Merge pull request opencv#22808 from zihaomu:nanotrack

[teset data in opencv_extra](opencv/opencv_extra#1016)

NanoTrack is an extremely lightweight and fast object-tracking model. 
The total size is **1.1 MB**.
And the FPS on M1 chip is **150**, on Raspberry Pi 4 is about **30**. (Float32 CPU only)

With this model, many users can run object tracking on the edge device.

The author of NanoTrack is @HonglinChu.
The original repo is https://github.com/HonglinChu/NanoTrack.

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

Author: zihaomu

modules/video/include/opencv2/video/tracking.hpp

@@ -849,6 +849,43 @@ class CV_EXPORTS_W TrackerDaSiamRPN : public Tracker
     //bool update(InputArray image, CV_OUT Rect& boundingBox) CV_OVERRIDE;
 };
 
+/** @brief the Nano tracker is a super lightweight dnn-based general object tracking.
+ *
+ *  Nano tracker is much faster and extremely lightweight due to special model structure, the whole model size is about 1.1 MB.
+ *  Nano tracker needs two models: one for feature extraction (backbone) and the another for localization (neckhead).
+ *  Please download these two onnx models at:https://github.com/HonglinChu/SiamTrackers/tree/master/NanoTrack/models/onnx.
+ *  Original repo is here: https://github.com/HonglinChu/NanoTrack
+ *  Author:HongLinChu, [email protected]
+ */
+class CV_EXPORTS_W TrackerNano : public Tracker
+{
+protected:
+    TrackerNano();  // use ::create()
+public:
+    virtual ~TrackerNano() CV_OVERRIDE;
+
+    struct CV_EXPORTS_W_SIMPLE Params
+    {
+        CV_WRAP Params();
+        CV_PROP_RW std::string backbone;
+        CV_PROP_RW std::string neckhead;
+        CV_PROP_RW int backend;
+        CV_PROP_RW int target;
+    };
+
+    /** @brief Constructor
+    @param parameters NanoTrack parameters TrackerNano::Params
+    */
+    static CV_WRAP
+    Ptr<TrackerNano> create(const TrackerNano::Params& parameters = TrackerNano::Params());
+
+    /** @brief Return tracking score
+    */
+    CV_WRAP virtual float getTrackingScore() = 0;
+
+    //void init(InputArray image, const Rect& boundingBox) CV_OVERRIDE;
+    //bool update(InputArray image, CV_OUT Rect& boundingBox) CV_OVERRIDE;
+};
 
 //! @} video_track
 

modules/video/misc/python/pyopencv_video.hpp

@@ -2,4 +2,5 @@
 typedef TrackerMIL::Params TrackerMIL_Params;
 typedef TrackerGOTURN::Params TrackerGOTURN_Params;
 typedef TrackerDaSiamRPN::Params TrackerDaSiamRPN_Params;
+typedef TrackerNano::Params TrackerNano_Params;
 #endif