公开(公告)号：US3689898A

公开(公告)日：1972-09-05

申请号：US3689898D

申请日：1971-04-29

Applicant: SERVO CORP OF AMERICA

Inventor： STITES FRANCIS H

IPC: G06K7/10 ,  G06K7/12

CPC classification number: G06K7/10861

Abstract: An information processing system in which data is encoded in labels having an array of stripes arranged in a plurality of selected stripe-pair code combinations; the first stripe of each pair being an orange, blue or white retroreflective stripe and the second stripe of each pair being an orange, blue, or white retroreflective stripe or a black non-retroreflective stripe. The stripes are scanned by a beam of light and the reflected light from the retroreflective stripes is employed to generate pulse signals representative of the data encoded in the label. The pulse signals generated by the scanning of the first stripe of a stripe-pair are stored in a first set of flip-flops and the pulse signals, if any, generated by the scanning of second stripe of a stripe-pair are stored in a second set of flip-flops. To load the pulse signals corresponding to the first stripe of a stripe-pair, a control signal to the first set of flip-flops, for enabling the pulse signals to be loaded therein, is produced by first loading circuitry in response to the leading edge of a pulse signal as the stripe-pair is scanned. To load the pulse signals corresponding to the second stripe of a stripe-pair, a control signal to the second set of flip-flops, for enabling the pulse signals to be loaded therein, is produced by second loading circuitry only if the pulse signals occur a predetermined period after the leading edge of a pulse signal derived from the first stripe of a strip-pair. The predetermined period (15 microseconds) is equal to the maximum width of a pulse signal generated by a single stripe, and therefore causes pulse signals generated by the scanning of the second stripe of a stripe-pair to be loaded into the second set of flip-flops. The second loading circuitry includes a first difference circuit to which the various pulse signals are applied. The pulse signals are also delayed by 15 microseconds and applied to the first difference circuit. The output of the first difference circuit is the difference between the pulse signals and the delayed pulse signals. The pulse signals and the output of the first difference circuit are applied to a second difference circuit. Thus, the second difference circuit produces an output pulse during the period the second stripe of a stripe-pair is being scanned, but only if the second stripe is reflective. This output pulse is coupled to the second set of flip-flops for causing pulse signals generated by scanning of the second stripe to be loaded therein.