Get/set minimum number of fingerprints that must match in order for a whole person to match.

Namespace:  SourceAFIS.Simple
Assembly:  SourceAFIS (in SourceAFIS.dll)


Visual Basic (Declaration)
Public Property MinMatches As Integer
public int MinMatches { get; set; }
Visual C++
property int MinMatches {
	int get ();
	void set (int value);
function get_minMatches();
function set_minMatches(value);

Field Value

Number of fingerprints that must match during multi-finger matching. Default value is 1 (person matches if any of its fingerprints matches).


When there are multiple Fingerprints per Person, SourceAFIS compares every probe Fingerprint to every candidate Fingerprint and takes the best match, the one with highest similarity score. This behavior improves FRR (false reject rate), because low similarity scores caused by damaged fingerprints are ignored. This happens when MinMatches is 1 (default).

When MinMatches is 2 or higher, SourceAFIS compares every probe Fingerprint to every candidate Fingerprint and records score for every comparison. It then sorts collected partial scores in descending order and picks score that is on position specified by MinMatches property, e.g. 2nd score if MinMatches is 2, 3rd score if MinMatches is 3, etc. When combined with Threshold, this property essentially specifies how many partial scores must be above Threshold in order for the whole Person to match. As a special case, when there are too few partial scores (less than value of MinMatches), SourceAFIS picks the lowest score.

MinMatches is useful in some rare cases where there is significant risk that some fingerprint might match randomly with high score due to a broken template or due to some rarely occuring matcher flaw. In these cases, MinMatches might improve FAR. This is discouraged practice though. Application developers seeking ways to improve FAR would do much better to increase Threshold. Threshold can be safely raised to levels where FAR is essentially zero as far as fingerprints are of good quality.

See Also