Chapter3 Programmingwith NI-IMAQ for 1394
NI-IMAQfor IEEE-1394 Cameras User Manual 3-4 ni.com
Scalable Image Size
IEEE-1394 digital cameras support a predefinedset of image sizes which
youcan select through the Format and Mode attributes in MAX. Seeyour
camerad ocumentation for a list of supported formats.
Ifyou are using IMAQ Vision, the NI-IMAQ for 1394 software recognizes
the predefinedformats and a utomatically allocates enough memory to
accommodate theimage in IMAQ Vision. When you use C or C++ with
NI-IMAQfor 1394 functions, you must know the size of the image for the
selectedformat and mode to allocate enough memory to contain the image.
Youcan obtain the size of the image using the Image Width and Image
Height attributes.
Some IEEE-1394 camerassupport the Scalable Image Format (format 7),
which allowsyou to define the size of the acquired image. If you use this
format, you must input the image size using the ROI parameter in
LabVIEW or the Rectangle parameterinCandC++,asshownin
Figure 3-1. The size and position of the sub-image you are acquiring must
be a multiple of the attributes Unit Width and Unit Height, or the driver
acquires the smallest sub-image that contains the ROIyou defined.
Figure3-1. Scalable Image Format (format 7)