Configuration
YOLO settings and hyperparameters play a critical role in the model's performance, speed, and accuracy. These settings and hyperparameters can affect the model's behavior at various stages of the model development process, including training, validation, and prediction.
YOLOv8 'yolo' CLI commands use the following syntax:
Where:
TASK(optional) is one of[detect, segment, classify]. If it is not passed explicitly YOLOv8 will try to guess theTASKfrom the model type.MODE(required) is one of[train, val, predict, export]ARGS(optional) are any number of customarg=valuepairs likeimgsz=320that override defaults. For a full list of availableARGSsee the Configuration page anddefaults.yamlGitHub source.
Tasks
YOLO models can be used for a variety of tasks, including detection, segmentation, and classification. These tasks differ in the type of output they produce and the specific problem they are designed to solve.
- Detect: Detection tasks involve identifying and localizing objects or regions of interest in an image or video. YOLO models can be used for object detection tasks by predicting the bounding boxes and class labels of objects in an image.
- Segment: Segmentation tasks involve dividing an image or video into regions or pixels that correspond to different objects or classes. YOLO models can be used for image segmentation tasks by predicting a mask or label for each pixel in an image.
- Classify: Classification tasks involve assigning a class label to an input, such as an image or text. YOLO models can be used for image classification tasks by predicting the class label of an input image.
Modes
YOLO models can be used in different modes depending on the specific problem you are trying to solve. These modes include train, val, and predict.
- Train: The train mode is used to train the model on a dataset. This mode is typically used during the development and testing phase of a model.
- Val: The val mode is used to evaluate the model's performance on a validation dataset. This mode is typically used to tune the model's hyperparameters and detect overfitting.
- Predict: The predict mode is used to make predictions with the model on new data. This mode is typically used in production or when deploying the model to users.
| Key | Value | Description |
|---|---|---|
| task | 'detect' | inference task, i.e. detect, segment, or classify |
| mode | 'train' | YOLO mode, i.e. train, val, predict, or export |
| resume | False | resume training from last checkpoint or custom checkpoint if passed as resume=path/to/best.pt |
| model | null | path to model file, i.e. yolov8n.pt, yolov8n.yaml |
| data | null | path to data file, i.e. i.e. coco128.yaml |
Training
Training settings for YOLO models refer to the various hyperparameters and configurations used to train the model on a dataset. These settings can affect the model's performance, speed, and accuracy. Some common YOLO training settings include the batch size, learning rate, momentum, and weight decay. Other factors that may affect the training process include the choice of optimizer, the choice of loss function, and the size and composition of the training dataset. It is important to carefully tune and experiment with these settings to achieve the best possible performance for a given task.
| Key | Value | Description |
|---|---|---|
| model | null | path to model file, i.e. yolov8n.pt, yolov8n.yaml |
| data | null | path to data file, i.e. i.e. coco128.yaml |
| epochs | 100 | number of epochs to train for |
| patience | 50 | epochs to wait for no observable improvement for early stopping of training |
| batch | 16 | number of images per batch (-1 for AutoBatch) |
| imgsz | 640 | size of input images as integer or w,h |
| save | True | save train checkpoints and predict results |
| cache | False | True/ram, disk or False. Use cache for data loading |
| device | null | device to run on, i.e. cuda device=0 or device=0,1,2,3 or device=cpu |
| workers | 8 | number of worker threads for data loading (per RANK if DDP) |
| project | null | project name |
| name | null | experiment name |
| exist_ok | False | whether to overwrite existing experiment |
| pretrained | False | whether to use a pretrained model |
| optimizer | 'SGD' | optimizer to use, choices=['SGD', 'Adam', 'AdamW', 'RMSProp'] |
| verbose | False | whether to print verbose output |
| seed | 0 | random seed for reproducibility |
| deterministic | True | whether to enable deterministic mode |
| single_cls | False | train multi-class data as single-class |
| image_weights | False | use weighted image selection for training |
| rect | False | support rectangular training |
| cos_lr | False | use cosine learning rate scheduler |
| close_mosaic | 10 | disable mosaic augmentation for final 10 epochs |
| resume | False | resume training from last checkpoint |
| lr0 | 0.01 | initial learning rate (i.e. SGD=1E-2, Adam=1E-3) |
| lrf | 0.01 | final learning rate (lr0 * lrf) |
| momentum | 0.937 | SGD momentum/Adam beta1 |
| weight_decay | 0.0005 | optimizer weight decay 5e-4 |
| warmup_epochs | 3.0 | warmup epochs (fractions ok) |
| warmup_momentum | 0.8 | warmup initial momentum |
| warmup_bias_lr | 0.1 | warmup initial bias lr |
| box | 7.5 | box loss gain |
| cls | 0.5 | cls loss gain (scale with pixels) |
| dfl | 1.5 | dfl loss gain |
| fl_gamma | 0.0 | focal loss gamma (efficientDet default gamma=1.5) |
| label_smoothing | 0.0 | label smoothing (fraction) |
| nbs | 64 | nominal batch size |
| overlap_mask | True | masks should overlap during training (segment train only) |
| mask_ratio | 4 | mask downsample ratio (segment train only) |
| dropout | 0.0 | use dropout regularization (classify train only) |
| val | True | validate/test during training |
| min_memory | False | minimize memory footprint loss function, choices=[False, True, |
Prediction
Prediction settings for YOLO models refer to the various hyperparameters and configurations used to make predictions with the model on new data. These settings can affect the model's performance, speed, and accuracy. Some common YOLO prediction settings include the confidence threshold, non-maximum suppression (NMS) threshold, and the number of classes to consider. Other factors that may affect the prediction process include the size and format of the input data, the presence of additional features such as masks or multiple labels per box, and the specific task the model is being used for. It is important to carefully tune and experiment with these settings to achieve the best possible performance for a given task.
| Key | Value | Description |
|---|---|---|
| source | 'ultralytics/assets' | source directory for images or videos |
| conf | 0.25 | object confidence threshold for detection |
| iou | 0.7 | intersection over union (IoU) threshold for NMS |
| half | False | use half precision (FP16) |
| device | null | device to run on, i.e. cuda device=0/1/2/3 or device=cpu |
| show | False | show results if possible |
| save_txt | False | save results as .txt file |
| save_conf | False | save results with confidence scores |
| save_crop | False | save cropped images with results |
| hide_labels | False | hide labels |
| hide_conf | False | hide confidence scores |
| max_det | 300 | maximum number of detections per image |
| vid_stride | False | video frame-rate stride |
| line_thickness | 3 | bounding box thickness (pixels) |
| visualize | False | visualize model features |
| augment | False | apply image augmentation to prediction sources |
| agnostic_nms | False | class-agnostic NMS |
| retina_masks | False | use high-resolution segmentation masks |
| classes | null | filter results by class, i.e. class=0, or class=[0,2,3] |
| box | True | Show boxes in segmentation predictions |
Validation
Validation settings for YOLO models refer to the various hyperparameters and configurations used to evaluate the model's performance on a validation dataset. These settings can affect the model's performance, speed, and accuracy. Some common YOLO validation settings include the batch size, the frequency with which validation is performed during training, and the metrics used to evaluate the model's performance. Other factors that may affect the validation process include the size and composition of the validation dataset and the specific task the model is being used for. It is important to carefully tune and experiment with these settings to ensure that the model is performing well on the validation dataset and to detect and prevent overfitting.
| Key | Value | Description |
|---|---|---|
| save_json | False | save results to JSON file |
| save_hybrid | False | save hybrid version of labels (labels + additional predictions) |
| conf | 0.001 | object confidence threshold for detection |
| iou | 0.6 | intersection over union (IoU) threshold for NMS |
| max_det | 300 | maximum number of detections per image |
| half | True | use half precision (FP16) |
| device | null | device to run on, i.e. cuda device=0/1/2/3 or device=cpu |
| dnn | False | use OpenCV DNN for ONNX inference |
| plots | False | show plots during training |
| rect | False | support rectangular evaluation |
Export
Export settings for YOLO models refer to the various configurations and options used to save or export the model for use in other environments or platforms. These settings can affect the model's performance, size, and compatibility with different systems. Some common YOLO export settings include the format of the exported model file (e.g. ONNX, TensorFlow SavedModel), the device on which the model will be run (e.g. CPU, GPU), and the presence of additional features such as masks or multiple labels per box. Other factors that may affect the export process include the specific task the model is being used for and the requirements or constraints of the target environment or platform. It is important to carefully consider and configure these settings to ensure that the exported model is optimized for the intended use case and can be used effectively in the target environment.
Augmentation
Augmentation settings for YOLO models refer to the various transformations and modifications applied to the training data to increase the diversity and size of the dataset. These settings can affect the model's performance, speed, and accuracy. Some common YOLO augmentation settings include the type and intensity of the transformations applied (e.g. random flips, rotations, cropping, color changes), the probability with which each transformation is applied, and the presence of additional features such as masks or multiple labels per box. Other factors that may affect the augmentation process include the size and composition of the original dataset and the specific task the model is being used for. It is important to carefully tune and experiment with these settings to ensure that the augmented dataset is diverse and representative enough to train a high-performing model.
| Key | Value | Description |
|---|---|---|
| hsv_h | 0.015 | image HSV-Hue augmentation (fraction) |
| hsv_s | 0.7 | image HSV-Saturation augmentation (fraction) |
| hsv_v | 0.4 | image HSV-Value augmentation (fraction) |
| degrees | 0.0 | image rotation (+/- deg) |
| translate | 0.1 | image translation (+/- fraction) |
| scale | 0.5 | image scale (+/- gain) |
| shear | 0.0 | image shear (+/- deg) |
| perspective | 0.0 | image perspective (+/- fraction), range 0-0.001 |
| flipud | 0.0 | image flip up-down (probability) |
| fliplr | 0.5 | image flip left-right (probability) |
| mosaic | 1.0 | image mosaic (probability) |
| mixup | 0.0 | image mixup (probability) |
| copy_paste | 0.0 | segment copy-paste (probability) |
Logging, checkpoints, plotting and file management
Logging, checkpoints, plotting, and file management are important considerations when training a YOLO model.
- Logging: It is often helpful to log various metrics and statistics during training to track the model's progress and diagnose any issues that may arise. This can be done using a logging library such as TensorBoard or by writing log messages to a file.
- Checkpoints: It is a good practice to save checkpoints of the model at regular intervals during training. This allows you to resume training from a previous point if the training process is interrupted or if you want to experiment with different training configurations.
- Plotting: Visualizing the model's performance and training progress can be helpful for understanding how the model is behaving and identifying potential issues. This can be done using a plotting library such as matplotlib or by generating plots using a logging library such as TensorBoard.
- File management: Managing the various files generated during the training process, such as model checkpoints, log files, and plots, can be challenging. It is important to have a clear and organized file structure to keep track of these files and make it easy to access and analyze them as needed.
Effective logging, checkpointing, plotting, and file management can help you keep track of the model's progress and make it easier to debug and optimize the training process.
| Key | Value | Description |
|---|---|---|
| project | 'runs' | project name |
| name | 'exp' | experiment name. exp gets automatically incremented if not specified, i.e, exp, exp2 ... |
| exist_ok | False | whether to overwrite existing experiment |
| plots | False | save plots during train/val |
| save | False | save train checkpoints and predict results |