ISCA Archive Interspeech 2011
ISCA Archive Interspeech 2011

A speaker line-up for the likelihood ratio

David A. van Leeuwen, Niko Brümmer

We propose an analogy to eye witness line-up in order to compute calibrated likelihood ratios for speaker recognition, by including the target model in an identification trial with a cohort of foils. Expressions for the likelihood ratio as a function of cohort size, identification rank and system ROC performance are derived, and some properties of the likelihood ratio function are discussed. The line-up procedure is used as a method to calibrate recognition scores. Using NIST SRE 2010, we find calibration loss comparable to linear calibration (FoCal), while the proposed method gives improved discrimination.