1、Designation:F14992b(Reapproved 2009)Standard Terminology Relating toOptical Character Recognition1This standard is issued under the fixed designation F149;the number immediately following the designation indicates the year of originaladoption or,in the case of revision,the year of last revision.Anum
2、ber in parentheses indicates the year of last reapproval.Asuperscriptepsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This set of definitions is intended for use by personswho,in the course of their duties,make use of OCR equipmentor interact with operators of
3、such equipment.2.Referenced Documents2.1 ANSI Standards:2ANSI X3.17 Character Set for Optical Character Recogni-tion(OCR-A)ANSI X3.49 Character Set for Optical Character Recogni-tion(OCR-B)3.Terminology3.1 Definitions:adjacencytwo OCR characters printed on the same line withcharacter spacing referen
4、ce lines separated by the properspace for the font and system.alphamericSee alphanumeric.alphanumericpertaining to a character set that containsletters,digits,and usually other characters such as punctua-tion marks.Syn.alphameric.alphanumeric character seta character set that containsboth letters an
5、d digits and may contain control characters,special characters,and the space character.alphanumeric character subseta character subset that con-tains both letters and digits and may contain control charac-ters,special characters,and the space character.average background reflectanceexpressed as a pe
6、rcent,isthe simple arithmetic average of the background reflectionreadings from at least five different points on a sheet.average edgean imaginary line bisecting the irregularities ofthe character edge.backer printingprinting on the reverse side of the sheet.ForOCR forms,the paper should have suffic
7、ient opacity so thatprinting on the back cant be seen on the front by the opticalscanner.background reflectancea measurement of the brightness ofpaper referring to the amount of light reflected back from thepaper at a particular point when that point is flooded withlight,as compared with the known v
8、alue representingabsolute white(such as BaSO4).bandthe light frequency spectrum between two definedlimits;also light band.bankingthe alignment of the first graphic shape in a linewith respect to the left(right)margin,by certain devices(that is,typewriters,line printers,etc.).bar codea binary coding
9、system consisting of vertical marksor bars that,when read by an optical scanner,can beconverted to machine language.barium sulfate(BaSO4)a standard reflecting agent used tocalibrate instruments for measuring the whiteness and re-flectance of papers.base linea reference line used to specify the nomin
10、al relativevertical position of OCR characters printed on the same line.basis weightthe weight in pounds of a ream cut to aspecified basic size.The number of sheets in a ream isusually 500.The basic size for writing papers commonlyused in OCR applications is 17 by 22 in.Also measuredmetrically in gr
11、ams per square metre(g/m2)and referred toas grammage.blind inkSee reflective ink.bridgingenlargement of a graphic shape beyond the COL,which produces undesired character fill in.brightnessin paper,a characteristic of white paper mea-sured in terms of reflectance in the blue and violet portionsof the
12、 spectrum.caliperthe thickness of a sheet of paper measured underspecified conditions and usually expressed in thousandths ofan inch(mils).carbon papera sheet composed of a supporting substrate onone or both sides of which is a coating containing a1This terminology is under the jurisdiction of ASTM
13、Committee F05 onBusiness Imaging Products and is the direct responsibility of Subcommittee F05.01on Nomenclature and Definitions.Current edition approved Oct.1,2009.Published October 2009.Originallyapproved in 1972.Last previous edition approved in 2003 as F149 92b(2003).DOI:10.1520/F0149-92BR09.2Av
14、ailable from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 transferable(usually colored)material.The coating is ofsuch nature that
15、it will transfer in part or entirely to a copysheet at the point of pressure contact.centerlinethe vertical axis around which character elementsare located for letters,numerals,or symbols of an OCR font.character(1)a member of a set of elements upon whichagreement has been reached and that is used f
16、or theorganization,control,or representation of information.Char-acters may be letters,digits,punctuation marks,or othersymbols,often represented in the form of a spatial arrange-ment of adjacent or connected strokes or in the form of otherphysical conditions in data media.(2)a letter,digit,or other symbol that is used as part of theorganization,control,or representation of data.A characteris often in the form of a spatial arrangement of adjacent orconnected strokes.character alignmentthe vertic
