1. A method for characterizing the performance of a device, comprising the following steps: (a) providing a printed symbol containing a control pattern, said printed symbol having been generated with a printer; (b) generating a pixel image of said printed symbol with imaging means, wherein said pixel image contains an imaged control pattern; (c) locating said imaged control pattern in said pixel image using a computer processor; (d) run-length encoding said imaged control pattern using the computer processor to generate a run-length-encoded imaged control pattern; (e) calculating a quality measure using the computer processor, said quality measure being a function of said run-length-encoded imaged control pattern and a run-length-encoded representation of a defined control pattern; and (f) characterizing the performance of said device in accordance with said quality measure using the computer processor, wherein said device is one of said printer and said imaging means.