US Patent 7221489 Live print scanner with holographic platen

This invention relates to the use of holographic optical elements in the design and application of biometric scanning instruments used typically for capturing biometric information such as fingerprints and handprints. A live print scanning system for generating a high contrast print image is presented. The system includes a flatbed scanner with a scanning surface and an image sensor, a holographic platen placed on the scanning surface, and a reference beam source that provides a reference beam to the holographic platen. A high contrast print image of a biometric object that is placed on the holographic platen is obtained at the image sensor. A method for generating a high contrast print image is also presented.