3D Endoscope System Using Asynchronously Blinking Grid Pattern Projection for HDR Image Synthesis

3D endoscopic systems have been researched and developed to measure the actual shape and size of living tissues for the purpose of remote surgery and diagnosis, to name a few. For such systems, active stereo that consists of a camera and a pattern projector (i.e., structured light systems) is a promising solution because of simple system with high accuracy. Recently, an active-stereo-based 3D endoscope system has been proposed, in which many practical problems were solved such as shallow focal range of the pattern projector or strong diffusion by living tissues. To use the laser pattern projector for endoscopic systems, two fundamental issues arise; a limited dynamic range of the endoscopic camera and a calibration of the system. In this paper, we proposed a new high dynamic range (HDR) image synthesis technique for a laser pattern projector as well as an auto-calibration technique for dynamic motion. Quantitative experiments are conducted to show the effectiveness of the method followed by a demonstration using real endoscopic system.