US 5,856,888 AGranted

Split beam optical character reader

AssigneeAIT Corporation

InventorsWilliam Ross, Gary van Beek

Life of this patent

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Abstract

An optical system for an optical character reader in which a camera, such as a TV camera, reads an image field in a document, includes at least one pair of mirrors which shift half of the image both laterally and vertically to convert a relatively long image, for example with a length to height aspect ratio of 1.5:8, into a rectangular image with a much lower aspect ratio, for example 3:4. Preferably two pairs of mirrors are used, so that the image light path for both parts of the image field is the same length. This optical system reshapes the image field from one having an aspect ratio which does not match the 3:4 aspect ratio of most cameras, such as camcorders, TV cameras, security and surveillance cameras and the like, into one that does, thus significantly simplifying the optical character reader, and lowering its cost.

Claims8

Dependent claims

An optical system for a document reader in which a data image having an aspect ratio of height to length of A:2B is viewed by reflected light contained in a reflected light path, and is converted by an imaging device having an optical axis into an electronic signal, which imaging device has an image field aspect ratio of height to length of about 2A:B, in which ratios 2A<B, wherein:

(i) the optical system includes two mirror pairs in the reflected light path between the document and the imaging device, in each of which pairs at least one mirror is tilted;
(ii) each pair of mirrors includes:
(a) a first mirror which reflects a half portion of the data image laterally to a second mirror located nearer to the imaging device optical axis than the first mirror, and
(b) the second mirror reflects the image of the half portion of the data image to the imaging device in a direction parallel to the optical axis of the imaging device;
(iii) a first mirror pair reflects the image of a first half portion of the data image to a focussing device;
and
(iv) a second mirror pair reflects the image of a second half portion of the data image to the focussing device;
to provide two focussed images at the imaging device image field which together have an aspect ratio of about 2A:B.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/647,599Filed 13 May 1996
Granted: 5 Jan 1999
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06K 7/1092
Further details of bar or optical code scanning devices: sensing by means of TV-scanning
G02B 27/1066
Beam splitting or combining systems: for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by…
G02B 27/143
Operating by reflection only: using macroscopically faceted or segmented reflective surfaces
G06V 10/147
Optical characteristics of the device performing the acquisition or on the illumination arrangements: details of sensors, e.g. sensor lenses