Merge pull request #26875 from asmorkalov:as/in_memory_models

Added trackers factory with pre-loaded dnn models #26875

Replaces https://github.com/opencv/opencv/pull/26295

Allows to substitute custom models or initialize tracker from in-memory model.

### 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
- [ ] 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

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

@@ -46,6 +46,9 @@
 
 #include "opencv2/core.hpp"
 #include "opencv2/imgproc.hpp"
+#ifdef HAVE_OPENCV_DNN
+# include "opencv2/dnn.hpp"
+#endif
 
 namespace cv
 {
@@ -826,6 +829,13 @@ public:
     static CV_WRAP
     Ptr<TrackerGOTURN> create(const TrackerGOTURN::Params& parameters = TrackerGOTURN::Params());
 
+#ifdef HAVE_OPENCV_DNN
+    /** @brief Constructor
+    @param model pre-loaded GOTURN model
+    */
+    static CV_WRAP Ptr<TrackerGOTURN> create(const dnn::Net& model);
+#endif
+
     //void init(InputArray image, const Rect& boundingBox) CV_OVERRIDE;
     //bool update(InputArray image, CV_OUT Rect& boundingBox) CV_OVERRIDE;
 };
@@ -853,6 +863,16 @@ public:
     static CV_WRAP
     Ptr<TrackerDaSiamRPN> create(const TrackerDaSiamRPN::Params& parameters = TrackerDaSiamRPN::Params());
 
+#ifdef HAVE_OPENCV_DNN
+    /** @brief Constructor
+     *  @param siam_rpn pre-loaded SiamRPN model
+     *  @param kernel_cls1 pre-loaded CLS model
+     *  @param kernel_r1 pre-loaded R1 model
+     */
+    static CV_WRAP
+    Ptr<TrackerDaSiamRPN> create(const dnn::Net& siam_rpn, const dnn::Net& kernel_cls1, const dnn::Net& kernel_r1);
+#endif
+
     /** @brief Return tracking score
     */
     CV_WRAP virtual float getTrackingScore() = 0;
@@ -891,6 +911,15 @@ public:
     static CV_WRAP
     Ptr<TrackerNano> create(const TrackerNano::Params& parameters = TrackerNano::Params());
 
+#ifdef HAVE_OPENCV_DNN
+    /** @brief Constructor
+     *  @param backbone pre-loaded backbone model
+     *  @param neckhead pre-loaded neckhead model
+     */
+    static CV_WRAP
+    Ptr<TrackerNano> create(const dnn::Net& backbone, const dnn::Net& neckhead);
+#endif
+
     /** @brief Return tracking score
     */
     CV_WRAP virtual float getTrackingScore() = 0;
@@ -929,6 +958,18 @@ public:
     static CV_WRAP
     Ptr<TrackerVit> create(const TrackerVit::Params& parameters = TrackerVit::Params());
 
+#ifdef HAVE_OPENCV_DNN
+    /** @brief Constructor
+     *  @param model pre-loaded DNN model
+     *  @param meanvalue mean value for image preprocessing
+     *  @param stdvalue std value for image preprocessing
+     *  @param tracking_score_threshold threshold for tracking score
+     */
+    static CV_WRAP
+    Ptr<TrackerVit> create(const dnn::Net& model, Scalar meanvalue = Scalar(0.485, 0.456, 0.406),
+                           Scalar stdvalue = Scalar(0.229, 0.224, 0.225), float tracking_score_threshold = 0.20f);
+#endif
+
     /** @brief Return tracking score
     */
     CV_WRAP virtual float getTrackingScore() = 0;