Hand geometry

Hand geometry systems have been in use for almost thirty years for access control to facilities ranging from nuclear power plants to day care centers. Hand geometry technology measures the width, height, and length of the fingers, distances between joints, and shapes of the knuckles. Hand geometry systems use an optical camera and light-emitting diodes with mirrors and reflectors to capture two orthogonal, two-dimensional images of the back and sides of the hand. Ninety-six measurements are then extracted and a 9 byte template is derived, making it the smallest in the biometric industry. Although the basic shape of an individual’s hand remains relatively stable over his or her lifetime, natural and environmental factors can cause slight changes.