UMAX Technologies Astra 2000U Owner's Manual page 111

UMAX Astra 2000U/P Owner's Guide
Highlight-The brightest part of an image that still has detail.
Setting a highlight point in an image is arguably the most important
step to achieving a good scan.
Histogram-A bar chart that represents the pixel count of an image.
The bar chart has a scale from 0-255, which represents 2 to the 8th
power or 256 levels of gray. All images, even a Polar bear in a
snowstorm should have a histogram that extends from 0 (darkest
area) to 255 (lightest area).
ICC-International Color Consortium
LAB-A color space that most closely resembles the color spectrum
a human eye can perceive. [L] represents the lightness or
luminosity of the image, [A] represents the Red/Green axis, [B]
represents the Blue/Yellow axis. These values are plotted at right
angles to each other in a three dimensional manner.
Linearization-The process of calibrating a scanner's white point,
50% gray point and black point. This is usually accomplished by
scanning a grayscale target.
Line art-An image having only one level of contrast or (1) bit
depth. A line art image can be either Bitmap or vector.
LPI-Lines Per Inch. Also referred to as line screen. The greater the
LPI the more continuous looking the image will appear to the
human eye. A newspaper is generally printed at 85-100 LPI while
magazines are printed from 133-175 or higher.
OCR (Optical Character Recognition)-A process which assists an
input device in converting pixels to ASCII information.
Pixel-An abbreviation for "Picture Element'. The basic building
block of computer images.
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