Omron V430-F-series User Manual page 400

Appendices
External Level — Allows a read cycle to be initiated by a trigger signal from an object
detector. The read cycle ends when the object moves out of the detector's range.
Falling Edge — A change of state (to inactive) associated with a level trigger.
Field-Programmable Gate Array (FPGA) — A semiconductor device containing programmable
interconnects and logic components.
Fill Factor — Percentage of pixel area used for light collection.
Firmware — Software hard-coded in non-volatile memory (ROM), and closely tied to
specific pieces of hardware.
Fixed Symbol Length — Increases data integrity by ensuring that only one symbol length
will be accepted.
Focal Distance — In camera-based vision, the distance from the front of the camera to
the object being viewed. (In optics, the distance from the lens to the focal plane.)
Focal Plane — Usually found at the image sensor, it is a plane perpendicular to the lens
axis at the point of focus (–).
Focus — Any given point in an image at which light converges; the focal point.
Frame — The total area captured in an image sensor while the video signal is not blanked.
Frame Grabber — A device that interfaces with a camera and, on command, samples the
video, converts the sample to a digital value and stores that in a computer's memory.
Front End System — The object, illumination, optics and imager blocks of a vision system.
Includes all components useful to acquire a good image for subsequent processing.
Full Duplex — A communications system in which signals can travel simultaneously
between devices.
Gain — The amount of energy applied to pixel gray scale values prior to output, expressed
in dB; optimal signal strength.
Good Read — A decode. The successful scanning and decoding of the information
encoded in a bar code symbol.
Gradient — The rate of change of pixel intensity (first derivative).
Gray Scale — Variations of values from white, through shades of gray, to black in a digitized
image with black assigned the value of zero and white the value of one.
Half Duplex — A communications system in which signals can travel between devices in
both directions, but not simultaneously.
Histogram — A graphical representation of the frequency of occurrence of each intensity
or range of intensities (gray levels) of pixels in an image. The height represents the number
of observations occurring in each interval.
Host — A computer, PLC, or other device that is used to execute commands and process
data and discrete signals.
Image — Projection of an object or scene onto a plane (i.e. screen or image sensor).
Image Processing (IP) — Transformation of an input image into an output image with
desired properties.
Image Resolution — The number of rows and columns of pixels in an image. A higher
resolution means that more pixels are available per element of the symbol being read.
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Auto Focus Multi Code Reader V430-series User's Manual (Z392)