17 June 2004
Daylight CIS UK Ltd
Over the years several coefficients have been developed to provide
a normalised scale of similarity.
All are f(a,b,c,d) where
= count of on-bits unique to fingerprint A
= count of on-bits unique to fingerprint B
= count of on-bits common to both fingerprints A and
= count of off-bits common to both fingerprints A and B
A list of the common ones are
The most common coefficient is that due to Tanimoto, but others are
now being seriously
Given the nature of Daylight fingerprints it is inappropriate to use
measures with the common off-bits
as this value can be arbitrarily
altered by adjusting the size.