opencv对图像进行边缘及角点检測

先看结果：

代码：

// ConsoleApplication1_812.cpp : Defines the entry point for the console application.

//

#include "stdafx.h"

#include "opencv2/opencv.hpp"

class Imagedetector{

public:

	Imagedetector():threshold(-1)

	,cross(5,5,CV_8U,cv::Scalar(0))  //初始化十字、菱形、方形、X形结构元素

	,diamond(5,5,CV_8U,cv::Scalar(1))

	,square(5,5,CV_8U,cv::Scalar(1))

	,x(5,5,CV_8U,cv::Scalar(0))

	{

		for(int i = 0;i < 5;++i){

			cross.at<uchar>(2,i) = 1;

			cross.at<uchar>(i,2) = 1;

		}

		diamond.at<uchar>(0,0)= 0;

		diamond.at<uchar>(0,1)= 0;

		diamond.at<uchar>(1,0)= 0;

		diamond.at<uchar>(4,4)= 0;

		diamond.at<uchar>(3,4)= 0;

		diamond.at<uchar>(4,3)= 0;

		diamond.at<uchar>(4,0)= 0;

		diamond.at<uchar>(4,1)= 0;

		diamond.at<uchar>(3,0)= 0;

		diamond.at<uchar>(0,4)= 0;

		diamond.at<uchar>(0,3)= 0;

		diamond.at<uchar>(1,4)= 0;

		for(int i = 0; i<5;++i)

		{

			x.at<uchar>(i,i) = 1;

			x.at<uchar>(4-i,i) = 1;

		}

	}

	void setThreshold(int thr){threshold = thr;}

	cv::Mat getEdges(const cv::Mat &image){

		cv::Mat result;

		cv::morphologyEx(image,result,cv::MORPH_GRADIENT,cv::Mat());//腐蚀和膨胀的差

		appThreshold(result);

		return result;

	}

	void appThreshold(cv::Mat &image){

		if(threshold > 0)

			cv::threshold(image,image,threshold,255,cv::THRESH_BINARY);

	}

	cv::Mat getCornres(const cv::Mat &image){

		cv::Mat result;

		cv::dilate(image,result,cross);

		cv::erode(result,result,diamond);

		cv::Mat result2;

		cv::dilate(image,result2,x);

		cv::erode(result2,result2,square);

		cv::absdiff(result2,result,result);

		appThreshold(result);

		return result;

	}

	void drawImage(const cv::Mat binary,cv::Mat image){

		cv::Mat_<uchar>::const_iterator it= binary.begin<uchar>();

		cv::Mat_<uchar>::const_iterator itend= binary.end<uchar>();

		for (int i=0; it!= itend; ++it,++i) {

			if (!*it)

				cv::circle(image,cv::Point(i%image.step,i/image.step),5,cv::Scalar(255,0,0));

		}

	}

private:

	int threshold;

	cv::Mat cross;

	cv::Mat diamond;

	cv::Mat square;

	cv::Mat x;

};

int _tmain(int argc, _TCHAR* argv[])

{

	Imagedetector detector;

	detector.setThreshold(40);

	cv::Mat image = cv::imread("building.jpg",0);

	if(!image.data)

		return -1;

	cv::Mat edges = detector.getEdges(image);

	cv::namedWindow("test",CV_WINDOW_AUTOSIZE);

	cv::imshow("test",edges);

	cv::Mat corners = detector.getCornres(image);

	cv::morphologyEx(corners,corners,cv::MORPH_TOPHAT,cv::Mat());

	cv::threshold(corners, corners, 40, 255, cv::THRESH_BINARY_INV);

	detector.drawImage(corners,image);

	cv::namedWindow("corners",CV_WINDOW_AUTOSIZE);

	cv::imshow("corners",image);

	cv::waitKey(0);

	return 0;

}

原理稍后再说。