Laser-Based Dynamic Optical Vortex Analysis for Remote Patient Health Diagnosis

Abstract

Lasers can be used to obtain optical speckles by shining collimated laser beam on an optically rough medium and collecting the scattered light on a CCD camera. These optical speckles are formed as a result of random additions of scattered waves from microscopic particles under motion. They may also be generated numerically assuming the random addition of phases at any spatial location. Optical vortices are points on these speckle fields with undefined phase and zero intensity. In this chapter, the optical vortex densities and trail lengths are computed and compared for different phase correlations. The temporal de-correlation behaviour of the speckle was modelled to follow three different variations. Optical vortices were identified on them after applying a 2D Hilbert filter algorithm. The optical vortices were tracked along the 2D sections using a nearest neighbour locator algorithm. It is shown quantitatively that the optical vortex trail length is larger for the slowly de-correlating phase sequences in all three cases. This could be combined with IoT and cloud for remote patient health monitoring.