Patent ID: 8542297

Claim:
A method for pre-setting a combination of a zoom lens and an illumination source in an optical imaging system having a camera used to inspect objects at a plurality of zoom magnifications m to a near optimum setting during programming of the optical imaging system to inspect objects, comprising: determining a desired illumination level of a reference light source in combination with a zoom lens, imaging optics, and an imager in the optical imaging system at a plurality of zoom magnifications; creating and storing a calibration file of reference light source intensities for a machine M 1 L RM1 (m) over the plurality of zoom magnifications m, required to achieve desired measurement accuracy over an area illuminated by the reference light source where L is the normalized intensity of the reference light source, R is a value designating a reference light source, and m is a value representing the magnification of the lens; measuring illumination light source intensities for an illumination light source L I (m) required to produce a signal at the camera that is a predetermined percentage of the intensity required to produce saturation at each magnification m for which the light source I is measured; storing an array of values R I (m)=L IM1 (m)/L RM1 (m); and then, in a measurement step, setting the intensity of an illumination light source I for a machine M 2 according to the following relationship: L IM2 ( m )= L RM2 ( m )* R I ( m ).