The invention relates to a system for processing image data corresponding a scene comprising an imaging device and an image reading instruction indicia. In accordance with the invention, image data corresponding to a scene comprising an image reading instruction indicia is processed in a manner that depends on features of the image reading instruction indicia. If the image reading instruction indicia is of a type whose size, scaling, orientation, and distortion can be determined, scaling, orientation, and distortion characteristics determined from the image reading instruction indicia can be used to improve the image reading process.