A method for determining whether a to-be-identified individual is a registered individual includes the steps of: a) providing the registered individual with a non-biometric target, which is provided with a to-be-detected surface capable of scattering coherent light that is to be detected by an image sensor so as to obtain a speckle image unique to the non-biometric target, and storing reference speckle image information corresponding to the speckle image associated with the non-biometric target in a database; b) obtaining speckle image information associated with the to-be-identified individual; c) determining whether the speckle image information of the to-be-identified individual has a match with the reference speckle image information stored in the database; and d) determining the to-be-identified individual as the registered individual when it is determined in step c) that there is a match, and determining the to-be-identified individual as a non-registered individual when otherwise.