Processing an image of an eye

An image of an eye is first captured and stored, as a 256 grey level image or as a colour image, and is then evaluated to determine thresholds between the values of pixels representing different parts of the eye. The thresholds are used to determine the boundary between the pupil and the iris and the boundary between the iris and the sclera by determing the points at which lines across the image change their value with respect to a threshold value. Once the location of the iris has been found, the image is further processed to extract a biometric code from the iris using a linearisation procedure followed by a wavelet transformation. Finally, a biometric code is output by the processor.