OpenCV轮廓分析

1.轮廓发现

• 基于联通组件
• 反映图像拓扑结构

void outline_demo()
{
	QString appPath = QCoreApplication::applicationDirPath();
	QString imagePath = appPath + "/morph3.png";
	Mat img = cv::imread(imagePath.toStdString());
	if (img.empty()) {
		return;
	}
	namedWindow("input", WINDOW_AUTOSIZE);
	imshow("input", img);

	//高斯模糊：降噪
	GaussianBlur(img, img, Size(3, 3), 0);

	//To gray image
	Mat gray, binary;
	cvtColor(img, gray, COLOR_BGR2GRAY);
	imshow("gray", gray);

	//OTSU
	double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
	imshow("BINARY", binary);

	vector<vector<Point>> contours;
	vector<Vec4i> hierachy;
	findContours(binary, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point());
	drawContours(img, contours, -1, Scalar(0, 0, 255), 2, 8);

	imshow("outline", img);

	waitKey();
	destroyAllWindows();
}

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2.轮廓分析

void outline_analysis_demo()
{
	QString appPath = QCoreApplication::applicationDirPath();
	QString imagePath = appPath + "/zhifang_ball.png";
	Mat img = cv::imread(imagePath.toStdString());
	if (img.empty()) {
		return;
	}
	namedWindow("input", WINDOW_AUTOSIZE);
	imshow("input", img);

	//高斯模糊：降噪
	GaussianBlur(img, img, Size(3, 3), 0);

	//To gray image
	Mat gray, binary;
	cvtColor(img, gray, COLOR_BGR2GRAY);
	imshow("gray", gray);

	//OTSU
	double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY_INV | THRESH_OTSU);
	imshow("BINARY", binary);

	vector<vector<Point>> contours;
	vector<Vec4i> hierachy;
	findContours(binary, contours, hierachy, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE, Point());
	for (size_t t = 0; t < contours.size(); t++)
	{
		double area = contourArea(contours[t]);
		double size = arcLength(contours[t],true);
		qDebug() << "area:" << area << "  " << "size:" << size;
		if (area < 100 || size < 10) continue;
		//最大矩形
		Rect box = boundingRect(contours[t]);
		rectangle(img,box,Scalar(0,0,255),2,8,0);
		//最小矩形
		RotatedRect rrt = minAreaRect(contours[t]);
		ellipse(img, rrt, Scalar(255, 0, 0), 2, 8);

		Point2f pts[4];
		rrt.points(pts);
		for (int i = 0; i < 4; i++)
		{
			line(img, pts[i], pts[(i + 1) % 4], Scalar(0, 255, 0), 2, 8);
		}
		//绘制轮廓
		drawContours(img, contours, t, Scalar(0, 0, 255), 2, 8);
	}

	imshow("outline", img);

	waitKey();
	destroyAllWindows();
}
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3.轮廓匹配

void outline_match_demo()
{
	QString appPath = QCoreApplication::applicationDirPath();
	Mat img1 = cv::imread(appPath.toStdString() + "/abc.png");
	Mat img2 = cv::imread(appPath.toStdString() + "/a5.png");
	if (img1.empty() || img2.empty()) {
		return;
	}
	imshow("input1", img1);
	imshow("input2", img2);

	vector<vector<Point>> contours1,contours2;
	contour_info(img1, contours1);
	contour_info(img2, contours2);

	Moments mm2 = moments(contours2[0]);
	Mat hu2;
	HuMoments(mm2, hu2);


	for (size_t t = 0; t < contours1.size(); t++)
	{
		Moments mm = moments(contours1[t]);
		double cx = mm.m10 / mm.m00;
		double cy = mm.m01 / mm.m00;
		circle(img1,Point(cx, cy), 3, Scalar(255, 0, 0), 2,8, 0);
		Mat hu;
		HuMoments(mm, hu);
		double dist = matchShapes(hu, hu2, CONTOURS_MATCH_I1,0);
		if (dist < 1.0)
		{
			drawContours(img1, contours1, t, Scalar(0, 0, 255), 2, 8);
		}
	}

	imshow("match contrours demo", img1);


	waitKey();
	destroyAllWindows();
}

void contour_info(Mat &image, vector<vector<Point>> &contours)
{
	//高斯模糊：降噪
	GaussianBlur(image, image, Size(3, 3), 0);

	//To gray image
	Mat gray, binary;
	cvtColor(image, gray, COLOR_BGR2GRAY);

	//OTSU
	double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);

	vector<Vec4i> hierachy;
	findContours(binary, contours, hierachy, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE, Point());
	
}
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4.多边形逼近

void outline_fit_clicked()
{
	QString appPath = QCoreApplication::applicationDirPath();
	QString imagePath = appPath + "/contours.png";
	Mat img = cv::imread(imagePath.toStdString());
	if (img.empty()) {
		return;
	}
	namedWindow("input", WINDOW_AUTOSIZE);
	imshow("input", img);

	//高斯模糊：降噪
	GaussianBlur(img, img, Size(3, 3), 0);

	//To gray image
	Mat gray, binary;
	cvtColor(img, gray, COLOR_BGR2GRAY);
	imshow("gray", gray);

	//OTSU
	double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
	imshow("BINARY", binary);

	vector<vector<Point>> contours;
	vector<Vec4i> hierachy;
	findContours(binary, contours, hierachy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point());
	//多边形逼近
	for (size_t t = 0; t < contours.size(); t++)
	{
		Moments mm = moments(contours[t]);
		double cx = mm.m10 / mm.m00;
		double cy = mm.m01 / mm.m00;
		circle(img, Point(cx, cy), 3, Scalar(255, 0, 0), 2, 8, 0);

		double area = contourArea(contours[t]);
		double clen = arcLength(contours[t], true);
		
		Mat result;
		approxPolyDP(contours[t], result, 4, true);
		qDebug() << result.rows << " " << result.cols;

		if (result.rows == 6)
		{
			putText(img, "poly", Point(cx,cy-10), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 0, 255), 1,8);
		}
		if (result.rows == 4)
		{
			putText(img, "rectangle", Point(cx, cy - 10), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 0, 255), 1, 8);
		}
		if (result.rows == 3)
		{
			putText(img, "trriangle", Point(cx, cy - 10), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 0, 255), 1, 8);
		}
		if (result.rows >10)
		{
			putText(img, "circle", Point(cx, cy - 10), FONT_HERSHEY_PLAIN, 1.0, Scalar(0, 0, 255), 1, 8);
		}
	}


	imshow("多边形逼近", img);

	waitKey();
	destroyAllWindows();
}
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5.拟合圆和椭圆

void actual::fit_circle_demo(Mat &image)
{
	//To gray image
	Mat gray, binary;
	cvtColor(image, gray, COLOR_BGR2GRAY);

	//OTSU
	double m_otsu = threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);

	vector<vector<Point>> contours;
	vector<Vec4i> hierachy;
	findContours(binary, contours, hierachy, RETR_EXTERNAL, CHAIN_APPROX_SIMPLE, Point());
	//多边形逼近
	for (size_t t = 0; t < contours.size(); t++)
	{
		RotatedRect rrt = fitEllipse(contours[t]);
		float w = rrt.size.width;
		float h = rrt.size.height;
		Point center = rrt.center;
		circle(image, center, 3, Scalar(255.0, 0), 2, 8, 0);
		ellipse(image, rrt, Scalar(0, 255, 0), 2, 8);

	}


	imshow("拟合圆和椭圆", image);
}
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