1D and 2D galvanometer scanning: multi-parameter analysis and optimization

Abstract

Optical and laser scanning is an essential technology for Remote Sensing. We present our one decade works on one of the most common scanning systems, galvanometer-based. These results can be extended to other scanners such as MEMS with oscillatory mirrors or 2D systems with a polygon mirror (PM) plus a galvanometer scanner (GS). The advantages and limitations of 1D GSs are discussed. Theoretical and experimental analyses and optimizations were performed for the three most common input signals: sinusoidal, triangular, and sawtooth. The trade-off between scan frequency and amplitude (i.e., between scan speed and Field-of-View (FOV)) was studied. Effective versus theoretical duty cycle was determined, in a multi-parameter analysis. Optimal linear plus parabolic custom-made input signals were demonstrated, in contrast to literature, where linear plus sinusoidal input signals were considered to produce the highest possible duty cycle. Further on, 2D GSs were approached for raster scanning modalities. Thus, for the slow scan axis, we demonstrated that step-by-step scanning is the best option, while constant speed scan requires electromechanical impulses (in the system) that should be avoided. Finally, optimal scanning laws are deduced for 2D GSs. Perspectives of laser scanning modalities are discussed.