Self-Contained Image Recalibration in a Scanning Fiber Endoscope Using Piezoelectric Sensing

The scanning fiber endoscope (SFE) is a new ultrathin (1.2 mm diameter) medical imaging device that utilizes a unique mechanical scanning technique to image large (120 deg) fields of view (FOVs). A single 80 μm optical fiber is circularly vibrated by a piezo-electric tube to illuminate a field while the reflected light is collected to construct an image pixel-by-pixel. Accurate scanning of the optical fiber is paramount to image quality. Previously, an optical calibration chamber in the base station was used to calibrate the scanning of the optical fiber. This analytical and experimental work eliminates the use of the calibration chamber by implementing a new piezoelectric sensing approach enabling self-contained recalibration to maintain high-image quality during long medical procedures and also reducing the cost, size, and power consumption of the SFE. This work provides a major step toward self-calibration through adaptive control without additional sensors.