1. A method for contamination detection in a time-of-flight (TOF) range imaging system, said TOF range imaging system receiving light reflected from a scene, through an optical interface, on an imager sensor having an array of pixels, wherein distance information and amplitude information are determined for said sensor pixels, and wherein the presence of contamination disposed on said optical interface is determined on the basis of said amplitude information determined for said sensor pixels, wherein the contamination deposited onto the optical interface includes at least one contaminant, further including the step of evaluating the statistics of the amplitude information over the entire image by determining a number of pixels having an amplitude lower than a given amplitude threshold, and concluding the presence of contamination if said number of pixels having an amplitude lower than said amplitude threshold is less than a predetermined number of pixels, or determining the amplitude value for which the sum of pixels of lower amplitude equals a predetermined number of pixels; and concluding the presence of contamination if the amplitude value equals or exceeds a predetermined amplitude threshold.