Microscan Quadrus EZ, Руководство пользователя, Страница: 341 / 366

Quadrus EZ Reader User’s Manual
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Appendices
Appendix Q — Glossary of Terms
Aberration—The failure of an optical lens to produce an exact point-to-point correspon-
dence between the object and its resulting image. Various types are chromatic, spherical,
coma, astigmatism and distortion.
Absorption—The loss of light of certain wavelengths as it passes through a material and
is converted to heat or other forms of energy. (-)
Active Illumination—Lighting a scene with a light source coordinated with the acquisition
of an image. Strobed flash tubes and pulsed lasers are examples.
Ambient light—Light which is present in the environment of the imaging front end of a
vision system and generated from outside sources. This light, unless used for actual
scene illumination, will be treated as background noise by the vision system.
Analog—A smooth, continuous voltage or current signal or function whose magnitude
(value) is the information. From the word “analogous,” meaning “similar to.”
Analog Gain Adjustment (AGC). Adjustment to signal strength that seeks to maintain a
constant level regardless of the range of the bar code symbol.
Analog-to-Digital Converter (A/D)—A device which converts an analog voltage or cur-
rent signal to a discrete series of digitally encoded numbers (signal) for computer process-
ing. Architecture—For a vision system, the hardware organization designed for high speed
image analysis.
ASIC—An acronym for Application Specific Integrated Circuit. All vision system elements
including firmware can be integrated onto one ASIC.
Aspect Ratio—The ratio between the height and width of a sensor or display. It is found
by dividing the vertical number of pixels (height) by the horizontal number of pixels (width)
leaving it in fractional format.
Auxiliary Port—RS-232 connections to an auxiliary terminal or device for remote viewing.
the transfer of data to and from the host, and under certain conditions a configuration port.
Blooming—The situation where too many photons are being produced to be received by
a pixel. The pixel overflows and causes the photons to go to adjacent pixels. Blooming is
similar to overexposure in film photography, except that in digital imaging, the result is a
number of vertical and/or horizontal streaks appearing from the light source in the picture.
Baud Rate—The number of discrete signal events per second. Bits per second.
Capture—The act of acquiring and storing video images in a reader or computer. Also, the
image captured.
CCD—Charged Coupled Device CCDs capture light onto an array of light-sensitive
diodes, each diode representing one pixel.
Check Digit—A Modulus 43 or Modulus 10 digit that is added to the bar code message for
additional data integrity.
CMOS—Complementary Metal Oxide Semiconductor. Like CCDs, CMOS readers include
an array of photo-sensitive diodes, one diode within each pixel. Unlike CCDs, however,
each pixel in a CMOS reader has its own individual amplifier integrated inside.