Fingerprint image quality is linked to the total surface of ridges found in the fingerprint ("usable" surface area which is not classified as background noise). Only ridges that are well defined and can be extracted safely are counted, if a ridge belongs to the background (noisy) zone, it is not considered. Total ridge surface is normalized by the total sensor/fingerprint image surface, fingerprint quality is therefore a number between 0 and 100.

This statement relates to following API functions of these products:

  1. Segmentation SDK
    1. ISegLib_GetImageQuality()
    1. IEngine_GetImageQuality()
    2. [ANSI/ISO]_GetTemplateParameter(PARAM_FINGER_QUALITY)
  3. IDKit SDK old versions (< 3.0)
    1. IEngine_GetFingerprintQuality()
  4. IDKit SDK version 3.0 and higher
    1. IEngine_GetFingerprintPresence()