Code reader
First Claim
1. Apparatus for reading a code provided as a word deriving sequence of radiation definable transitions carried on an object and selectively spaced from said first to last in accordance with a predetermined ratio defining first-bit and second-bit information, comprising:
- imaging means for imaging at least a portion of said code carrying object for generating an imaged output signal having image signal transitions occurring in a time spaced sequence corresponding with said code sequence of spaced transitions;
signal treatment means responsive to said imaging means for converting said image signal transition into a corresponding train of pulses;
sequencer means for receiving said train of pulses and having a sequence of timing stages positioned from first to last for selectively delaying the transmission of said pulses therethrough to establish a sequence of pulse occurrence timing signals commencing with said train of pulses;
first sampling network means responsive to a given said timing signal established in conjunction with a sampling said timing stage positioned subsequent in said sequence from said first stage for deriving a valid first-bit condition following a first interval corresponding with a said time spaced sequence representing said first-bit select spacing and responsive to a next said timing signal occurring during said valid first-bit condition established at a next pulse said timing stage position prior in said sequence to said sampling timing stage to provide a first-bit datum;
second sampling network means responsive simultaneously with said first sampling network means to said given timing signal for deriving a valid second-bit condition following a second interval corresponding with a said time spaced sequence representing said second-bit select spacing and responsive to said next timing signal occurring during said valid second-bit condition established by said next pulse timing stage to provide a second bit datum;
serial-to-parallel alignment means responsive to each said first-bit datum and said second-bit datum in the sequence of their occurrence for deriving a serial alignment corresponding therewith defining a word and having a parallel output corresponding therewith representing said word; and
control means responsive to said parallel output for carrying out the decoding thereof.
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Accused Products
Abstract
A code reader and method which is capable of reading "black-on-black" codes such as bar codes which are molded in the surface of an object. The code is illuminated so as to provide light-to-shadow transitions which are read by an imaging device such as a video camera. The resultant video signal transitions representing light-to-dark transitions are differentiated and converted to a train of pulses which are submitted to a delay line sequencing network to develop a series of timing signals. These timing signals are utilized to operate a sampling network to derive 0-bit and 1-bit code information which is submitted serially to a serial-to-parallel shift register to permit code reading by a microcomputer function. Legality checks are carried out with respect to sampling and the developed work and quiescent zones are developed with respect to the start and stop of a given code sequence.
36 Citations
26 Claims
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1. Apparatus for reading a code provided as a word deriving sequence of radiation definable transitions carried on an object and selectively spaced from said first to last in accordance with a predetermined ratio defining first-bit and second-bit information, comprising:
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imaging means for imaging at least a portion of said code carrying object for generating an imaged output signal having image signal transitions occurring in a time spaced sequence corresponding with said code sequence of spaced transitions; signal treatment means responsive to said imaging means for converting said image signal transition into a corresponding train of pulses; sequencer means for receiving said train of pulses and having a sequence of timing stages positioned from first to last for selectively delaying the transmission of said pulses therethrough to establish a sequence of pulse occurrence timing signals commencing with said train of pulses; first sampling network means responsive to a given said timing signal established in conjunction with a sampling said timing stage positioned subsequent in said sequence from said first stage for deriving a valid first-bit condition following a first interval corresponding with a said time spaced sequence representing said first-bit select spacing and responsive to a next said timing signal occurring during said valid first-bit condition established at a next pulse said timing stage position prior in said sequence to said sampling timing stage to provide a first-bit datum; second sampling network means responsive simultaneously with said first sampling network means to said given timing signal for deriving a valid second-bit condition following a second interval corresponding with a said time spaced sequence representing said second-bit select spacing and responsive to said next timing signal occurring during said valid second-bit condition established by said next pulse timing stage to provide a second bit datum; serial-to-parallel alignment means responsive to each said first-bit datum and said second-bit datum in the sequence of their occurrence for deriving a serial alignment corresponding therewith defining a word and having a parallel output corresponding therewith representing said word; and control means responsive to said parallel output for carrying out the decoding thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for reading a code at the surface of an object provided as a word deriving sequence of three-dimensional code components selectively spaced from first to last in a spacing ratio defining first-bit and second-bit information, comprising:
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radiation source means for exposing said surface to radiation from a location deriving radiation definable transitions at said code components; imaging means for imaging said surface to generate a video type output signal having transitions occurring in a time spaced sequence corresponding with said code component spacing; signal treatment means responsive to said imaging means for differentiating the said transition thereof and converting said differentiated transition to a corresponding train of pulses; sequencer means for receiving said train of pulses and having a sequence of timing stages from first to last for selectively delaying the transmission of said pulses therethrough to establish a sequence of pulse occurrence timing signals; a sampling circuit including; first sampling network means having a first tansition interval timing stage responsive to a given said timing signal established with respect to a sampling said timing stage positioned subsequent in said sequence from said first stage, or providing a first output following an interval corresponding with a said time spaced sequence representing said first-bit select spacing, a first tolerance interval timing stage responsive to said first output for deriving a valid first-bit condition for a predetermined first tolerance interval, first latch means responsive to a next said timing signal occurring during said valid first-bit condition corresponding with a next pulse said timing stage position located prior in said sequence to said sampling timing stage to provide a first-bit datum, and second sampling network means having a second transition interval timing stage responsive to said given timing signal for providing a second output following an interval corresponding with a said time spaced sequence representing said second-bit select spacing, a second tolerance interval timing stage responsive to said second output for deriving a valid second-bit condition for a predetermined second tolerance interval, and second latch means responsive to said next timing signal occurring during said valid bit condition to provide a second bit datum; serial-to-parallel alignment means responsive to each said first-bit datum and said second-bit datum in the sequence of their occurrence for deriving a parallel output representing a said word; and control means responsive to treat said parallel output. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. The method for reading a code at the surface of an object provided as a word deriving sequence of radiation definable transitions selectively spaced in accordance with a predetermined ratio defining first-bit and second-bit information comprising the steps of:
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imaging said surface with a video device to generate an output signal having transitions occurring in a time spaced sequence corresponding with said code sequence of spaced transitions; forming a train of pulses from said output signal transitions; applying said train of pulses to a sequence of timing stages from first to a sampling stage to establish a sequence of pulse occurrence timing signals; applying a given timing signal associated with said sampling stage to a first sampling network having a valid first-bit condition during a first tolerance interval following a first interval corresponding with a said time spaced sequence representing said first-bit select spacing; simultaneously applying said given timing signal to a second sampling network having a valid second-bit condition during a second tolerance interval following a second interval corresponding with a said time spaced sequence representing said second bit spacing; deriving a first-bit datum when the next pulse of said train of pulses following said given timing signal occurs during said first tolerance interval; deriving a second-bit datum when the said next pulse occurs during said second tolerance interval; arranging each said derived first-bit datum and said second-bit datum serially in the sequence of their occurence to develop a said word; and reading said word. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification