Registers – Coded record sensors – Particular sensor structure
Patent
1991-09-10
1993-12-21
Shepperd, John W.
Registers
Coded record sensors
Particular sensor structure
G06K 710
Patent
active
052723232
ABSTRACT:
A bar code scanner employs a digitizer for the signal produced by a photodetector in response to light reflected from a bar code symbol. The digitizer uses a first derivative of the signal to detect peaks, and determines the amount of movement of the signal after each peak to see if a threshold amount of movement has occurred. A second derivative of the signal is used to detect inflection points, and when one occurs after the threshold amount of movement following a peak, a valid transition of the signal is signalled. These valid transitions are decoded to recover the bar code pattern. The threshold used is adjustable to optimize the digitizing for different types of bar code symbols and other conditions, or to provide a squelch function. Dynamic control of the threshold provides a varying response to the scanned bar code symbol. Zero-crossing detectors used with the first and second derivative circuits may also have variable thresholds.
REFERENCES:
patent: 3909594 (1975-09-01), Allais et al.
patent: 4000397 (1976-12-01), Hebert et al.
patent: 4020357 (1977-04-01), Punis
patent: 4091379 (1978-05-01), Wu et al.
patent: 4158435 (1979-06-01), Nakanishi et al.
patent: 4356389 (1982-10-01), Quirey et al.
patent: 4740675 (1988-04-01), Brosnan et al.
patent: 4749879 (1988-06-01), Peterson et al.
patent: 4833309 (1989-05-01), Yomogida
Shepperd John W.
Symbol Technologies Inc.
LandOfFree
Digitizer for barcode scanner does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Digitizer for barcode scanner, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digitizer for barcode scanner will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-310563