Patent ID: 7382394

Claim:
A method of correcting scan position errors in an imaging system comprising a direct digital synthesizer (DDS) unit, comprising: (a) computing a nominal frequency tuning word used by the DDS unit; (b) determining a number of corrections per scan line of an image; (c) determining a next correction position; (d) determining an image beam velocity error for the next correction position; (e) determining a corrected frequency tuning word; (f) utilizing the corrected frequency tuning word to determine a pixel clock frequency for the next correction position; wherein computing a nominal frequency tuning word step (a) comprises: (g) generating a nominal linear scanning beam velocity by multiplying a rotational speed of an imaging system motor by an effective focal length of a scan lens assembly of the imaging system; (h) generating a nominal pixel clock frequency by multiplying the nominal linear scanning beam velocity by an image resolution; and (i) applying a formula relating an output frequency of the DDS unit, a system clock frequency of the DDS unit, and the nominal frequency tuning word; and (j) solving the formula for the nominal frequency tuning word.