A calibration system is disclosed for use with an imaging system including a laser line illumination source (10). The calibration system includes an imaging head (16), a mask (24) having a calibration opening (26) through which a portion of the line of laser illumination (10) may pass, and a calibration unit (20). The imaging head (16) is movable along a slow scan direction with respect to an imaging surface (18) for imaging a line of laser illumination (22) in the slow scan direction. The calibration opening (26) has a width in the slow scan direction that is larger than a full width half maximum distance of an imaging spot of a smallest addressable picture element of the line of laser illumination (22). The calibration unit (20) is for receiving a portion of the line of laser illumination (22) through the calibration opening (26) and for processing the received portion of the line of laser illumination (22).