1. A method of processing an iris image data, comprising: providing data representing an image of an iris of an eye; performing a Daubechies wavelet transform on the iris image data, thereby dividing the iris image data into multiple data segments; repeating the Daubechies wavelet transform a predetermined number of times on one of the data segments divided in the immediately previous transform, thereby dividing the data segment on which the transform is performed into smaller data segments, wherein the data segment on which the transform is performed represents more information on iris patterns than the other data segments divided in the immediately previous transform; and forming a characteristic vector of the iris image comprising information of at least one data segment divided in each Daubechies wavelet transform.