3D hand and palmprint acquisition using full-field composite color fringe projection

This paper presents a method to simultaneously get 3D hand and palmprint information by projecting composite color fringe patterns. The existing researches mainly focus on 2D biological features, and the extracted features from 2D image are distorted by pressure or lose the third dimensional information. But 3D features with non-contact operation can obtain the characteristic distribution patterns without distortion, and simultaneously obtain real hand morphology and the global properties of hand and palmprint. A prototype 3D imaging system is designed to capture and process the composite color fringe patterns on the hand surface. The hardware configuration comprises a DLP (digital light processing) projector, a color CCD camera with fireware port and a personal computer (PC). In order to fast acquire 3D accurate shape data, sinusoidal and binary fringe patterns are coded into red, green and blue channels to generate composite color fringe pattern images. The DLP projector projects composite RGB fringe patterns onto the surface of human hands. From another viewpoint, the CCD camera captures the images and saves them into the computer for post-processing. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. While the absolute fringe order of each sinusoidal fringe pattern is determined by the binary fringe pattern sequences. The absolute phase map of each pixel can be calculated by combining the obtained wrapped phase and the absolute fringe order. Some experimental results on human hands show that the proposed method correctly obtains the absolute phase (shape) data of hand and palmprint.