How and when to get results from MontiVision
DirectShow Filters
Some of the MontiVision DirectShow
Filters do calculations and produce results.
These MontiVision DirectShow
Filter provide specific interfaces to facilitate such data
retrieval. Since these interfaces can be called at any stage of the
graph's lifetime, a timer may be used to facilitate regular
retrieval of filter data.
If however, you require results for every processed frame, the
timer approach would not be appropriate. In this case the
MontiVision Smart
Control provides a more appropriate method in
it's event
interface . The _IMVSmartControlEvents::FilterEvent
method is called for every filter event from a
filter. In order to use this, you will need to enable the filter
events with the IMVFilterEvents::Enable method.
This methods returns a 'cookie' to distinguish between
filter events from different MontiVision Imaging
Filter.
The FindObject
sample uses filter events to retrieve an object count on
every frame.
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