arXiv subjects

Marco La Manna

Publications and source records attributed to Marco La Manna.

3 recordsLinked to original sources

arXiv2020

A Physical Light Transport Model for Non-Line-of-Sight Imaging Applications

Non-line-of-sight (NLOS) imaging has recently attracted a lot of interest from the scientific community. The goal of this paper is to provide the basis for a comprehensive mathematical framework for NLOS imaging that is directly derived from physical concepts. We introduce the irradiance phasor field (P-field) as an abstract quantity for irradiance fluctuations, akin to the complex envelope of the Electrical field (E-field) that is used to describe propagation of electromagnetic energy. We demonstrate that the P-field propagator is analogous to the Huygens-Fresnel propagator that describes the propagation of other waves and show that NLOS light transport can be described with the processing methods that are available for LOS imaging. We perform simulations to demonstrate the accuracy and validity of the P-field formulation and provide experimental results to demonstrate a Huygens-like P-field summation behavior.

physics.optics↗

arXiv2019

Virtual Wave Optics for Non-Line-of-Sight Imaging

Non-Line-of-Sight (NLOS) imaging allows to observe objects partially or fully occluded from direct view, by analyzing indirect diffuse reflections off a secondary, relay surface. Despite its many potential applications, existing methods lack practical usability due to several shared limitations, including the assumption of single scattering only, lack of occlusions, and Lambertian reflectance. We lift these limitations by transforming the NLOS problem into a virtual Line-Of-Sight (LOS) one. Since imaging information cannot be recovered from the irradiance arriving at the relay surface, we introduce the concept of the phasor field, a mathematical construct representing a fast variation in irradiance. We show that NLOS light transport can be modeled as the propagation of a phasor field wave, which can be solved accurately by the Rayleigh-Sommerfeld diffraction integral. We demonstrate for the first time NLOS reconstruction of complex scenes with strong multiply scattered and ambient light, arbitrary materials, large depth range, and occlusions. Our method handles these challenging cases without explicitly developing a light transport model. By leveraging existing fast algorithms, we outperform existing methods in terms of execution speed, computational complexity, and memory use. We believe that our approach will help unlock the potential of NLOS imaging, and the development of novel applications not restricted to lab conditions. For example, we demonstrate both refocusing and transient NLOS videos of real-world, complex scenes with large depth.

cs.CV↗

arXiv2019

Wave-like Properties of Phasor Fields: Experimental Demonstrations

Recently, an optical meta concept called the Phasor Field (P-Field) was proposed that yields great quality in the reconstruction of hidden objects imaged by non-line-of-sight (NLOS) imaging. It is based on virtual sinusoidal modulation of the light with frequencies in the MHz range. Phasor Field propagation was shown to be described by the Rayleigh-Sommerfeld diffraction integral. We extend this concept and stress the analogy between electric field and Phasor Field. We introduce Phasor Field optical elements and present experiments demonstrating the validity of the approach. Straightforward use of the Phasor Field concept in real-world applications is also discussed.

physics.optics↗