approxPolyDP函数

来源：互联网发布：传奇3物品数据库编辑：程序博客网时间：2024/05/22 04:59

1、approxPolyDP函数

函数的作用：

对图像轮廓点进行多边形拟合

2、函数的调用形式

C++: void approxPolyDP(InputArray curve, OutputArray approxCurve, double epsilon, bool closed)

参数详解;

InputArray curve:一般是由图像的轮廓点组成的点集

OutputArray approxCurve：表示输出的多边形点集

double epsilon：主要表示输出的精度，就是另个轮廓点之间最大距离数，5,6,7，，8，，,,，

bool closed：表示输出的多边形是否封闭

3、opencv代码

#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <iostream>#include <stdio.h>#include <stdlib.h>using namespace cv;using namespace std;Mat src; Mat src_gray;int thresh = 100;int max_thresh = 255;RNG rng(12345);/// Function headervoid thresh_callback(int, void*);/** @function main */int main(int argc, char** argv){/// 加载源图像src = imread("D:6.jpg", 1);/// 转成灰度图并进行模糊降噪cvtColor(src, src_gray, CV_BGR2GRAY);blur(src_gray, src_gray, Size(3, 3));/// 创建窗体char* source_window = "Source";namedWindow(source_window, CV_WINDOW_AUTOSIZE);imshow(source_window, src);createTrackbar(" Threshold:", "Source", &thresh, max_thresh, thresh_callback);thresh_callback(0, 0);waitKey(0);return(0);}/** @function thresh_callback */void thresh_callback(int, void*){Mat src_copy = src.clone();Mat threshold_output;vector<vector<Point> > contours;vector<Vec4i> hierarchy;/// 对图像进行二值化threshold(src_gray, threshold_output, thresh, 255, THRESH_BINARY);/// 寻找轮廓findContours(threshold_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));/*Mat drawing = Mat::zeros(threshold_output.size(), CV_8UC3);*//* 对每个轮廓计算其凸包*/vector<vector<Point> >poly(contours.size());for (int i = 0; i < contours.size(); i++){approxPolyDP(Mat(contours[i]), poly[i], 5,true);}/* 绘出轮廓及其凸包*/Mat drawing = Mat::zeros(threshold_output.size(), CV_8UC3);for (int i = 0; i< contours.size(); i++){Scalar color = Scalar(rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255));drawContours(drawing, contours, i, color, 1, 8, vector<Vec4i>(), 0, Point());drawContours(drawing, poly, i, color, 1, 8, vector<Vec4i>(), 0, Point());}/*vector<Point> poly;approxPolyDP(Mat(contours[3]), poly, 5, false);vector<Point>::const_iterator itp = poly.begin();while (itp != (poly.end() - 2)){line(drawing, *itp, *(itp + 1), Scalar(255), 2);++itp;}line(drawing, *itp, *(poly.begin()), Scalar(255), 2);*//// 把结果显示在窗体namedWindow("Hull demo", CV_WINDOW_AUTOSIZE);imshow("Hull demo", drawing);}

0 0