Decoding bar patterns

Claim 3

A method of discriminating indicia defining different intervals in accordance with claim 1 and further including establishing the duration between successive changes in said reference signal sufficiently short so that the width category of each scanned indicium is unambiguously indicated.

Claim 4

A method of discriminating indicia defining different intervals in accordance with claim 2 and further including the step of storing a sequence of said indications.

Claim 5

Apparatus for discriminating indicia defining intervals of different widths along a predetermined scanning direction representative of a sequence of digits comprising, transducing means for scanning said indicia at a rate subject to variations to provide corresponding electrical signals defining time intervals representative of said widths and said scanning rate, means for relatively displacing said transducing means and Said indicia at said scanning rate subject to variation to provide said signals defining time intervals, means responsive to the first of said signals defining time intervals on a scan for providing a stored reference signal of reference time duration representative of the first interval width and said scanning rate when scanning said first interval, means responsive to at least another of said signals defining time intervals for updating said reference signal to alter said reference signal in accordance with any changes in said scanning rate so that the updated stored reference signal is representative of said first interval width for the duration of each scan, means for comparing each signal defining time intervals after the first with the stored reference signal to provide for each interval after the first a digit signal each representative of the relationship of the associated interval widths to that of the first interval width to always provide on each scan a sequence of as many digit signals as there are intervals after the first and always derived by the comparison of one of said signals defining time intervals with the stored reference signal, and means for establishing the duration between successive changes in the stored reference signal short enough so that the width category of each scanned interval is unambiguously indicated by comparison with the stored reference signal.

Claim 6

Apparatus for discriminating indicia defining intervals of different widths along a predetermined scanning direction representative of a sequence of digits comprising, transducing means for scanning said indicia at a rate subject to variations to provide corresponding electrical signals defining time intervals representative of said widths and said scanning rate, means for relatively displacing said transducing means and Said indicia at said scanning rate subject to variation to provide said signals defining time intervals, means responsive to the first of said signals defining time intervals on a scan for providing a stored reference signal of reference time duration representative of the first interval width and said scanning rate when scanning said first interval, means responsive to at least another of said signals defining time intervals for updating said reference signal to alter said reference signal in accordance with any changes in said scanning rate so that the updated stored reference signal is representative of said first interval width for the duration of each scan, means for comparing each signal defining time intervals after the first with the stored reference signal to provide for each interval after the first a digit signal each representative of the relationship of the associated interval widths to that of the first interval width to always provide on each scan a sequence of as many digit signals as there are intervals after the first and always derived by the comparison of one of said signals defining time intervals with the stored reference signal, and means for establishing the duration between successive changes in the stored reference signal short enough so that the width category of each scanned interval is unambiguously indicated by comparison with the stored reference signal.

Claim 7

Apparatus for discriminating indicia in accordance with claim 4 and further comprising, a manually movable light pen reader comprising said transducing means for providing a sequence of pulses of time duration corresponding to said widths and said scanning rate, a source of clock pulses, a binary counter, gating means for transmitting said clock pulses to said binary counter to advance the count therein when enabled by a pulse provided by said light pen reader, an up-down shift register for receiving a count signal from said binary counter and shifting it up and down in response to first and second signals from said means for comparing to provide said stored reference signal therein, said means for comparing being responsive to the count in said counter being greater and less than said stored reference signal for providing said second and first signals respectively.

Claim 8

Apparatus for discriminating indicia defining intervals of different widths along a predetermined scanning direction in accordance with claim 5 and further comprising, storage register means for storing the sequence of said first and second signals provided by said means for comparing during each scan.

Claim 9

Apparatus for discriminating indicia defining intervals of different width along a predetermined scanning direction comprising, means including the first of said indicia defining a reference interval of reference width for providing a reference signal of reference time duration, means including others of said indicia spaced from said first indicia along said scanning direction defining data intervals of different widths along said scanning direction having a predetermined relationship to said reference width whereby the data represented by said data intervals may be unambiguously identified solely on the basis of comparison of a data interval width with said reference width, transducing means for scanning said indicia at a scanning rate subject to change to provide corresponding electrical signals defining time intervals representative of the width of said reference and data intervals, means for relatively displacing said transducing means and said indicia to provide said signals defining time intervals, means responsive to the first of said signals defining time intervals for storing said reference signal, means responsive to at least another of said signals defining time intervals for updating the stored reference signal to alter said stored reference signal in accordance with any changes in scanning velocity so that the updated stored reFerence signal is representative of said reference width for the duration of each scan, and means for comparing each signal defining time intervals after the first with said stored reference signal to provide an indication of the relative width of said intervals whereby each data signal derived on a scan is compared with said stored reference signal as updated on that scan to unambiguously identify the data represented by said data intervals solely on the basis of comparing the stored updated reference signal representative of said reference width and the substantially contemporary scanning velocity with each data signal representative of each data interval width on each scan, said means for comparing including means for providing for each data interval on a scan a digit signal each representative of the relationship of the associated data interval widths relative to that of said reference interval width to always provide on each scan a sequence of as many digit signals as there are data intervals identifying the sequence of digits represented by the data intervals and always derived by the comparison of a signal representative of a data interval width with the stored reference signal.

Claim 10

Apparatus for discriminating indicia defining intervals of different width along a predetermined scanning direction comprising, means including the first of said indicia defining a reference interval of reference width for providing a reference signal of reference time duration, means including others of said indicia spaced from said first indicia along said scanning direction defining data intervals of different widths along said scanning direction having a predetermined relationship to said reference width whereby the data represented by said data intervals may be unambiguously identified solely on the basis of comparison of a data interval width with said reference width, transducing means for scanning said indicia at a scanning rate subject to change to provide corresponding electrical signals defining time intervals representative of the width of said reference and data intervals, means for relatively displacing said transducing means and said indicia to provide said signals defining time intervals, means responsive to the first of said signals defining time intervals for storing said reference signal, means responsive to at least another of said signals defining time intervals for updating the stored reference signal to alter said stored reference signal in accordance with any changes in scanning velocity so that the updated stored reFerence signal is representative of said reference width for the duration of each scan, and means for comparing each signal defining time intervals after the first with said stored reference signal to provide an indication of the relative width of said intervals whereby each data signal derived on a scan is compared with said stored reference signal as updated on that scan to unambiguously identify the data represented by said data intervals solely on the basis of comparing the stored updated reference signal representative of said reference width and the substantially contemporary scanning velocity with each data signal representative of each data interval width on each scan, said means for comparing including means for providing for each data interval on a scan a digit signal each representative of the relationship of the associated data interval widths relative to that of said reference interval width to always provide on each scan a sequence of as many digit signals as there are data intervals identifying the sequence of digits represented by the data intervals and always derived by the comparison of a signal representative of a data interval width with the stored reference signal.

Claim 11

Apparatus in accordance with claim 7 wherein the duration between successive changes in said reference signal is short enough so that the width category of each scanned indicium is unambiguously indicated by comparison with the stored updated reference signal.

Claim 12

Apparatus in accordance with claim 8 wherein a first of said widths is four times a second of said widths.

Claim 13

Apparatus in accordance with claim 9 and further comprising means for effectively multiplying each signal representative of a second width by two and each signal representative of a first width by one half in providing said stored updated reference signal.

Claim 14

Apparatus in accordance with claim 10 and further comprising means for providing each of said signals defining time intervals and said reference signals in digital form.

Claim 15

Apparatus for discriminating indicia defining different intervals along a predetermined scanning direction comprising, transducing means for scanning said indicia to provide corresponding electrical signals defining time intervals representative of said different intervals, means for relatively displacing said transducing means and said indicia to provide said signals defining time intervals, means responsive to a first of said signals defining time intervals for providing a reference signal, means responsive to at least another of said signals defining time intervals for updating said reference signal to alter said reference signal in accordance with any changes in scanning velocity, means for comparing each signal defining time intervals after the first with said reference signal to provide an indication of the relative width of said intervals, the duration between successive changes in said reference signal being short enough so that the width category of each scanned indicium is unambiguously indicated by comparison with the reference signal, the first of said widths being four times a second of said widths, means for effectively multiplying each signal representative of a second width by two and each signal representative of a first width by one half to provide said reference signal, and means for providing each of said signals defining time intervals and said reference signals in digital form, said transducing means comprising a manually movable light pen reader, and said means for providing said signals in digital form comprising a source of clock pulses, a binary counter, gating means for transmitting said clock pulse to said binary counter to advance the count therein when enabled by a signal from said transducing means, an up-down shift register for receiving a count signal from said binary counter and shifting it up and down in response to first and second signals from said means for comparing to Provide said reference signal therein, said means for comparing being responsive to the count in said counter being greater and less than said reference signal for providing said second and first signals respectively.

Claim 16

Apparatus for discriminating indicia defining different intervals along a predetermined scanning direction comprising, transducing means for scanning said indicia to provide corresponding electrical signals defining time intervals representative of said different intervals, means for relatively displacing said transducing means and said indicia to provide said signals defining time intervals, means responsive to a first of said signals defining time intervals for providing a reference signal, means responsive to at least another of said signals defining time intervals for updating said reference signal to alter said reference signal in accordance with any changes in scanning velocity, means for comparing each signal defining time intervals after the first with said reference signal to provide an indication of the relative width of said intervals, the duration between successive changes in said reference signal being short enough so that the width category of each scanned indicium is unambiguously indicated by comparison with the reference signal, the first of said widths being four times a second of said widths, means for effectively multiplying each signal representative of a second width by two and each signal representative of a first width by one half to provide said reference signal, and means for providing each of said signals defining time intervals and said reference signals in digital form, said transducing means comprising a manually movable light pen reader, and said means for providing said signals in digital form comprising a source of clock pulses, a binary counter, gating means for transmitting said clock pulse to said binary counter to advance the count therein when enabled by a signal from said transducing means, an up-down shift register for receiving a count signal from said binary counter and shifting it up and down in response to first and second signals from said means for comparing to Provide said reference signal therein, said means for comparing being responsive to the count in said counter being greater and less than said reference signal for providing said second and first signals respectively.

Claim 17

Apparatus in accordance with claim 12 and further comprising storage means for storing a sequence of said first and second signals to store a sequence of binary digits representative of a scanned sequence of said first and second widths.