05541419 is referenced by 239 patents and cites 23 patents.

A symbology reader which reduces the effects of specular reflection. A plurality of illumination sources emit light toward a target object. A first polarization filter receives the unpolarized light from the illumination sources and transmits only light polarized in a first direction. Light reflected from the target object travels back to the reader where it is received by a second polarizer which is oriented to block light polarized in the first direction and transmit only light polarized in a second direction orthogonal to the first polarization direction. Non-specularly reflected light reflected from the target object is largely transmitted by the second polarizer to a detector assembly within the symbology reader. In one embodiment the polarization filters are part of a window which covers an output aperture of the reader. The polarization filters are implemented as discrete pieces of laminar polarizing film attached to a transparent window base. In an alternative embodiment, a wavelength filter is employed to block ambient light at wavelengths other than the wavelength of the illumination sources to improve the sensitivity of the detector assembly to reflected illumination light.

Title
Symbology reader wth reduced specular reflection
Application Number
8/215133
Publication Number
5541419
Application Date
March 21, 1994
Publication Date
July 30, 1996
Inventor
Kevork G Arackellian
Everett
WA, US
Agent
Seed and Berry
Assignee
Intermec Corporation
WA, US
IPC
G06K 7/10
View Original Source