A MEMS Mirror-Based Confocal Laser Endomicroscope with Image Distortion Correction
Teng Pan, Xun Gao, Hengzhang Yang, Yingchao Cao, Hui Zhao, Qian Chen, Huikai Xie
Abstract
Scanning MEMS mirrors can extend confocal laser microscopy into endoscopic applications, but the practical use of MEMS mirror-based confocal endomicroscopy is hindered partially by various image distortions such as barrel, fan-shaped and nonlinear distortions. In this work, the nonlinear scanning behaviors of an electrothermal MEMS mirror are analyzed and incorporated into an optical scanning model that takes all these three types of distortions into account. The model generates a 2D spatial mapping that can be applied to correct all of the image distortions in one step without a calibration board. To experimentally validate this method, a confocal laser endomicroscope employing a two-axis scanning electrothermal MEMS micromirror is designed and constructed, and confocal fluorescence images of a patterned micro-structure are obtained with the MEMS endomicroscope. The results show that the overall image distortion is reduced by at least one order of magnitude in the length direction.