/// <summary>
/// preprocess input data and transform to 1d feature vector for DTW
/// according to specific gesture model
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
private ArrayList PreprocessGesture(Gesture input, int gid)
{
ArrayList dtw_data = new ArrayList();
// each frame
for(int i=0; i<input.data.Count; i++)
{
// Extract the coordinates of the points.
List<Point> pts = new List<Point>();
Point shoulderRight = new Point(
input.data[i].Joints[JointType.ShoulderRight].Position.X,
input.data[i].Joints[JointType.ShoulderRight].Position.Y);
Point shoulderLeft = new Point(
input.data[i].Joints[JointType.ShoulderLeft].Position.X,
input.data[i].Joints[JointType.ShoulderLeft].Position.Y);
foreach (Joint j in input.data[i].Joints)
{
if (GESTURE_CONFIG[gid].jointWeights[j.JointType] > 0)
{
Point p = new Point(j.Position.X, j.Position.Y);
pts.Add(p);
}
}
// Center the data
var center = new Point(
input.data[i].Joints[JointType.ShoulderCenter].Position.X,
input.data[i].Joints[JointType.ShoulderCenter].Position.Y);
for (int k = 0; k < pts.Count; k++)
pts[k] = new Point(pts[k].X - center.X, pts[k].Y - center.Y);
// Normalization of the coordinates
double shoulderDist =
Math.Sqrt(Math.Pow((shoulderLeft.X - shoulderRight.X), 2) +
Math.Pow((shoulderLeft.Y - shoulderRight.Y), 2));
for (int k = 0; k < pts.Count; k++)
pts[k] = new Point(pts[k].X / shoulderDist, pts[k].Y / shoulderDist);
// save in 1d double array
double[] feat_vec = new double[pts.Count * 2];
for (int k = 0; k < pts.Count; k++)
{
feat_vec[k * 2] = pts[k].X;
feat_vec[k * 2 + 1] = pts[k].Y;
}
dtw_data.Add(feat_vec);
}
return dtw_data;
}
/// <summary>
/// read database data from files
/// </summary>
public bool LoadGestureDatabase(string database_dir)
{
// enumerate gesture directories
if (!Directory.Exists(database_dir))
return false;
// clear
GESTURE_LIST.Clear();
GESTURE_CONFIG.Clear();
GESTURE_DATABASE.Clear();
// load all gesture config
if (!LoadAllGestureConfig())
{
Debug.WriteLine("Fail to load gesture config.");
return false;
}
// load actual gesture data for each type
foreach (int gid in GESTURE_LIST.Keys)
{
string gdir = GESTURE_DATABASE_DIR + GESTURE_LIST[gid] + "\\";
List<Gesture> cur_gestures = new List<Gesture>();
IEnumerable<string> gesture_files = Directory.EnumerateFiles(gdir, "*.xml");
foreach (string filename in gesture_files)
{
Gesture gtemp = new Gesture();
gtemp.data = KinectRecorder.ReadFromSkeletonFile(filename);
gtemp.name = GESTURE_LIST[gid];
if (gtemp.data.Count > gesture_max_len)
gesture_max_len = gtemp.data.Count;
if (gtemp.data.Count < gesture_min_len)
gesture_min_len = gtemp.data.Count;
cur_gestures.Add(gtemp);
}
// add to database
if (cur_gestures.Count > 0)
GESTURE_DATABASE.Add(gid, cur_gestures);
}
// no actual model data
if (GESTURE_DATABASE.Count == 0)
return false;
return true;
}
/// <summary>
/// match to each database template
/// </summary>
public double MatchToDatabase(Gesture input, out string res)
{
// find the most similar gesture in database to test gesture
double mindist = double.PositiveInfinity;
res = "Unknown";
foreach (int gid in GESTURE_DATABASE.Keys)
{
foreach (Gesture temp in GESTURE_DATABASE[gid])
{
double dist = GestureSimilarity(input, temp, gid);
if(dist < mindist)
{
mindist = dist;
res = GESTURE_LIST[gid];
}
}
}
return mindist;
}
/// <summary>
/// measure similarity between input gesture and a gesture template
/// </summary>
public double GestureSimilarity(Gesture input, Gesture template, int gid)
{
ArrayList input_data = PreprocessGesture(input, gid);
ArrayList temp_data = PreprocessGesture(template, gid);
double dist = DynamicTimeWarping(input_data, temp_data, GESTURE_CONFIG[gid].jointWeights);
return dist;
}
