MicroHAWK Engine Integration Guide A-15
Appendices
Connector — A plug or socket on a device or cable providing in/out connectivity for various
circuits and pins.
Concentrator
— Intermediary device that relays data from imagers to a host and commands
from the host to the imagers or other devices.
Counter — Memory space allocated to keep track of imager events.
Daisy Chain — Linkage of primary and secondary imagers allowing data to be relayed up
to the host via auxiliary port connections.
Decode — A Good Read. The successful interpretation and output of the information
encoded in a symbol.
Default — Restores ROM or flash settings, initializes serial commands and resets all
counters.
Delimited — A delimited command or field is bracketed by predefined characters.
Decode Rate — The number of good reads per second ahieved by an imager.
Dark Field Illumination — Lighting of objects, surfaces, or particles at very shallow or low
angles, so that light does not directly enter a reader’s optical hardware.
Depth-of-Field — The in-focus range of an imaging system. Measured from the distance
behind an object to the distance in front of the object with all objects appearing in focus.
Diffused Lighting — Scattered soft lighting from a wide variety of angles used to eliminate
shadows and specular glints from profiled, highly reflective surfaces.
Digital-to-Analog Converter (DAC) — A VLSI circuit used to convert digitally processed
images to analog for display on a monitor.
Digital Imaging — Conversion of an image into pixels by means of an Analog-to-Digital
Converter where the level of each pixel can be stored digitally.
Digital Signal Processor (DSP) — A VLSI chip designed for ultra-high-speed arithmetic
processing. Often imbedded in a vision engine.
Discrete I/O — Inputs and outputs characterized by discrete signal transitions from one
voltage level to another so that digital switching can occur.
Direct Memory Access (DMA)
— A capability 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 — Image processing method to strengthen high-spatial frequencies
in 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; “non-volatile memory”.
External Edge — Allows a read cycle to be initiated by a trigger signal from an object
detector when it detects the appearance of an object (rising edge). The read cycle ends
with a good read, a timeout, or a new trigger.
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