System for determining a distortion model for an optically distorting
medium, the system including an image sensor located at an image
acquisition position behind the optically distorting medium, and an image
processor coupled with the image sensor, the image sensor acquiring an
obstructed image of an object located substantially at infinity, when the
optically distorting medium is located between the image sensor and the
object in a line of sight connecting the image sensor and the object, the
image sensor acquiring an unobstructed image of the object, when the
optically distorting medium is absent from the line of sight, the image
processor receiving information respective of the obstructed image and
the unobstructed image from the image sensor, the image processor
identifying a plurality of features in the unobstructed image, and a
respective feature in the obstructed image for each of the identified
features in the unobstructed image, thereby determining pairs of
associated features, the image processor determining a distortion
parameter for each of the pairs of associated features, the image
processor determining a reference distortion model for the optically
distorting medium, respective of the image acquisition position,
according to the distortion parameters.