Optical readers and methods employing polarization sensing of light from decodable indicia
AssigneeHoneywell International Inc.
InventorsWilliam H. Havens, Ynjiun P. Wang
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Abstract
A method for decoding decodable indicia includes sensing the polarization of light from a plurality of orientations in connection with the decodable indicia, and controlling at least one of energizing an illumination subsystem based on the sensed polarization indicating a generally randomly polarized light, and inhibiting energization of the illumination subsystem based on the sensed polarization indicating a generally linearly polarized light. One or more images are captured, and an attempt is made to decode the decodable indicia using at least one of the one or more images.
Claims32
An indicia reading terminal comprising:
- an illumination subsystem;
- an imaging subsystem comprising an image sensor array and an imaging optics assembly operable for focusing an image onto said image sensor array;
- a polarization sensor;
- a housing incorporating said illumination subsystem, said imaging subsystem, and said polarization sensor;
- wherein said indicia reading terminal is adapted based on said polarization sensor to at least one of control said illumination subsystem and capture one or more images;
- wherein said indicia reading terminal is operable to attempt to decode a decodable indicia using the one or more images;
- and
- wherein said polarization sensor is operable to provide a plurality of signals regarding polarization of light from a plurality of different orientations, and said indicia reading terminal is adapted based on at least one ratio of the plurality of signals being equal to about 1 to control said illumination subsystem to energize said illumination subsystem and capture the one or more images, and being less than about 0.8 or greater than about 1.2 to control said illumination subsystem to inhibit energization of said illumination subsystem and capture the one or more images.
A method for decoding a decodable indicia, the method comprising:
- sensing the polarization of light from a plurality of orientations in connection with the decodable indicia;
- controlling at least one of energizing an illumination subsystem based on the sensed polarization indicating a generally randomly polarized light, and inhibiting energization of the illumination subsystem based on the sensed polarization indicating a generally linearly polarized light;
- capturing one or more images, and
- attempting to decode the decodable indicia using at least one of the one or more images;
- wherein the sensing comprises sensing the polarization of light from a plurality of different orientations in connection with the decodable indicia, and wherein the controlling comprises inhibiting energization of the illumination subsystem based on a ratio of the sensed polarization from the sensed polarization from the plurality of different orientations being less than about 0.8 or greater than about 1.2.
Dependencies are inferred from the claim text.