public double getMetric(CompressedTrack t1, CompressedTrack t2, int fps)
{
TimeSpan dt = new TimeSpan(0, 0, 0, 0, (int)Math.Floor(1000.0 / fps));
DateTime startTime1 = t1.startTime;
DateTime startTime2 = t2.startTime;
DateTime endTime1 = t1.endTime;
DateTime endTime2 = t2.endTime;
//is there any overlap at all?
if (startTime1 > endTime2 || startTime2 > endTime1)
{
return(0);
}
//find overlap times
DateTime commonStartTime = startTime1;
if (startTime2 > startTime1)
{
commonStartTime = startTime2;
}
DateTime commonEndTime = endTime1;
if (endTime2 < endTime1)
{
commonEndTime = endTime2;
}
if (commonEndTime - commonStartTime < dt)
{
return(0);
}
//now compute the integral
double sum = 0;
for (DateTime t = commonStartTime; t <= commonEndTime; t += dt)
{
SpaceTime l1 = t1.getSpaceTimeAt(t);
SpaceTime l2 = t2.getSpaceTimeAt(t);
double overlap = BoundingBox.ComputeOverlapAreaFraction(l1.region, l2.region);
sum += (overlap * dt.Milliseconds); //pixel-sec
}
TimeSpan deltat1 = endTime1 - startTime1;
TimeSpan deltat2 = endTime2 - startTime2;
double max_ms = Math.Max((double)deltat1.TotalMilliseconds, (double)deltat2.TotalMilliseconds);
return(sum / max_ms);
}