AN OPTICAL MODEL FOR IMAGE ARTIFACTS PRODUCED BY DUST PARTICLES ON LENSES

Machine vision systems often have to work with cameras that become dusty during use. Dust particles produce image artifacts that can affect the performance of a machine vision algorithm. Modeling these artifacts allows us to add them to test images to characterize an algorithm's sensitivity to dust and help develop counter measures. This paper presents an optics-based model that simulates the size and optical density of image artifacts produced by dust particles. For dust particles smaller than the aperture area the image artifact size is determined by the size of the lens aperture and not the size of the particle, while the artifact’s optical density is determined by the ratio of the particle and aperture areas. We show how the model has been used to evaluate the effect of dust on two machine vision algorithms used on the 2003 Mars Exploration Rovers.