ANSI INCITS 93M-2017 pdf free download – Optical Character Recognition (OCR) Character Positioning
1.1 Scope. This standard specifies the location of OCR-A and OCR-B characters in relationship to other characters on a document or page and to reference points of the document or page.
1.2 Purpose. The purpose of this standard is to estab- lish definitions and tolerances for the positioning of OCR-A and OCR-B characters that will ensure satis- factory optical recognition.
1.3 Application. This standard shah be used in con- junction with American National Standards for OCR character shapes and sizes (ANSI X3.1 7-1 981 and ANSI X3.49-1975) OCR paper (ANSI X3.62-1979), and OCR inks (ANSI X3.86-1980). These standards are listed in detail in Section 5 of this standard. For most OCR systems to function reliably, each OCR character should be located and positioned so that other OCR characters or non-OCR data cannot interfere with rec- ognition.
The values in this standard are chosen on the basis that they are reasonably obtainable. Although each parameter is independently specified, a deterioration in reader performance may occur if the limits of two or more parameters are approached simultaneously. Every effort should be made to keep well within the specified limits. It is recognized, however, that in bulk printing from any device the limits will occasionally and ran- domly be exceeded.
2. Character Positioning The position of a character is as important as the shape and quality of the printed character. Character position- ing specifications (format rules) are needed to ensure that each OCR character is seen by the reading device without interference from other OCR characters or from non-OCR matter. The format rules given in this standard are the minimum requirements and may need to be supplemented by further rules for specific sys- tems. The four general conditions that must be consid- ered are:
(1) The position of the character relative to the edge of the document
(2) Character separation
(3) Character alignment
(4) Character skew
3. Definitions
3.1 Document Reference Edges. Document reference edges are any edges used to locate the document (see Fig. 1).
3.2 Printing Area. A printing area is a rectangle inside the clear area in which OCR characters are to be printed (see Fig. 1). The sides of this rectangle should be paral- lel or perpendicular to a document reference edge.
3.3 Clear Area. A clear area is the printing area ex- tended by dimensions a, b. c, and d as shown in Fig. 1. A document may contain more than one clear area. The locations and dimensions of clear areas wilI be determined by individual applications and the require- ments specified in 4.2.1 and 4.2.2. This does not pre- clude the use of nonread inks.
3.4 Maqin. A margin is the perpendicular distance between any boundary of the printing area and the nearest document edge (see Fig. 1).
3.5 Field. A field is any group of characters on one or more lines defined as a unit of information. A line may comprise several fields.
3.6 Llle Boundary. A line boundary is the smallest rectangle with sides parallel and perpendicular to the document reference edge and containing all the bound- aries of the component characters of the line (see Fig. 2).ANSI INCITS 93M pdf download.