opencv c++函数 imgproc模块 24 多边形测试

目的

本教程指导用户:

• 使用OpenCV函数 pointPolygonTest

理论

代码

本教程代码如下所示. 用户也可以点击 这里下载

#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>#include <stdlib.h>using namespace cv;using namespace std;/** @function main */int main( int argc, char** argv ){  /// 创建一个图形     const int r = 100;  Mat src = Mat::zeros( Size( 4*r, 4*r ), CV_8UC1 );  /// 绘制一系列点创建一个轮廓:  vector<Point2f> vert(6);  vert[0] = Point( 1.5*r, 1.34*r );  vert[1] = Point( 1*r, 2*r );  vert[2] = Point( 1.5*r, 2.866*r );  vert[3] = Point( 2.5*r, 2.866*r );  vert[4] = Point( 3*r, 2*r );  vert[5] = Point( 2.5*r, 1.34*r );  /// 在src内部绘制  for( int j = 0; j < 6; j++ )     { line( src, vert[j],  vert[(j+1)%6], Scalar( 255 ), 3, 8 ); }  /// 得到轮廓  vector<vector<Point> > contours; vector<Vec4i> hierarchy;  Mat src_copy = src.clone();  findContours( src_copy, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE);  /// 计算到轮廓的距离  Mat raw_dist( src.size(), CV_32FC1 );  for( int j = 0; j < src.rows; j++ )     { for( int i = 0; i < src.cols; i++ )          { raw_dist.at<float>(j,i) = pointPolygonTest( contours[0], Point2f(i,j), true ); }     }  double minVal; double maxVal;  minMaxLoc( raw_dist, &minVal, &maxVal, 0, 0, Mat() );  minVal = abs(minVal); maxVal = abs(maxVal);  /// 图形化的显示距离  Mat drawing = Mat::zeros( src.size(), CV_8UC3 );  for( int j = 0; j < src.rows; j++ )     { for( int i = 0; i < src.cols; i++ )          {            if( raw_dist.at<float>(j,i) < 0 )              { drawing.at<Vec3b>(j,i)[0] = 255 - (int) abs(raw_dist.at<float>(j,i))*255/minVal; }            else if( raw_dist.at<float>(j,i) > 0 )              { drawing.at<Vec3b>(j,i)[2] = 255 - (int) raw_dist.at<float>(j,i)*255/maxVal; }            else              { drawing.at<Vec3b>(j,i)[0] = 255; drawing.at<Vec3b>(j,i)[1] = 255; drawing.at<Vec3b>(j,i)[2] = 255; }          }     }  /// 创建窗口显示结果  char* source_window = "Source";  namedWindow( source_window, CV_WINDOW_AUTOSIZE );  imshow( source_window, src );  namedWindow( "Distance", CV_WINDOW_AUTOSIZE );  imshow( "Distance", drawing );  waitKey(0);  return(0);}

解释

结果

1. 输出如下: