OpenCV3.2图像分割 实例9：K-Means-证件照背景替换

  1 #include <opencv2/opencv.hpp>
  2 #include <iostream>
  3  
  4 using namespace cv;
  5 using namespace std;
  6  
  7 Mat mat_to_samples(Mat &image);
  8 int main(int argc, char** argv) {
  9     Mat src = imread("tx.png");
 10     if (src.empty()) {
 11         printf("could not load image...\n");
 12         return -1;
 13     }
 14     namedWindow("输入图像", CV_WINDOW_AUTOSIZE);
 15     imshow("输入图像", src);
 16  
 17     // 组装数据
 18     Mat points = mat_to_samples(src);
 19  
 20     // 运行KMeans
 21     int numCluster = 4;
 22     Mat labels;
 23     Mat centers;
 24     TermCriteria criteria = TermCriteria(TermCriteria::EPS + TermCriteria::COUNT, 10, 0.1);
 25     kmeans(points, numCluster, labels, criteria, 3, KMEANS_PP_CENTERS, centers);
 26  
 27     // 去背景+遮罩生成
 28     Mat mask=Mat::zeros(src.size(), CV_8UC1);
 29     int index = src.rows*2 + 2;
 30     int cindex = labels.at<int>(index, 0);
 31     int height = src.rows;
 32     int width = src.cols;
 33     //Mat dst;
 34     //src.copyTo(dst);
 35     for (int row = 0; row < height; row++) {
 36         for (int col = 0; col < width; col++) {
 37             index = row*width + col;
 38             int label = labels.at<int>(index, 0);
 39             if (label == cindex) { // 背景
 40                 //dst.at<Vec3b>(row, col)[0] = 0;
 41                 //dst.at<Vec3b>(row, col)[1] = 0;
 42                 //dst.at<Vec3b>(row, col)[2] = 0;
 43                 mask.at<uchar>(row, col) = 0; 
 44             } else {
 45                 mask.at<uchar>(row, col) = 255;
 46             }
 47         }
 48     }
 49     imshow("mask-遮罩", mask);
 50  
 51     // 腐蚀 + 高斯模糊
 52     Mat k = getStructuringElement(MORPH_RECT, Size(3, 3), Point(-1, -1));//用3*3像素进行腐蚀（减少3*3）
 53     erode(mask, mask, k);
 54     imshow("腐蚀-mask", mask);
 55     GaussianBlur(mask, mask, Size(3, 3), 0, 0);//用3*3像素进行高斯模糊（增加3*3）  所以边界不变
 56     imshow("高斯模糊-mask", mask);
 57  
 58     // 通道混合
 59     RNG rng(12345);//随机数
 60     Vec3b color;
 61     color[0] = 217;//rng.uniform(0, 255);
 62     color[1] = 60;// rng.uniform(0, 255);
 63     color[2] = 160;// rng.uniform(0, 255);
 64     Mat result(src.size(), src.type());
 65  
 66     double w = 0.0;
 67     int b = 0, g = 0, r = 0;
 68     int b1 = 0, g1 = 0, r1 = 0;
 69     int b2 = 0, g2 = 0, r2 = 0;
 70  
 71     for (int row = 0; row < height; row++) {
 72         for (int col = 0; col < width; col++) {
 73             int m = mask.at<uchar>(row, col);
 74             if (m == 255) {
 75                 result.at<Vec3b>(row, col) = src.at<Vec3b>(row, col); // 前景
 76             }
 77             else if (m == 0) {
 78                 result.at<Vec3b>(row, col) = color; // 背景
 79             } 
 80             else {
 81                 w = m / 255.0;
 82                 b1 = src.at<Vec3b>(row, col)[0];
 83                 g1 = src.at<Vec3b>(row, col)[1];
 84                 r1 = src.at<Vec3b>(row, col)[2];
 85  
 86                 b2 = color[0];
 87                 g2 = color[1];
 88                 r2 = color[2];
 89  
 90                 b = b1*w + b2*(1.0 - w);
 91                 g = g1*w + g2*(1.0 - w);
 92                 r = r1*w + r2*(1.0 - w);
 93  
 94                 result.at<Vec3b>(row, col)[0] = b;
 95                 result.at<Vec3b>(row, col)[1] = g;
 96                 result.at<Vec3b>(row, col)[2] = r;
 97             }
 98         }
 99     }
100     imshow("背景替换", result);
101  
102     waitKey(0);
103     return 0;
104 }
105  
106 Mat mat_to_samples(Mat &image) {
107     int w = image.cols;
108     int h = image.rows;
109     int samplecount = w*h;
110     int dims = image.channels();
111     Mat points(samplecount, dims, CV_32F, Scalar(10));
112  
113     int index = 0;
114     for (int row = 0; row < h; row++) {
115         for (int col = 0; col < w; col++) {
116             index = row*w + col;
117             Vec3b bgr = image.at<Vec3b>(row, col);
118             points.at<float>(index, 0) = static_cast<int>(bgr[0]);
119             points.at<float>(index, 1) = static_cast<int>(bgr[1]);
120             points.at<float>(index, 2) = static_cast<int>(bgr[2]);
121         }
122     }
123     return points;
124 }