30-bit color
30-bit color images have 3 color channels of 10 bits each - one
channel each for red, green and blue, When combined, the red, green and
blue channels provide up to more than 1 billion colors.
8-bit grayscale
Images that contain 256 possible shades of gray.
Address
A number that identifies the I/O location of the device to the host
computer.
Alpha channel
An 8-bit channel reserved by some image-processing applications
for masking or additional color information.
Analog
Continuously variable signals or data. Description of the continuous
wave or signal (such as the human voice) using an electrical voltage variation.
Used for voice, visual, and computer data communication. The digital or
pulse output of a computer or terminal must be converted to an analog signal
before it can be transmitted over analog grade lines
Anti-aliasing
The rendering of hard-edged objects so they blend smoothly into
the background. A technique for merging object-oriented art into bitmaps.
Application Software
General term referring to software packages. For scanner-related
application software, they usually function as editing, drawing and optical
character recognition (OCR).
ASCII (American Standard Code for Information Interchange)
Standard by which many computers assign code numbers to letters,
numbers and symbols. Used for text exchange between computer platforms.
Aspect Ratio
The ratio of horizontal and vertical units
Automatic Configuration
A MiraScan driver feature that automatically finds the available
I/O address to use
Automatic Exposure
A MiraScan driver feature that automatically sets the suitable brightness
and contrast for the user.
Automatic Preview
A MiraScan driver feature that automatically present a preview instantly
whenever brought up.
Banding
A visible stair-stepping of shades in a gradient.
Bit
A unit that can hold information on or off with values of 1 and
0, respectively
Bit depth
The number or bits used to represent each pixel in an image, determining
its color or tonal range
Bitmap
An image formed by rectangular grid of picture elements (pixels).
The computer assigns a value to each pixel, from one bit of information
(indicating black or white) to 24 bits per pixel (for full-color computer
displays), to as many as 64 bits per pixel for some types of full-color
images. A bitmap is an image defined by a collection of dots, as opposed
to a vector image, which is defined by mathematical formulas.
Brightness
A measurement of image intensity
Byte
An unit that contains 8 bits representing values 0 to 255
Calibration
A process that extracts some runtime dynamic information from devices
CCD
A charge-coupled device, or CCD, is a light sensitive electronic
device that converts light into an electrical charge.
CMYK (Cyan, Magenta, Yellow, Black)
The subtractive primaries, or process colors, used in color printing.
Black (K) is usually added to enhance color and to print a true black.
Color channel
Color images on the computer are created by combining different
color channels. In RGB, the most commonly used color model, the channels
are red, green and blue.
Color Match
Match the color between source device and destination device.
Color separation
The division of an image into its component colors for printing.
Each color separation is a piece of negative or positive film.
Compression
Encoding the bits of information in an image file so that it takes
up less space when stored. Compression results in little or no distortion.
Continuous-tone
Image with complete range of tones from black to white such as photographs,
paintings and drawings. Negatives or positives with a broad range of tones
that have no screened dots.
Contrast
The relativity between the light and dark areas of an image. The
more the difference, the greater the contrast.
Data compression
"Squeezing" of data for the purpose of transmission through put
or storage efficiency. Portions of the data are removed by an algorithm
that will restore the data when needed.
DCS
Desktop color separation is an image format consisting of four separate
CMYK PostScript files at full-resolution, together with a fifth EPS master
for placement in documents.
Decompression
The expansion of compressed image files. See also lossy and non-lossy.
Default
Command or parameter that takes effect if no other option is specified.
Density
The ability of a material to absorb light. Measurement of the light
transmission of a transparent or translucent object or the light-absorbency
of a reflective surface. In photography, measurement of the opacity of
a transparent or translucent object. On a film negative, the greater the
density area, the more black or more developed it is. Density is measured
from 0 to 4.0. It is calculated by measuring the reflectance or transmittance
of light and calculating theoretical light absorption.
Descreen
Removal of halftone dot patterns during or after scanning printed
matter by defocusing the image. This avoids moire patterning and color
shifts during subsequent halftone reprinting. The Descreen filter is used
for the image printed out by halftoning or dithering. Without the Descreen
filter process, the scanned halftoning / dithering image will have a moire
effect.
Dialog Box
A window that allows user to make options, key in data and receive
messages
Dither
A technique that uses dispersed dots to simulate gray shades to
fool the eye into seeing grayscale data
Dot
Smallest visible point that can be displayed on a surface.
DPI
An acronym for dot per inch. A measurement of resolution.
Driver
A program functioning as a bridge between application software and
hardware. It usually encapsulates the hardware details to provide easier
interface with the application software.
Drum scanner
An optical input device that mounts reflective or transparent input
media on a revolving cylinder for digitizing.
EPS (Encapsulated PostScript)
This format carries a pict preview and is the only format that supports
saving line screen data and transfer functions. In bitmapped mode, it also
supports transparent whites.
Export
To output data in a form that another program can read.
File
A named collection of information stored as an apparent unit on
a secondary storage medium such as a disk drive.
Film
Photosensitive material, generally on a transparent base, which
will receive character images, and may be chemically processed to expose
those images. In imagesetting, any photosensitive material, transparent
or not, may be called film.
Film negative
A piece of film with a reversed image, in which dark areas appear
white, and vice versa.
Flatbed scanner
Any scanning device that incorporates a flat transparent plate,
on which original images are placed for scanning. The scanning process
is linear rather than rotational.
Gamma
A mathematical function used to describe the relationship between
input densities (levels) and output densities (levels.) The measurement
of how compressed or expanded dark or light shades become in an image.
Gamma Correction
An operation used to correct data that is not realistically reproduced
by some devices. In order to make the correction, the characteristic of
the output device (i.e., gamma value) must be known.
Gradation
A smooth transition between black and white, one color and another,
or colorful and colorless.
Gray balance
The balance between CMYK colorants required to produce neutral grays
without a color cast.
Grey levels
Discrete tonal steps in a continuous tone image, inherent to digital
data. Most CT images will contain 256 gray levels per color.
Grayscale
A range of intensity (i.e., gray shade) for a color plane
Halftone
A technique that uses clustered dots to simulate gray shades to
fool the eye into seeing grayscale data
Highlight
The brightest intensity for an image
Histogram
A graphic representation of the number of pixels with given color
values, showing the breakdown or distribution of color values in a picture.
Hue
The wavelength of light of a color in its purest state (without
the addition of white or black).
Image Type
The image type used to represent a document. It affects how information
is saved and therefore affects how original documents can be reproduced.
Input
Raw data, text, graphics, imagery or commands inserted into a computer.
Interpolation
The process of increasing the resolution of an image by the addition
of new pixels throughout the image, the colors of which are based on neighboring
pixels.
Interface Cable
A cable connecting the scanner with a host computer. In a PC system,
it connects to the PC through the connector on the SCSI interface card.
Interface Card
An I/O (input/output) card inserted into the host computer expansion
slot. It serves as a bridge between scanner and host computer.
Interpolation
An operation performed by the driver. It enhances the resolution
of scanned images by applying an appropriate algorithm to generate a new
and higher resolution image from a lower resolution image.
Inverse Image
A MiraScan driver feature that negates the grayscale value of each
pixel in an image
JPEG (Joint Photographic Expert Group)
An image compression/decompression standard that divides the image
area into cells to condense information based on content analysis.
Line Art
A graph or image containing only lines, text and drawings
Lossless
Data compression algorithms that store data in a more efficient
format and won't cause any data loss in the compression process. Typically
this type of compression has a ratio of up to 8:1.
Lossy
Data compression algorithms that assumes some of the data in an
image file is unnecessary and can be eliminated without affecting the perceived
image quality. Typically this type of compression has ratios between 10:1
and 100:1.
LPI (Lines Per Inch)
A term used in printing as a measurement of the frequency of lines
of a halftone screen (usually ranging from 55-200). Originally, halftones
were made by placing an etched glass plate over an image and exposing it
to produce dots. Lip refers to the frequency of the horizontal and vertical
lines.
Luminance
A value corresponding to the brightness of color.
LAW
The Lempel-Ziv-Welch image compression technique.
Mirror Image
A MiraScan driver feature that flips an image left and right
Moiré Pattern
An interference pattern usually unexpected and annoying
Monitor calibration
The process of optimizing the color settings of a monitor to match
selected colors of a printed output.
Monochrome
Single-colored. An image or medium displaying only black-and-white
or grayscale information, Grayscale information displayed in one color
is also monochrome.
Neutral gray
Any level of optical density (from white to black) having no apparent
hue. It consists of equal levels of red, green, and blue (RGB).
Noise
In the scanning context, this refers to random, incorrectly read
pixel values, normally due to electrical interference or device instability.
Non-lossy
Image compression without loss of quality.
Non-Uniform Resolution
A MiraScan driver feature that allows horizontal and vertical resolution
to be different
Non-Uniform Scaling
A MiraScan driver feature that allows horizontal and vertical scaling
to be different.
Optical resolution
In the scanning context, this refers to the number of truly separate
readings taken from an original within a given distance, as opposed to
the subsequent increase in resolution (but not detail) created by software
interpolation.
Original
A term used for any artwork or photograph that is scanned.
Output
Process of sending computer results to a CRT or printer.
PICT / PICT2
A common format for defining bitmapped or object-oriented images
on the Macintosh. The more recent format (PICT2) supports 24-bit color.
Pixel
The smallest picture element unit in an image
PostScript
The standard device-independent language developed by Adobe Systems
that describes the appearance of pages in documents. PostScript is a page
in its final form, ready for imaging on an output device. Encapsulated
PostScript describes a graphic, image or complete page in a final form
that can be exchanged between application programs. Under such circumstances
one PostScript described item can be included in another layout.
PPI (Pixels Per Inch)
A measurement of the amount of scanned information. The finer the
optics of the scanner the higher the scan resolution. PPI is equivalent
to DPI.
Preview
An operation that gets a rough image of a document for setting parameters
and image analysis.
Preview Size
The size of the preview window area
RAM (Random Access Memory)
The memory a computer needs to store the information it is processing
at any given moment. This is short-term memory and is lost when the power
is shut off. RAM may be expanded by adding memory chips or memory boards.
RGB (Red, Green and Blue)
The color model in which color images are composed of red, green
and blue color channels. Most computer displays and image editing programs
use the RGB color model.
Resolution
The measure of image details. The smallest discernible detail in
visual rendering. Resolution may be stated in terms of spot diameter, line
width, pixel matrix dimension, raster lines or dots/inch.
Sampling
The process of converting analog data into digital data by taking
a series of samples or readings at equal time intervals.
Saturation
The amount of gray in a color. The higher the gray content, the
lower the saturation.
Scaling
An operation that enlarges or shrinks an image
SCSI
An acronym for Small Computer System Interface. It provides an interface
to the computer system with device independence within a class of devices.
SCSI ID
A number for a device on the SCSI bus chain can be 0 through 7.
This number represents the device when it is communicating on the SCSI
bus.
Shadow
The darkest intensity of an image
Sharpen
Electronic photo-retouching function for enhancing image detail
and contrast either globally or in selected regions of the picture.
Sheetfed
Type of scanning device in which the original is moved past the
scanning head, rather than having the scanner head moved. Usually appropriate
only for sheets of paper.
Single-bit images
Black and white bitmapped images, of either line art or halftone
image type.
TGA (Targa)
A file format for exchanging 24-bit color files on PCs.
Threshold
A value for text data type. For pixel value above the threshold
value, it is represented by 1 (i.e., white). For pixel value below the
threshold value, it is represented by 0 (i.e., black).
TIFF (Tag Image File Format)
A popular image file format. It contains several effective compression
schemes which save space when storing data
Tone curves
Also known as gamma curves. These are used to smoothly adjust the
overall tonal range of an image, or the individual tonal ranges of each
color channel.
TWAIN
A standard software protocol and API (Application Programming Interface)
for communication between application software and image acquisition devices
TWAIN-Compliant
A term that identifies application software or devices that follow
the TWAIN standard
Zoom
A MiraScan driver feature allowing the user to see more details
of the document. Users can zoom-in on the scanning area repeatedly.