internal List <MtripletPair> FindNoRotateAllSimilar(MTriplet queryMTp)
{
// Indexing by MaxDistance
double dThr = MTriplet.DistanceThreshold;
double d = queryMTp.MaxDistance - dThr;
int iniIdx = BinarySearch(MTriplets, d);
d = queryMTp.MaxDistance + dThr;
var result = new List <MtripletPair>();
for (int j = iniIdx; j < MTriplets.Count && MTriplets[j].MaxDistance <= d; j++)
{
MTriplet currMTp = MTriplets[j];
byte[] currOrder;
double currSim = queryMTp.NoRotateMatch(currMTp, out currOrder);
if (currSim > 0)
{
result.Add(new MtripletPair
{
queryMTp = queryMTp,
templateMTp = currMTp,
matchingValue = currSim,
templateMtiaOrder = currOrder
}
);
}
}
if (result.Count > 0)
{
return(result);
}
return(null);
}
private double MatchBetaAngles(MTriplet compareTo, byte[] order)
{
var idxArr = new[] { 0, 1, 2, 0 };
double maxdiff = 0;
for (int i = 0; i < 3; i++)
{
int j = idxArr[i + 1];
Minutia qMtiai = minutiae[MtiaIdxs[i]];
Minutia qMtiaj = minutiae[MtiaIdxs[j]];
double qbeta = Angle.Difference2Pi(qMtiai.Angle, qMtiaj.Angle);
Minutia tMtiai = compareTo.minutiae[compareTo.MtiaIdxs[order[i]]];
Minutia tMtiaj = compareTo.minutiae[compareTo.MtiaIdxs[order[j]]];
double tbeta = Angle.Difference2Pi(tMtiai.Angle, tMtiaj.Angle);
double diff1 = Math.Abs(tbeta - qbeta);
double diff = Math.Min(diff1, 2 * Math.PI - diff1);
if (diff >= aThr)
{
return(0);
}
if (diff > maxdiff)
{
maxdiff = diff;
}
}
return(1 - maxdiff / aThr);
}
private int[] GetAlphaCodes(MTriplet mtp)
{
int[] alpha = new int[3];
for (int i = 0; i < 3; i++)
{
int j;
if (i == 2)
{
j = 0;
}
else
{
j = i + 1;
}
Minutia qMtiai = mtp[i];
Minutia qMtiaj = mtp[j];
double x = qMtiai.X - qMtiaj.X;
double y = qMtiai.Y - qMtiaj.Y;
double angleij = Angle.ComputeAngle(x, y);
double qAlpha = Angle.Difference2Pi(qMtiai.Angle, angleij);
alpha[i] = DiscretizeAngle(qAlpha);
}
return(alpha);
}
/// <summary>
/// Extract features of type <see cref="MtripletsFeature"/> from the specified minutiae.
/// </summary>
/// <param name="minutiae">
/// The list of <see cref="Minutia"/> to extract the features from.
/// </param>
/// <returns>
/// Features of type <see cref="MtripletsFeature"/> extracted from the specified minutiae.
/// </returns>
public MtripletsFeature ExtractFeatures(List <Minutia> minutiae)
{
List <MTriplet> result = new List <MTriplet>();
Dictionary <int, int> triplets = new Dictionary <int, int>();
var nearest = new short[minutiae.Count, neighborsCount];
var distance = new double[minutiae.Count, neighborsCount];
// Initializing distances
for (int i = 0; i < minutiae.Count; i++)
{
for (int j = 0; j < neighborsCount; j++)
{
distance[i, j] = double.MaxValue;
nearest[i, j] = -1;
}
}
// Computing m-triplets
for (short i = 0; i < minutiae.Count; i++)
{
// Updating nearest minutiae
UpdateNearest(minutiae, i, nearest, distance);
// Building m-triplets
for (int j = 0; j < neighborsCount - 1; j++)
{
for (int k = j + 1; k < neighborsCount; k++)
{
if (nearest[i, j] != -1 && nearest[i, k] != -1)
{
if (i == nearest[i, j] || i == nearest[i, k] || nearest[i, j] == nearest[i, k])
{
throw new Exception("Wrong mtp");
}
MTriplet newMTriplet = new MTriplet(new short[] { i, nearest[i, j], nearest[i, k] }, minutiae);
int newHash = newMTriplet.GetHashCode();
if (!triplets.ContainsKey(newHash))
{
triplets.Add(newHash, 0);
result.Add(newMTriplet);
}
}
}
}
}
result.TrimExcess();
return(new MtripletsFeature(result, minutiae));
}
public double NoRotateMatch(MTriplet target, out byte[] mtiaOrder)
{
byte[] matchOrder = null;
double maxSimil = 0;
if (Math.Abs(MaxDistance - target.MaxDistance) < dThr && Math.Abs(MidDistance - target.MidDistance) < dThr && Math.Abs(MinDistance - target.MinDistance) < dThr /* && Angle.AngleDif180(maxBeta, target.maxBeta) < aThr*/)
{
foreach (byte[] order in Orders)
{
double dirSim = MatchMtiaDirections(target, order);
if (dirSim == 0)
{
continue;
}
double distSim = MatchDistances(target, order);
if (distSim == 0)
{
continue;
}
double betaSim = MatchBetaAngles(target, order);
if (betaSim == 0)
{
continue;
}
double alphaSim = MatchAlphaAngles(target, order);
if (alphaSim == 0)
{
continue;
}
double currentSimil = 1 - (1 - distSim) * (1 - alphaSim) * (1 - betaSim);
if (currentSimil > maxSimil)
{
matchOrder = order;
maxSimil = currentSimil;
}
}
}
mtiaOrder = matchOrder;
return(maxSimil);
}
private int[] GetAllRotationsHashes(MTriplet mtp)
{
// Computing hash for alpha angles
int[] alphaCodes = GetAlphaCodes(mtp);
// Generating all possible hashes
int[] hashes = new int[3];
int i = 0;
foreach (byte[] order in MTriplet.Orders)
{
int a0 = alphaCodes[order[0]];
int a1 = alphaCodes[order[1]];
int a2 = alphaCodes[order[2]];
hashes[i++] = MergeHashes(a0, a1, a2);
}
return(hashes);
}
private double MatchAlphaAngles(MTriplet compareTo, byte[] order)
{
double maxdiff = 0;
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
if (i != j)
{
Minutia qMtiai = minutiae[MtiaIdxs[i]];
Minutia qMtiaj = minutiae[MtiaIdxs[j]];
double x = qMtiai.X - qMtiaj.X;
double y = qMtiai.Y - qMtiaj.Y;
double angleij = Angle.ComputeAngle(x, y);
double qAlpha = Angle.Difference2Pi(qMtiai.Angle, angleij);
Minutia tMtiai = compareTo.minutiae[compareTo.MtiaIdxs[order[i]]];
Minutia tMtiaj = compareTo.minutiae[compareTo.MtiaIdxs[order[j]]];
x = tMtiai.X - tMtiaj.X;
y = tMtiai.Y - tMtiaj.Y;
angleij = Angle.ComputeAngle(x, y);
double tAlpha = Angle.Difference2Pi(tMtiai.Angle, angleij);
double diff1 = Math.Abs(tAlpha - qAlpha);
double diff = Math.Min(diff1, 2 * Math.PI - diff1);
if (diff >= aThr)
{
return(0);
}
if (diff > maxdiff)
{
maxdiff = diff;
}
}
}
}
return(1 - maxdiff / aThr);
}
private double MatchDistances(MTriplet compareTo, byte[] order)
{
double diff0 = Math.Abs(d[0] - compareTo.d[order[0]]);
if (diff0 > dThr)
{
return(0);
}
double diff1 = Math.Abs(d[1] - compareTo.d[order[1]]);
if (diff1 > dThr)
{
return(0);
}
double diff2 = Math.Abs(d[2] - compareTo.d[order[2]]);
if (diff2 > dThr)
{
return(0);
}
return(1 - (Math.Max(diff0, Math.Max(diff1, diff2))) / dThr);
}
private double MatchMtiaDirections(MTriplet compareTo, byte[] order)
{
double maxdiff = 0;
for (int i = 0; i < 3; i++)
{
Minutia qMtiai = minutiae[MtiaIdxs[i]];
Minutia tMtiai = compareTo.minutiae[compareTo.MtiaIdxs[order[i]]];
double alpha = qMtiai.Angle;
double beta = tMtiai.Angle;
double diff1 = Math.Abs(beta - alpha);
double diff = Math.Min(diff1, 2 * Math.PI - diff1);
if (diff >= Math.PI / 4)
{
return(0);
}
if (diff > maxdiff)
{
maxdiff = diff;
}
}
return(1);
}
