Python Usage

Welcome to the YOLO11 Python Usage documentation! This guide is designed to help you seamlessly integrate YOLO11 into your Python projects for object detection, segmentation, and classification. Here, you'll learn how to load and use pretrained models, train new models, and perform predictions on images. The easy-to-use Python interface is a valuable resource for anyone looking to incorporate YOLO11 into their Python projects, allowing you to quickly implement advanced object detection capabilities. Let's get started!

Watch: Mastering Ultralytics YOLO11: Python

For example, users can load a model, train it, evaluate its performance on a validation set, and even export it to ONNX format with just a few lines of code.

from ultralytics import YOLO

# Create a new YOLO model from scratch
model = YOLO("yolo11n.yaml")

# Load a pretrained YOLO model (recommended for training)
model = YOLO("yolo11n.pt")

# Train the model using the 'coco8.yaml' dataset for 3 epochs
results = model.train(data="coco8.yaml", epochs=3)

# Evaluate the model's performance on the validation set
results = model.val()

# Perform object detection on an image using the model
results = model("https://ultralytics.com/images/bus.jpg")

# Export the model to ONNX format
success = model.export(format="onnx")

Train

Train mode is used for training a YOLO11 model on a custom dataset. In this mode, the model is trained using the specified dataset and hyperparameters. The training process involves optimizing the model's parameters so that it can accurately predict the classes and locations of objects in an image.

from ultralytics import YOLO

model = YOLO("yolo11n.pt")  # pass any model type
results = model.train(epochs=5)

from ultralytics import YOLO

model = YOLO("yolo11n.yaml")
results = model.train(data="coco8.yaml", epochs=5)

model = YOLO("last.pt")
results = model.train(resume=True)

Train Examples

Val

Val mode is used for validating a YOLO11 model after it has been trained. In this mode, the model is evaluated on a validation set to measure its accuracy and generalization performance. This mode can be used to tune the hyperparameters of the model to improve its performance.

from ultralytics import YOLO

# Load a YOLO11 model
model = YOLO("yolo11n.yaml")

# Train the model
model.train(data="coco8.yaml", epochs=5)

# Validate on training data
model.val()

from ultralytics import YOLO

# Load a YOLO11 model
model = YOLO("yolo11n.yaml")

# Train the model
model.train(data="coco8.yaml", epochs=5)

# Validate on separate data
model.val(data="path/to/separate/data.yaml")

Val Examples

Predict

Predict mode is used for making predictions using a trained YOLO11 model on new images or videos. In this mode, the model is loaded from a checkpoint file, and the user can provide images or videos to perform inference. The model predicts the classes and locations of objects in the input images or videos.

import cv2
from PIL import Image

from ultralytics import YOLO

model = YOLO("model.pt")
# accepts all formats - image/dir/Path/URL/video/PIL/ndarray. 0 for webcam
results = model.predict(source="0")
results = model.predict(source="folder", show=True)  # Display preds. Accepts all YOLO predict arguments

# from PIL
im1 = Image.open("bus.jpg")
results = model.predict(source=im1, save=True)  # save plotted images

# from ndarray
im2 = cv2.imread("bus.jpg")
results = model.predict(source=im2, save=True, save_txt=True)  # save predictions as labels

# from list of PIL/ndarray
results = model.predict(source=[im1, im2])

# results would be a list of Results object including all the predictions by default
# but be careful as it could occupy a lot memory when there're many images,
# especially the task is segmentation.
# 1. return as a list
results = model.predict(source="folder")

# results would be a generator which is more friendly to memory by setting stream=True
# 2. return as a generator
results = model.predict(source=0, stream=True)

for result in results:
    # Detection
    result.boxes.xyxy  # box with xyxy format, (N, 4)
    result.boxes.xywh  # box with xywh format, (N, 4)
    result.boxes.xyxyn  # box with xyxy format but normalized, (N, 4)
    result.boxes.xywhn  # box with xywh format but normalized, (N, 4)
    result.boxes.conf  # confidence score, (N, 1)
    result.boxes.cls  # cls, (N, 1)

    # Segmentation
    result.masks.data  # masks, (N, H, W)
    result.masks.xy  # x,y segments (pixels), List[segment] * N
    result.masks.xyn  # x,y segments (normalized), List[segment] * N

    # Classification
    result.probs  # cls prob, (num_class, )

# Each result is composed of torch.Tensor by default,
# in which you can easily use following functionality:
result = result.cuda()
result = result.cpu()
result = result.to("cpu")
result = result.numpy()

Predict Examples

Export

Export mode is used for exporting a YOLO11 model to a format that can be used for deployment. In this mode, the model is converted to a format that can be used by other software applications or hardware devices. This mode is useful when deploying the model to production environments.

from ultralytics import YOLO

model = YOLO("yolo11n.pt")
model.export(format="onnx", dynamic=True)

from ultralytics import YOLO

model = YOLO("yolo11n.pt")
model.export(format="onnx", device=0)

Export Examples

Track

Track mode is used for tracking objects in real-time using a YOLO11 model. In this mode, the model is loaded from a checkpoint file, and the user can provide a live video stream to perform real-time object tracking. This mode is useful for applications such as surveillance systems or self-driving cars.

from ultralytics import YOLO

# Load a model
model = YOLO("yolo11n.pt")  # load an official detection model
model = YOLO("yolo11n-seg.pt")  # load an official segmentation model
model = YOLO("path/to/best.pt")  # load a custom model

# Track with the model
results = model.track(source="https://youtu.be/LNwODJXcvt4", show=True)
results = model.track(source="https://youtu.be/LNwODJXcvt4", show=True, tracker="bytetrack.yaml")

Track Examples

Benchmark

Benchmark mode is used to profile the speed and accuracy of various export formats for YOLO11. The benchmarks provide information on the size of the exported format, its mAP50-95 metrics (for object detection and segmentation) or accuracy_top5 metrics (for classification), and the inference time in milliseconds per image across various export formats like ONNX, OpenVINO, TensorRT and others. This information can help users choose the optimal export format for their specific use case based on their requirements for speed and accuracy.

from ultralytics.utils.benchmarks import benchmark

# Benchmark
benchmark(model="yolo11n.pt", data="coco8.yaml", imgsz=640, half=False, device=0)

Benchmark Examples

Using Trainers

YOLO model class is a high-level wrapper on the Trainer classes. Each YOLO task has its own trainer that inherits from BaseTrainer.

from ultralytics.models.yolo import DetectionPredictor, DetectionTrainer, DetectionValidator

# trainer
trainer = DetectionTrainer(overrides={})
trainer.train()
trained_model = trainer.best

# Validator
val = DetectionValidator(args=...)
val(model=trained_model)

# predictor
pred = DetectionPredictor(overrides={})
pred(source=SOURCE, model=trained_model)

# resume from last weight
overrides["resume"] = trainer.last
trainer = detect.DetectionTrainer(overrides=overrides)

You can easily customize Trainers to support custom tasks or explore R&D ideas. Learn more about Customizing Trainers, Validators and Predictors to suit your project needs in the Customization Section.

Customization tutorials

FAQ

How can I integrate YOLO11 into my Python project for object detection?

Integrating Ultralytics YOLO11 into your Python projects is simple. You can load a pre-trained model or train a new model from scratch. Here's how to get started:

from ultralytics import YOLO

# Load a pretrained YOLO model
model = YOLO("yolo11n.pt")

# Perform object detection on an image
results = model("https://ultralytics.com/images/bus.jpg")

# Visualize the results
for result in results:
    result.show()

See more detailed examples in our Predict Mode section.

What are the different modes available in YOLO11?

Ultralytics YOLO11 provides various modes to cater to different machine learning workflows. These include:

• Train: Train a model using custom datasets.
• Val: Validate model performance on a validation set.
• Predict: Make predictions on new images or video streams.
• Export: Export models to various formats like ONNX, TensorRT.
• Track: Real-time object tracking in video streams.
• Benchmark: Benchmark model performance across different configurations.

Each mode is designed to provide comprehensive functionalities for different stages of model development and deployment.

How do I train a custom YOLO11 model using my dataset?

To train a custom YOLO11 model, you need to specify your dataset and other hyperparameters. Here's a quick example:

from ultralytics import YOLO

# Load the YOLO model
model = YOLO("yolo11n.yaml")

# Train the model with custom dataset
model.train(data="path/to/your/dataset.yaml", epochs=10)

For more details on training and hyperlinks to example usage, visit our Train Mode page.

How do I export YOLO11 models for deployment?

Exporting YOLO11 models in a format suitable for deployment is straightforward with the export function. For example, you can export a model to ONNX format:

from ultralytics import YOLO

# Load the YOLO model
model = YOLO("yolo11n.pt")

# Export the model to ONNX format
model.export(format="onnx")

For various export options, refer to the Export Mode documentation.

Can I validate my YOLO11 model on different datasets?

Yes, validating YOLO11 models on different datasets is possible. After training, you can use the validation mode to evaluate the performance:

from ultralytics import YOLO

# Load a YOLO11 model
model = YOLO("yolo11n.yaml")

# Train the model
model.train(data="coco8.yaml", epochs=5)

# Validate the model on a different dataset
model.val(data="path/to/separate/data.yaml")

Check the Val Mode page for detailed examples and usage.

📅 Created 1 year ago ✏️ Updated 1 month ago

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