A hand-supportable linear-type planar laser illumination and imaging
(PLIIM) based device comprising a linear image formation and detection
(IFD) module having a linear array of image detection elements and also
image formation optics having a field of view (FOV) focusing a linear
image of an object onto the linear array of image detection elements. A
pair of planar laser illumination arrays (PLIAs) is arranged on opposite
sides of the linear image formation and detection module, and produces a
plurality of spatially-incoherent planar laser illumination beam (PLIB)
components that are optically combined with respect to other PLIB
components so as to produce a composite planar laser illumination beam
(PLIB) that is arranged in a coplanar relationship with at least a
portion of the FOV. Each PLIA includes a plurality of planar laser
illumination modules (PLIMs). Each PLIM includes a laser diode and beam
focusing and diverging optics for producing one spatially-incoherent PLIB
component. The composite PLIB produces a number of substantially
different individual speckle noise patterns at the linear array of image
detection elements during the photo-integration time period thereof. The
speckle noise power observed at the linear array of image detection
elements is reduced through temporal averaging of the individual speckle
noise patterns during the photo-integration time period. By virtue of the
present invention, it is now possible to use visible laser diodes (VLDs)
to produce speckle-reduced images of objects suitable for OCR processing,
while enjoying improved working distances offered by planar laser
illumination techniques.