Welch Allyn Data Collection, Inc.

Welch Allyn, Inc.

John A Pettinelli

Timothy P Meier

Matthew William Pankow

Robert C Gardiner

Andrew E Reynolds

James A Parker

Thomas Ruhlman

Bradley A Randolph

Dennis W McEnery

Dennis McEnery

Joseph Guszcza

Louis Bruno

David Marrs

An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the illumination level at the image sensor. A window detecting circuit samples the illumination signal during a predetermined part of each scan to determine whether the illumination signal is within the window, has exited the window, or has re-entered the window. Exposure control circuitry uses the output of the window detecting circuit to control which of a plurality of the subdivisions of the exposure control range of the image sensor will be used. Changes in exposure time are made only between adjacent subdivisions of the exposure control range. Together with a predetermined hysteresis between the exit and re-entry thresholds of the window, the latter changes stabilize the operation of the reader by reducing exposure control &ldquo;hunting&rdquo;.

Optical reader exposure control apparatus comprising illumination level detection circuitry

The invention is a multiterminal data collection network including a plurality of terminals and a base station configured so that each data collection terminal can be programmed in accordance with one of a predetermined number of available application. When a data collection terminal such as a bar code reader is programmed to operate in accordance with a particular application, the reader operates according to a data collection protocol that is the same as the data collection protocol of each other reader in the network programmed to operate in accordance with that same application. In another aspect of the invention, a base station normally transmits messages received from different readers according to different transmission protocols if the readers are programmed to operate in accordance with different applications, and transmits messages received from different readers according to the same protocol if the readers are programmed in accordance with the same application. A reader of the network can be associated with a new application group by reading of a specially designed application selector symbol.

Multiple application multiterminal data collection network

An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the time averaged value of the illumination level at the image sensor. A window detecting circuit periodically samples the illumination signal to determine if that signal is or is not within a window of acceptability. Exposure period determining circuitry uses the output of the window detecting circuit to upwardly or downwardly adjust the value of a control variable as necessary to cause the illumination signal to approach, enter and remain within the window of acceptability.

Exposure control apparatus for use with optical readers

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Rome, NY, United States of America

John A Pettinelli