@ -69,35 +69,57 @@ The following detector types are supported:
Creating Own Tracker
--------------------
If you want create a new tracker, you should follow some simple rules.
First, your tracker should be inherit from :ocv:class: `Tracker` , so you must implement two method:
* Tracker: initImpl, it should be called once in the first frame, here you should initialize all structures. The second argument is the initial bounding box of the target.
* Tracker:updateImpl, it should be called at the begin of in loop through video frames. Here you should overwrite the bounding box with new location.
Example of creating specialized Tracker `` TrackerMIL `` : ::
class CV_EXPORTS_W TrackerMIL : public Tracker
{
public:
TrackerMIL( const TrackerMIL::Params ¶meters = TrackerMIL::Params() );
virtual ~TrackerMIL();
...
If you want create a new tracker, here's what you have to do. First, decide on the name of the class for the tracker (to meet the existing style,
we suggest something with prefix "tracker", e.g. trackerMIL, trackerBoosting) -- we shall refer to this choice as to "classname" in subsequent. Also,
you should decide upon the name of the tracker, is it will be known to user (the current style suggests using all capitals, say MIL or BOOSTING) --
we'll call it a "name".
* Declare your tracker in `` include/opencv2/tracking/tracker.hpp `` .
Your tracker should inherit from :ocv:class: `Tracker` (please, see the example below). You should declare the specialized `` Param ``
structure, where you probably will want to put the data, needed to initialize your tracker. Also don't forget to put the
BOILERPLATE_CODE(name,classname) macro inside the class declaration. That macro will generate static `` createTracker() `` function, which
we'll talk about later. You should get something similar to ::
class CV_EXPORTS_W TrackerMIL : public Tracker
{
public:
struct CV_EXPORTS Params
{
Params();
//parameters for sampler
float samplerInitInRadius; // radius for gathering positive instances during init
int samplerInitMaxNegNum; // # negative samples to use during init
float samplerSearchWinSize; // size of search window
float samplerTrackInRadius; // radius for gathering positive instances during tracking
int samplerTrackMaxPosNum; // # positive samples to use during tracking
int samplerTrackMaxNegNum; // # negative samples to use during tracking
int featureSetNumFeatures; // #features
void read( const FileNode& fn );
void write( FileStorage& fs ) const;
};
of course, you can also add any additional methods of your choice. It should be pointed out, however, that it is not expected to have a constructor
declared, as creation should be done via the corresponding `` createTracker() `` method.
* In `` src/tracker.cpp `` file add BOILERPLATE_CODE(name,classname) line to the body of `` Tracker::create() `` method you will find there, like ::
Ptr<Tracker> Tracker::create( const String& trackerType )
{
BOILERPLATE_CODE("BOOSTING",TrackerBoosting);
BOILERPLATE_CODE("MIL",TrackerMIL);
return Ptr<Tracker>();
}
* Finally, you should implement the function with signature ::
protected:
bool initImpl( const Mat& image, const Rect2d& boundingBox );
bool updateImpl( const Mat& image, Rect2d& boundingBox );
...
};
Ptr<classname> classname::createTracker(const classname::Params ¶meters){
...
}
That function can (and probably will) return a pointer to some derived class of "classname", which will probably have a real constructor.
Every tracker has three component :ocv:class: `TrackerSampler` , :ocv:class: `TrackerFeatureSet` and :ocv:class: `TrackerModel` .
The first two are instantiated from Tracker base class, instead the last component is abstract, so you must implement your TrackerModel.
Finally add your tracker in the file tracking_init.cpp
TrackerSampler
..............
Antonella Cascitelli
11 years ago