296 lines
14 KiB
Markdown
296 lines
14 KiB
Markdown
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<a href="https://www.ultralytics.com/" target="_blank"><img src="https://raw.githubusercontent.com/ultralytics/assets/main/logo/Ultralytics_Logotype_Original.svg" width="320" alt="Ultralytics logo"></a>
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# Multi-Object Tracking with Ultralytics YOLO
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<img width="1024" src="https://user-images.githubusercontent.com/26833433/243418637-1d6250fd-1515-4c10-a844-a32818ae6d46.png" alt="Ultralytics YOLO trackers visualization">
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[Object tracking](https://www.ultralytics.com/glossary/object-tracking), a key aspect of [video analytics](https://en.wikipedia.org/wiki/Video_content_analysis), involves identifying the location and class of objects within video frames and assigning a unique ID to each detected object as it moves. This capability enables a wide range of applications, from surveillance and security systems to [real-time](https://www.ultralytics.com/glossary/real-time-inference) sports analysis and autonomous vehicle navigation. Learn more about tracking on our [tracking documentation page](https://docs.ultralytics.com/modes/track/).
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## 🎯 Why Choose Ultralytics YOLO for Object Tracking?
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Ultralytics YOLO trackers provide output consistent with standard [object detection](https://docs.ultralytics.com/tasks/detect/) but add persistent object IDs. This simplifies the process of tracking objects in video streams and performing subsequent analyses. Here’s why Ultralytics YOLO is an excellent choice for your object tracking needs:
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- **Efficiency:** Process video streams in real-time without sacrificing accuracy.
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- **Flexibility:** Supports multiple robust tracking algorithms and configurations.
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- **Ease of Use:** Offers straightforward [Python API](https://docs.ultralytics.com/usage/python/) and [CLI](https://docs.ultralytics.com/usage/cli/) options for rapid integration and deployment.
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- **Customizability:** Easily integrates with [custom-trained YOLO models](https://docs.ultralytics.com/modes/train/), enabling deployment in specialized, domain-specific applications.
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**Watch:** Object Detection and Tracking with Ultralytics YOLOv8.
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[](https://www.youtube.com/watch?v=hHyHmOtmEgs)
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## ✨ Features at a Glance
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Ultralytics YOLO extends its powerful object detection features to deliver robust and versatile object tracking:
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- **Real-Time Tracking:** Seamlessly track objects in high-frame-rate videos.
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- **Multiple Tracker Support:** Choose from a selection of established tracking algorithms.
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- **Customizable Tracker Configurations:** Adapt the tracking algorithm to specific requirements by adjusting various parameters.
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## 🛠️ Available Trackers
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Ultralytics YOLO supports the following tracking algorithms. Enable them by passing the relevant YAML configuration file, such as `tracker=tracker_type.yaml`:
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- **BoT-SORT:** Use [`botsort.yaml`](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/cfg/trackers/botsort.yaml) to enable this tracker. Based on the [BoT-SORT paper](https://arxiv.org/abs/2206.14651) and its official [code implementation](https://github.com/NirAharon/BoT-SORT).
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- **ByteTrack:** Use [`bytetrack.yaml`](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/cfg/trackers/bytetrack.yaml) to enable this tracker. Based on the [ByteTrack paper](https://arxiv.org/abs/2110.06864) and its official [code implementation](https://github.com/FoundationVision/ByteTrack).
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The default tracker is **BoT-SORT**.
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## ⚙️ Usage
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To run the tracker on video streams, use a trained Detect, Segment, or Pose model like [Ultralytics YOLO11n](https://docs.ultralytics.com/models/yolo11/), YOLO11n-seg, or YOLO11n-pose.
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```python
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# Python
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from ultralytics import YOLO
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# Load an official or custom model
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model = YOLO("yolo11n.pt") # Load an official Detect model
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# model = YOLO("yolo11n-seg.pt") # Load an official Segment model
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# model = YOLO("yolo11n-pose.pt") # Load an official Pose model
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# model = YOLO("path/to/best.pt") # Load a custom trained model
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# Perform tracking with the model
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results = model.track(source="https://youtu.be/LNwODJXcvt4", show=True) # Tracking with default tracker
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# results = model.track(source="https://youtu.be/LNwODJXcvt4", show=True, tracker="bytetrack.yaml") # Tracking with ByteTrack tracker
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```
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```bash
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# CLI
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# Perform tracking with various models using the command line interface
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yolo track model=yolo11n.pt source="https://youtu.be/LNwODJXcvt4" # Official Detect model
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# yolo track model=yolo11n-seg.pt source="https://youtu.be/LNwODJXcvt4" # Official Segment model
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# yolo track model=yolo11n-pose.pt source="https://youtu.be/LNwODJXcvt4" # Official Pose model
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# yolo track model=path/to/best.pt source="https://youtu.be/LNwODJXcvt4" # Custom trained model
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# Track using ByteTrack tracker
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# yolo track model=path/to/best.pt tracker="bytetrack.yaml"
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```
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As shown above, tracking is available for all [Detect](https://docs.ultralytics.com/tasks/detect/), [Segment](https://docs.ultralytics.com/tasks/segment/), and [Pose](https://docs.ultralytics.com/tasks/pose/) models when run on videos or streaming sources.
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## 🔧 Configuration
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### Tracking Arguments
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Tracking configuration shares properties with the Predict mode, such as `conf` (confidence threshold), `iou` ([Intersection over Union](https://www.ultralytics.com/glossary/intersection-over-union-iou) threshold), and `show` (display results). For additional configurations, refer to the [Predict mode documentation](https://docs.ultralytics.com/modes/predict/).
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```python
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# Python
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from ultralytics import YOLO
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# Configure the tracking parameters and run the tracker
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model = YOLO("yolo11n.pt")
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results = model.track(source="https://youtu.be/LNwODJXcvt4", conf=0.3, iou=0.5, show=True)
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```
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```bash
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# CLI
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# Configure tracking parameters and run the tracker using the command line interface
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yolo track model=yolo11n.pt source="https://youtu.be/LNwODJXcvt4" conf=0.3 iou=0.5 show
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```
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### Tracker Selection
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Ultralytics allows you to use a modified tracker configuration file. Create a copy of a tracker config file (e.g., `custom_tracker.yaml`) from [ultralytics/cfg/trackers](https://github.com/ultralytics/ultralytics/tree/main/ultralytics/cfg/trackers) and adjust any configurations (except `tracker_type`) according to your needs.
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```python
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# Python
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from ultralytics import YOLO
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# Load the model and run the tracker with a custom configuration file
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model = YOLO("yolo11n.pt")
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results = model.track(source="https://youtu.be/LNwODJXcvt4", tracker="custom_tracker.yaml")
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```
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```bash
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# CLI
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# Load the model and run the tracker with a custom configuration file using the command line interface
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yolo track model=yolo11n.pt source="https://youtu.be/LNwODJXcvt4" tracker='custom_tracker.yaml'
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```
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For a comprehensive list of tracking arguments, consult the [Tracking Configuration files](https://github.com/ultralytics/ultralytics/tree/main/ultralytics/cfg/trackers) in the repository.
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## 🐍 Python Examples
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### Persisting Tracks Loop
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This Python script uses [OpenCV (`cv2`)](https://opencv.org/) and Ultralytics YOLO11 to perform object tracking on video frames. Ensure you have installed the necessary packages (`opencv-python` and `ultralytics`). The [`persist=True`](https://docs.ultralytics.com/modes/predict/#tracking) argument indicates that the current frame is the next in a sequence, allowing the tracker to maintain track continuity from the previous frame.
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```python
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# Python
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import cv2
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from ultralytics import YOLO
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# Load the YOLO11 model
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model = YOLO("yolo11n.pt")
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# Open the video file
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video_path = "path/to/video.mp4"
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cap = cv2.VideoCapture(video_path)
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# Loop through the video frames
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while cap.isOpened():
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# Read a frame from the video
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success, frame = cap.read()
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if success:
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# Run YOLO11 tracking on the frame, persisting tracks between frames
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results = model.track(frame, persist=True)
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# Visualize the results on the frame
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annotated_frame = results[0].plot()
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# Display the annotated frame
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cv2.imshow("YOLO11 Tracking", annotated_frame)
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# Break the loop if 'q' is pressed
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if cv2.waitKey(1) & 0xFF == ord("q"):
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break
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else:
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# Break the loop if the end of the video is reached
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break
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# Release the video capture object and close the display window
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cap.release()
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cv2.destroyAllWindows()
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```
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Note the use of `model.track(frame)` instead of `model(frame)`, which specifically enables object tracking. This script processes each video frame, visualizes the tracking results, and displays them. Press 'q' to exit the loop.
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### Plotting Tracks Over Time
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Visualizing object tracks across consecutive frames offers valuable insights into movement patterns within a video. Ultralytics YOLO11 makes plotting these tracks efficient.
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The following example demonstrates how to use YOLO11's tracking capabilities to plot the movement of detected objects. The script opens a video, reads it frame by frame, and uses the YOLO model built on [PyTorch](https://pytorch.org/) to identify and track objects. By storing the center points of the detected [bounding boxes](https://www.ultralytics.com/glossary/bounding-box) and connecting them, we can draw lines representing the paths of tracked objects using [NumPy](https://numpy.org/) for numerical operations.
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```python
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# Python
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from collections import defaultdict
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import cv2
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import numpy as np
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from ultralytics import YOLO
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# Load the YOLO11 model
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model = YOLO("yolo11n.pt")
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# Open the video file
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video_path = "path/to/video.mp4"
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cap = cv2.VideoCapture(video_path)
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# Store the track history
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track_history = defaultdict(lambda: [])
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# Loop through the video frames
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while cap.isOpened():
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# Read a frame from the video
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success, frame = cap.read()
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if success:
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# Run YOLO11 tracking on the frame, persisting tracks between frames
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result = model.track(frame, persist=True)[0]
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# Get the boxes and track IDs
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if result.boxes and result.boxes.is_track:
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boxes = result.boxes.xywh.cpu()
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track_ids = result.boxes.id.int().cpu().tolist()
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# Visualize the result on the frame
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frame = result.plot()
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# Plot the tracks
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for box, track_id in zip(boxes, track_ids):
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x, y, w, h = box
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track = track_history[track_id]
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track.append((float(x), float(y))) # x, y center point
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if len(track) > 30: # retain 30 tracks for 30 frames
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track.pop(0)
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# Draw the tracking lines
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points = np.hstack(track).astype(np.int32).reshape((-1, 1, 2))
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cv2.polylines(frame, [points], isClosed=False, color=(230, 230, 230), thickness=10)
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# Display the annotated frame
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cv2.imshow("YOLO11 Tracking", frame)
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# Break the loop if 'q' is pressed
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if cv2.waitKey(1) & 0xFF == ord("q"):
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break
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else:
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# Break the loop if the end of the video is reached
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break
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# Release the video capture object and close the display window
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cap.release()
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cv2.destroyAllWindows()
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```
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### Multithreaded Tracking
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Multithreaded tracking allows running object tracking on multiple video streams simultaneously, which is highly beneficial for systems handling inputs from several cameras, improving efficiency through concurrent processing.
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This Python script utilizes Python's [`threading`](https://docs.python.org/3/library/threading.html) module for concurrent tracker execution. Each thread manages tracking for a single video file.
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The `run_tracker_in_thread` function accepts parameters like the video file path, model, and a unique window index. It contains the main tracking loop, reading frames, running the tracker, and displaying results in a dedicated window.
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This example uses two models, `yolo11n.pt` and `yolo11n-seg.pt`, tracking objects in `video_file1` and `video_file2`, respectively.
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Setting `daemon=True` in `threading.Thread` ensures threads exit when the main program finishes. Threads are started with `start()` and the main thread waits for their completion using `join()`.
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Finally, `cv2.destroyAllWindows()` closes all OpenCV windows after the threads finish.
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```python
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# Python
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import threading
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import cv2
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from ultralytics import YOLO
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# Define model names and video sources
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MODEL_NAMES = ["yolo11n.pt", "yolo11n-seg.pt"]
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SOURCES = ["path/to/video.mp4", "0"] # local video, 0 for webcam
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def run_tracker_in_thread(model_name, filename):
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"""
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Run YOLO tracker in its own thread for concurrent processing.
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Args:
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model_name (str): The YOLO11 model object.
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filename (str): The path to the video file or the identifier for the webcam/external camera source.
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"""
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model = YOLO(model_name)
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results = model.track(filename, save=True, stream=True)
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for r in results:
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pass
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# Create and start tracker threads using a for loop
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tracker_threads = []
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for video_file, model_name in zip(SOURCES, MODEL_NAMES):
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thread = threading.Thread(target=run_tracker_in_thread, args=(model_name, video_file), daemon=True)
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tracker_threads.append(thread)
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thread.start()
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# Wait for all tracker threads to finish
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for thread in tracker_threads:
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thread.join()
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# Clean up and close windows
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cv2.destroyAllWindows()
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```
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This setup can be easily scaled to handle more video streams by creating additional threads following the same pattern. Explore more applications in our [blog post on object tracking](https://www.ultralytics.com/blog/object-detection-and-tracking-with-ultralytics-yolov8).
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## 🤝 Contribute New Trackers
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Are you experienced in multi-object tracking and have implemented or adapted an algorithm with Ultralytics YOLO? We encourage you to contribute to our Trackers section in [ultralytics/cfg/trackers](https://github.com/ultralytics/ultralytics/tree/main/ultralytics/cfg/trackers)! Your contributions can help expand the tracking solutions available within the Ultralytics [ecosystem](https://docs.ultralytics.com/).
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To contribute, please review our [Contributing Guide](https://docs.ultralytics.com/help/contributing/) for instructions on submitting a [Pull Request (PR)](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests) 🛠️. We look forward to your contributions!
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Let's work together to enhance the tracking capabilities of Ultralytics YOLO and provide more powerful tools for the [computer vision](https://www.ultralytics.com/glossary/computer-vision-cv) and [deep learning](https://www.ultralytics.com/glossary/deep-learning-dl) community 🙏!
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