Terminal with flicker-corrected aimer and alternating illumination

摘要

An indicia reading terminal is disclosed that eliminates unwanted flickering effects in an illuminated screen reading mode, among other advantageous features. The indicia reading terminal, in response to a screen reading signal, is operative to activate a screen reading cycle. In the screen reading cycle, an imaging subsystem is activated at least once at the same time that an illumination subsystem is activated for one of a plurality of active illumination periods, for a first illuminated exposure period. The imaging subsystem is activated at least once while the illumination subsystem is not activated, for a first unilluminated exposure period, which is longer than the first illuminated exposure period. An aimer subsystem is activated for a plurality of active aimer periods when neither the imaging subsystem or the illumination subsystem is activated, wherein intervals of time between the active aimer periods are equal, within nominal tolerances.

主权项

1. An indicia reading terminal comprising:
an illumination subsystem operative for projecting an illumination pattern; an aimer subsystem operative for projecting an aiming pattern; an imaging subsystem comprising an image sensor array and an imaging optics assembly operative for focusing an image onto the image sensor array; a housing encapsulating the illumination subsystem, the aimer subsystem, and the imaging subsystem; a memory capable of storing frames of image data representing light incident on the image sensor array; and a processor operative for addressing said memory, wherein said processor is operative to attempt to decode a decodable indicia represented in at least one of the frames of image data; wherein the indicia reading terminal, in response to a screen reading signal, is operative to activate a screen reading cycle, wherein:
the imaging subsystem is activated to acquire frames of image data at least once at the same time that the illumination subsystem is activated for one of a plurality of active illumination periods, for a first illuminated exposure period;the imaging subsystem is activated to acquire frames of image data at least once while the indicia reading terminal does not project illumination, for a first unilluminated exposure period, which is longer than the first illuminated exposure period; andthe aimer subsystem is activated for a plurality of active aimer periods when neither the imaging subsystem or the illumination subsystem is activated, wherein intervals of time between the active aimer periods are equal, within nominal tolerances.