Ridgecounter: a program for obtaining semi-automated finger ridge counts

Finger ridge count is a valuable quantitative phenotype used in a wide range of biological and anthropological research. However, the scoring of the phenotype is both labour intensive and error prone. This paper describe a freely available software program, RIDGECOUNTER, that can be used to obtain ridge counts from digitized prints (either collected using a digital fingerprint scanner or scanned from an inked print). The program yields semi-automated ridge counts and logs the location of the user-selected core and delta points to aid in the training of new researchers and ensure the repeatability of count. In a validity study of 451 prints, the semi-automated ridge counts of digital prints showed good agreement (r = 0.957) with traditional manual counts of inked-rolled prints (which were obtained 2 years apart and counted by different researchers). In a reliability study of 200 prints, semi-automated ridge counts derived from digital prints collected at two different time points also showed good agreement (r = 0.962) (the prints were obtained 2 years apart and counted by the same researcher). Although designed for use with fingerprints, the program is suitable for use with palm, foot or toe prints using user-defined landmarks.