Omron V440-F User Manual page 497

Appendices
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 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. Examples: 640 x 480
(VGA); 854 x 480 (WVGA); 1280 x 1024 (SXGA); 2048 x 1536 (QXGA).
Image Sensor — A device that converts a visual image to an electrical signal; a CCD or CMOS array.
Initialize — Implement serial configuration commands into the imager's active memory.
Input — A channel or communications line. Decoded data or a discrete signal that is received by a device.
Integration — Exposure of pixels on a CMOS sensor.
Ladder Orientation — A linear symbol orientation in which the bars are parallel to the symbol's
direction of travel.
Light-Emitting Diode (LED) — A semiconductor device that emits light when conducting current.
Lens — A transparent piece of material with curved surfaces which either converge or diverge light rays.
Machine Vision — The automatic acquisition and analysis of images to obtain desired data for
controlling a specific activity.
Multidrop — A communications protocol for networking two or more imagers or other devices with a concentrator
(or controller) and characterized by the use of individual device addresses and the RS-485 standard.
Noise — The same as static in a phone line or "snow" in a television picture, noise is any unwanted
electrical signal that interferes with the image being read and transferred by the imager.
Normally Closed — A discrete output state that is only active when open.
Normally Open — A discrete output state that is only active when closed.
Object Plane — An imaginary plane in the field of view, focused by an imager's optical system at the
corresponding image plane on the sensor.
Output — A channel or communications line. Data or discrete signals that are transmitted or displayed
by a device.
S-4
V440-F C-Mount Code Reader User Manual