Source code for tonic.datasets.ncaltech101

import os
from typing import Callable, Optional

import numpy as np

from tonic.dataset import Dataset
from tonic.io import read_mnist_file


class NCALTECH101(Dataset):
    """`N-CALTECH101 <https://www.garrickorchard.com/datasets/n-caltech101>`_

    Events have (xytp) ordering.
    ::

        @article{orchard2015converting,
          title={Converting static image datasets to spiking neuromorphic datasets using saccades},
          author={Orchard, Garrick and Jayawant, Ajinkya and Cohen, Gregory K and Thakor, Nitish},
          journal={Frontiers in neuroscience},
          volume={9},
          pages={437},
          year={2015},
          publisher={Frontiers}
        }

    Parameters:
        save_to (string): Location to save files to on disk.
        transform (callable, optional): A callable of transforms to apply to the data.
        target_transform (callable, optional): A callable of transforms to apply to the targets/labels.
        transforms (callable, optional): A callable of transforms that is applied to both data and
                                         labels at the same time.
    """

    url = "https://data.mendeley.com/public-files/datasets/cy6cvx3ryv/files/36b5c52a-b49d-4853-addb-a836a8883e49/file_downloaded"
    filename = "N-Caltech101-archive.zip"
    file_md5 = "66201824eabb0239c7ab992480b50ba3"
    data_filename = "Caltech101.zip"
    folder_name = "Caltech101"

    sensor_size = None  # all recordings are of different size
    dtype = np.dtype([("x", int), ("y", int), ("t", int), ("p", int)])
    ordering = dtype.names

    def __init__(
        self,
        save_to: str,
        transform: Optional[Callable] = None,
        target_transform: Optional[Callable] = None,
        transforms: Optional[Callable] = None,
    ):
        super().__init__(
            save_to,
            transform=transform,
            target_transform=target_transform,
            transforms=transforms,
        )

        if not self._check_exists():
            self.download()

        file_path = os.path.join(self.location_on_system, self.folder_name)
        for path, dirs, files in os.walk(file_path):
            dirs.sort()
            for file in files:
                if file.endswith("bin"):
                    self.data.append(path + "/" + file)
                    label_number = os.path.basename(path)
                    self.targets.append(label_number)

    def __getitem__(self, index):
        """
        Returns:
            a tuple of (events, target) where target is the index of the target class.
        """
        events = read_mnist_file(self.data[index], dtype=self.dtype)
        target = self.targets[index]
        events["x"] -= events["x"].min()
        events["y"] -= events["y"].min()
        if self.transform is not None:
            events = self.transform(events)
        if self.target_transform is not None:
            target = self.target_transform(target)
        if self.transforms is not None:
            events, target = self.transforms(events, target)
        return events, target

    def __len__(self):
        return len(self.data)

    def _check_exists(self):
        return (
            self._is_file_present()
            and self._folder_contains_at_least_n_files_of_type(8709, ".bin")
        )