OpenCV2.4.10之samples_cpp_tutorial-code_learn-----ImgTrans(Hough变换)

#include "stdafx.h"    //预编译头文件    

/**
霍夫圆变换demo
 */

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>

using namespace cv;

namespace
{
    // 滑动条命名
    const std::string windowName = "Hough Circle Detection Demo";
    const std::string cannyThresholdTrackbarName = "Canny threshold";
    const std::string accumulatorThresholdTrackbarName = "Accumulator Threshold";
    const std::string usage = "Usage : tutorial_HoughCircle_Demo <path_to_input_image>\n";

    // 初始值和最大值
    const int cannyThresholdInitialValue = 200;
    const int accumulatorThresholdInitialValue = 50;
    const int maxAccumulatorThreshold = 200;
    const int maxCannyThreshold = 255;

	//霍夫圆检测主函数
    void HoughDetection(const Mat& src_gray, const Mat& src_display, int cannyThreshold, int accumulatorThreshold)
    {
        // 存储检测到的圆
        std::vector<Vec3f> circles;
        // 霍夫圆检测函数
        HoughCircles( src_gray, circles, CV_HOUGH_GRADIENT, 1, src_gray.rows/8, cannyThreshold, accumulatorThreshold, 0, 0 );

        // 显示
        Mat display = src_display.clone();
        for( size_t i = 0; i < circles.size(); i++ )
        {
            Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
            int radius = cvRound(circles[i][2]);
            // 圆中心
            circle( display, center, 3, Scalar(0,255,0), -1, 8, 0 );
            // 圆周线
            circle( display, center, radius, Scalar(0,0,255), 3, 8, 0 );
        }

        // 显示检测结果
        imshow( windowName, display);
    }
}


int main(int argc, char** argv)
{
    Mat src, src_gray;


    // 读入图像
    src = imread("D:\\opencv\\lena.png", 1 );

    if( !src.data )
    {
        std::cerr<<"Invalid input image\n";
        std::cout<<usage;
        return -1;
    }

    // 转换成灰度图
    cvtColor( src, src_gray, COLOR_BGR2GRAY );

    // 减少图像噪声以避免错误的检测
    GaussianBlur( src_gray, src_gray, Size(9, 9), 2, 2 );

    //初始化
    int cannyThreshold = cannyThresholdInitialValue;
    int accumulatorThreshold = accumulatorThresholdInitialValue;

    // 创建窗口和滑动条
    namedWindow( windowName, WINDOW_AUTOSIZE );
    createTrackbar(cannyThresholdTrackbarName, windowName, &cannyThreshold,maxCannyThreshold);
    createTrackbar(accumulatorThresholdTrackbarName, windowName, &accumulatorThreshold, maxAccumulatorThreshold);

    // 无限循环显示
    // 更新检测图像直到输入q或者Q
    int key = 0;
    while(key != 'q' && key != 'Q')
    {
        //确保这些参数不为0
        cannyThreshold = std::max(cannyThreshold, 1);
        accumulatorThreshold = std::max(accumulatorThreshold, 1);

        //检测与显示
        HoughDetection(src_gray, src, cannyThreshold, accumulatorThreshold);

        key = waitKey(10);
    }

    return 0;
}