docs/en/guides/distance-calculation.md
Measuring the gap between two objects is known as distance calculation within a specified space. In the case of Ultralytics YOLO26, the bounding box centroid is employed to calculate the distance for bounding boxes highlighted by the user.
<p align="center"> <iframe loading="lazy" width="720" height="405" src="https://www.youtube.com/embed/Oe0vmsvnY74" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen> </iframe><strong>Watch:</strong> How to estimate distance between detected objects with Ultralytics YOLO in Pixels 🚀
</p>| Distance Calculation using Ultralytics YOLO26 |
|---|
???+ tip "Distance Calculation"
- Click any two bounding boxes with the left mouse button to calculate distance.
- Use the right mouse button to delete all drawn points.
- Left-click anywhere in the frame to add new points.
???+ warning "Distance is an estimate"
Distance is an estimate and may not be fully accurate because it is calculated using 2D data,
which lacks depth information.
!!! example "Distance Calculation using Ultralytics YOLO"
=== "Python"
```python
import cv2
from ultralytics import solutions
cap = cv2.VideoCapture("path/to/video.mp4")
assert cap.isOpened(), "Error reading video file"
# Video writer
w, h, fps = (int(cap.get(x)) for x in (cv2.CAP_PROP_FRAME_WIDTH, cv2.CAP_PROP_FRAME_HEIGHT, cv2.CAP_PROP_FPS))
video_writer = cv2.VideoWriter("distance_output.avi", cv2.VideoWriter_fourcc(*"mp4v"), fps, (w, h))
# Initialize distance calculation object
distancecalculator = solutions.DistanceCalculation(
model="yolo26n.pt", # path to the YOLO26 model file.
show=True, # display the output
)
# Process video
while cap.isOpened():
success, im0 = cap.read()
if not success:
print("Video frame is empty or processing is complete.")
break
results = distancecalculator(im0)
print(results) # access the output
video_writer.write(results.plot_im) # write the processed frame.
cap.release()
video_writer.release()
cv2.destroyAllWindows() # destroy all opened windows
```
DistanceCalculation() ArgumentsHere's a table with the DistanceCalculation arguments:
{% from "macros/solutions-args.md" import param_table %} {{ param_table(["model"]) }}
You can also make use of various track arguments in the DistanceCalculation solution.
{% from "macros/track-args.md" import param_table %} {{ param_table(["tracker", "conf", "iou", "classes", "verbose", "device"]) }}
Moreover, the following visualization arguments are available:
{% from "macros/visualization-args.md" import param_table %} {{ param_table(["show", "line_width", "show_conf", "show_labels"]) }}
The DistanceCalculation class works by tracking objects across video frames and calculating the Euclidean distance between the centroids of selected bounding boxes. When you click on two objects, the solution:
The implementation uses the mouse_event_for_distance method to handle mouse interactions, allowing users to select objects and clear selections as needed. The process method handles the frame-by-frame processing, tracking objects, and calculating distances.
Distance calculation with YOLO26 has numerous practical applications:
To calculate distances between objects using Ultralytics YOLO26, you need to identify the bounding box centroids of the detected objects. This process involves initializing the DistanceCalculation class from Ultralytics' solutions module and using the model's tracking outputs to calculate the distances.
Using distance calculation with Ultralytics YOLO26 offers several advantages:
Yes, you can perform distance calculation in real-time video streams with Ultralytics YOLO26. The process involves capturing video frames using OpenCV, running YOLO26 object detection, and using the DistanceCalculation class to calculate distances between objects in successive frames. For a detailed implementation, see the video stream example.
To delete points drawn during distance calculation with Ultralytics YOLO26, you can use a right mouse click. This action will clear all the points you have drawn. For more details, refer to the note section under the distance calculation example.
The key arguments for initializing the DistanceCalculation class in Ultralytics YOLO26 include:
model: Path to the YOLO26 model file.tracker: Tracking algorithm to use (default is 'botsort.yaml').conf: Confidence threshold for detections.show: Flag to display the output.For an exhaustive list and default values, see the arguments of DistanceCalculation.