private bool MatchBetaAngles(MinutiaTriplet compareTo)
{
for (var i = 0; i < 3; i++)
{
for (var j = 0; j < 3; j++)
{
if (i != j)
{
var qMtiai = Minutiae[MtiaIdxs[i]];
var qMtiaj = Minutiae[MtiaIdxs[j]];
double x = qMtiai.X - qMtiaj.X;
double y = qMtiai.Y - qMtiaj.Y;
var angleij = Angle.ComputeAngle(x, y);
var qBeta = Angle.DifferencePi(qMtiai.Angle, angleij);
var tMtiai = compareTo.Minutiae[compareTo.MtiaIdxs[i]];
var tMtiaj = compareTo.Minutiae[compareTo.MtiaIdxs[j]];
x = tMtiai.X - tMtiaj.X;
y = tMtiai.Y - tMtiaj.Y;
angleij = Angle.ComputeAngle(x, y);
var tBeta = Angle.DifferencePi(tMtiai.Angle, angleij);
var diff = Angle.DifferencePi(qBeta, tBeta);
if (diff >= BetaThreshold)
{
return(false);
}
}
}
}
return(true);
}
private bool MatchDistances(MinutiaTriplet compareTo)
{
var ratio = Math.Abs(D[0] - compareTo.D[0]) / Math.Min(D[0], compareTo.D[0]);
if (ratio >= DistanceThreshold)
{
return(false);
}
ratio = Math.Abs(D[1] - compareTo.D[1]) / Math.Min(D[1], compareTo.D[1]);
if (ratio >= DistanceThreshold)
{
return(false);
}
ratio = Math.Abs(D[2] - compareTo.D[2]) / Math.Min(D[2], compareTo.D[2]);
return(!(ratio >= DistanceThreshold));
}
internal List <MinutiaTripletPair> FindAllSimilar(MinutiaTriplet queryMTp)
{
var result = new List <MinutiaTripletPair>();
for (var j = 0; j < MTriplets.Count; j++)
{
var currMTp = MTriplets[j];
if (queryMTp.Match(currMTp))
{
result.Add(new MinutiaTripletPair
{
QueryMTp = queryMTp,
TemplateMTp = currMTp
}
);
}
}
return(result.Count > 0 ? result : null);
}
private bool MatchAlphaAngles(MinutiaTriplet compareTo)
{
var idxArr = new[] { 0, 1, 2, 0 };
for (var i = 0; i < 3; i++)
{
var j = idxArr[i + 1];
var qMtiai = Minutiae[MtiaIdxs[i]];
var qMtiaj = Minutiae[MtiaIdxs[j]];
var qAlpha = Angle.DifferencePi(qMtiai.Angle, qMtiaj.Angle);
var tMtiai = compareTo.Minutiae[compareTo.MtiaIdxs[i]];
var tMtiaj = compareTo.Minutiae[compareTo.MtiaIdxs[j]];
var tAlpha = Angle.DifferencePi(tMtiai.Angle, tMtiaj.Angle);
var diff = Angle.DifferencePi(qAlpha, tAlpha);
if (diff >= AlphaThreshold)
{
return(false);
}
}
return(true);
}
public bool Match(MinutiaTriplet target)
{
return(MatchDistances(target) && MatchAlphaAngles(target) && MatchBetaAngles(target));
}
public override PartialeFeatures Extract(Bitmap image)
{
var minutiae = MinutiaeExtractor.ExtractFeatures(image);
var result = new List <MinutiaTriplet>();
if (minutiae.Count > 3)
{
foreach (var triangle in Delaunay2D.Triangulate(minutiae))
{
var idxArr = new[]
{
(short)triangle.A,
(short)triangle.B,
(short)triangle.C
};
var newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
idxArr = new[]
{
(short)triangle.A,
(short)triangle.C,
(short)triangle.B
};
newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
idxArr = new[]
{
(short)triangle.B,
(short)triangle.A,
(short)triangle.C
};
newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
idxArr = new[]
{
(short)triangle.B,
(short)triangle.C,
(short)triangle.A
};
newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
idxArr = new[]
{
(short)triangle.C,
(short)triangle.A,
(short)triangle.B
};
newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
idxArr = new[]
{
(short)triangle.C,
(short)triangle.B,
(short)triangle.A
};
newMTriplet = new MinutiaTriplet(idxArr, minutiae);
result.Add(newMTriplet);
}
}
result.TrimExcess();
return(new PartialeFeatures(result, minutiae));
}
