core/utility.hpp>
#include <iostream>
#include <string>
 
using namespace std;
using namespace cv;
 
static void help()
{
printf("\n"
            “此程序演示了一种基于形状上下文进行形状比较的方法\n”
            “您应该运行程序，提供一个 1 到 20 之间的数字来选择 ../data/shape_sample 文件夹中的图像。\n”
            “调用\n”
            "./shape_example [1 到 20 之间的数字，默认为 1]\n\n");
}
 
static vector<Point> simpleContour( const Mat& currentQuery, int n=300 )
{
vector<vector<Point> > _contoursQuery;
vector <Point> contoursQuery;
findContours(currentQuery, _contoursQuery, RETR_LIST, CHAIN_APPROX_NONE);
    for (size_t border=0; border<_contoursQuery.size(); border++)
    {
        for (size_t p=0; p<_contoursQuery[border].size(); p++)
        {
contoursQuery.push_back( _contoursQuery[border][p] );
        }
    }
 
    // 如果实际点数少于 n
    int dummy=0;
    for (int add=(int)contoursQuery.size()-1; add<n; add++)
    {
contoursQuery.push_back(contoursQuery[dummy++]); //添加虚拟值
    }
 
    // 均匀采样
    cv::randShuffle(contoursQuery);
vector<Point> cont;
    for (int i=0; i<n; i++)
    {
cont.push_back(contoursQuery[i]);
    }
    return cont;
}
 
int main(int argc, char** argv)
{
    string path = "data/shape_sample/";
    cv::CommandLineParser parser(argc, argv, "{help h||}{@input|1|}");
    if (parser.has("help"))
    {
help();
        return 0;
    }
    int indexQuery = parser.get<int>("@input");
    if (!parser.check())
    {
parser.printErrors();
help();
        return 1;
    }
    if (indexQuery < 1 || indexQuery > 20)
    {
help();
        return 1;
    }
    cv::Ptr <cv::ShapeContextDistanceExtractor> mysc = cv::createShapeContextDistanceExtractor();
 
    Size sz2Sh(300,300);
stringstream queryName;
queryName<<path<<indexQuery<<".png";
    Mat query=imread(queryName.str(), IMREAD_GRAYSCALE);
    Mat queryToShow;
    resize(query, queryToShow, sz2Sh, 0, 0, INTER_LINEAR_EXACT);
    imshow("QUERY", queryToShow);
    moveWindow("TEST", 0,0);
vector<Point> contQuery = simpleContour(query);
    int bestMatch = 0;
    float bestDis=FLT_MAX;
    for ( int ii=1; ii<=20; ii++ )
    {
        if (ii==indexQuery) continue;
        waitKey(30);
stringstream iiname;
iiname<<path<<ii<<".png";
cout<<"名称: "<<iiname.str()<<endl;
        Mat iiIm=imread(iiname.str(), 0);
        Mat iiToShow;
        resize(iiIm, iiToShow, sz2Sh, 0, 0, INTER_LINEAR_EXACT);
        imshow("TEST", iiToShow);
        moveWindow("TEST", sz2Sh.width+50,0);
vector<Point> contii = simpleContour(iiIm);
        float dis = mysc->computeDistance( contQuery, contii );
        if ( dis<bestDis )
        {
bestMatch = ii;
bestDis = dis;
        }
std::cout<<" "<<queryName.str()<<" 与 "<<iiname.str()<<" 之间的距离是: "<<dis<<std::endl;
    }
    destroyWindow("TEST");
stringstream bestname;
bestname<<path<<bestMatch<<".png";
    Mat iiIm=imread(bestname.str(), 0);
    Mat bestToShow;
    resize(iiIm, bestToShow, sz2Sh, 0, 0, INTER_LINEAR_EXACT);
    imshow("最佳匹配", bestToShow);
    moveWindow("最佳匹配", sz2Sh.width+50,0);
    waitKey();
 
    return 0;
}