/*
* Created by: Miguel Angel Medina P�rez (miguel.medina.perez@gmail.com)
* Created:
* Comments by: Miguel Angel Medina P�rez (miguel.medina.perez@gmail.com)
*/
using System;
using System.Collections.Generic;
using PatternRecognition.FingerprintRecognition.Core;
using PatternRecognition.FingerprintRecognition.FeatureRepresentation;
namespace PatternRecognition.FingerprintRecognition.Matchers
{
/// <summary>
/// An implementation of the algorithm proposed by Medina-Pérez et al. in 2011.
/// </summary>
/// <remarks>
/// <para>
/// This is an implementation of the algorithm proposed in [1].
/// </para>
/// <para>
/// Take into account that this algorithm is created to work with fingerprint images at 500 dpi. Proper modifications have to be made for different image resolutions.
/// </para>
/// <para>
/// References:
/// </para>
/// <para>
/// <list type="number">
/// <item>
/// M. A. Medina-Pérez, M. García-Borroto, A. E. Gutierrez-Rodriguez, L. Altamirano-Robles, "Robust fingerprint verification using m-triplets," in: International Conference on Hand-Based Biometrics (ICHB 2011), Hong Kong, 2011, pp. 1-5. (DOI: 10.1109/ICHB.2011.6094348. E-ISBN: 978-1-4577-0489-5. Print ISBN: 978-1-4577-0491-8).
/// </item>
/// </list>
/// </para>
/// </remarks>
public class MPN : Matcher<MtripletsFeature>, IMinutiaMatcher
{
#region public
public double LocalAngleThr
{
get { return MTriplet.AngleThreshold * 180 / Math.PI; }
set { MTriplet.AngleThreshold = value * Math.PI / 180; }
}
public double LocalDistThr
{
get { return MTriplet.DistanceThreshold; }
set { MTriplet.DistanceThreshold = value; }
}
public int GlobalDistThr
{
get { return gdThr; }
set { gdThr = value; }
}
public double GlobalAngleThr
{
get { return gaThr * 180 / Math.PI; }
set { gaThr = value * Math.PI / 180; }
}
/// <summary>
/// Matches the specified fingerprint features.
/// </summary>
/// <param name="query">
/// The query fingerprint features.
/// </param>
/// <param name="template">
/// The template fingerprint features.
/// </param>
/// <returns>
/// The fingerprint similarity value.
/// </returns>
public override double Match(MtripletsFeature query, MtripletsFeature template)
{
List<MinutiaPair> matchingMtiae;
return Match(query, template, out matchingMtiae);
}
/// <summary>
/// Matches the specified fingerprint features and outputs the matching minutiae.
/// </summary>
/// <param name="query">
/// The query fingerprint features.
/// </param>
/// <param name="template">
/// The template fingerprint features.
/// </param>
/// <param name="matchingMtiae">
/// The matching minutiae.
/// </param>
/// <exception cref="ArgumentOutOfRangeException">Thrown when the specified features has invalid type.</exception>
/// <returns>
/// The fingerprint similarity value.
/// </returns>
public double Match(object query, object template, out List<MinutiaPair> matchingMtiae)
{
MtripletsFeature qMtripletsFeature = query as MtripletsFeature;
MtripletsFeature tMtripletsFeature = template as MtripletsFeature;
try
{
matchingMtiae = new List<MinutiaPair>();
IList<MtripletPair> matchingTriplets = GetMatchingTriplets(qMtripletsFeature, tMtripletsFeature);
if (matchingTriplets.Count == 0)
return 0;
List<MinutiaPair> localMatchingMtiae = new List<MinutiaPair>(3600);
foreach (var qMtia in qMtripletsFeature.Minutiae)
foreach (var tMtia in tMtripletsFeature.Minutiae)
localMatchingMtiae.Add(new MinutiaPair() { QueryMtia = qMtia, TemplateMtia = tMtia, MatchingValue = 1 });
//List<MinutiaPair> localMatchingMtiae = GetLocalMatchingMtiae(qMtripletsFeature, tMtripletsFeature, matchingTriplets);
//if (localMatchingMtiae.Count == 0)
// return 0;
List<MinutiaPair> refMtiaePairs = GetReferenceMtiae(matchingTriplets);
// Iterating over the reference Minutia pair
int max = 0;
int notMatchingCount = int.MaxValue;
for (int i = 0; i < refMtiaePairs.Count; i++)
{
List<MinutiaPair> currMatchingMtiae =
GetGlobalMatchingMtiae(localMatchingMtiae, refMtiaePairs[i], ref notMatchingCount);
if (currMatchingMtiae != null && currMatchingMtiae.Count > max)
{
max = currMatchingMtiae.Count;
matchingMtiae = currMatchingMtiae;
}
}
return 100 * Math.Sqrt(1.0 * max * max / (qMtripletsFeature.Minutiae.Count * tMtripletsFeature.Minutiae.Count));
}
catch (Exception e)
{
if (query.GetType() != typeof(MtripletsFeature) || template.GetType() != typeof(MtripletsFeature))
{
string msg = "Unable to match fingerprints: Invalid features type!";
throw new ArgumentOutOfRangeException(msg, e);
}
throw e;
}
}
#endregion
#region private
private List<MtripletPair> GetMatchingTriplets(MtripletsFeature t1, MtripletsFeature t2)
{
var mostSimilar = new List<MtripletPair>();
foreach (MTriplet queryTriplet in t1.MTriplets)
{
var mtpPairs = t2.FindSimilarMTriplets(queryTriplet);
if (mtpPairs != null)
mostSimilar.AddRange(mtpPairs);
}
//mostSimilar.Sort(new MtpPairComparer());
return mostSimilar;
}
private List<MinutiaPair> GetReferenceMtiae(IList<MtripletPair> matchingTriplets)
{
var pairs = new List<MinutiaPair>();
var matches = new Dictionary<MinutiaPair, byte>(60);
var qMatches = new Dictionary<MTriplet, byte>(matchingTriplets.Count);
var tMatches = new Dictionary<MTriplet, byte>(matchingTriplets.Count);
foreach (MtripletPair pair in matchingTriplets)
if (!qMatches.ContainsKey(pair.queryMTp) || !tMatches.ContainsKey(pair.templateMTp))
{
Minutia qMtia0 = pair.queryMTp[0];
Minutia qMtia1 = pair.queryMTp[1];
Minutia qMtia2 = pair.queryMTp[2];
Minutia tMtia0 = pair.templateMTp[0];
Minutia tMtia1 = pair.templateMTp[1];
Minutia tMtia2 = pair.templateMTp[2];
Minutia qRefMtia = new Minutia();
qRefMtia.X = Convert.ToInt16(Math.Round((qMtia0.X + qMtia1.X + qMtia2.X) / 3.0));
qRefMtia.Y = Convert.ToInt16(Math.Round((qMtia0.Y + qMtia1.Y + qMtia2.Y) / 3.0));
double diffY = (Math.Sin(qMtia0.Angle) + Math.Sin(qMtia1.Angle) + Math.Sin(qMtia2.Angle)) / 3.0;
double diffX = (Math.Cos(qMtia0.Angle) + Math.Cos(qMtia1.Angle) + Math.Cos(qMtia2.Angle)) / 3.0;
qRefMtia.Angle = Angle.ComputeAngle(diffX, diffY);
Minutia tRefMtia = new Minutia();
tRefMtia.X = Convert.ToInt16(Math.Round((tMtia0.X + tMtia1.X + tMtia2.X) / 3.0));
tRefMtia.Y = Convert.ToInt16(Math.Round((tMtia0.Y + tMtia1.Y + tMtia2.Y) / 3.0));
diffY = (Math.Sin(tMtia0.Angle) + Math.Sin(tMtia1.Angle) + Math.Sin(tMtia2.Angle)) / 3.0;
diffX = (Math.Cos(tMtia0.Angle) + Math.Cos(tMtia1.Angle) + Math.Cos(tMtia2.Angle)) / 3.0;
tRefMtia.Angle = Angle.ComputeAngle(diffX, diffY);
var mPair = new MinutiaPair { QueryMtia = qRefMtia, TemplateMtia = tRefMtia };
if (!matches.ContainsKey(mPair))
{
matches.Add(mPair, 0);
pairs.Add(mPair);
}
if (!qMatches.ContainsKey(pair.queryMTp))
qMatches.Add(pair.queryMTp, 0);
if (!tMatches.ContainsKey(pair.templateMTp))
tMatches.Add(pair.templateMTp, 0);
}
return pairs;
}
private List<MinutiaPair> GetGlobalMatchingMtiae(List<MinutiaPair> localMatchingPairs, MinutiaPair refMtiaPair, ref int notMatchingCount)
{
List<MinutiaPair> globalMatchingMtiae = new List<MinutiaPair>(localMatchingPairs.Count);
var qMatches = new Dictionary<Minutia, Minutia>(localMatchingPairs.Count);
var tMatches = new Dictionary<Minutia, Minutia>(localMatchingPairs.Count);
MtiaMapper mm = new MtiaMapper(refMtiaPair.QueryMtia, refMtiaPair.TemplateMtia);
int currNotMatchingMtiaCount = 0;
int i;
for (i = 0; i < localMatchingPairs.Count; i++)
{
MinutiaPair mtiaPair = localMatchingPairs[i];
if (!qMatches.ContainsKey(mtiaPair.QueryMtia) && !tMatches.ContainsKey(mtiaPair.TemplateMtia))
{
Minutia query = mm.Map(mtiaPair.QueryMtia);
Minutia template = mtiaPair.TemplateMtia;
if (dist.Compare(query, template) <= gdThr && MatchDirections(query, template))
{
globalMatchingMtiae.Add(mtiaPair);
qMatches.Add(mtiaPair.QueryMtia, mtiaPair.TemplateMtia);
tMatches.Add(mtiaPair.TemplateMtia, mtiaPair.QueryMtia);
}
else
currNotMatchingMtiaCount++;
}
if (currNotMatchingMtiaCount >= notMatchingCount)
break;
}
if (i == localMatchingPairs.Count)
{
notMatchingCount = currNotMatchingMtiaCount;
return globalMatchingMtiae;
}
return null;
}
private bool MatchDirections(Minutia query, Minutia template)
{
return Angle.DifferencePi(query.Angle, template.Angle) <= gaThr;
}
private int gdThr = 12;
private double gaThr = Math.PI / 6;
private readonly MtiaEuclideanDistance dist = new MtiaEuclideanDistance();
#endregion
}
}
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