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Reference for ultralytics/models/yolo/classify/val.py

Note

Full source code for this file is available at https://github.com/ultralytics/ultralytics/blob/main/ultralytics/models/yolo/classify/val.py. Help us fix any issues you see by submitting a Pull Request 🛠️. Thank you 🙏!


ultralytics.models.yolo.classify.val.ClassificationValidator

Bases: BaseValidator

A class extending the BaseValidator class for validation based on a classification model.

Notes
  • Torchvision classification models can also be passed to the 'model' argument, i.e. model='resnet18'.
Example
from ultralytics.models.yolo.classify import ClassificationValidator

args = dict(model='yolov8n-cls.pt', data='imagenet10')
validator = ClassificationValidator(args=args)
validator()
Source code in ultralytics/models/yolo/classify/val.py
class ClassificationValidator(BaseValidator):
    """
    A class extending the BaseValidator class for validation based on a classification model.

    Notes:
        - Torchvision classification models can also be passed to the 'model' argument, i.e. model='resnet18'.

    Example:
        ```python
        from ultralytics.models.yolo.classify import ClassificationValidator

        args = dict(model='yolov8n-cls.pt', data='imagenet10')
        validator = ClassificationValidator(args=args)
        validator()
        ```
    """

    def __init__(self, dataloader=None, save_dir=None, pbar=None, args=None, _callbacks=None):
        """Initializes ClassificationValidator instance with args, dataloader, save_dir, and progress bar."""
        super().__init__(dataloader, save_dir, pbar, args, _callbacks)
        self.targets = None
        self.pred = None
        self.args.task = 'classify'
        self.metrics = ClassifyMetrics()

    def get_desc(self):
        """Returns a formatted string summarizing classification metrics."""
        return ('%22s' + '%11s' * 2) % ('classes', 'top1_acc', 'top5_acc')

    def init_metrics(self, model):
        """Initialize confusion matrix, class names, and top-1 and top-5 accuracy."""
        self.names = model.names
        self.nc = len(model.names)
        self.confusion_matrix = ConfusionMatrix(nc=self.nc, conf=self.args.conf, task='classify')
        self.pred = []
        self.targets = []

    def preprocess(self, batch):
        """Preprocesses input batch and returns it."""
        batch['img'] = batch['img'].to(self.device, non_blocking=True)
        batch['img'] = batch['img'].half() if self.args.half else batch['img'].float()
        batch['cls'] = batch['cls'].to(self.device)
        return batch

    def update_metrics(self, preds, batch):
        """Updates running metrics with model predictions and batch targets."""
        n5 = min(len(self.names), 5)
        self.pred.append(preds.argsort(1, descending=True)[:, :n5])
        self.targets.append(batch['cls'])

    def finalize_metrics(self, *args, **kwargs):
        """Finalizes metrics of the model such as confusion_matrix and speed."""
        self.confusion_matrix.process_cls_preds(self.pred, self.targets)
        if self.args.plots:
            for normalize in True, False:
                self.confusion_matrix.plot(save_dir=self.save_dir,
                                           names=self.names.values(),
                                           normalize=normalize,
                                           on_plot=self.on_plot)
        self.metrics.speed = self.speed
        self.metrics.confusion_matrix = self.confusion_matrix
        self.metrics.save_dir = self.save_dir

    def get_stats(self):
        """Returns a dictionary of metrics obtained by processing targets and predictions."""
        self.metrics.process(self.targets, self.pred)
        return self.metrics.results_dict

    def build_dataset(self, img_path):
        return ClassificationDataset(root=img_path, args=self.args, augment=False, prefix=self.args.split)

    def get_dataloader(self, dataset_path, batch_size):
        """Builds and returns a data loader for classification tasks with given parameters."""
        dataset = self.build_dataset(dataset_path)
        return build_dataloader(dataset, batch_size, self.args.workers, rank=-1)

    def print_results(self):
        """Prints evaluation metrics for YOLO object detection model."""
        pf = '%22s' + '%11.3g' * len(self.metrics.keys)  # print format
        LOGGER.info(pf % ('all', self.metrics.top1, self.metrics.top5))

    def plot_val_samples(self, batch, ni):
        """Plot validation image samples."""
        plot_images(
            images=batch['img'],
            batch_idx=torch.arange(len(batch['img'])),
            cls=batch['cls'].view(-1),  # warning: use .view(), not .squeeze() for Classify models
            fname=self.save_dir / f'val_batch{ni}_labels.jpg',
            names=self.names,
            on_plot=self.on_plot)

    def plot_predictions(self, batch, preds, ni):
        """Plots predicted bounding boxes on input images and saves the result."""
        plot_images(batch['img'],
                    batch_idx=torch.arange(len(batch['img'])),
                    cls=torch.argmax(preds, dim=1),
                    fname=self.save_dir / f'val_batch{ni}_pred.jpg',
                    names=self.names,
                    on_plot=self.on_plot)  # pred

__init__(dataloader=None, save_dir=None, pbar=None, args=None, _callbacks=None)

Initializes ClassificationValidator instance with args, dataloader, save_dir, and progress bar.

Source code in ultralytics/models/yolo/classify/val.py
def __init__(self, dataloader=None, save_dir=None, pbar=None, args=None, _callbacks=None):
    """Initializes ClassificationValidator instance with args, dataloader, save_dir, and progress bar."""
    super().__init__(dataloader, save_dir, pbar, args, _callbacks)
    self.targets = None
    self.pred = None
    self.args.task = 'classify'
    self.metrics = ClassifyMetrics()

finalize_metrics(*args, **kwargs)

Finalizes metrics of the model such as confusion_matrix and speed.

Source code in ultralytics/models/yolo/classify/val.py
def finalize_metrics(self, *args, **kwargs):
    """Finalizes metrics of the model such as confusion_matrix and speed."""
    self.confusion_matrix.process_cls_preds(self.pred, self.targets)
    if self.args.plots:
        for normalize in True, False:
            self.confusion_matrix.plot(save_dir=self.save_dir,
                                       names=self.names.values(),
                                       normalize=normalize,
                                       on_plot=self.on_plot)
    self.metrics.speed = self.speed
    self.metrics.confusion_matrix = self.confusion_matrix
    self.metrics.save_dir = self.save_dir

get_dataloader(dataset_path, batch_size)

Builds and returns a data loader for classification tasks with given parameters.

Source code in ultralytics/models/yolo/classify/val.py
def get_dataloader(self, dataset_path, batch_size):
    """Builds and returns a data loader for classification tasks with given parameters."""
    dataset = self.build_dataset(dataset_path)
    return build_dataloader(dataset, batch_size, self.args.workers, rank=-1)

get_desc()

Returns a formatted string summarizing classification metrics.

Source code in ultralytics/models/yolo/classify/val.py
def get_desc(self):
    """Returns a formatted string summarizing classification metrics."""
    return ('%22s' + '%11s' * 2) % ('classes', 'top1_acc', 'top5_acc')

get_stats()

Returns a dictionary of metrics obtained by processing targets and predictions.

Source code in ultralytics/models/yolo/classify/val.py
def get_stats(self):
    """Returns a dictionary of metrics obtained by processing targets and predictions."""
    self.metrics.process(self.targets, self.pred)
    return self.metrics.results_dict

init_metrics(model)

Initialize confusion matrix, class names, and top-1 and top-5 accuracy.

Source code in ultralytics/models/yolo/classify/val.py
def init_metrics(self, model):
    """Initialize confusion matrix, class names, and top-1 and top-5 accuracy."""
    self.names = model.names
    self.nc = len(model.names)
    self.confusion_matrix = ConfusionMatrix(nc=self.nc, conf=self.args.conf, task='classify')
    self.pred = []
    self.targets = []

plot_predictions(batch, preds, ni)

Plots predicted bounding boxes on input images and saves the result.

Source code in ultralytics/models/yolo/classify/val.py
def plot_predictions(self, batch, preds, ni):
    """Plots predicted bounding boxes on input images and saves the result."""
    plot_images(batch['img'],
                batch_idx=torch.arange(len(batch['img'])),
                cls=torch.argmax(preds, dim=1),
                fname=self.save_dir / f'val_batch{ni}_pred.jpg',
                names=self.names,
                on_plot=self.on_plot)  # pred

plot_val_samples(batch, ni)

Plot validation image samples.

Source code in ultralytics/models/yolo/classify/val.py
def plot_val_samples(self, batch, ni):
    """Plot validation image samples."""
    plot_images(
        images=batch['img'],
        batch_idx=torch.arange(len(batch['img'])),
        cls=batch['cls'].view(-1),  # warning: use .view(), not .squeeze() for Classify models
        fname=self.save_dir / f'val_batch{ni}_labels.jpg',
        names=self.names,
        on_plot=self.on_plot)

preprocess(batch)

Preprocesses input batch and returns it.

Source code in ultralytics/models/yolo/classify/val.py
def preprocess(self, batch):
    """Preprocesses input batch and returns it."""
    batch['img'] = batch['img'].to(self.device, non_blocking=True)
    batch['img'] = batch['img'].half() if self.args.half else batch['img'].float()
    batch['cls'] = batch['cls'].to(self.device)
    return batch

print_results()

Prints evaluation metrics for YOLO object detection model.

Source code in ultralytics/models/yolo/classify/val.py
def print_results(self):
    """Prints evaluation metrics for YOLO object detection model."""
    pf = '%22s' + '%11.3g' * len(self.metrics.keys)  # print format
    LOGGER.info(pf % ('all', self.metrics.top1, self.metrics.top5))

update_metrics(preds, batch)

Updates running metrics with model predictions and batch targets.

Source code in ultralytics/models/yolo/classify/val.py
def update_metrics(self, preds, batch):
    """Updates running metrics with model predictions and batch targets."""
    n5 = min(len(self.names), 5)
    self.pred.append(preds.argsort(1, descending=True)[:, :n5])
    self.targets.append(batch['cls'])




Created 2023-07-16, Updated 2023-08-20
Authors: glenn-jocher (6), Laughing-q (1)