(39)Air Band OpenCV_找到图像中的轮廓

本文是对OpenCV2.4.13文档的部分翻译，作个人学习之用，并不完整。

#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 header
void thresh_callback(int, void* );

/**
* @function main
*/
int main()
{
/// 载入图像
src = imread("HappyFish.jpg");
if (src.empty())
{
cerr << "No image supplied ..." << endl;
return -1;
}

/// 将图像转换成灰度图并将其模糊
cvtColor( src, src_gray, COLOR_BGR2GRAY );
blur( src_gray, src_gray, Size(3,3) );

/// 创建窗口
const char* source_window = "Source";
namedWindow( source_window, WINDOW_AUTOSIZE );
imshow( source_window, src );

createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback );
thresh_callback( 0, 0 );

waitKey(0);
return(0);
}

/**
* @function thresh_callback
*/
void thresh_callback(int, void* )
{
Mat canny_output;
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;

/// 用Canny检测边缘
Canny( src_gray, canny_output, thresh, thresh*2, 3 );
/// 找到轮廓
findContours( canny_output, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );

/// 画出轮廓
Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
for( size_t i = 0; i< contours.size(); i++ )
{
Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
drawContours( drawing, contours, (int)i, color, 2, 8, hierarchy, 0, Point() );
}

/// 显示图像
namedWindow( "Contours", WINDOW_AUTOSIZE );
imshow( "Contours", drawing );
}
结果：