|
| acquisition window |
The image size specific to a video standard or camera resolution. |
| active line region |
The region of lines actively being stored. Defined by a line start (relative to the vertical synchronization signal) and a line count. |
| active pixel region |
The region of pixels actively being stored. Defined by a pixel start (relative to the horizontal synchronization signal) and a pixel count. |
| API |
Application programming interface. |
| area |
A rectangular portion of an acquisition window or frame that is controlled and defined by software. |
|
| base configuration |
A configuration defined by the Camera Link specification that uses one cable between the camera and the image acquisition device. This configuration supports combinations of camera bit depths and number of taps that allow the data to be transmitted and received by a single 28-signal interface chip. |
| black reference level |
The level that represents the darkest value an image can have. |
| buffer |
Temporary storage for acquired data. |
| bus |
A group of conductors that interconnect individual circuitry in a computer, such as the PCI bus; typically the expansion vehicle to which I/O or other devices are connected. |
|
| Camera Link |
Interface standard for digital video data and camera control based on the Channel Link chipset. |
| Channel Link chipset |
The physical interface chip on which Camera Link is based. Accepts 28 signals and serializes the data and enable signals at a 7:1 ratio for transmission across the Camera Link cable. |
|
| DAQ |
Data acquisition. (1) Collecting and measuring electrical signals from sensors, transducers, and test probes or fixtures and inputting them to a computer for processing. (2) Collecting and measuring the same kinds of electrical signals with A/D or DIO devices plugged into a computer, and possibly generating control signals with D/A and/or DIO devices in the same computer. |
| DIO |
Digital input/output. |
| DLL |
Dynamic link library. A software module in Microsoft Windows containing executable code and data that can be called or used by Windows applications or other DLLs; functions and data in a DLL are loaded and linked at run time when they are referenced by a Windows application or other DLLs. |
| DMA |
Direct memory access. A method by which data can be transferred to and from computer memory from and to a device or memory on the bus while the processor does something else; DMA is the fastest method of transferring data to/from computer memory. |
| down-plugging |
Plugging a larger device into a smaller connector. An example of down-plugging is plugging a 64-bit PCI device into a 32-bit connector. Down-plugging is not allowed by the PCI Express specification; a larger link device will not mechanically fit into a smaller link connector. |
| drivers |
Software that controls a specific hardware device, such as an image acquisition device. |
|
| full configuration |
A configuration defined by the Camera Link specification that uses two cables between the camera and the image acquisition device. This configuration supports combinations of camera bit depths and number of taps that allow the data to be transmitted and received by three 28-signal interface chips. |
|
| gray level |
The brightness of a pixel in an image. |
|
| handshaking |
A type of protocol that makes it possible for two devices to synchronize operations. |
| HSL |
A color encoding scheme using hue, saturation, and luminance information where each image in the pixel is encoded using 32 bits: 8 bits for hue, 8 bits for saturation, 8 bits for luminance, and 8 unused bits. |
| hue |
Determination of color, such as red, blue, green, and yellow. White, black, and gray are not considered hues. They are intensities. |
|
| I/O |
Input/output. The transfer of data to/from a computer system involving communications channels, operator interface devices, and/or data acquisition and control interfaces. |
|
| LabVIEW |
Laboratory Virtual Instrument Engineering Workbench. Program development environment based on the G programming language. LabVIEW is used commonly for test and measurement applications. |
| lane |
PCI Express Lane. A PCI Express lane contains one differential pair for transmitting data and one differential pair for receiving data. |
| link |
PCI Express Link. A collection of one or more PCI Express lanes. A xN Link is composed on N lanes. The number of lanes in the link limits device throughput. A x1 link theoretically provides 250 MB/s in each direction—to and from the device. Once overhead is accounted for, a x1 link can provide approximately 200 MB/s of input capability and 200 MB/s of output capability. Increasing the number of lanes in a link increases maximum throughput by approximately the same factor. |
| luminance |
The brightness or intensity of a color. The monochrome level of a video signal. |
| LVDS |
Low Voltage Differential Signaling (EIA-644). |
|
| MAX |
Measurement & Automation Explorer. The National Instruments Windows-based graphical configuration utility you can use to configure NI software and hardware, execute system diagnostics, add new channels and interfaces, and view the devices and instruments you have connected to your computer. MAX is installed on the desktop during the National Instruments driver software installation. |
| medium configuration |
A configuration defined by the Camera Link specification that uses two cables between the camera and the image acquisition device. This configuration supports combinations of camera bit depths and number of taps that allow the data to be transmitted and received by two 28-signal interface chips. |
|
| NI-IMAQ |
Driver software for National Instruments image acquisition hardware. |
|
| parity |
Method of error checking. Ensures that there is always either an even number or an odd number of asserted bits in a byte, character, or word, according to the logic of the system. If a bit should be lost in data transmission, its loss can be detected by checking the parity |
| PCI |
Peripheral component interconnect. A high-performance expansion bus architecture originally developed by Intel to replace ISA and EISA. PCI offers a theoretical maximum transfer rate of 133 Mbytes/s shared among all devices on the bus for input and output. |
| PCIe |
PCI Express. A high-performance expansion bus architecture originally developed by Intel to replace PCI. PCIe offers a theoretical maximum transfer rate that is dependent upon lane width. A x1 link theoretically provides 250 MB/s in each direction—to and from the device. Once overhead is accounted for, a x1 link can provide approximately 200 MB/s of input capability and 200 MB/s of output capability. Increasing the number of lanes in a link increases maximum throughput by approximately the same factor. |
| pixel |
Picture element. The smallest division that makes up the video scan line; for display on a computer monitor, a pixel's optimum dimension is square (aspect ratio of 1:1, or the width equal to the height). |
| pixel clock |
Divides the incoming horizontal video line into pixels. |
| PLC |
Programmable logic controller. (1) A highly reliable special-purpose computer used in industrial monitoring and control applications. PLCs typically have proprietary programming and networking protocols, and special-purpose digital and analog I/O ports. (2) A device with multiple inputs and outputs that contains a program you can alter. |
| protocol |
The exact sequence of bits, characters, and control codes used to transfer data between computers and peripherals through a communications channel. |
|
| quadrature encoder |
An encoding technique for a rotating device where two tracks of information are placed on the device, with the signals on the tracks offset by 90 degrees from each other. The phase difference indicates the position and direction of rotation. |
|
| real time |
A property of an event or system in which data is processed as it is acquired instead of being accumulated and processed at a later time. |
| resolution |
The smallest signal increment that can be detected by a measurement system. Resolution can be expressed in bits, in proportions, or in percent of full scale. For example, a system has 12-bit resolution, on part in 4,096 resolution, and 0.0244 percent of full scale. |
| RGB |
Red, green, blue—A three-component video signal in which all the colors in a scene or image are conveyed as three primary colors (red, green, and blue) on three separate channels. Sometimes, the green signal also carries the horizontal and vertical synchronization information. |
| ROI |
Region of interest. A hardware-programmable rectangular portion of the acquisition window. |
| RTSI bus |
Real-Time System Integration Bus. The National Instruments timing bus that connects Vision and DAQ devices directly, by means of connectors on the devices, for precise synchronization of functions. |
|
| saturation |
The amount of color pigment present. The lower the saturation, the more white is present in the color. |
| scatter-gather DMA |
A type of DMA that allows the DMA controller to reconfigure on-the-fly. |
|
| tap |
A set of data lines that deliver one pixel per pixel clock from the camera. Some cameras send multiple streams, or taps, of data over a cable simultaneously to increase transfer rate. Also referred to as channels or simultaneous pixels. |
| transfer rate |
The rate, measured in bytes/s, at which data is moved from source to destination after software initialization and set up operations. The maximum rate at which the hardware can operate. |
| trigger |
Any event that causes or starts some form of data capture. |
| trigger control and mapping circuitry |
Circuitry that routes, monitors, and drives external and RTSI bus trigger lines. You can configure each of these lines to start or stop acquisition on a rising edge or a falling edge. |
| TTL |
Transistor-transistor logic. A digital circuit composed of bipolar transistors wired in a certain manner. A typical medium-speed digital technology. Nominal TTL logic levels are 0 and 5 V. |
|
| up-plugging |
Plugging a smaller link device into a larger link connector. For example, for the PCI Express bus, up-plugging is plugging a x1 device into a x4 connector or plugging a x4 device into a x16 connector. |
|
| VI |
Virtual instrument. (1) A combination of hardware and/or software elements, typically used with a PC, that has the functionality of a classic stand-alone instrument (2) A LabVIEW software module (VI), which consists of a front panel user interface and a block diagram program. |
|
| web inspection |
Applications that involve acquiring images of objects on a fast-moving conveyor or stage in a production system. |
|
| YUV |
A representation of a color image used for the coding of NTSC or PAL video signals. The luminance information is called Y, while the chrominance information is represented by two components, U and V, that represent the coordinates in a color plane. |