Rockwell Automation Publication 48CR-UM001A-EN-P - November 2019
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Glossary
digital signal processor (DSP)
A VLSI chip that is designed for ultra-high-speed arithmetic processing. Often
imbedded in a vision engine.
direct memory access (DMA)
A capability that is provided by some computer bus architectures that allows data
to be sent directly to memory from an attached device.
dynamic range
The difference between the minimum and maximum thresholds of discernible
images; the amount of usable signal.
edge enhancement
Method of image-processing that strengthens the high-spatial frequencies of
the image.
embedded memory
Onboard memory device such as EPROM or flash.
end of read cycle
The time or condition at which the imager stops expecting symbol information
to decode.
erasable programmable read-only
memory (EPROM)
A memory chip that retains data when its power supply is turned off; nonvolatile
memory.
error correcting code (ECC)
The process of adding redundancy to the transmitted information by using an
algorithm to help control errors when data is passed over unreliable or noisy
communication channels.
external edge
Allows a trigger signal from an object detector when it detects the appearance of
an object (rising edge) to initiate a read cycle. The read cycle ends with a good
read, a timeout, or a new trigger.
external level
Allows a trigger signal from an object detector to initiate a read cycle. The read
cycle ends when the object moves out of the range of the detector.
falling edge
A change of state (to inactive) associated with a level trigger.
field-programmable gate array
(FPGA)
A semiconductor device that contains programmable interconnects and logic
components.
fill factor
Percentage of pixel area that is used for light collection.
firmware
Software hard-coded in nonvolatile memory (ROM), and closely tied to specific
pieces of hardware.
fixed symbol length
Increases data integrity by confirming that only one symbol length is 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
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.
