detection_sub_classing_test.py

import unittest
import numpy as np

from super_gradients.training.datasets import DetectionDataset
from super_gradients.training.utils.detection_utils import DetectionTargetsFormat
from super_gradients.common.exceptions.dataset_exceptions import EmptyDatasetException, DatasetValidationException


class DummyDetectionDataset(DetectionDataset):
    def __init__(self, input_dim, *args, **kwargs):
        """Dummy Dataset testing subclassing, designed with no annotation that includes class_2."""

        self.dummy_targets = [
            np.array([[0, 0, 10, 10, 0], [0, 5, 10, 15, 0], [0, 5, 15, 20, 0]]),
            np.array([[0, 0, 10, 10, 0], [0, 5, 10, 15, 0], [0, 15, 55, 20, 1]]),
        ]

        self.image_size = input_dim
        kwargs["all_classes_list"] = ["class_0", "class_1", "class_2"]
        kwargs["original_target_format"] = DetectionTargetsFormat.XYXY_LABEL
        super().__init__(data_dir="", input_dim=input_dim, *args, **kwargs)

    def _setup_data_source(self):
        return len(self.dummy_targets)

    def _load_annotation(self, sample_id: int) -> dict:
        """Load 2 different annotations.
        - Annotation 0 is made of: 3 targets of class 0, 0 of class_1 and 0 of class_2
        - Annotation 1 is made of: 2 targets of class_0, 1 of class_1 and 0 of class_2
        """
        return {"img_path": "", "resized_img_shape": None, "target": self.dummy_targets[sample_id]}

    # DetectionDatasetV2 will call _load_image but since we don't have any image we patch this method with
    # tensor of image shape
    def _load_image(self, index: int) -> np.ndarray:
        return np.random.random(self.image_size)


class TestDetectionDatasetSubclassing(unittest.TestCase):
    def setUp(self) -> None:
        self.config_keep_empty_annotation = [
            {"class_inclusion_list": ["class_0", "class_1", "class_2"], "expected_n_targets_after_subclass": [3, 3]},
            {"class_inclusion_list": ["class_0"], "expected_n_targets_after_subclass": [3, 2]},
            {"class_inclusion_list": ["class_1"], "expected_n_targets_after_subclass": [0, 1]},
            {"class_inclusion_list": ["class_2"], "expected_n_targets_after_subclass": [0, 0]},
        ]
        self.config_ignore_empty_annotation = [
            {"class_inclusion_list": ["class_0", "class_1", "class_2"], "expected_n_targets_after_subclass": [3, 3]},
            {"class_inclusion_list": ["class_0"], "expected_n_targets_after_subclass": [3, 2]},
            {"class_inclusion_list": ["class_1"], "expected_n_targets_after_subclass": [1]},
        ]

    def test_subclass_keep_empty(self):
        """Check that subclassing only keeps annotations of wanted class"""
        for config in self.config_keep_empty_annotation:
            test_dataset = DummyDetectionDataset(input_dim=(640, 512), ignore_empty_annotations=False, class_inclusion_list=config["class_inclusion_list"])
            n_targets_after_subclass = _count_targets_after_subclass_per_index(test_dataset)
            self.assertListEqual(config["expected_n_targets_after_subclass"], n_targets_after_subclass)

    def test_subclass_drop_empty(self):
        """Check that empty annotations are not indexed (i.e. ignored) when ignore_empty_annotations=True"""
        for config in self.config_ignore_empty_annotation:
            test_dataset = DummyDetectionDataset(input_dim=(640, 512), ignore_empty_annotations=True, class_inclusion_list=config["class_inclusion_list"])
            n_targets_after_subclass = _count_targets_after_subclass_per_index(test_dataset)
            self.assertListEqual(config["expected_n_targets_after_subclass"], n_targets_after_subclass)

        # Check last case when class_2, which should raise EmptyDatasetException because not a single image has
        # a target in class_inclusion_list
        with self.assertRaises(EmptyDatasetException):
            DummyDetectionDataset(input_dim=(640, 512), ignore_empty_annotations=True, class_inclusion_list=["class_2"])

    def test_wrong_subclass(self):
        """Check that ValueError is raised when class_inclusion_list includes a class that does not exist."""
        with self.assertRaises(DatasetValidationException):
            DummyDetectionDataset(input_dim=(640, 512), class_inclusion_list=["non_existing_class"])
        with self.assertRaises(DatasetValidationException):
            DummyDetectionDataset(input_dim=(640, 512), class_inclusion_list=["class_0", "non_existing_class"])


def _count_targets_after_subclass_per_index(test_dataset: DummyDetectionDataset):
    """Iterate through every index of the dataset and count the associated number of targets per index"""
    dataset_target_len = []
    for index in range(len(test_dataset)):
        _img, targets = test_dataset[index]
        dataset_target_len.append(len(targets))
    return dataset_target_len


if __name__ == "__main__":
    unittest.main()