You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
88 lines
4.3 KiB
88 lines
4.3 KiB
--- |
|
comments: true |
|
description: Learn how to leverage callbacks in Ultralytics YOLO framework to perform custom tasks in trainer, validator, predictor and exporter modes. |
|
keywords: callbacks, Ultralytics framework, Trainer, Validator, Predictor, Exporter, train, val, export, predict, YOLO, Object Detection |
|
--- |
|
|
|
## Callbacks |
|
|
|
Ultralytics framework supports callbacks as entry points in strategic stages of train, val, export, and predict modes. |
|
Each callback accepts a `Trainer`, `Validator`, or `Predictor` object depending on the operation type. All properties of |
|
these objects can be found in Reference section of the docs. |
|
|
|
## Examples |
|
|
|
### Returning additional information with Prediction |
|
|
|
In this example, we want to return the original frame with each result object. Here's how we can do that |
|
|
|
```python |
|
def on_predict_batch_end(predictor): |
|
# Retrieve the batch data |
|
_, im0s, _, _ = predictor.batch |
|
|
|
# Ensure that im0s is a list |
|
im0s = im0s if isinstance(im0s, list) else [im0s] |
|
|
|
# Combine the prediction results with the corresponding frames |
|
predictor.results = zip(predictor.results, im0s) |
|
|
|
# Create a YOLO model instance |
|
model = YOLO(f'yolov8n.pt') |
|
|
|
# Add the custom callback to the model |
|
model.add_callback("on_predict_batch_end", on_predict_batch_end) |
|
|
|
# Iterate through the results and frames |
|
for (result, frame) in model.track/predict(): |
|
pass |
|
``` |
|
|
|
## All callbacks |
|
|
|
Here are all supported callbacks. See callbacks [source code](https://github.com/ultralytics/ultralytics/blob/main/ultralytics/yolo/utils/callbacks/base.py) for additional details. |
|
|
|
### Trainer Callbacks |
|
|
|
| Callback | Description | |
|
|-----------------------------|---------------------------------------------------------| |
|
| `on_pretrain_routine_start` | Triggered at the beginning of pre-training routine | |
|
| `on_pretrain_routine_end` | Triggered at the end of pre-training routine | |
|
| `on_train_start` | Triggered when the training starts | |
|
| `on_train_epoch_start` | Triggered at the start of each training epoch | |
|
| `on_train_batch_start` | Triggered at the start of each training batch | |
|
| `optimizer_step` | Triggered during the optimizer step | |
|
| `on_before_zero_grad` | Triggered before gradients are zeroed | |
|
| `on_train_batch_end` | Triggered at the end of each training batch | |
|
| `on_train_epoch_end` | Triggered at the end of each training epoch | |
|
| `on_fit_epoch_end` | Triggered at the end of each fit epoch | |
|
| `on_model_save` | Triggered when the model is saved | |
|
| `on_train_end` | Triggered when the training process ends | |
|
| `on_params_update` | Triggered when model parameters are updated | |
|
| `teardown` | Triggered when the training process is being cleaned up | |
|
|
|
### Validator Callbacks |
|
|
|
| Callback | Description | |
|
|----------------------|-------------------------------------------------| |
|
| `on_val_start` | Triggered when the validation starts | |
|
| `on_val_batch_start` | Triggered at the start of each validation batch | |
|
| `on_val_batch_end` | Triggered at the end of each validation batch | |
|
| `on_val_end` | Triggered when the validation ends | |
|
|
|
### Predictor Callbacks |
|
|
|
| Callback | Description | |
|
|------------------------------|---------------------------------------------------| |
|
| `on_predict_start` | Triggered when the prediction process starts | |
|
| `on_predict_batch_start` | Triggered at the start of each prediction batch | |
|
| `on_predict_postprocess_end` | Triggered at the end of prediction postprocessing | |
|
| `on_predict_batch_end` | Triggered at the end of each prediction batch | |
|
| `on_predict_end` | Triggered when the prediction process ends | |
|
|
|
### Exporter Callbacks |
|
|
|
| Callback | Description | |
|
|-------------------|------------------------------------------| |
|
| `on_export_start` | Triggered when the export process starts | |
|
| `on_export_end` | Triggered when the export process ends | |