We study experimentally the scanning functions of galvanometer-based scanners (GSs) in order to optimize them for biomedical imaging in general, and for Optical Coherence Tomography (OCT) in particular. The main scanning parameters of the scanning process are taken into account: theoretical duty cycle (of the input signal of the GS), scan frequency (f_s), and scan amplitude (θ_m). Triangular to sawtooth scanning regimes are thus considered. We demonstrate that when increasing the scan frequency and amplitude, the scanning function (i.e., the angular position of the galvomirror) is not able to follow anymore the input signal. Furthermore, as the theoretical duty cycle is increased, the result is unexpected: the effective duty cycle actually decreases – for high f_s and θ_m. A saturation of the device therefore occurs. The practical limits of this phenomenon are discussed. GS users are thus provided with a multi-parameter analysis that allows them for optimizing their scanning regimes and to avoid pushing the devices to their limit – when that actually results in decreasing the quality of the images obtained, by example in OCT. Gabor Domain Optical Coherence Microscopy (GD-OCM) images are made to show effects of this phenomenon.

Date Published: 5 March 2015
PDF: 8 pages
Proc. SPIE 9315, Design and Quality for Biomedical Technologies VIII, 93150J (5 March 2015); doi: 10.1117/12.2079776

Published in SPIE Proceedings Vol. 9315:
Design and Quality for Biomedical Technologies VIII
Ramesh Raghavachari; Rongguang Liang, Editor(s)