A hand-supportable planar laser illumination and imaging (PLIIM) based camera
system
for producing digital linear images of a object within a working range, having
a substantially uniform white level independent of the velocity of the object.
The hand-supportable PLIIM based camera system comprises a PLIIM based imaging
system having a linear image detection array with a field of view (FOV), a planar
laser illumination array (PLIA) with a plurality of laser diodes arranged in a
linear array for producing a planar laser illumination beam (PLIB) coplanar with
the FOV, and a micro-controller for controlling the operation of the PLIIM based
imaging system. An object velocity measurement subsystem is mounted within its
hand-supportable housing, for determining the velocity of the object relative to
the hand-supportable housing and generating object velocity data indicative of
the determined velocity of the object. During object illumination and imaging operations,
the micro-controller uses the object velocity data compute the optical power which
each laser diode must produce in order that each digital image of the object, formed
by illuminating the object with the computed optical power, will have substantially
the same white intensity level independent of the velocity of the object relative
to the PLIIM-based imaging system. The computed optical power value(s) are transmitted
to the micro-controller, and the micro-controller uses the computed optical power
value(s) to drive each laser diode so that it produces a planar laser illumination
beam having the computed optical power level with the FOV. By virtue of the present
invention, the planar laser illumination beam illuminates the object, and the PLIIM-based
imaging system automatically produces a digital image of the moving object, with
pixels having a substantially uniform white level, independent of the velocity
of the object. Such image characteristics enables simpler and more reliable image
processing in applications such as, for example, optical character recognition
(OCR) processing, where image pixels having a substantially uniform white level,
and a uniform aspect-ratio, are often desired or required.