CA1207431A - Optical character reader - Google Patents
Optical character readerInfo
- Publication number
- CA1207431A CA1207431A CA000453940A CA453940A CA1207431A CA 1207431 A CA1207431 A CA 1207431A CA 000453940 A CA000453940 A CA 000453940A CA 453940 A CA453940 A CA 453940A CA 1207431 A CA1207431 A CA 1207431A
- Authority
- CA
- Canada
- Prior art keywords
- characters
- circuit
- image sensor
- base
- image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Character Input (AREA)
- Character Discrimination (AREA)
Abstract
Title of the invention Optical Character Reader Abstract of the Disclosure An optical character reader in which analog electrical signals produced by a photoelectrical conversion device are converted into binary signals representative of a background region and a character region, the characters or the like being recognized by a discrimination circuit according to the predescribed binary signals, the discrimi-nation circuit being into operation only when one complete view of the character or the like is detected within a range of a scope of the image sensor used.
For detecting the image-formation picture of the image sensor positioned completely to mate with the form, a base of reflection factor lower than that of the form is used for fixing the form to thereby utilize different reflection factors of the form and base, or a difference between the reflection factors thereof, so that when the image-formation picture is positioned even in part corresponding to the base, the read command signal is not given, thereby preventing the edge of form and characters or symbols not entered therein from being read by mistake.
For detecting the image-formation picture of the image sensor positioned completely to mate with the form, a base of reflection factor lower than that of the form is used for fixing the form to thereby utilize different reflection factors of the form and base, or a difference between the reflection factors thereof, so that when the image-formation picture is positioned even in part corresponding to the base, the read command signal is not given, thereby preventing the edge of form and characters or symbols not entered therein from being read by mistake.
Description
~Z~t74,3~
1 This invention rel~tes ~o an opti.cal character reader for reading with accuracy characters or symbols entered in a form~
~ig~ 1 i.s a plan vie~l explanatory or read-scanni.ng characters on a form, Fig. 2 ;.s. a perspective schemati.c vi.ew of an opti.cal c~aracter reader of the i.nvention when in use, F~g. 3 i.s a plan vi.ew of a picture of an image sensor at the same, and Fig. 4 i5 a circuit diagram of a detection c~rcuit for detecting the form Generally, the optical charactex reader scans characters entered in the ~orm, images the charactexs through a lens system on an image sensor compr~.sing a photo-, 15 electric conversion.element, converts by a binary circuit analog signals from the image sensor into binary signalscorrespondîng to the background region and characters on the form and discriminates ~y a discrimination ci.rcuit the binary signals as the characters on the form. For reading the characters given on the forms~ such as slips or price tags, a hand~scan type optical character reader (to be herei.nafter called the hand scan OCR~ which hand-operates a scanning unit and a stationary type optical character reader ~to be hereînafter called the stationary OCR) which fixes the scanning uni.t and transports the form, are used. These OCR~s as shown i.n F~.g 1, sc.ans object ch~racters 13 to be read and entered in the form 11, ~ .
L. .
I 7~t3~
1 r;ghtwardly or le~t~ardly i`n the directions of the arxows in the dra~ing~ ther,e~y carry~.ng out the readi.ng operat~.on~
However, when the characters 13 on the ~orm 11 ~re read~ a scanner 14 after moves from the base out of the form 1.1 toward the ch~racter line. thereon beyond the ed~e 12 of form 11, ~hRreby there is a fear of reading un~
necessary characters or symbols out of th.e form 11 ~on the base). carrying the object characters 13 to be read. Also, si,nce the edges 12 o~ form 11 are liable to be optically shaded~ the shade will be read ~y mistake~ Furthermore~
in a case where t~e. edges 12 oE form 11 are close to the object characters 13 to be readl the character 13 have . often ~een misread.
In the light of the above problems, this i,nvent;on ; 15 has been designed, An o~ject of the invention is'to pro-vide an optical character reader which prevents misreading of the edges of the form or chc~racters or symbols not th,ereon, thereby enabling reliable read of the object characters entered in the form onl~
The above and ot.her objects and features of the i,nvention ~ill appear more fully hereinafter from a con-sideration of the follow;ng description taken in connection with the accompanying drawing wherein one example i,s illus- -trated by way o~ example~
The opti.cal character reader of the invention!
as shown in F;g. 2, provides a b~se 21 for placing thereon ~2(~ 43~
1 a ~orm 11, i.n which ob~ect characters 13 to be read are entered ! the base 21 usi.ng a metal plate painted black or the like so as to have a reflection factor lowe~ (for example, 2% or less~ than that of form 11 (usually~ 70%
S or moxe because of the use of the white form~ Alternatively, a member, such. as a hollow ~arrel holdîng the form at ~oth vertical edges thereo~ of reflection factor lo~er than that of the form may be substituted for the base 21.
The scanner 14 houses therein an image sensor . 10. ~photoelectric conversi.on element~ ~y whïch images 22 formed through the lens system are converted into analog electri.c si.gnals, the image sensor ~eing utilized to provide a circuit for detecting the form 11. In addition, a picture of the image sensor, on which.the image 22 i.s formed, is shown in Fig~ 3! and the detection ci.rcuit i~s shown in Fig. 4.
The detectinn circuit for t~e orm, as sho~n in Figs. 3 and 4, comprises the ma~imum black line detection ~3 .4 ~t~ ,91 ql~4 Y~
l OR circuit I detecting the maximum lines including black portions~among the respective lines at the picture 23 of image sensor, a reflection factor comparison circuit II which compa~es whether the reflection factor of the maximum black lines detected by the maximum black line detection OR circuit I corresponds to that of the form, and a character level detection-elimination circu~t III which compares whether the sum of the maxirnum black lines is smaller than the level correspond-ing to the characters 13 entered in the form ll 50 that a reading command signal a is output only when the same is lower than the level.
The maximum black line detection OR circuit I
comprises a resistance R1 through which a comparison circuit A is connected with a power source and diode~
D1 and Dn throu~h which the imput terminal of comparator A is connected to both lateral end lines V1 and Vn at the picture 23 of image sensor respecti~ely as shown in Fig. 3. In addition, in this case, the diodes D1 and Dn . may be connected to lines deemed neccessary other than both the lateral end lines. In such circuit I, the comparator A is given analog electric si~nals from the maximum black lines of the maximum black portions.
The reflection factor comparison circuit II sets at the minus input terminal of a comparator A reference 7~
l potential corresponding to the reflection factor of the form 11 through voltage dividing resistances R2 and ~3 so that the reflection factors given into the plus input terminal of the comparator A are compared in order of each line whether or not the reflection factors corresponds to that of form 11, thereby outputt-ing the black portion of higher level than reference potential only from the comparator A.
The character level detection ~limination circuit III includes an integration circuit comprising a resistance R4 and a capacitor C1, through which integra-tion circuit the output line of comparator A is connectecl with an input terminal at a comparator B, the integration circuit integrating the black portions of the maximum black lines output from the comparator A. Also, at the minus inpu~ terrninal of comparator B, voltaye dividing resistance RS and R6 set reference voltage correspond-ing to the level of characters 13 entered in the form 11 ~hereby a read command sic3nal a is output from the comparator B only when the sum of black portions is lower than the reference potential. In other words, since the sum of black portions in the lines is integrated by the integration circuit, the levels of the black portions are measurable. Also, the comparator B
compares the level of Dlack portion with the character ~t7~
l level set by the reference potential so that only when the su~ o~ black ~ortions is smaller than the set value, the comparator B will output the read command signal a to discrimination circuit IV~ ~hich i.s housed in the reader, decides whether or not the discrimination result read rom the scanner 14 is adopted, and is controlled by the read command signal a given from the comparator B.
Accordinyly, when one latèral end line at the picture 23 of image sensor is positioned on the b~ack base 21, the read command signal a is not yiven and the character images 22 forMed on the picture 23 of ima~e sensor axe not read. In other owrds, the readin~
operation starts after the imaging picture 23 of image sensor is positioned to completely meet with the form 11, and continues until the read com~and signal a is eliminated, thereby enabling preventiny of misread-ing out of the form 11~ As a result, although the convention reader has hitherto misread abo~t 10 of 500 sli~s, the reader of the invention has done nothing~
Alternatively, the aforesaid circuit may be constructed ofr white portions in the lines. Also, the present invention may of course be applicable to a hand scan OCR manually operating the scanner for scanning the characters, or a stationary type OCR
~'7~3~
1 which fixes the scanner and moves the form for scanning.
As seen frpm the above, this invention carries out reading operation only when the image-formation screen of image sensor at the sc~ner is positioned completely on the form, so that there is no fear of reading by mistake the edges of the form or characters`
and symbols not therein, thereby prPvPnting mlsreading, thus havin~ enabled a large improvement in reading performance.
While an embodiment of the invention has been shown and described, the invention is not limited to the specific construction thereof, which is merely exernplary in the specifica~ion rather than defined.
-- 7 ~
. ,
1 This invention rel~tes ~o an opti.cal character reader for reading with accuracy characters or symbols entered in a form~
~ig~ 1 i.s a plan vie~l explanatory or read-scanni.ng characters on a form, Fig. 2 ;.s. a perspective schemati.c vi.ew of an opti.cal c~aracter reader of the i.nvention when in use, F~g. 3 i.s a plan vi.ew of a picture of an image sensor at the same, and Fig. 4 i5 a circuit diagram of a detection c~rcuit for detecting the form Generally, the optical charactex reader scans characters entered in the ~orm, images the charactexs through a lens system on an image sensor compr~.sing a photo-, 15 electric conversion.element, converts by a binary circuit analog signals from the image sensor into binary signalscorrespondîng to the background region and characters on the form and discriminates ~y a discrimination ci.rcuit the binary signals as the characters on the form. For reading the characters given on the forms~ such as slips or price tags, a hand~scan type optical character reader (to be herei.nafter called the hand scan OCR~ which hand-operates a scanning unit and a stationary type optical character reader ~to be hereînafter called the stationary OCR) which fixes the scanning uni.t and transports the form, are used. These OCR~s as shown i.n F~.g 1, sc.ans object ch~racters 13 to be read and entered in the form 11, ~ .
L. .
I 7~t3~
1 r;ghtwardly or le~t~ardly i`n the directions of the arxows in the dra~ing~ ther,e~y carry~.ng out the readi.ng operat~.on~
However, when the characters 13 on the ~orm 11 ~re read~ a scanner 14 after moves from the base out of the form 1.1 toward the ch~racter line. thereon beyond the ed~e 12 of form 11, ~hRreby there is a fear of reading un~
necessary characters or symbols out of th.e form 11 ~on the base). carrying the object characters 13 to be read. Also, si,nce the edges 12 o~ form 11 are liable to be optically shaded~ the shade will be read ~y mistake~ Furthermore~
in a case where t~e. edges 12 oE form 11 are close to the object characters 13 to be readl the character 13 have . often ~een misread.
In the light of the above problems, this i,nvent;on ; 15 has been designed, An o~ject of the invention is'to pro-vide an optical character reader which prevents misreading of the edges of the form or chc~racters or symbols not th,ereon, thereby enabling reliable read of the object characters entered in the form onl~
The above and ot.her objects and features of the i,nvention ~ill appear more fully hereinafter from a con-sideration of the follow;ng description taken in connection with the accompanying drawing wherein one example i,s illus- -trated by way o~ example~
The opti.cal character reader of the invention!
as shown in F;g. 2, provides a b~se 21 for placing thereon ~2(~ 43~
1 a ~orm 11, i.n which ob~ect characters 13 to be read are entered ! the base 21 usi.ng a metal plate painted black or the like so as to have a reflection factor lowe~ (for example, 2% or less~ than that of form 11 (usually~ 70%
S or moxe because of the use of the white form~ Alternatively, a member, such. as a hollow ~arrel holdîng the form at ~oth vertical edges thereo~ of reflection factor lo~er than that of the form may be substituted for the base 21.
The scanner 14 houses therein an image sensor . 10. ~photoelectric conversi.on element~ ~y whïch images 22 formed through the lens system are converted into analog electri.c si.gnals, the image sensor ~eing utilized to provide a circuit for detecting the form 11. In addition, a picture of the image sensor, on which.the image 22 i.s formed, is shown in Fig~ 3! and the detection ci.rcuit i~s shown in Fig. 4.
The detectinn circuit for t~e orm, as sho~n in Figs. 3 and 4, comprises the ma~imum black line detection ~3 .4 ~t~ ,91 ql~4 Y~
l OR circuit I detecting the maximum lines including black portions~among the respective lines at the picture 23 of image sensor, a reflection factor comparison circuit II which compa~es whether the reflection factor of the maximum black lines detected by the maximum black line detection OR circuit I corresponds to that of the form, and a character level detection-elimination circu~t III which compares whether the sum of the maxirnum black lines is smaller than the level correspond-ing to the characters 13 entered in the form ll 50 that a reading command signal a is output only when the same is lower than the level.
The maximum black line detection OR circuit I
comprises a resistance R1 through which a comparison circuit A is connected with a power source and diode~
D1 and Dn throu~h which the imput terminal of comparator A is connected to both lateral end lines V1 and Vn at the picture 23 of image sensor respecti~ely as shown in Fig. 3. In addition, in this case, the diodes D1 and Dn . may be connected to lines deemed neccessary other than both the lateral end lines. In such circuit I, the comparator A is given analog electric si~nals from the maximum black lines of the maximum black portions.
The reflection factor comparison circuit II sets at the minus input terminal of a comparator A reference 7~
l potential corresponding to the reflection factor of the form 11 through voltage dividing resistances R2 and ~3 so that the reflection factors given into the plus input terminal of the comparator A are compared in order of each line whether or not the reflection factors corresponds to that of form 11, thereby outputt-ing the black portion of higher level than reference potential only from the comparator A.
The character level detection ~limination circuit III includes an integration circuit comprising a resistance R4 and a capacitor C1, through which integra-tion circuit the output line of comparator A is connectecl with an input terminal at a comparator B, the integration circuit integrating the black portions of the maximum black lines output from the comparator A. Also, at the minus inpu~ terrninal of comparator B, voltaye dividing resistance RS and R6 set reference voltage correspond-ing to the level of characters 13 entered in the form 11 ~hereby a read command sic3nal a is output from the comparator B only when the sum of black portions is lower than the reference potential. In other words, since the sum of black portions in the lines is integrated by the integration circuit, the levels of the black portions are measurable. Also, the comparator B
compares the level of Dlack portion with the character ~t7~
l level set by the reference potential so that only when the su~ o~ black ~ortions is smaller than the set value, the comparator B will output the read command signal a to discrimination circuit IV~ ~hich i.s housed in the reader, decides whether or not the discrimination result read rom the scanner 14 is adopted, and is controlled by the read command signal a given from the comparator B.
Accordinyly, when one latèral end line at the picture 23 of image sensor is positioned on the b~ack base 21, the read command signal a is not yiven and the character images 22 forMed on the picture 23 of ima~e sensor axe not read. In other owrds, the readin~
operation starts after the imaging picture 23 of image sensor is positioned to completely meet with the form 11, and continues until the read com~and signal a is eliminated, thereby enabling preventiny of misread-ing out of the form 11~ As a result, although the convention reader has hitherto misread abo~t 10 of 500 sli~s, the reader of the invention has done nothing~
Alternatively, the aforesaid circuit may be constructed ofr white portions in the lines. Also, the present invention may of course be applicable to a hand scan OCR manually operating the scanner for scanning the characters, or a stationary type OCR
~'7~3~
1 which fixes the scanner and moves the form for scanning.
As seen frpm the above, this invention carries out reading operation only when the image-formation screen of image sensor at the sc~ner is positioned completely on the form, so that there is no fear of reading by mistake the edges of the form or characters`
and symbols not therein, thereby prPvPnting mlsreading, thus havin~ enabled a large improvement in reading performance.
While an embodiment of the invention has been shown and described, the invention is not limited to the specific construction thereof, which is merely exernplary in the specifica~ion rather than defined.
-- 7 ~
. ,
Claims (4)
1. An optical character reader provided with an image sensor which scans characters or the like entered in a form and outputs analog electric signals correspond-ing to said characters, a binary circuit for converting said analog electric signals into binary signals corresponding to the character region and background region, and a discrimination circuit which recognizes said characters or the like on the basis of said binary signals, said reader characterized in that a base is used for fixing said form carrying said characters or the like, said base is formed to be of a reflection factor lower than that of said form, and a circuit is provided which detects that the image-formation picture of said image sensor is positioned completely on said form, thereby outputting a read command signal.
2. An optical character reader according to claim 1, characterized in that said base comprises a metal plate painted black and of the reflection factor of 2 % or less.
3. An optical character reader according to claim 1, characterized in that said base is a hollow barrel holding said form at the vertically upper and lower ends only.
4. An optical character reader according to claim 1, characterized in that a circuit, which detects that the image-formation picture of said image sensor is positioned completely on said form and outputs a read command signal, comprises a detection OR circuit for detecting the maximum block lines rich in black portions to a maximum in the image-forming picture at said image sensor, a reflection factor comparison circuit for comparing the reflection factor of the maximum black lines with that of said form, and a character level detection elimination circuit which outputs a read command signal only when the sum of said black portions at the maximum black lines is lower in the level than said characters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000453940A CA1207431A (en) | 1984-05-09 | 1984-05-09 | Optical character reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000453940A CA1207431A (en) | 1984-05-09 | 1984-05-09 | Optical character reader |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1207431A true CA1207431A (en) | 1986-07-08 |
Family
ID=4127831
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000453940A Expired CA1207431A (en) | 1984-05-09 | 1984-05-09 | Optical character reader |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1207431A (en) |
-
1984
- 1984-05-09 CA CA000453940A patent/CA1207431A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |