Glossary

Common Document Management Terms

The electronic information management industry is full of specific terminology and acronyms. To assist you in better understanding the industry, we’ve put together the following list of common terms:

Automatic Document Feeder (ADF) – Scanner accessory that automatically feeds a stack of paper into the scanner.

B

Back to Top

Barcode – A system of portraying data in a series of machine-readable lines of varying widths. The “UPC” on consumer items is a barcode. In document management, a barcode is used to encode indexing information.

Bitonal – A scanner that outputs 1 bit per pixel, resulting in an image composed entirely of pixels that are either black or white.

C

Back to Top

CCITT Group 3 Compression – A one-dimensional compression algorithm for binary images of text and line art, used by most fax machines.

CCITT Group 4 Compression – A two-dimensional compression algorithm for binary images of text and line art.

Character Recognition – Conversion of an image representation of a character to ASCII text representation. Sometimes called OCR or ICR.

Charge-Coupled Device (CCD) – The type of image sensor used in scanners.

Compression Ratio – The ratio of the uncompressed to compressed file size. Typical CCITT Group 4 compression ratios are 10 or 20 to 1.

Contact Sensor – An image sensor, similar to a CCD, used in some low cost scanners.

D

Back to Top

Decompress – To reverse the procedure conducted by compression software, and thereby return a compressed image file to its original size and condition for display or editing.

Deskew – Slight rotation of an image to align horizontal and vertical directions in the original with corresponding directions in the image.

Digitize – To convert an analog image or signal into bits.

Dither – To represent gray tones in bitonal output by a pattern of dots.

Document Preparation – Steps to ready documents for scanning by removing paper clips, staples, bindings, etc.

Dots Per Inch (dpi) – A measurement of scanner resolution, relative to the original document. The term “dot” means a pixel, whether binary, grayscale, or color. More dpi means higher resolution and greater detail.

Double Feed – An error condition in a scanner caused when the ADF moves two pages at once through the scanner.

Dropout – Use of colored lamps or filters inside a scanner in conjunction with specially printed forms, in order to make certain pre-printed text or rulings invisible in the scanned image. This aids character recognition and results in smaller image files.

Duplex – A scanner capable of imaging both the front and back sides of a page in a single pass.

Duty Cycle – The scanner manufacturer’s rated frequency of usage, usually measured in pages per month.

E

Back to Top

Endorser – Scanner accessory that automatically prints an ID number on documents as they are scanned. Sometimes called an imprinter.

Enhancement – Technique for processing an image so that the result is visually clearer than the original image.

Error Diffusion – A type of dithering in which the dot pattern includes an element of randomness to reduce visual artifact.

F

Back to Top

Flatbed – A type of scanner in which the document is placed face down on a glass platen and the imaging assembly moves.

G

Back to Top

Grayscale – A scanner that outputs multiple shades of gray per pixel.

H

Back to Top

Host - The primary or controlling computer to which a scanner is attached.

I

Back to Top

Imaging Assembly – Scanner component comprising the lamp, illumination and collection optics, and CCD.

Intelligent Character Recognition (ICR) – A term applied to the recognition of hand printed characters.

ISIS – A popular software interface for high-speed scanners.

J

Back to Top

Joint Binary Image Group (JBIG) – A compression algorithm for bitonal and grayscale images. JBIG givers higher compression ratios than CCITT Group 4.

Joint Photographic Experts Group (JPEG) – A compression algorithm for continuous tone color and grayscale images. JPEG is “lossy” compression, meaning some fine detail is lost and cannot be recovered when the image is decompressed.

K

Back to Top

L

M

N

Back to Top

Noise Removal – A form of image enhancement in which isolated black pixels are assumed to be caused by dust and dirt and are turned to white in the image.

O

Back to Top

Optical Character Recognition/Reader (OCR) – A term applied to the recognition of machine printed characters.

Orientation – The relative direction of a display or printer page, either horizontal (“landscape” orientation) or vertical (“portrait” orientation).

P

Back to Top

Pages Per Minutes (ppm) – The standard unit of scanner speed.

Parallel Port – A standard interface to a PC most often used in computer-to-printer connections, used to attach scanners slower than 10 ppm.

Patch Code – Marks placed on separator sheets in a scanned batch that can be read by the scanner to indicate a new document or section for indexing purposes.

Pixel – Short for Picture Element. Also called a Pel. The fundamental spatial element in an image.

Pixel Depth – The number of bits per pixel captured by the scanner. A pixel depth of N bits corresponds to 2N distinct colors or shades.

Q

Back to Top

R

Back to Top

Resolution – Density of pixels in a scanned image, measured in dots per inch (dpi). The higher the resolution, the greater amount of detail may be shown.

S

Back to Top

Sheet Fed – A type of scanner that moves cut sheet paper past a stationary imaging assembly.

Simplex – A scanner capable of reading only one side of a pge in one pass.

Skew – Slight rotation of an image relative to the original document, usually caused by imperfect alignment of the page in the scanner’s document feeder.

Small Computer System Interface (SCSI) – An industry standard for connecting peripheral devices and their controllers to a PC. SCSI can be used to attach scanners of any speed.

T

Back to Top

Text – Digital representation of information as alphanumeric characters, encoded in a format such as ASCII; as distinguished from an image or bitmap representation of the information.

Thresholds – Conversion of grayscale image data into a bitonal image. Usually thresholds occur inside the scanner.

Throughput – The number of items completed in a process such as scanning or character recognition, usually measured in pages per minute.

Transport – Component of the scanner that feeds and moves paper.

TWAIN – A popular software interface for low speed scanners and digital cameras.

U

V

Back to Top

Video Interface – A type of connection of a scanner to a PC via a vendor-proprietary interface card; used as an alternative to SCSI in some high-speed scanners.

W

X

Y

Z

Back to Top

This Glossary has been excerpted from “Document Scanning Across the Enterprise” from the Rheinner Document Imaging & Workflow Technology Series.