Droplet characteristic measurement in Fourier interferometry imaging and behavior at the rainbow angle

Abstract

This paper presents the possibility of measuring the three-dimensional (3D) relative locations and diameters of a set of spherical particles and discusses the behavior of the light recorded around the rainbow angle, an essential step toward refractive index measurements. When a set of particles is illuminated by a pulsed incident wave, the particles act as spherical light wave sources. When the pulse duration is short enough to fix the particle location (typically about 10 ns), interference fringes between these different spherical waves can be recorded. The Fourier transform of the fringes divides the complex fringe systems into a series of spots, with each spot characterizing the interference between a pair of particles. The analyses of these spots (in position and shape) potentially allow the measurement of particle characteristics (3D relative position, particle diameter, and particle refractive index value).

Simple calibration method for dual-camera structured light system

“…Three-dimensional (3D) shape measurement is an active topic in various applications such as reverse engineering, industrial inspection, augmented reality, and cultural heritage recording. Existing 3D measurement techniques include stereo vision [1,2], laser scanning [3], interferometry [4] and structured light method. Among them, structured light is a very popular 3D shape measurement technique because of the advantages of full-field acquisition, fast data processing, low cost, and high resolution [5,6].…”