Miniaturized Three-Dimensional Endoscopic Imaging System Based on Active Stereovision

A miniaturized three-dimensional endoscopic imaging system is presented. The system consists of two imaging channels that can be used to obtain an image from an object of interest and to project a structured light onto the imaged object to measure the urface topology. The structured light was generated with a collimated monochromatic light source and a holographic binary phase grating. The imaging and projection channels were calibrated by use of a modified pinhole camera. The surface profile was extracted by use of triangulation between the projected feature points and the two channels of the endoscope. The imaging system was evaluated in three-dimensional measurements of several objects with known geometries. The results show that surface profiles of the objects with different surfaces and dimensions can be obtained at high accuracy. The in vivo measurements at tissue sites of human skin and an oral cavity demonstrated the potential of the technique for clinical applications.