private double EuclideanDistanceAtBestAngle(List <Point> points, DollarTemplate T, double thetaA, double thetaB, double thetaDelta, out double theta)
{
double f1 = EuclideanDistanceAtAngle(points, T, thetaA);
double f2 = EuclideanDistanceAtAngle(points, T, thetaB);
while (Math.Abs(thetaB - thetaA) > thetaDelta)
{
if (f1 < f2)
{
thetaB = (1 - PHI) * thetaA + PHI * thetaB;
f2 = EuclideanDistanceAtAngle(points, T, thetaB);
}
else
{
thetaA = PHI * thetaA + (1 - PHI) * thetaB;
f1 = EuclideanDistanceAtAngle(points, T, thetaA);
}
}
if (f1 < f2)
{
theta = thetaB;
return(f1);
}
else
{
theta = thetaA;
return(f2);
}
}
/// <summary>
/// Match this symbol to the best Template in templates.
/// </summary>
/// <param name="templates">Existing templates with which to match</param>
/// <param name="score">Score of best matching template</param>
public DollarTemplate RecognizeSymbol(List <DollarTemplate> templates, out double score)
{
score = 0.0;
if (templates.Count == 0)
{
return(null);
}
DollarTemplate Tbest = templates[0];
double bestD = double.MaxValue;
double bestTheta = 0.0;
double d = 0.0;
for (int i = 0; i < templates.Count; i++)
{
double theta;
d = EuclideanDistanceAtBestAngle(m_Points, templates[i], -THETA_MAX, THETA_MAX, THETA_DELTA, out theta);
if (d < bestD)
{
bestD = d;
bestTheta = theta;
Tbest = templates[i];
}
}
score = 1 - bestD / (0.5 * Math.Sqrt(Math.Pow(SIZE, 2.0) * 2));
return(Tbest);
}
public string Recognize(List <DollarTemplate> templates)
{
if (m_Points.Count != NumResampledPoints)
{
return("Unknown");
}
double score = 0.0;
DollarTemplate best = RecognizeSymbol(templates, out score);
if (score < SCORE_THRESHOLD)
{
return("Unknown");
}
return(best.Name);
}
/// <summary>
/// Gets the result for the best matching template
/// </summary>
/// <param name="stroke">Stroke to be recognized</param>
/// <returns>Class name of the best match</returns>
public string Recognize(Substroke stroke)
{
DollarTemplate unknown = new DollarTemplate(stroke.PointsL);
return(unknown.Recognize(_templates));
}
/// <summary>
/// Computes the total Euclidean Distance between two templates at a specified angle
/// </summary>
/// <param name="avgPoints"></param>
/// <param name="T"></param>
/// <param name="theta"></param>
/// <returns></returns>
private double EuclideanDistanceAtAngle(List <Point> points, DollarTemplate T, double theta)
{
List <Point> newPoints = rotateBy(points, theta);
return(EuclideanDistance(newPoints, T.m_Points) / (double)points.Count);
}
