add new C++ tutorial

dnn_tutorial/connected_components_stats.cpp

@@ -0,0 +1,114 @@
+#include <opencv2/opencv.hpp>
+#include <iostream>
+
+using namespace cv;
+using namespace std;
+
+RNG rng(12345);
+void connected_component_demo(Mat &image);
+void connected_component_stats_demo(Mat &image);
+int main(int argc, char** argv) {
+	Mat src = imread("D:/javaopencv/rice.png");
+	if (src.empty()) {
+		printf("could not load image...\n");
+	}
+	imshow("input", src);
+	connected_component_stats_demo(src);
+
+	waitKey(0);
+	return 0;
+}
+
+void connected_component_demo(Mat &image) {
+	// 二值化
+	Mat gray, binary;
+	cvtColor(image, gray, COLOR_BGR2GRAY);
+	threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
+	// 形态学操作
+	Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));
+	morphologyEx(binary, binary, MORPH_OPEN, k);
+	morphologyEx(binary, binary, MORPH_CLOSE, k);
+	imshow("binary", binary);
+	imwrite("D:/ccla_binary.png", binary);
+	Mat labels = Mat::zeros(image.size(), CV_32S);
+	int num_labels = connectedComponents(binary, labels, 8, CV_32S);
+	printf("total labels : %d\n", (num_labels - 1));
+	vector<Vec3b> colors(num_labels);
+
+	// background color
+	colors[0] = Vec3b(0, 0, 0);
+
+	// object color
+	for (int i = 1; i < num_labels; i++) {
+		colors[i] = Vec3b(rng.uniform(0, 256), rng.uniform(0, 256), rng.uniform(0, 256));
+	}
+
+	// render result
+	Mat dst = Mat::zeros(image.size(), image.type());
+	int w = image.cols;
+	int h = image.rows;
+	for (int row = 0; row < h; row++) {
+		for (int col = 0; col < w; col++) {
+			int label = labels.at<int>(row, col);
+			if (label == 0) continue;
+			dst.at<Vec3b>(row, col) = colors[label];
+		}
+	}
+	imshow("ccla-demo", dst);
+	imwrite("D:/ccla_dst.png", dst);
+}
+
+void connected_component_stats_demo(Mat &image) {
+	// 二值化
+	Mat gray, binary;
+	cvtColor(image, gray, COLOR_BGR2GRAY);
+	threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
+	// 形态学操作
+	Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));
+	morphologyEx(binary, binary, MORPH_OPEN, k);
+	morphologyEx(binary, binary, MORPH_CLOSE, k);
+	imshow("binary", binary);
+	Mat labels = Mat::zeros(image.size(), CV_32S);
+	Mat stats, centroids;
+	int num_labels = connectedComponentsWithStats(binary, labels, stats, centroids, 8, 4);
+	printf("total labels : %d\n", (num_labels - 1));
+	vector<Vec3b> colors(num_labels);
+
+	// background color
+	colors[0] = Vec3b(0, 0, 0);
+
+	// object color
+	int b = rng.uniform(0, 256);
+	int g = rng.uniform(0, 256);
+	int r = rng.uniform(0, 256);
+	for (int i = 1; i < num_labels; i++) {
+		colors[i] = Vec3b(0, 255, 0);
+	}
+
+	// render result
+	Mat dst = Mat::zeros(image.size(), image.type());
+	int w = image.cols;
+	int h = image.rows;
+	for (int row = 0; row < h; row++) {
+		for (int col = 0; col < w; col++) {
+			int label = labels.at<int>(row, col);
+			if (label == 0) continue;
+			dst.at<Vec3b>(row, col) = colors[label];
+		}
+	}
+
+	// 输出统计信息
+	for (int i = 1; i < num_labels; i++) {
+		Vec2d pt = centroids.at<Vec2d>(i, 0);
+		int x = stats.at<int>(i, CC_STAT_LEFT);
+		int y = stats.at<int>(i, CC_STAT_TOP);
+		int width = stats.at<int>(i, CC_STAT_WIDTH);
+		int height = stats.at<int>(i, CC_STAT_HEIGHT);
+		int area = stats.at<int>(i, CC_STAT_AREA);
+		printf("area : %d, center point(%.2f, %.2f)\n", area, pt[0], pt[1]);
+		circle(dst, Point(pt[0], pt[1]), 2, Scalar(0, 0, 255), -1, 8, 0);
+		rectangle(dst, Rect(x, y, width, height), Scalar(255, 0, 255), 1, 8, 0);
+	}
+	imshow("ccla-demo", dst);
+	imwrite("D:/ccla_stats_dst.png", dst);
+}