Bar code reading apparatus

Claim 2

A bar code reading apparatus comprising scanning means (20, 21) for scanning a bar code including a character bar and a guard bar facing a margin area surrounded by a margin defining area and for generating a pulse signal corresponding to said bar code; measuring means (1) coupled to said scanning means, for measuring a width of each white bar contained in said bar code and a width of each black bar contained therein and for outputting a measurement signal indicative of the width of said each white or black bar; and first detection means (2), operatively coupled to said measuring means, for detecting, from said measurement signal, a white bar having a width equal to or greater than a first reference value and for outputting a first detection signal indicative of the width of said white bar, characterized in that said bar code reading apparatus comprises: second detection means (4), operatively coupled to said measuring means, for detecting, from said measurement signal, a white bar having a width equal to or greater than a second reference value and for outputting a second detection signal indicative of the width of said white bar, said second reference being less than said first reference; third detection means (6), operatively coupled to said measuring means, for detecting, from said measurement signal, a black bar having a width equal or greater than a third reference value and for outputting a third detection signal indicative of the width of said black bar; and logic means (8, 10; 28, 30, 32) coupled to said first, second and third detection means, for receiving said first, second and third detection signals and outputting a margin detection signal indicating detection of said margin area on the basis of the first, second and third detection signals.

Claim 3

A bar code reading apparatus as claimed in claim 1, characterized in that said first reference value corresponds to a predetermined normal width of said margin area, said second reference value is equal to a predetermined minimum value of said margin area, and said third reference value corresponds to said predetermined normal width of said margin area.

Claim 4

A bar code reading apparatus as claimed in claim 1 or claim 2, characterized in that said measurement signal includes a time-series of measured value signals T n-1 (n is an integer), T n and T n+1 , in that said bar code reading apparatus comprises: first holding means (5) coupled to said measuring means, for holding one of said measured value signals until a next one of said measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured value signal T n ; and second holding means (6) coupled to said first holding means, for holding one of said measurement value signals from said first holding means until a next one of said measured value signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 , and in that said measured value signal T n-1 is supplied to said first, second and third detection means, said measured value signal T n is supplied to said first and second detection means, and said measured value signal T n+1 is supplied to said third detection means.

Claim 5

A bar code reading apparatus as claimed in claim 3, characterized in that: said first detection means (2) comprises multiplying means (2 1a ) for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 , and comparing means (2₂) for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting said first detection signal based on a comparison result; said second detection means (4) comprises multiplying means (4₁) for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 , and comparing means (4₂) for determining whether said measured value signal T n is equal to or greater A₂T n-1 and for outputting said second detection signal based on a comparison result; and said third detection means (6) comprises multiplying means (2 1b ) for multiplying said measured value signal T n-1 by a third coefficient A₃ and for outputting a signal A₃T n-1 , and comparing means (6₁) for determining whether said measured value signal T n+1 is equal to or greater than said signal A₃T n-1 and for outputting said third detection signal based on a comparison result.

Claim 6

A bar code reading apparatus as claimed in claim 4, characterized in that said logic means comprises: an AND gate (8) provided with said second and third detection signals from said comparators of said second and third detection means and generating an output signal; and an OR gate (10) provided with said first detection signal from said comparator of said first detection means and said output signal from said AND gate, said OR gate outputting said margin detection signal.

Claim 7

A bar code reading apparatus as claimed in claim 4 or claim 5, characterized in that said first constant A₁ is set equal to said third constant A₃, and said multiplying means of said first and third means are provided by a single multiplier.

Claim 8

A bar cord reading apparatus as claimed in claim 1, characterized in that said measurement signal includes a time-series of measured value signals T n-1 (n is an integer , T n and T n+1 , in that said bar code reading apparatus comprises: first holding means (3) coupled to said measuring means, for holding one of said measurement value signals until a next one of the measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured value signal T n ; and second holding means (5) coupled to said first holding means, for holding one of said measured value signals from said first holding means until a next one of the measurement signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 , and in that said measured value signal T n-1 is supplied to said third detection means, said measured value signal T n is supplied to said first and second detection means, and said measured value signal T n+1 is supplied to said first, second and third detection means.

Claim 9

A bar code reading apparatus as claimed in claim 7, characterized in that: said first detection means (2) comprises multiplying means (2 3a ) for multiplying said measured value signal T n+1 by a first constant A₁ and for outputting a signal A₁T n+1 , and comparing means (2₂) for determining whether said measured value signal T n is equal to or greater than A₁T n+1 and for outputting said first detection signal based on a comparison result, said second detection means (4) comprises multiplying means (4₃) for multiplying said measured value signal T n+1 by a second constant A₂ and for outputting a signal A₂T n+1 , and comparing means (4₄) for determining whether said measured value signal T n is equal to A₂T n+1 and for outputting said second detection signal based on a comparison result, and said third detection means (6) comprises multiplying means (2 3b ) for multiplying said measured value signal T n+1 by a third coefficient A₃ and for outputting a signal A₃T n-1 , and comparing means (6₂) for determining whether said measured value signal T n-1 is equal to or greater than said signal A₃T n+1 and for outputting said third detection signal based on a comparison result.

Claim 10

A bar code reading apparatus as claimed in claim 8, characterized in that said logic means comprises: an AND gate (28) provided with said second and third detection signals from said comparators of said second and third detection means and generating an output signal; and an OR gate (30) provided with said first detection signal from said comparator of said first detection means and said output signal from said AND gate, said OR gate outputting said margin detection signal.

Claim 11

A bar code reading apparatus as claimed in claim 8 or 9, characterized in that said first constant A₁ is set equal to said third constant A₃, and said multiplying means of said first and third means are provided by a single multiplier.

Claim 12

A bar code reading apparatus as claimed in claim 1, characterized in that said logic means comprises: an AND gate (8; 28) provided with said second and third detection signals from said second and third detection means and generating an output signal; and an OR gate (10, 30) provided with said first detection signal from said first detection means and said output signal from said AND gate, and said margin detection signal is output from said OR gate.

Claim 13

A bar code reading apparatus as claimed in claim 3, characterized in that: said first detection means (2) comprises multiplying means (2₁) for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 , and comparing means (2₂) for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting said first detection signal based on a comparison result; said second detection means (4) comprises multiplying means (4₁) for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 , and comparing means (4₂) for determining whether said measured value signal T n is equal to or greater A₂T n-1 and for outputting said second detection signal based on a comparison result; and said third detection means (6) comprises comparing means (6₁) for determining whether said measured value signal T n+1 supplied from said measuring means is equal to or greater than said signal A₁T n-1 supplied from said multiplying means of said first detection means and for outputting said third detection signal based on a comparison result.

Claim 14

A bar code reading apparatus as claimed in claim 7, characterized in that: said first detection means (2) comprises multiplying means (2₃) for multiplying said measured value signal T n+1 by a first constant A₁ and for outputting a signal A₁T n+1 , and comparing means (2₄) for determining whether said measured value signal T n is equal to or greater than A₁T n+1 and for outputting said first detection signal based on a comparison result; said second detection means (4) comprises multiplying means (4₃) for multiplying said measured value signal T n+1 by a second constant A₂ and for outputting a signal A₂T n+1 , and comparing means (4₄) for determining whether said measured value signal T n is equal to A₂T n+1 and for outputting said second detection signal based on a comparison result; and said third detection means (6) comprises comparing means (6₂) for determining whether said measured value signal T n-1 supplied from said second holding means is equal to or greater than said signal A₁T n+1 supplied from said multiplying means of said first detection means and for outputting said third detection signal based on a comparison result.

Claim 15

A bar code reading apparatus comprising scanning means (20, 21) for scanning a bar code including a character bar and guard bars facing front and back margin areas surrounded by a margin defining area and for generating a pulse signal corresponding to said bar code; measuring means (1) coupled to said scanning means, for measuring a width of each white bar contained in said bar code and a width of each black bar contained therein and for outputting a measurement signal indicative of the width of said each white or black bar, said measurement signal includes a time-series of measured value signals T n-1 (n is an integer), T n and T n+1 ; and first holding means (3) coupled to said measuring means, for holding one of said measured value signals until a next one of the measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured signal T n , characterized in that said bar code reading apparatus comprises: second holding means (5) coupled to said first holding means, for holding one of said measured value signals from said first holding means until a next one of the measured value signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 ; first multiplying means (2₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 ; first comparing means (2₂) coupled to said first holding means and said first multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting a first detection signal based on a comparison result; second multiplying means (4₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 ; second comparing means (4₂) coupled to said first holding means and said second multiplying means, for determining whether said measured value signal T n is equal to A₂T n-1 and for outputting a second detection signal based on a comparison result; third comparing means (6₁) coupled to said measuring means and said first multiplying means, for determining whether said measured value signal T n+1 is equal to or greater than said signal A₁T n-1 and for outputting a third detection signal based on a comparison result; third multiplying means (2₃) coupled to said first holding means, for multiplying said measured value signal T n+1 by a third constant A₁′ and for outputting a signal A₁′T n+1 ; fourth comparing means (2₄) coupled to said measuring means and said third multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁′T n+1 and for outputting a fourth detection signal based on a comparison result; fourth multiplying means (4₃) coupled to said measuring means, for multiplying said measured value signal T n+1 by a fifth constant A₂′ and for outputting a signal A₂′T n+1 ; fifth comparing means (4₄) coupled to said first holding means and said fourth multiplying means, for determining whether said measured value signal T n is equal to A₂′T n+1 and for outputting a fifth detection signal based on a comparison result; sixth comparing means (6₂) coupled to said second holding means and said third multiplying means, for determining whether said measured value signal T n-1 is equal to or greater than said signal A₁′T n+1 and for outputting a sixth detection signal based on a comparison result; and logic means (8, 10, 28, 30, 32) for receiving said first through sixth detection signals and for outputting a margin detection signal indicative of said front and back margins on the basis of said first through sixth detection signal.

Claim 16

A bar code reading apparatus comprising scanning means (20, 21) for scanning a bar code including a character bar and guard bars facing front and back margin areas surrounded by a margin defining area and for generating a pulse signal corresponding to said bar code; measuring means (1) coupled to said scanning means, for measuring a width of each white bar contained in said bar code and a width of each black bar contained therein and for outputting a measurement signal indicative of the width of said each white or black bar, said measurement signal includes a time-series of measured value signals T n-1 (n is an integer), T n and T n+1 ; and first holding means (3) coupled to said measuring means, for holding one of said measured value signals until a next one of the measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured signal T n , characterized in that said bar code reading apparatus comprises: second holding means (5) coupled to said first holding means, for holding one of said measured value signals from said first holding means until a next one of the measured value signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 ; first multiplying means (2₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 ; first comparing means (2₂) coupled to said first holding means and said first multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting a first detection signal based on a comparison result; second multiplying means (4₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 ; second comparing means (4₂) coupled to said first holding means and said second multiplying means, for determining whether said measured value signal T n is equal to A₂T n-1 and for outputting a second detection signal based on a comparison result; third comparing means (6₁) coupled to said measuring means and said first multiplying means, for determining whether said measured value signal T n+1 is equal to or greater than said signal A₁T n-1 and for outputting a third detection signal based on a comparison result; third multiplying means (2₃) coupled to said first holding means, for multiplying said measured value signal T n+1 by a third constant A₁′ and for outputting a signal A₁′T n+1 ; fourth comparing means (2₄) coupled to said measuring means and said third multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁′T n+1 and for outputting a fourth detection signal based on a comparison result; fourth multiplying means (4₃) coupled to said measuring means, for multiplying said measured value signal T n+1 by a fifth constant A₂′ and for outputting a signal A₂′T n+1 ; fifth comparing means (4₄) coupled to said first holding means and said fourth multiplying means, for determining whether said measured value signal T n is equal to A₂′T n+1 and for outputting a fifth detection signal based on a comparison result; sixth comparing means (6₂) coupled to said second holding means and said third multiplying means, for determining whether said measured value signal T n-1 is equal to or greater than said signal A₁′T n+1 and for outputting a sixth detection signal based on a comparison result; and logic means (8, 10, 28, 30, 32) for receiving said first through sixth detection signals and for outputting a margin detection signal indicative of said front and back margins on the basis of said first through sixth detection signal.

Claim 17

A bar code reading apparatus as claimed in claim 14, characterized in that said logic means comprises: a first AND gate (8) supplied with said second and third detection signals and generating a first AND output signal; a first OR gate (10) supplied with said first detection signal and said first AND output signal and a first OR output signal; a second AND gate (28) supplied with said fifth and sixth detection signals and generating a second AND output signal; a second OR gate (30) supplied with said fourth detection signal and said second AND output signal and outputting a second OR output signal; and a third OR gate (32) supplied with said first and second OR output signals and outputting said margin detection signal.

Claim 18

A bar code reading apparatus as claimed in claim 14 or claim 15, characterized in that each of said first and third reference values corresponds to a predetermined normal width of each of said front and back margin area, and each of said second and third reference values corresponds to a predetermined minimum width of each of said front and back margin areas.

Claim 19

A bar code reading apparatus comprising scanning means (20, 21) for scanning a bar code including a character bar and guard bars facing front and margin areas surrounded by a margin defining area and for generating a pulse signal corresponding to said bar code; measuring means (1) coupled to said scanning means, for measuring a width of each white bar contained in said bar code and a width of each black bar contained therein and for outputting a measurement signal indicative of the width of said each white or black bar, said measurement signal includes a time-series of measured value signals T n-1 (n is an integer), T n and T n+1 ; and first holding means (3) coupled to said measuring means, for holding one of said measured value signals until a next one of the measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured signal T n , characterized in that said bar code reading apparatus comprises: second holding means (5) coupled to said first holding means, for holding one of said measured value signals from said first holding means until a next one of the measured value signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 ; first multiplying means (2 1a ) coupled to said second holding means, for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 ; first comparing means (2₂) coupled to said first holding means and said first multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting a first detection signal based on a comparison result; second multiplying means (4₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 ; second comparing means (4₂) coupled to said first holding means and said second multiplying means, for determining whether said measured value signal T n is equal to A₂T n-1 and for outputting a second detection signal based on a comparison result; third multiplying means (2 1b ) coupled to said second holding means, for multiplying said measured value signal T n-1 by a third coefficient A₃ and for outputting a signal A₃T n-1 ; third comparing means (6₁) coupled to said measuring means and said third multiplying means, for determining whether said measured value signal T n+1 is equal to or greater than said signal A₃T n-1 and for outputting a third detection signal based on a comparison result; fourth multiplying means (2 3a ) coupled to said measuring means, for multiplying said measured value signal T n+1 by a fourth constant A₁′ and for outputting a signal A₁′T n+1 ; fourth comparing means (2₄) coupled to said first holding means and said fourth multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁′T n+1 and for outputting a fourth detection signal based on a comparison result; fifth multiplying means (4₃) coupled to said first holding means, for multiplying said measured value signal T n+1 by a fifth constant A₂′ and for outputting a signal A₂′T n+1 ; fifth comparing means (4₄) coupled to said measuring means and said fifth multiplying means, for determining whether said measured value signal T n is equal to A₂′T n+1 , and for outputting a fifth detection signal based on a comparison result; sixth multiplying means (2 3b ) coupled to said second holding means, for multiplying said measured value signal T n+1 by a sixth coefficient A₃′ and for outputting a signal A₃′T n-1 ; sixth comparing means (6₂) coupled to said measuring means and said sixth multiplying means, for determining whether said measured value signal T n-1 is equal to or greater than said signal A₃′T n+1 and for outputting a sixth detection signal based on a comparison result; and logic means (8, 10, 28, 30, 32) for receiving said first through sixth detection signals and for outputting a margin detection signal indicative of said front and back margins on the basis of said first through sixth detection signal.

Claim 20

A bar code reading apparatus comprising scanning means (20, 21) for scanning a bar code including a character bar and guard bars facing front and margin areas surrounded by a margin defining area and for generating a pulse signal corresponding to said bar code; measuring means (1) coupled to said scanning means, for measuring a width of each white bar contained in said bar code and a width of each black bar contained therein and for outputting a measurement signal indicative of the width of said each white or black bar, said measurement signal includes a time-series of measured value signals T n-1 (n is an integer), T n and T n+1 ; and first holding means (3) coupled to said measuring means, for holding one of said measured value signals until a next one of the measured value signals is output from said measuring means so that when the measured value signal T n+1 is applied to said first holding means, said first holding means outputs said measured signal T n , characterized in that said bar code reading apparatus comprises: second holding means (5) coupled to said first holding means, for holding one of said measured value signals from said first holding means until a next one of the measured value signals is output from said first holding means so that when the measured value signal T n+1 is applied to said second holding means, said second holding means outputs said measured value signal T n-1 ; first multiplying means (2 1a ) coupled to said second holding means, for multiplying said measured value signal T n-1 by a first constant A₁ and for outputting a signal A₁T n-1 ; first comparing means (2₂) coupled to said first holding means and said first multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁T n-1 and for outputting a first detection signal based on a comparison result; second multiplying means (4₁) coupled to said second holding means, for multiplying said measured value signal T n-1 by a second constant A₂ and for outputting a signal A₂T n-1 ; second comparing means (4₂) coupled to said first holding means and said second multiplying means, for determining whether said measured value signal T n is equal to A₂T n-1 and for outputting a second detection signal based on a comparison result; third multiplying means (2 1b ) coupled to said second holding means, for multiplying said measured value signal T n-1 by a third coefficient A₃ and for outputting a signal A₃T n-1 ; third comparing means (6₁) coupled to said measuring means and said third multiplying means, for determining whether said measured value signal T n+1 is equal to or greater than said signal A₃T n-1 and for outputting a third detection signal based on a comparison result; fourth multiplying means (2 3a ) coupled to said measuring means, for multiplying said measured value signal T n+1 by a fourth constant A₁′ and for outputting a signal A₁′T n+1 ; fourth comparing means (2₄) coupled to said first holding means and said fourth multiplying means, for determining whether said measured value signal T n is equal to or greater than A₁′T n+1 and for outputting a fourth detection signal based on a comparison result; fifth multiplying means (4₃) coupled to said first holding means, for multiplying said measured value signal T n+1 by a fifth constant A₂′ and for outputting a signal A₂′T n+1 ; fifth comparing means (4₄) coupled to said measuring means and said fifth multiplying means, for determining whether said measured value signal T n is equal to A₂′T n+1 , and for outputting a fifth detection signal based on a comparison result; sixth multiplying means (2 3b ) coupled to said second holding means, for multiplying said measured value signal T n+1 by a sixth coefficient A₃′ and for outputting a signal A₃′T n-1 ; sixth comparing means (6₂) coupled to said measuring means and said sixth multiplying means, for determining whether said measured value signal T n-1 is equal to or greater than said signal A₃′T n+1 and for outputting a sixth detection signal based on a comparison result; and logic means (8, 10, 28, 30, 32) for receiving said first through sixth detection signals and for outputting a margin detection signal indicative of said front and back margins on the basis of said first through sixth detection signal.

Claim 21

A bar code reading apparatus as claimed in claim 17, characterized in that said logic means comprises: a first AND gate (8) supplied with said second and third detection signals and generating a first AND output signal; a first OR gate (10) supplied with said first detection signal and said first AND output signal and a first OR output signal; a second AND gate (28) supplied with said fifth and sixth detection signals and generating a second AND output signal; a second OR gate (30) supplied with said fourth detection signal and said second AND output signal and outputting a second OR output signal; and a third OR gate (32) supplied with said first and second OR output signals and outputting said margin detection signal.

Claim 22

A bar code reading apparatus as claimed in claim 17 or claim 18, characterized in that each of said first, third, fourth and sixth reference values corresponds to a predetermined normal width of each of said front and back margin areas, and each of said second and fourth reference values corresponds to a predetermined minimum width of each of said front and back margin areas.