120 CONTENTS
16 Glossary
A/D reference Upper threshold of video signal to be digitized. All values above this limit value are digitized
to 255. Increasing the reference level results in contrast deterioration and vice versa.
ADC Analog to digital converter (A/D converter)
Resolution Number of pixels (horizontal x vertical)
Base address Starting address from which the memory or register are inserted.
Image refresh rate Number of transferred images per second. Normally specified in Hz (e.g. 70 Hz)
Bpp Bits per pixel
Bus A group line via which the various parts of the computer communicate with one another.
CCIR Comité Consulatif International of the Radio Communications European video standard for
50 Hz gray scale.
Clamp signal Clamp signal means, that a AC coupled video signal is clamped on the porch to get a
signal transfer with less noise and independent from the d.c. voltage portion.
CPU Central processing unit
DAC Digital to analog converter (D/A converter)
Defaults Standard system settings
DIO Digital inputs and outputs
DIP switch Dual inline package (housing design)
External trigger External event used to initiate image capture.
False colors Colors are assigned to gray scale via a look-up table. This allows even small gray scale
differences can be displayed clearly.
Field All odd lines of a field (odd field) or all even lines of a field (even field) of an interlaced video
image.
Frame grabber Here: PC plug-in card for digitization and storage of video images.
Horizontal sync The portion of the analog signal which specifies the line end of the video signal.
Host Here: the PC
Interlaced Interlacing method; conforming to the television standard, this method involves acquiring
two fields in succession (all odd lines, all even lines) and combining them to create a frame.
The result is greatly reduced flicker during on-screen display.
Interrupt Interrupt signal sent to the processor. The program currently running is interrupted and a
predefined function is executed.
ISR Interrupt service routine
IRQ Interrupt request
Look-up table Table of assignments. Here, new gray scale or colors are normally assigned to gray scale.
Look-up tables can, however, also be used for any other math functions.
LSB Least significant bit
LUT Look-up table
Monochrome A single-color (black and white) image
MSB Most significant bit
Non-interlaced Image acquisition and output line by line
NTSC National Television Standard Code. US video standard for 60 Hz colors.
Overlay Image memory for outputting text and graphics via the video monitor.
PAL Phase alteration line; 50 Hz video standard for color.
Pixels Picture element
PoCL
Power over CameraLink - The cameras are powered over CL cable and therefore need
no additional power supply. The mvHYPERIONs which supports PoCL, are "Switchable
PoCL frame grabbers" as described in the CameraLink™ specification. This means that
both camera and cable have to support PoCL otherwise Pin 1 and Pin 26 of the CL con-
nectors act like internal shields.
Pseudo colors Display of gray scale images in false colors. A corresponding color is assigned to a specific
gray scale value.
MATRIX VISION GmbH
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