I'm capturing the optical flow in a video by Farneback's method, but I need to delimit it to be done only in one part, which I must select with the mouse. The problem is similar to this: link
Someone has some idea how I can do this, I tried to adapt the link code above, but I did not succeed.
Code:
#include "opencv2/video/tracking.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
using namespace cv;
using namespace std;
static void help()
{
cout <<
"\nThis program demonstrates dense optical flow algorithm by Gunnar Farneback\n"
"Mainly the function: calcOpticalFlowFarneback()\n"
"Call:\n"
"./fback\n"
"This reads from video camera 0\n" << endl;
}
static void drawOptFlowMap(const Mat& flow, Mat& cflowmap, int step,
double, const Scalar& color)
{
for (int y = 0; y < cflowmap.rows; y += step)
for (int x = 0; x < cflowmap.cols; x += step)
{
const Point2f& fxy = flow.at<Point2f>(y, x)*5;
line(cflowmap, Point(x, y), Point(cvRound(x + fxy.x), cvRound(y + fxy.y)),
color);
circle(cflowmap, Point(x, y), 2, color, -1);
}
}
int main(int argc, char** argv)
{
CommandLineParser parser(argc, argv, "{help h||}");
if (parser.has("help")){
help();
return 0;
}
VideoCapture cap("completo.MPG");
help();
if (!cap.isOpened())
return -1;
Mat flow, cflow, frame;
UMat gray, prevgray, uflow;
namedWindow("flow", 1);
for (;;) {
cap >> frame;
cvtColor(frame, gray, COLOR_BGR2GRAY);
if (!prevgray.empty())
{
calcOpticalFlowFarneback(prevgray, gray, uflow, 0.5, 3, 15, 3, 5, 1.2, 0);
cvtColor(prevgray, cflow, COLOR_GRAY2BGR);
uflow.copyTo(flow);
drawOptFlowMap(flow, cflow, 30, 1.5, Scalar(0, 255, 0));
imshow("flow", cflow);
VideoWriter(gray);
}
if (waitKey(30) >= 0)
break;
std::swap(prevgray, gray);
}
return 0;
}