图像分割之分水岭算法[通俗易懂]

#include "stdafx.h"
#include "opencv2/imgproc/imgproc.hpp"  
#include "opencv2/highgui/highgui.hpp"  
#include <iostream>  
#include <fstream>  

using namespace cv;
using namespace std;

#define WINDOW_NAME1 "【程序窗口1】"        //为窗口标题定义的宏   
#define WINDOW_NAME2 "【分水岭算法效果图】"        //为窗口标题定义的宏  

//描述：全局变量的声明  
Mat g_maskImage, g_srcImage;
Point prevPt(-1, -1);
//描述：全局函数的声明  
static void ShowHelpText();
static void on_Mouse(int event, int x, int y, int flags, void*);

int main()
{
	//【0】改变console字体颜色  
	system("color 02");

	//【1】载入原图并显示，初始化掩膜和灰度图
	g_srcImage = imread("D:\\pic-sam\\哀.JPG", 1);
	namedWindow(WINDOW_NAME1, WINDOW_NORMAL);
	imshow(WINDOW_NAME1, g_srcImage);
	Mat srcImage, grayImage;
	g_srcImage.copyTo(srcImage);
	cvtColor(g_srcImage, g_maskImage, COLOR_BGR2GRAY);
	cvtColor(g_maskImage, grayImage, COLOR_GRAY2BGR);
	g_maskImage = Scalar::all(0);
	//【2】设置鼠标回调函数
	setMouseCallback(WINDOW_NAME1, on_Mouse, 0);

	//【3】轮询按键，进行处理
	while (1)
	{
		//获取键值
		int c = waitKey(0);

		//若按键键值为ESC时，退出
		if ((char)c == 27)
			break;

		//按键键值为2时，恢复源图
		if ((char)c == '2')
		{
			g_maskImage = Scalar::all(0);
			srcImage.copyTo(g_srcImage);
			imshow("image", g_srcImage);
		}

		//若检测到按键值为1或者空格，则进行处理
		if ((char)c == '1' || (char)c == ' ')
		{
			//定义一些参数
			int i, j, compCount = 0;
			vector<vector<Point> > contours;
			vector<Vec4i> hierarchy;

			//寻找轮廓
			findContours(g_maskImage, contours, hierarchy, RETR_CCOMP, CHAIN_APPROX_SIMPLE);

			//轮廓为空时的处理
			if (contours.empty())
				continue;

			//拷贝掩膜
			Mat maskImage(g_maskImage.size(), CV_32S);
			maskImage = Scalar::all(0);

			//循环绘制出轮廓
			for (int index = 0; index >= 0; index = hierarchy[index][0], compCount++)
				drawContours(maskImage, contours, index, Scalar::all(compCount + 1), -1, 8, hierarchy, INT_MAX);

			//compCount为零时的处理
			if (compCount == 0)
				continue;

			//生成随机颜色
			/*vector<Vec3b> colorTab;
			for (i = 0; i < compCount; i++)
			{
				int b = theRNG().uniform(0, 255);
				int g = theRNG().uniform(0, 255);
				int r = theRNG().uniform(0, 255);

				colorTab.push_back(Vec3b((uchar)b, (uchar)g, (uchar)r));
			}*/

			//计算处理时间并输出到窗口中
			double dTime = (double)getTickCount();
			watershed(srcImage, maskImage);
			dTime = (double)getTickCount() - dTime;
			printf("\t处理时间 = %gms\n", dTime*1000. / getTickFrequency());

			//双层循环，将分水岭图像遍历存入watershedImage中
			Mat watershedImage(maskImage.size(), CV_8UC3);
			int index1 = 0;
			for (i = 0; i < maskImage.rows; i++)
				for (j = 0; j < maskImage.cols; j++)
				{
					if(maskImage.at<int>(i, j)>index1)
					index1 = maskImage.at<int>(i, j);
				}
			for (i = 0; i < maskImage.rows; i++)
				for (j = 0; j < maskImage.cols; j++)
				{
					int index = maskImage.at<int>(i, j);
					//对watershed函数生成的index的规律不是很清楚，经测试，并不是按照标记顺序给出index的
					//具体每一块的index是怎么给出的还需要研究源码
					if (index == -1)
						watershedImage.at<Vec3b>(i, j) = Vec3b(255, 255, 255);
					else if (index <= 0 || index > compCount)
						watershedImage.at<Vec3b>(i, j) = Vec3b(0, 0, 0);
					else if (index ==index1)
						watershedImage.at<Vec3b>(i, j) = Vec3b(255, 255, 255);
					else
						watershedImage.at<Vec3b>(i, j) = Vec3b(index*10, 0, 0);//这里想给不同的物体标记为不同程度的颜色
																				//方便后面去除背景，显示目标物体
				}

			//混合灰度图和分水岭效果图并显示最终的窗口
			//watershedImage = watershedImage*0.5 + grayImage*0.5;
			imshow(WINDOW_NAME2, watershedImage);//直接显示分水岭的效果图
			//这里想直接根据index，将背景显示为黑色，需要分割出来的目标物体直接显示
			//但对index生成的规律还未搞清楚，结果可能不是很稳定
			Mat src = imread("D:\\pic-sam\\哀.JPG", 1);
			for (int i = 0; i < src.rows; i++)
				for (int j = 0; j < src.cols; j++)
				{
					int a = abs(watershedImage.at<Vec3b>(i, j)[0] - 250) / 150;
					src.at<Vec3b>(i, j)[0] *= a;
					src.at<Vec3b>(i, j)[1] *= a;
					src.at<Vec3b>(i, j)[2] *= a;
				}
			namedWindow("dst", WINDOW_NORMAL);
			imshow("dst", src);
		}
	}	
	return 0;
}

//鼠标消息回调函数  
static void on_Mouse(int event, int x, int y, int flags, void*)
{
	//处理鼠标不在窗口中的情况  
	if (x < 0 || x >= g_srcImage.cols || y < 0 || y >= g_srcImage.rows)
		return;

	//处理鼠标左键相关消息  
	if (event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON))
		prevPt = Point(-1, -1);
	else if (event == CV_EVENT_LBUTTONDOWN)
		prevPt = Point(x, y);

	//鼠标左键按下并移动，绘制出线条  
	else if (event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))
	{
		Point pt(x, y);
		if (prevPt.x < 0)
			prevPt = pt;
		line(g_maskImage, prevPt, pt, Scalar::all(255), 4, 8, 0);
		line(g_srcImage, prevPt, pt, Scalar::all(255), 4, 8, 0);
		prevPt = pt;
		imshow(WINDOW_NAME1, g_srcImage);
	}
}

//      描述：输出一些帮助信息    
static void ShowHelpText()
{
	printf("\n\n\t\t\t   当前使用的OpenCV版本为：" CV_VERSION);
	printf("\n\n  ----------------------------------------------------------------------------\n");
	//输出一些帮助信息    
	printf("\n\n\n\t欢迎来到【分水岭算法】示例程序~\n\n");
	printf("\t请先用鼠标在图片窗口中标记出大致的区域，\n\n\t然后再按键【1】或者【SPACE】启动算法。"
		"\n\n\t按键操作说明: \n\n"
		"\t\t键盘按键【1】或者【SPACE】- 运行的分水岭分割算法\n"
		"\t\t键盘按键【2】- 恢复原始图片\n"
		"\t\t键盘按键【ESC】- 退出程序\n\n\n");
}