A NUMERICAL PROCEDURE FOR CALCULATING THE EFFECT OF A TURBID MEDIUM ON THE MTF OF AN OPTICAL-SYSTEM

A Monte Carlo based method of calculation of the effect of a turbid medium on the modulation transfer function (MTF) of an optical system is presented. A positive comparison of the results was made with published experimental data of Kuga and Ishimaru both for small and large size particulate. The comparison also showed that one limitation of the small angle approximation (SAA) scheme of calculating the MTF can come from the choice of the object point source. Our numerical data obtained by using a Lambertian source agree well with all the experimental data, while the data obtained for an isotropic point source agree with the theoretical data based on the SAA scheme in the case of a particulate not small in comparison with the wavelength.