A system for use in monitoring application is described. The system comprises a light detection unit and an illumination arrangement. The detection unit is configured for collecting light returning from a selected inspection region for determining variations in collected light intensity. The illumination arrangement comprises one or more light sources configured for providing illumination of a selected wavelength range directed toward said inspection region. Wherein the illumination arrangement is arranged around the detection unit to provide symmetrical illumination conditions with respect to an axis connecting said detection unit and said inspection region.
