1. A method for identifying a predefined graphic symbol having a plurality of graphical characters, said method comprising: a) receiving a digital image having a plurality of pixels depicting a scene; b) identifying a plurality of first groups of contiguous pixels in the proximity of one another, members of each one said first group having a first common pixel defining property; and c) identifying at least one of said plurality of first groups as one of the plurality of graphical characters, thereby detecting the predefined graphic symbol in said digital image.