National Instruments Image Acquisition Software - Manual (Page 25)

Chapter 3 Programming with NI-IMAQ
© National Instruments Corporation 3-5 NI-IMAQ User Manual
attribute value is a numeric value of type integer. Float indicates that the
attribute value is a numeric value of type floating point. The valid integer
and float values are indicated in Possible Values.
Use the imgSetCameraAttributeString and
imgGetCameraAttributeString functions to set and get the value of
String, Float and Integer attributes. Use the
imgSetCameraAttributeNumeric and
imgGetCameraAttributeNumeric functions to set and get the value of
Float and Integer attributes.
Note The spelling and syntax of the Attribute Name and string values must match the
camera attribute file exactly.
NI-IMAQ Status Signals
NI-IMAQ has several status signals that can be used to trigger the
generation of a pulse or invoke a callback function. Acquisition in
Progress indicates that the board is acquiring image data. This signal goes
TRUE when the board initiates the acquisition either through a software or
hardware triggered start. When the last piece of image data is transferred to
memory, this signal goes FALSE. If the acquisition is a sequence,
acquisition in progress will stay TRUE throughout the acquisition until the
entire sequence is completed. Acquisition Done is the reverse of
Acquisition in Progress. This signal goes TRUE when the last piece of
data is transferred to memory indicating that the acquisition has completed.
Frame Start and Frame Stop indicate the status of an acquisition on a
buffer basis. Frame Start indicates that a buffer is being acquired. This
signal goes TRUE when the first valid pixel is detected by the board (even
if this pixel is not in the current region of interest). The signal goes FALSE
when the last valid pixel is detected by the board. If the acquisition is a
sequence or a ring, Frame Start will pulse for every buffer in the
acquisition. Frame Done is the reverse of Frame Start and indicates when
the image is transferred from the camera to the IMAQ board.
Buffer Complete indicates when the image data has been transferred to
memory and is available for image processing. Buffer Complete will go
TRUE when the data in an image buffer has been transferred to memory
(either onboard or system memory, depending on the acquisition).
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