title: Smartphone snapshot mapping of skin chromophores under triple-wavelength laser illumination.
abstract: Chromophore distribution maps are useful tools for skin malformation severity assessment and for monitoring of skin recovery after burns, surgeries, and other interactions. The chromophore maps can be obtained by processing several spectral images of skin, e.g., captured by hyperspectral or multispectral cameras during seconds or even minutes. To avoid motion artifacts and simplify the procedure, a single-snapshot technique for mapping melanin, oxyhemoglobin, and deoxyhemoglobin of in-vivo skin by a smartphone under simultaneous three-wavelength (448–532–659 nm) laser illumination is proposed and examined. Three monochromatic spectral images related to the illumination wavelengths were extracted from the smartphone camera RGB image data set with respect to crosstalk between the RGB detection bands. Spectral images were further processed accordingly to Beer’s law in a three chromophore approximation. Photon absorption path lengths in skin at the exploited wavelengths were estimated by means of Monte Carlo simulations. The technique was validated clinically on three kinds of skin lesions: nevi, hemangiomas, and seborrheic keratosis. Design of the developed add-on laser illumination system, image-processing details, and the results of clinical measurements are presented and discussed.
authors.affiliation: University of Latvia, Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, Riga, Latvia.
authors.forename: Janis
authors.initials: J
authors.lastname: Spigulis
authors.affiliation: University of Latvia, Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, Riga, Latvia.
authors.forename: Ilze
authors.initials: I
authors.lastname: Oshina
authors.affiliation: University of Latvia, Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, Riga, Latvia.
authors.forename: Anna
authors.initials: A
authors.lastname: Berzina
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Unit, Faculty of Information Technology and Electrical Engineering, Oulu, Finland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Bykov
mesh_terms: D003880:Dermatology / Q000295:instrumentation*; D006801:Humans; D007834:Lasers; D008027:Light; D008029:Lighting; D012867:Skin / Q000000981:diagnostic imaging*; D012871:Skin Diseases / Q000000981:diagnostic imaging; D000068997:Smartphone