private double DistantBlobTrack(CvBlob b, CvTrack t)
{
double d1;
if (b.Centroid.X < t.MinX)
{
if (b.Centroid.Y < t.MinY)
{
d1 = Math.Max(t.MinX - b.Centroid.X, t.MinY - b.Centroid.Y);
}
else if (b.Centroid.Y > t.MaxY)
{
d1 = Math.Max(t.MinX - b.Centroid.X, b.Centroid.Y - t.MaxY);
}
else // if (t.MinY < b.Centroid.Y)&&(b.Centroid.Y < t.MaxY)
{
d1 = t.MinX - b.Centroid.X;
}
}
else if (b.Centroid.X > t.MaxX)
{
if (b.Centroid.Y < t.MinY)
{
d1 = Math.Max(b.Centroid.X - t.MaxX, t.MinY - b.Centroid.Y);
}
else if (b.Centroid.Y > t.MaxY)
{
d1 = Math.Max(b.Centroid.X - t.MaxX, b.Centroid.Y - t.MaxY);
}
else
{
d1 = b.Centroid.X - t.MaxX;
}
}
else // if (t.MinX =< b.Centroid.X) && (b.Centroid.X =< t.MaxX)
{
if (b.Centroid.Y < t.MinY)
{
d1 = t.MinY - b.Centroid.Y;
}
else if (b.Centroid.Y > t.MaxY)
{
d1 = b.Centroid.Y - t.MaxY;
}
else
{
return(0.0);
}
}
double d2;
if (t.Centroid.X < b.MinX)
{
if (t.Centroid.Y < b.MinY)
{
d2 = Math.Max(b.MinX - t.Centroid.X, b.MinY - t.Centroid.Y);
}
else if (t.Centroid.Y > b.MaxY)
{
d2 = Math.Max(b.MinX - t.Centroid.X, t.Centroid.Y - b.MaxY);
}
else // if (b.MinY < t.Centroid.Y)&&(t.Centroid.Y < b.MaxY)
{
d2 = b.MinX - t.Centroid.X;
}
}
else if (t.Centroid.X > b.MaxX)
{
if (t.Centroid.Y < b.MinY)
{
d2 = Math.Max(t.Centroid.X - b.MaxX, b.MinY - t.Centroid.Y);
}
else if (t.Centroid.Y > b.MaxY)
{
d2 = Math.Max(t.Centroid.X - b.MaxX, t.Centroid.Y - b.MaxY);
}
else
{
d2 = t.Centroid.X - b.MaxX;
}
}
else // if (b.MinX =< t.Centroid.X) && (t.Centroid.X =< b.MaxX)
{
if (t.Centroid.Y < b.MinY)
{
d2 = b.MinY - t.Centroid.Y;
}
else if (t.Centroid.Y > b.MaxY)
{
d2 = t.Centroid.Y - b.MaxY;
}
else
{
return(0.0);
}
}
return(Math.Min(d1, d2));
}
/// <summary>
/// Updates list of tracks based on current blobs.
/// </summary>
/// <param name="tracks">List of tracks.</param>
/// <param name="thDistance">Max distance to determine when a track and a blob match.</param>
/// <param name="thInactive">Max number of frames a track can be inactive.</param>
/// <param name="thActive">If a track becomes inactive but it has been active less than thActive frames, the track will be deleted.</param>
/// <remarks>
/// Tracking based on:
/// A. Senior, A. Hampapur, Y-L Tian, L. Brown, S. Pankanti, R. Bolle. Appearance Models for
/// Occlusion Handling. Second International workshop on Performance Evaluation of Tracking and
/// Surveillance Systems & CVPR'01. December, 2001.
/// (http://www.research.ibm.com/peoplevision/PETS2001.pdf)
/// </remarks>
public void UpdateTracks(CvTracks tracks, double thDistance, int thInactive, int thActive)
{
if (tracks == null)
{
throw new ArgumentNullException("tracks");
}
int nBlobs = this.Count;
int nTracks = tracks.Count;
if (nBlobs == 0)
{
return;
}
// Proximity matrix:
// Last row/column is for ID/label.
// Last-1 "/" is for accumulation.
ProximityMatrix close = new ProximityMatrix(nBlobs, nTracks);
// Initialization:
int i = 0;
foreach (CvBlob blob in Values)
{
close.AB[i] = 0;
close.IB[i] = blob.Label;
i++;
}
int maxTrackID = 0;
int j = 0;
foreach (CvTrack track in tracks.Values)
{
close.AT[j] = 0;
close.AT[j] = track.Id;
if (track.Id > maxTrackID)
{
maxTrackID = track.Id;
}
j++;
}
// Proximity matrix calculation and "used blob" list inicialization:
for (i = 0; i < nBlobs; i++)
{
for (j = 0; j < nTracks; j++)
{
CvBlob b = this[close.IB[i]];
CvTrack t = tracks[close.IT[j]];
close[i, j] = (DistantBlobTrack(b, t) < thDistance) ? 1 : 0;
if (close[i, j] < thDistance)
{
close.AB[i]++;
close.AT[j]++;
}
}
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Detect inactive tracks
for (j = 0; j < nTracks; j++)
{
int c = close[nBlobs, j];
if (c == 0)
{
//cout << "Inactive track: " << j << endl;
// Inactive track.
CvTrack track = tracks[j];
track.Inactive++;
track.Label = 0;
}
}
// Detect new tracks
for (i = 0; i < nBlobs; i++)
{
int c = close.AB[i];
if (c == 0)
{
//cout << "Blob (new track): " << maxTrackID+1 << endl;
//cout << *B(i) << endl;
// New track.
maxTrackID++;
CvBlob blob = this[i + 1];
CvTrack track = new CvTrack
{
Id = maxTrackID,
Label = blob.Label,
MinX = blob.MinX,
MinY = blob.MinY,
MaxX = blob.MaxX,
MaxY = blob.MaxY,
Centroid = blob.Centroid,
LifeTime = 0,
Active = 0,
Inactive = 0,
};
tracks[maxTrackID] = track;
}
}
// Clustering
for (j = 0; j < nTracks; j++)
{
int c = close.AT[j];
if (c != 0)
{
List <CvTrack> tt = new List <CvTrack> {
tracks[j]
};
List <CvBlob> bb = new List <CvBlob>();
GetClusterForTrack(j, close, nBlobs, nTracks, this, tracks, bb, tt);
// Select track
CvTrack track = null;
int area = 0;
foreach (CvTrack t in tt)
{
int a = (t.MaxX - t.MinX) * (t.MaxY - t.MinY);
if (a > area)
{
area = a;
track = t;
}
}
// Select blob
CvBlob blob = null;
area = 0;
foreach (CvBlob b in Values)
{
if (b.Area > area)
{
area = b.Area;
blob = b;
}
}
if (blob == null || track == null)
{
throw new NotSupportedException();
}
// Update track
track.Label = blob.Label;
track.Centroid = blob.Centroid;
track.MinX = blob.MinX;
track.MinY = blob.MinY;
track.MaxX = blob.MaxX;
track.MaxY = blob.MaxY;
if (track.Inactive != 0)
{
track.Active = 0;
}
track.Inactive = 0;
// Others to inactive
foreach (CvTrack t in tt)
{
if (t != track)
{
//cout << "Inactive: track=" << t->id << endl;
t.Inactive++;
t.Label = 0;
}
}
}
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////
int[] trackKeys = new int[tracks.Count];
tracks.Keys.CopyTo(trackKeys, 0);
foreach (int tkey in trackKeys)
{
CvTrack t = tracks[tkey];
if ((t.Inactive >= thInactive) ||
((t.Inactive != 0) && (thActive != 0) && (t.Active < thActive)))
{
tracks.Remove(tkey);
}
else
{
t.LifeTime++;
if (t.Inactive == 0)
{
t.Active++;
}
}
}
}
