Method and apparatus for optical code reading

Claim 5

A method of reading binary coded characters as in claim 1 wherein the radiation observing step further includes: selecting said first and second areas so that one of them brackets the other on both sides with respect to the direction of scan.

Claim 6

A method of reading binary coded characters as in claim 1 wherein the first and second areas are substantially equal.

Claim 9

A method as in claim 4 wherein said code elements include interspersed marks and spaces; the excursion-detecting step including sensing the excursions of the comparison output past a space-related threshold level during the traversal of the scanning spot over a space element and sensing the excursions of the comparison signal past a mark-related threshold level during the traversal of the scanning spot over a mark element; and the output signal generating step providing output signals representing both space-related excursions and mark-related excursions so as to decipher said binary code which includes said marks and spaces.

Claim 10

The method of claim 4 wherein the scanning step further includes scanning the binary code with a scanning spot selected so that the wide code element has a width in the scanning direction which is greater than about 90 percent of the width of the scanning spot in said direction and the narrow code element in said direction is less than about 80 percent of said width of the scanning spot.

Claim 11

Apparatus for reading a binary code wherein the binary code is formed of narrow and wide code elements to denote a binary digit; comprising: means for scanning a spot across the code, said scanning spot being sized larger than the width of narrow code elements and generally smaller than the width of wide code elements; radiation detectors oriented to respond to radiation received from the scanning spot, said radiation detectors providing first and second input signals respectively which are representative of the amount of radiation incident thereon from respective selected portions of the scanning spot; means responsive to the first and second input signals for producing a comparison output the amplitude of which is representative of the difference between the radiation incident upon the detectors, said comparison signal being characterized by a cross-over level corresponding to the location of the scanning spot over a generally uniformly radiating region of the binary coded surface or over an edge of a code element; and means responsive to the comparison output for detecting excursions thereof past a predetermined threshold level to produce output signals representative of the binary code.

Claim 12

Apparatus for reading a binary code wherein the binary code is formed of narrow and wide code elements to denote a binary digit; comprising: means for scanning a spot across the code, said scanning spot being sized larger than the width of narrow code elements and generally smaller than the width of wide code elements; radiation detectors oriented to respond to radiation received from the scanning spot, said radiation detectors providing first and second input signals respectively which are representative of the amount of radiation incident thereon from respective selected portions of the scanning spot; means responsive to the first and second input signals for producing a comparison output the amplitude of which is representative of the difference between the radiation incident upon the detectors, said comparison signal being characterized by a cross-over level corresponding to the location of the scanning spot over a generally uniformly radiating region of the binary coded surface or over an edge of a code element; and means responsive to the comparison output for detecting excursions thereof past a predetermined threshold level to produce output signals representative of the binary code.

Claim 13

The apparatus of claim 7 wherein the means for detecting excursions of the comparison output further includes: means for detecting crossings by the comparison output of said cross-over level and producing signals indicative thereof; means for detecting excursions in the comparison output when said output exceeds the predetermined threshold level, and producing signals indicative thereof; and means controlled by the cross-over-indicating signals and responsive to the excursion-indicating signals for determining the number of excursions between successive cross-overs and producing a first binary output signal indicative of the occurrence of a single excursion between successive cross-overs and a second binary output signal representing the occurrence of a pair of excursions between successive cross-overs.

Claim 14

A scanner for detecting a binary code formed of narrow and wide code elements, the width of said elements representing binary bits; comprising: means for effectively comparing radiation energy emitted from selected first and second scan areas which are selectively sized with respect to a direction of scan to fit within a wide code element and not within a narrow code element, and producing a comparison output representative of the difference between the radiated energies from said first and second scan areas which comparison output is characterized by excursions with respect to a cross-over level as the elements and the comparing means are moved relative to one another; said cross-over level corresponding to the location of both said first and second scan areas over a uniform energy radiating portion of the surface or over an edge of a code element; means for detecting equality between said cross-over level and said comparison output; and means for determining the number of excursions of the comparison output past a selected threshold level between successive crossings of the cross-over level by the comparison output to produce a binary output signal indicative of the binary code.

Claim 15

A scanner for detecting a binary code formed of narrow and wide code elements, the width of said elements representing binary bits; comprising: means for effectively comparing radiation energy emitted from selected first and second scan areas which are selectively sized with respect to a direction of scan to fit within a wide code element and not within a narrow code element, and producing a comparison output representative of the difference between the radiated energies from said first and second scan areas which comparison output is characterized by excursions with respect to a cross-over level as the elements and the comparing means are moved relative to one another; said cross-over level corresponding to the location of both said first and second scan areas over a uniform energy radiating portion of the surface or over an edge of a code element; means for detecting equality between said cross-over level and said comparison output; and means for determining the number of excursions of the comparison output past a selected threshold level between successive crossings of the cross-over level by the comparison output to produce a binary output signal indicative of the binary code.

Claim 16

Apparatus for detecting binary coded legends including wide and narrow detectable segments whose widths identify the binary code; comprising: means for selecting a first scan area, said first scan area having a generally predetermined size with respect to the narrow and wide segments of the binary coded legend; means for producing a first signal representative of radiation energy emanating from the selected first scan area; means for selecting a second scan area on said surface, said second scan area having a predetermined size with respect to the first scan area and being at a pre-selected location relative to said first scan area, means for producing a second signal representative of radiation energy emanating from the second scan area; means responsive to said first and second signals for producing a comparison output representative of the difference between the radiation energy emanating from the selected first and second scan areas, said comparison-output with respect to a cross-over level selected to correspond with the positioning of the first and second scan areas over a region of generally uniform radiation energy or over an edge of a segment; means responsive to the comparison output for detecting the number of excursions thereof between its crossings of said cross-over level to produce binary output signals discriminating between the wide and narrow segments of the binary coded legend.

Claim 17

Apparatus for detecting binary coded legends including wide and narrow detectable segments whose widths identify the binary code; comprising: means for selecting a first scan area, said first scan area having a generally predetermined size with respect to the narrow and wide segments of the binary coded legend; means for producing a first signal representative of radiation energy emanating from the selected first scan area; means for selecting a second scan area on said surface, said second scan area having a predetermined size with respect to the first scan area and being at a pre-selected location relative to said first scan area, means for producing a second signal representative of radiation energy emanating from the second scan area; means responsive to said first and second signals for producing a comparison output representative of the difference between the radiation energy emanating from the selected first and second scan areas, said comparison-output with respect to a cross-over level selected to correspond with the positioning of the first and second scan areas over a region of generally uniform radiation energy or over an edge of a segment; means responsive to the comparison output for detecting the number of excursions thereof between its crossings of said cross-over level to produce binary output signals discriminating between the wide and narrow segments of the binary coded legend.

Claim 18

A scanner for detecting binary coded characters, the width of narrow and wide elements in the code representing binary bits; said scanner comprising: means responsive to radiation energy emanating from the binary code for effectively comparing the radiation energy emanating from selected first and second scan areas and for producing a comparison output representative of the difference between the radiation energy emanating from said first and second scan areas, said comparison output being characterized by a cross-over level corresponding to the location of the first and second scan areas over a generally uniformly distributed radiation-energy-emanating portion of the binary code so as to provide crossings by the comparison output of said cross-over level in correspondence with transitions between successively located code elements; and means for determining the number of excursions in the comparison output between crossings of the cross-over level and for producing binary output signals representative of the binary code on the surface.

Claim 19

A scanner for detecting binary coded characters, the width of narrow and wide elements in the code representing binary bits; said scanner comprising: means responsive to radiation energy emanating from the binary code for effectively comparing the radiation energy emanating from selected first and second scan areas and for producing a comparison output representative of the difference between the radiation energy emanating from said first and second scan areas, said comparison output being characterized by a cross-over level corresponding to the location of the first and second scan areas over a generally uniformly distributed radiation-energy-emanating portion of the binary code so as to provide crossings by the comparison output of said cross-over level in correspondence with transitions between successively located code elements; and means for determining the number of excursions in the comparison output between crossings of the cross-over level and for producing binary output signals representative of the binary code on the surface.

Claim 20

The scanner of claim 11 wherein the excursion-determining means further includes: means responsive to the comparison output for producing signals indicative of when the comparison output exceeds a predetermined threshold level; means for counting the number of excursion-indicating signals; and means responsive to the comparison output for producing a cross-over signal when the comparison output crosses the cross-over level and applying said cross-over signal to the counting means for resetting thereof.