Microscan Quadrus Verifier, User Manual

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Quadrus Verifier User’s Manual
Glossary of Terms
Appendix K — Glossary of Terms
Aberration —The failure of an optical lens to produce an exact point-to-point correspondence
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 —The process of lighting an area coordinated with the simultaneous
acquisition of an image. Strobed flash tubes and pulsed lasers are examples.
Ambient Light —Light that is present in the environment of a vision system and that is
generated from outside sources. This light, unless used for actual field of view illumination,
will be treated as background noise by the vision system.
Analog —A smooth, continuous voltage or current signal. From the word “analogous,”
meaning “similar to.”
Analog Gain Adjustment (AGC)—Adjustment of signal strength that seeks to maintain a
constant level regardless of the range of the candidate symbol.
Analog-to-Digital Converter (ADC)—A device that converts an analog voltage or current
signal to a discrete series of digitally encoded numbers (signal) for processing.
Angle of Distortion —The deviation from a 90 degree relation between a 2D symbol’s
rows and columns.
Architecture —For a vision system, the hardware organization designed for high speed
image analysis.
AS9132 —The Aerospace Standard for direct part marking (DPM) using Data Matrix
symbols.
ASIC —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).
Auxiliary Port— An alternate port that can be configured to communicate in RS-232 in
several modes including Daisy Chain .
Axial Non-Uniformity— Uneven scaling of a 2D symbol’s grid.
Baud Rate— Bits per second, or the number of discrete signal events per second.
Binarized Image— A black and white image created by applying the Global Threshold to
the pixel values in the reference grey scale image.
Blooming —A condition in which too many photons are being produced to be received by
a pixel. The pixel overflows and causes the photons to move 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.
Capture —The act of acquiring and storing video images in a reader or host computer.
Also, the image captured.
CCD —Charge-Coupled Device. CCDs capture light with an array of light-sensitive diodes,
each diode representing one pixel.