From 7c7c9a383b44a1de3de3ae866f056da50975f099 Mon Sep 17 00:00:00 2001
From: bsdnoobz <nash@bsd-noobz.com>
Date: Fri, 4 Jan 2013 23:47:36 +0700
Subject: Added watershed.cpp

---
 watershed.cpp | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 watershed.cpp

diff --git a/watershed.cpp b/watershed.cpp
new file mode 100644
index 0000000..64fe039
--- /dev/null
+++ b/watershed.cpp
@@ -0,0 +1,95 @@
+/**
+ * Count and segment overlapping objects with Watershed and Distance Transform.
+ *
+ * See the tutorial at:
+ * http://opencv-code.com/count-and-segment-overlapping-objects-with-watershed-and-distance-transform/
+ */
+#include <opencv2/imgproc/imgproc.hpp>
+#include <opencv2/highgui/highgui.hpp>
+#include <iostream>
+
+int main()
+{
+	cv::Mat src = cv::imread("coins.jpg");
+	if (!src.data)
+		return -1;
+
+	cv::imshow("src", src);
+
+	// Create binary image from source image
+	cv::Mat bw;
+	cv::cvtColor(src, bw, CV_BGR2GRAY);
+	cv::threshold(bw, bw, 40, 255, CV_THRESH_BINARY);
+	cv::imshow("bw", bw);
+
+	// Perform the distance transform algorithm
+	cv::Mat dist;
+	cv::distanceTransform(bw, dist, CV_DIST_L2, 3);
+
+	// Normalize the distance image for range = {0.0, 1.0}
+	// so we can visualize and threshold it
+	cv::normalize(dist, dist, 0, 1., cv::NORM_MINMAX);
+	cv::imshow("dist", dist);
+
+	// Threshold to obtain the peaks 
+	// This will be the markers for the foreground objects
+	cv::threshold(dist, dist, .5, 1., CV_THRESH_BINARY);
+	cv::imshow("dist2", dist);
+
+	// Create the CV_8U version of the distance image
+	// It is needed for cv::findContours()
+	cv::Mat dist_8u;
+	dist.convertTo(dist_8u, CV_8U);
+
+	// Find total markers
+	std::vector<std::vector<cv::Point> > contours;
+	cv::findContours(dist_8u, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
+	int ncomp = contours.size();
+
+	// Create the marker image for the watershed algorithm
+	cv::Mat markers = cv::Mat::zeros(dist.size(), CV_32SC1);
+
+	// Draw the foreground markers
+	for (int i = 0; i < ncomp; i++)
+		cv::drawContours(markers, contours, i, cv::Scalar::all(i+1), -1);
+
+	// Draw the background marker
+	cv::circle(markers, cv::Point(5,5), 3, CV_RGB(255,255,255), -1);
+	cv::imshow("markers", markers*10000);
+
+	// Perform the watershed algorithm
+	cv::watershed(src, markers);
+
+	// Generate random colors
+	std::vector<cv::Vec3b> colors;
+	for (int i = 0; i < ncomp; i++)
+	{
+		int b = cv::theRNG().uniform(0, 255);
+		int g = cv::theRNG().uniform(0, 255);
+		int r = cv::theRNG().uniform(0, 255);
+
+		colors.push_back(cv::Vec3b((uchar)b, (uchar)g, (uchar)r));
+	}
+
+	// Create the result image
+	cv::Mat dst = cv::Mat::zeros(markers.size(), CV_8UC3);
+
+	// Fill labeled objects with random colors
+	for (int i = 0; i < markers.rows; i++)
+	{
+		for (int j = 0; j < markers.cols; j++)
+		{
+			int index = markers.at<int>(i,j);
+			if (index > 0 && index <= ncomp)
+				dst.at<cv::Vec3b>(i,j) = colors[index-1];
+			else
+				dst.at<cv::Vec3b>(i,j) = cv::Vec3b(0,0,0);
+		}
+	}
+
+	cv::imshow("dst", dst);
+
+	cv::waitKey(0);
+	return 0;
+}
+
-- 
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