Opencv实现绿幕视频背景替换功能

基于hsv颜色空间的实时背景替换： 

#include
using namespace cv;
Mat replace_and_blend(Mat &frame, Mat&mask);
Mat background,frame, hsv, mask,result;
int main(int arc, char** argv) { 
 background = imread("2.jpg");
 namedWindow("input", CV_WINDOW_AUTOSIZE);
 imshow("src", background);
 
 VideoCapture capture;
 capture.open("1.mp4");
 
    CvSize size = cvSize(capture.get(CV_CAP_PROP_frame_WIDTH), capture.get(CV_CAP_PROP_frame_HEIGHT)); 
 VideoWriter writer("qq.avi", VideoWriter::fourcc('M', 'J', 'P', 'G'),12.0, size, true);
  
 while (capture.read(frame)) {
 imshow("input", frame);
 cvtColor(frame, hsv, CV_BGR2HSV);
 inRange(hsv, Scalar(35, 43, 46), Scalar(77, 255, 255), mask);//颜色过滤，得到mask绿色部分为1，其它部分都为0
 imshow("mask", mask);
 Mat kernel = getStructuringElement(MORPH_RECT,Size(3,3));
 morphologyEx(mask, mask, MORPH_DILATE, kernel);
 GaussianBlur(mask, mask, Size(3, 3), 0, 0);//0,0会根据Size自动算的
 
 result = replace_and_blend(frame, mask);
 writer.write(result);
 char c = waitKey(1);
 if (c == 27) {
  break;
 } 
 imshow("input", frame);
 imshow("result", result);
 }
 waitKey(0);
 return 0;
}
 
//通过颜色过滤得到的掩码为单通道图像
Mat replace_and_blend(Mat &frame, Mat &mask)
{
 int rows = frame.rows;
 int cols = frame.cols;
 result = Mat::zeros(frame.size(), frame.type());
 for (int i = 0; i < rows; i++)
 {
 uchar *pf = frame.ptr(i);//人物前景
 uchar *pm = mask.ptr(i);//掩码
 uchar *pb = background.ptr(i);//背景
 uchar *pr = result.ptr(i);//结果
 
 for (int j = 0; j < cols; j++)
 {
  pm++;
  if (*pm == 255)//背景
  {
  pr[3 * j] = pb[3 * j];
  pr[3 * j + 1] = pb[3 * j + 1];
  pr[3 * j + 2] = pb[3 * j + 2];
  }
  else if (*pm == 0)//前景
  {
  pr[3 * j] = pf[3 * j];
  pr[3 * j + 1] = pf[3 * j + 1];
  pr[3 * j + 2] = pf[3 * j + 2];
  }
  else //融合部分
  {
  int m = *pm;
  double w = m / 255.0;
  pr[3 * j] = w *pb[3 * j] + (1-w) * pf[3 * j];
  pr[3 * j + 1] = w * pb[3 * j + 1] + (1-w) * pf[3 * j + 1];
  pr[3 * j + 2] = w * pb[3 * j + 2] + (1-w) * pf[3 * j + 2];
  //或者取前景和背景的平均值
  
  }
 }
 }
 return result; 
}

 

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