Most biometric systems do not keep an image of the fingerprint but a template. A template is basically a number that is calculated based on various characteristics of the fingerprint. This is done so that persons may not sneak unauthorised images of fingerprints into the database. When a fingerprint is to be matched, its "template number" is computed and compared with that stored in the database. Most systems allow for dry, greasy, chaffed and minor cuts on the fingers. The other biometric systems are based on retina of the eye, palm, photograph or voice pattern recognition. The palm-based systems take the image of the palm from various angles and compare them.