An automatic vehicle identification (AVI) system for installation along a roadway,
comprising one or more a planar laser illumination and imaging (PLIIM) based linear
imaging subsystems mounted above the roadway in a spaced apart manner. The PLIIM
based subsystems are arranged for capturing digital linear images of both the front
and rear license plates mounted on each moving vehicle travelling under the PLIIM
based linear imaging subsystem, and generating digital image data representative
of each captured digital linear image. An image processing subsystem is provided
for receiving and processing the digital image data generated by the PLIIM-based
imaging systems, so as to automatically read the alphanumeric strings on the front
and/or rear license plates of each the vehicle. These recognized strings are then
compared against vehicle registration information stored in a database in order
to identify each vehicle travelling under along the roadway. By virtual of the
present invention, it is now possible to capture and buffer high-resolution linear
images of the license plates on moving vehicles using planar laser illumination
beams and coplanar fields of view, so that these linear images can be sequentially
assembled to construct 2-D images for OCR processing so that such vehicles can
be automatically identified, while avoiding the need for large and expensive high-intensity
lighting equipment required by conventional digital cameras employing 2-D electronic
image detectors.