000152238 001__ 152238 000152238 005__ 20250401114419.0 000152238 0247_ $$2doi$$a10.1364/OE.553755 000152238 0248_ $$2sideral$$a143433 000152238 037__ $$aART-2025-143433 000152238 041__ $$aeng 000152238 100__ $$0(orcid)0000-0001-6070-0509$$aGarcia-Pueyo, Jorge$$uUniversidad de Zaragoza 000152238 245__ $$aForward and inverse diffraction in phasor fields 000152238 260__ $$c2025 000152238 5060_ $$aAccess copy available to the general public$$fUnrestricted 000152238 5203_ $$aNon-line-of-sight (NLOS) imaging is an inverse problem that consists of reconstructing a hidden scene out of the direct line-of-sight given the time-resolved light scattered back by the hidden scene on a relay wall. Phasor fields transforms NLOS imaging into virtual LOS imaging by treating the relay wall as a secondary camera, which allows reconstruction of the hidden scene using a forward diffraction operator based on the Rayleigh-Sommerfeld diffraction (RSD) integral. In this work, we leverage the unitary property of the forward diffraction operator and the dual space it introduces, concepts already studied in inverse diffraction, to explain how phasor fields can be understood as an inverse diffraction method for solving the hidden object reconstruction, even though initially it might appear it is using a forward diffraction operator. We present two analogies, alternative to the classical virtual camera metaphor in phasor fields, to NLOS imaging, relating the relay wall either as a phase conjugator and a hologram recorder. Based on this, we express NLOS imaging as an inverse diffraction problem, which is ill-posed under general conditions, in a formulation named inverse phasor fields, that we solve numerically. This enables us to analyze which conditions make the NLOS problem formulated as inverse diffraction well-posed, and propose a new quality metric based on the matrix rank of the forward diffraction operator, which we relate to the Rayleigh criterion for lateral resolution of an imaging system already used in phasor fields. 000152238 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000152238 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000152238 700__ $$0(orcid)0000-0002-8160-7159$$aMuñoz, Adolfo$$uUniversidad de Zaragoza 000152238 7102_ $$15007$$2570$$aUniversidad de Zaragoza$$bDpto. Informát.Ingenie.Sistms.$$cÁrea Lenguajes y Sistemas Inf. 000152238 773__ $$g33, 5 (2025), 11420$$pOpt. express$$tOPTICS EXPRESS$$x1094-4087 000152238 8564_ $$s5525798$$uhttps://zaguan.unizar.es/record/152238/files/texto_completo.pdf$$yVersión publicada 000152238 8564_ $$s2481409$$uhttps://zaguan.unizar.es/record/152238/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000152238 909CO $$ooai:zaguan.unizar.es:152238$$particulos$$pdriver 000152238 951__ $$a2025-04-01-11:03:27 000152238 980__ $$aARTICLE