尝试重新创建一个基本的变更检测程序,我是从Adrian Rosebrock撰写的一篇很棒的博客中获得的(如果希望了解python和OpenCV,请转到此处)。该代码是用python设计的,我正在尝试将其转换为C++。您可以找到博客文章here。我的难题是使用absdiff(firsFrame, gray, imageDifference)
,因为循环的每次迭代都使firstFrame和grey相等。我认为问题出在我初始化firstFrame = gray
的地方,但是我做了cout
检查以查看它被击中了多少次,所以不确定。这是代码:
int min_area = 500; //min area of motion detectable
//get camera operational and make sure working correctly
VideoCapture camera(0);
if(!camera.isOpened()){
cout << "cannot open camera" << endl;
return(1);
}
Mat firstFrame, gray, imageDifference, thresh;
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
while(true){
Mat frame;
camera.read(frame);
if(frame.empty()){
cout << "frame was not captured" << endl;
return(2);
}
//pre processing
//resize(frame, frame, Size (1200,900));
cvtColor(frame, gray, COLOR_BGR2GRAY);
GaussianBlur(gray, gray, Size( 21, 21 ), 0, 0 );
//initrialize first frame if necessary
if(firstFrame.empty()){
cout << "hit" << endl;
firstFrame = gray;
continue;
}
//get difference
absdiff(firstFrame, gray, imageDifference);
threshold(imageDifference, thresh, 25, 255, THRESH_BINARY);
//fill in holes
dilate(thresh, thresh, Mat(), Point(-1, -1), 2, 1, 1);
findContours(thresh, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
//loop over contours
for(int i = 0; i < contours.size(); i++){
//get the boundboxes and save the ROI as an Image
if (contourArea(contours[i]) < min_area){
continue;
}
Rect boundRect = boundingRect( Mat(contours[i]));
rectangle( frame, boundRect.tl(), boundRect.br(), (0,255,0), 1, 8, 0 );
}
//draw everything
imshow("Security feed", frame);
imshow("Thresh", thresh);
imshow("Difference", imageDifference);
if (waitKey(30) >= 0)
break;
}
camera.release();
destroyAllWindows();
return(0);
最佳答案
有待改进:
firstFrame = gray
=> gray.copyTo(firstFrame)
您在同一行定义firstFrame
和gray
,然后在执行firstFrame = gray
之后,它们共享相同的数据存储器。所以每次他们都是一样的。由于相机刚刚启动,因此第一帧不太稳定,因此应跳过一些帧(例如10帧)。
在C++中:
cv::Scalar(b,g,r) <==> tuple(b,g,r)
(b,g,r) ==> r
修改后的代码:
int cnt = 0;
while(true) {
Mat frame;
camera.read(frame);
if(frame.empty()) {
cout << "frame was not captured" << endl;
return(2);
}
//pre processing
//resize(frame, frame, Size (1200,900));
cvtColor(frame, gray, COLOR_BGR2GRAY);
GaussianBlur(gray, gray, Size( 21, 21 ), 0, 0 );
//initrialize first frame if necessary
if(firstFrame.empty()) {
if(cnt<10){
++cnt;
}else{
cout << "hit" << endl;
gray.copyTo(firstFrame);
}
continue;
}
// ...
/// cv::Scalar(b,g,r) <==> tuple(b,g,r)
/// (b,g,r) ==> r
rectangle( frame, boundRect.tl(), boundRect.br(), Scalar(0,255,0), 1, 8, 0 );
// ...
}