A model to assess visibility in scattering environments

Abstract A numerical evaluation of visibility through a scattering medium was performed with the underlying idea of application to media involving water mist and/or smoke. The model uses the principles of incoherent imaging which is based on the Point Spread Function (PSF) concept. This PSF corresponds to the image of a single object point produced by an optical system. Here the light propagates through a scattering and possibly absorbing medium between the object and the imaging system, that leads to a supplementary spreading of the PSF. In this work the PSF was calculated by a Monte-Carlo Method (MCM) and it was applied to the image reconstruction of a USAF1951 resolution pattern. The results of the model were validated through comparison with an experiment in which the USAF1951 pattern was imaged through a cell containing a mixture of silica spheres in suspension in water, the optical properties of this medium being fully characterized. The experiment was made in two limit cases: a luminous object in a dark room and a reflecting object in a luminous room. A good agreement was observed in these two cases and the distance of visibility was found close to the prediction given by the T. Jin's correlation.