Modified Phase-Offset-Driven Lissajous Scanning Endomicroscopy With a Polyimide-Film-Based Frequency Separator

Abstract

This article presents a Lissajous scanning confocal endomicroscopy comprising an easily manufacturable thin polyimide (PI) film and modified phase-offsetdriven scanning. The Lissajous scanning confocal probe has a piezoelectric tube actuator and the PI film-attached fiber cantilever designed to resonate with the lever mechanism. Data from a finite element analysis and experiments are used to optimize the dimensions of the PI film, which produces a frequency separation and field of view of 195 Hz and 180 µm × 180 µm, respectively, at driving voltages less than 30 V pp . The best combination of decimal frequencies with optimized driving phase offsets is determined to achieve a scanning density (SD) exceeding 80% consistently with an imaging speed of 8 Hz. By analyzing the Lissajous patterns at different decimal frequency combinations via time-delay analysis, it is possible to find more diverse combinations that meet the SD criterion. When the scanning patterns deviate from the desired paths, the proposed modified phase-offset-driven method is applied to maintain the best scanning pattern. The USAF 1951 test pattern, several plants, and rat gastrointestinal tract were imaged successfully using the confocal endomicroscopic system with the PI film and modified phase-offset-driven scanning.

A Novel Flexible Endomicroscopic Scanning Instrument with Visual Servoing Control

“…This instrument could greatly increase the areas of the in vivo tissue scanning with the help of pCLE platform. [41][42][43] The proposed instrument is to address the problems associated with mechanical scanning over large tissue areas in confocal endomicroscopy, which can greatly improve the prospects for intraoperative in vivo digestive tract margin evaluation.…”

Research on Active Repetitive Control for Tracking Lissajous Scan Trajectories with Voice Coil Motors Actuated Fast Steering Mirror

“…Currently, the sinusoids-based non-raster scanning patterns, including the spiral scan, Lissajous scan, cycloid scan, rotational scan, and so on, have been investigated, and thus contribute to a significant increase in the scanning speed. Among these patterns, the Lissajous scan trajectories [8,9], a self-repeating pattern where both the X and Y-axis are driven by sinusoids with a suitable frequency ratio, can be regarded as a promising alternative to the raster scan trajectories with their extremely simple spectrum for both axes and easy implementation for sequential scanning. Although this scanning pattern can alleviate the existing problem of the traditional trajectory itself, the advanced control techniques are still a requisite to handle the residual tracking errors resulting from the hysteresis nonlinearity for ensuring tracking precision.…”