OpenCV3.2图像分割 实例7：基于分水岭图像分割

 1 #include <opencv2/opencv.hpp>
 2 #include <iostream>
 3  
 4 using namespace cv;
 5 using namespace std;
 6  
 7 Mat watershedCluster(Mat &image, int &numSegments);
 8 //参数分别为分割后图像，分割块数，输入原图
 9 void createDisplaySegments(Mat &segments, int numSegments, Mat &image);
10 int main(int argc, char** argv) {
11     Mat src = imread("cvtest.png");
12     if (src.empty()) {
13         printf("could not load image...\n");
14         return -1;
15     }
16     namedWindow("input image", CV_WINDOW_AUTOSIZE);
17     imshow("input image", src);
18  
19     int numSegments;
20     Mat markers = watershedCluster(src, numSegments);
21     createDisplaySegments(markers, numSegments, src);
22     waitKey(0);
23     return 0;
24 }
25  
26 Mat watershedCluster(Mat &image, int &numComp) {
27     // 二值化
28     Mat gray, binary;
29     cvtColor(image, gray, COLOR_BGR2GRAY);
30     threshold(gray, binary, 0, 255, THRESH_BINARY | THRESH_OTSU);
31     // 形态学与距离变换
32     Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));
33     morphologyEx(binary, binary, MORPH_OPEN, k, Point(-1, -1));
34     Mat dist;
35     distanceTransform(binary, dist, DistanceTypes::DIST_L2, 3, CV_32F);
36     normalize(dist, dist, 0.0, 1.0, NORM_MINMAX);
37  
38     // 开始生成标记
39     threshold(dist, dist, 0.1, 1.0, THRESH_BINARY);
40     normalize(dist, dist, 0, 255, NORM_MINMAX);
41     dist.convertTo(dist, CV_8UC1);
42  
43     // 标记开始
44     vector<vector<Point>> contours;
45     vector<Vec4i> hireachy;
46     findContours(dist, contours, hireachy, RETR_CCOMP, CHAIN_APPROX_SIMPLE);
47     if (contours.empty()) {
48         return Mat();
49     }
50  
51     Mat markers(dist.size(), CV_32S);
52     markers = Scalar::all(0);
53     for (int i = 0; i < contours.size(); i++) {
54         drawContours(markers, contours, i, Scalar(i + 1), -1, 8, hireachy, INT_MAX);
55     }
56     circle(markers, Point(5, 5), 3, Scalar(255), -1);
57  
58     // 分水岭变换
59     watershed(image, markers);
60     numComp = contours.size();
61     return markers;
62 }
63  
64 void createDisplaySegments(Mat &markers, int numSegments, Mat &image) {
65     // generate random color
66     vector<Vec3b> colors;
67     for (size_t i = 0; i < numSegments; i++) {
68         int r = theRNG().uniform(0, 255);
69         int g = theRNG().uniform(0, 255);
70         int b = theRNG().uniform(0, 255);
71         colors.push_back(Vec3b((uchar)b, (uchar)g, (uchar)r));
72     }
73  
74     // 颜色填充与最终显示
75     Mat dst = Mat::zeros(markers.size(), CV_8UC3);
76     int index = 0;
77     for (int row = 0; row < markers.rows; row++) {
78         for (int col = 0; col < markers.cols; col++) {
79             index = markers.at<int>(row, col);
80             if (index > 0 && index <= numSegments) {
81                 dst.at<Vec3b>(row, col) = colors[index - 1];
82             }
83             else {
84                 dst.at<Vec3b>(row, col) = Vec3b(255, 255, 255);
85             }
86         }
87     }
88     imshow("分水岭图像分割-演示",dst);
89     return;
90 }