Methods of and systems for illuminating objects using planar laser illumination
beams having substantially-planar spatial distribution characteristics that extend
through the field of view (FOV) of image formation and detection modules employed
in such systems. Each planar laser illumination beam is produced from a planar
laser illumination beam array (PLIA) comprising an plurality of planar laser illumination
modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens,
and a cylindrical optical element arranged therewith. The individual planar laser
illumination beam components produced from each PLIM are optically combined to
produce a composite substantially planar laser illumination beam having substantially
uniform power density characteristics over the entire spatial extend thereof and
thus the working range of the system. Preferably, each planar laser illumination
beam component is focused so that the minimum beam width thereof occurs at a point
or plane which is the farthest or maximum object distance at which the system is
designed to acquire images, thereby compensating for decreases in the power density
of the incident planar laser illumination beam due to the fact that the width of
the planar laser illumination beam increases in length for increasing object distances
away from the imaging optics. Advanced high-resolution wavefront control methods
and devices are disclosed for use with the PLIIM-based systems in order to reduce
the power of speckle-noise patterns observed at the image detections thereof. By
virtue of the present invention, it is now possible to use both VLDs and high-speed
CCD-type image detectors in conveyor, hand-held and hold-under type imaging applications
alike, enjoying the advantages and benefits that each such technology has to offer,
while avoiding the shortcomings and drawbacks hitherto associated therewith.