Opencv4轮廓分析与检测

Myth丶恋晨 2023-06-30 14:55 15阅读 0赞

关键词：轮廓检测，分析，霍夫圆检测，外接矩形，外接旋转矩形，中心点，多变形填充，目标对象检测和分割

输入：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70][]

轮廓检测和分析：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70 1][]

包括圆检测，位置，中心点，外接矩形，外切矩形，轮廓面积，周长，旋转角度等。

轮廓背景分离和提取：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70 2][]

方法2，

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70 3][]

目标对象检测和分割：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70 4][]

方法二，

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NodWZhYw_size_16_color_FFFFFF_t_70 5][]

参考代码，

void Test22()
    {
        //0:铅笔；1:打火机；2:上面带阴影的圆；3:右边的大圆；4:左下的小圆
    	vector<Point> contoursorder[5];
    	Mat src, srcback, srcback2, src_gray0, src_gray, binImg;
    	//1.读入并检测
    	src = imread("D:/images/stuff.jpg", 1);
    	srcback = imread("D:/images/stuff.jpg");
    	srcback2 = srcback.clone();
    	string str = "Hello, 2020!";
    	putText(srcback2, str, Point(100,200), FONT_HERSHEY_SIMPLEX, 2.0, Scalar(0, 0, 255), 2, 16);
    
    	imshow("src", srcback2);
    	waitKey(0);
    	Mat RoiSrcImg(src.rows, src.cols, CV_8UC3);
    	RoiSrcImg.setTo(255);//颜色都设置为白色
    	//imshow("RoiSrcImg", RoiSrcImg);
    	//waitKey(0);
    
    	Mat RoiSrcImg0(src.rows, src.cols, CV_8UC3);
    	RoiSrcImg0.setTo(255);//颜色都设置为白色
    
    	//【声明&初始化两个参数】declare and initialize both parameters that are subjects to change
    	int cannyThreshold = 21;
    	int accumulatorThreshold = 34;
    
    	cannyThreshold = std::max(cannyThreshold, 1);
    	accumulatorThreshold = std::max(accumulatorThreshold, 1);
    
    
    	Mat src1 = CalculateImageGradient(src, false);
    	//imshow("src1", src1);
    	//waitKey(0);
    	//查找轮廓
    	灰度化
    	//src_gray = src1;
    	int iii = src1.channels();
    	cvtColor(src1, src_gray, COLOR_RGB2GRAY);
    
    	//2.转为灰度，并模糊除噪- -预处理
    	cvtColor(src, src_gray0, COLOR_BGR2GRAY);
    	GaussianBlur(src_gray0, src_gray0, Size(9, 9), 2, 2);
    
    	//二值化	
    	threshold(src_gray, binImg, 0, 255, THRESH_BINARY | THRESH_OTSU);
    	//imshow("bin", binImg);
    	//waitKey(0);
    	///
    	vector<vector<Point>> contours;
    	//vector<Rect> boundRect(contours.size());
    
    	//注意第5个参数为CV_RETR_EXTERNAL，只检索外框   //找轮廓
    	findContours(binImg, contours, RETR_EXTERNAL, CHAIN_APPROX_NONE);
    	//
    	cout << contours.size() << endl;
    	int iSeq = -1;
    	for (int i = 0; i < contours.size(); i++)
    	{
    		double area = contourArea(contours[i]);
    		double len = arcLength(contours[i], true);
    
    		if (area > 1000)// continue;
    		{
    			if (area > 6300 && area < 6400)
    			{
    				contoursorder[1] = contours[i];
    				Rect  recttt = boundingRect(Mat(contours[i]));
    
    				rectangle(src, recttt, (0, 0, 255), 2, 8, 0);
    				//cv::drawContours(RoiSrcImg, contours, i, Scalar(0), FILLED);
    				rectangle(RoiSrcImg, recttt,Scalar(0), -1);
    				//imshow("RoiSrcImg1", RoiSrcImg);
    				//waitKey(0);
    				cv::RotatedRect &&rotate_rect = cv::minAreaRect(contours[i]);
    				circle(src, rotate_rect.center, 3, Scalar(0, 0, 255), -1, 8, 0);
    				string strarea = "area:" + doubleConverToString(area);
    
    				putText(src, strarea, rotate_rect.center, FONT_HERSHEY_SIMPLEX, 1.0, Scalar(255, 0, 0), 1, 8);
    			}
    			else if (area > 5900 && area < 6000)
    			{
    				contoursorder[0] = contours[i];
    				//cv::drawContours(RoiSrcImg, contours, i, Scalar(0), FILLED);
    				DrawCircumscribedRectangle2(src, RoiSrcImg,contours[i]);
    			}
    			else
    			{
    
    				//参数：src【gray】， src【显示】，canny阈值，累加阈值
    				HoughDetection2(src_gray0, src, RoiSrcImg,cannyThreshold, accumulatorThreshold);
    			}
    		}
    		else
    		{
    			drawContours(binImg, contours, i, Scalar(0), FILLED);
    		}
    	}
    	bitwise_not(RoiSrcImg, RoiSrcImg);
    	imshow("轮廓+背景", RoiSrcImg);
    	waitKey(0);	
    }

霍夫圆检测参考代码，

void HoughDetection2(const Mat& src_gray, const Mat& src_display, Mat& src_display2, int cannyThreshold, int accumulatorThreshold)
    {
    	//检测结果 向量
    	std::vector<Vec3f> circles;
    	//霍夫圆检测
    	//参数：src，输出数组，霍夫梯度，dp?，最小圆心距，Canny阈值，累加阈值
    	HoughCircles(src_gray, circles, HOUGH_GRADIENT, 1, src_gray.rows / 8, cannyThreshold, accumulatorThreshold, 0, 0);
    
    	Mat display = src_display.clone();
    	for (size_t i = 0; i < circles.size(); i++)
    	{
    		//Center ——(x,y)
    		Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
    		//半径——r
    		int radius = cvRound(circles[i][2]);
    		Point ptlt, ptlb, ptrb, ptrt;
    		ptlt.x = circles[i][0] - radius;
    		ptlt.y = circles[i][1] - radius;
    		//
    		ptlb.x = circles[i][0] - radius;
    		ptlb.y = circles[i][1] + radius;
    		/
    		ptrb.x = circles[i][0] + radius;
    		ptrb.y = circles[i][1] + radius;
    		/
    		ptrt.x = circles[i][0] + radius;
    		ptrt.y = circles[i][1] - radius;
    		/
    		//中心圆
    		circle(display, center, 3, Scalar(0, 255, 0), -1, 8, 0);
    		if (0 == i)
    		{
    			//外轮廓圆
    			circle(display, center, radius, Scalar(0, 0, 255), 3, 8, 0);
    			circle(src_display2, center, radius, Scalar(0, 0, 0), -1);
    			//rectangle(display, ptlt, ptrb, Scalar(0, 0, 255), 2, 8, 0);
    			double darea = PI * radius*radius;
    			string strarea = "area:" + doubleConverToString(darea);
    			double dlength = 2 * PI*radius;
    			string strperimeter = "length:" + doubleConverToString(dlength);
    			putText(display, strarea, Point(cvRound(circles[i][0]), cvRound(circles[i][1])), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    			//putText(display, strperimeter, Point(cvRound(circles[i][0]), cvRound(circles[i][1] + radius / 2)), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    		}
    		else if (1 == i)
    		{
    			//外轮廓圆
    			circle(display, center, radius, Scalar(0, 0, 255), 3, 8, 0);
    			circle(src_display2, center, radius, Scalar(0, 0, 0), -1);
    			//rectangle(display, ptlt, ptrb, Scalar(0, 0, 255), 2, 8, 0);
    			double darea = PI * radius*radius;
    			string strarea = "area:" + doubleConverToString(darea);
    			double dlength = 2 * PI*radius;
    			string strperimeter = "length:" + doubleConverToString(dlength);
    			putText(display, strarea, Point(cvRound(circles[i][0]), cvRound(circles[i][1] - radius / 2)), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    			putText(display, strperimeter, Point(cvRound(circles[i][0]), cvRound(circles[i][1] + radius / 2)), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    		}
    		else if (2 == i)
    		{
    			//外轮廓圆
    			circle(display, center, radius, Scalar(0, 0, 255), 3, 8, 0);
    			circle(src_display2, center, radius, Scalar(0, 0, 0), -1);
    			//rectangle(display, ptlt, ptrb, Scalar(0, 0, 255), 2, 8, 0);
    			double darea = PI * radius*radius;
    			string strarea = "area:" + doubleConverToString(darea);
    			double dlength = 2 * PI*radius;
    			string strperimeter = "length:" + doubleConverToString(dlength);
    			//putText(display, strarea, Point(cvRound(circles[i][0]), cvRound(circles[i][1] - radius / 2)), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    			putText(display, strperimeter, Point(cvRound(circles[i][0]), cvRound(circles[i][1] + radius / 2)), FONT_HERSHEY_SIMPLEX, 1.0, Scalar(0, 255, 0), 1, 8);
    		}
    		else
    		{
    
    		}
    
    	}
    
    	imshow("轮廓检测和分析", display);
    	waitKey(0);
    	destroyAllWindows();
    }

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