Data Translation DT3120, User Manual

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Chapter 2
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This mode also has a synchronization mechanism using a WIN32
event object. Using this object, you can synchronize your application
with the DT3120 board to process data as it becomes available.
Continuous-acquire passthru operations continues until you stop
them using software.
Source Origin
The source origin of an image is the upper left corner of the image.
On the DT3120 board, the source origin is always 0,0.
Passthru Scaling
On a DT3120 board, the same scaling mechanism that is used to scale
frames is used to scale passthru images.
The number of lines per frame in the scaled image can range from 1 to
480 for 60 Hz image formats or from 1 to 576 for 50 Hz image formats
(in increments of 1). The number of pixels per line in the scaled image
can range from 4 to 640 for 60 Hz image formats or from 4 to 768 for
50 Hz image formats (in increments of 4).
Using software, you provide the scale factor for the horizontal and
vertical directions. The scale factor is the ratio of the target values (the
total number of pixels or lines in the resulting scaled image) to the
source values (the total number of pixels or lines in the image to
scale) in each direction.
The minimum scale factor is 1; the maximum scale factor is 100
(nominal is 100).