ICML2022/resefa

1# python3.72"""Contains utility functions used for formatting."""3 4import cv25import numpy as np6 7__all__ = [8    'format_time', 'format_range', 'format_image_size', 'format_image',9    'raw_label_to_one_hot', 'one_hot_to_raw_label'10]11 12 13def format_time(seconds):14    """Formats seconds to readable time string.15 16    Args:17        seconds: Number of seconds to format.18 19    Returns:20        The formatted time string.21 22    Raises:23        ValueError: If the input `seconds` is less than 0.24    """25    if seconds < 0:26        raise ValueError(f'Input `seconds` should be greater than or equal to '27                         f'0, but `{seconds}` is received!')28 29    # Returns seconds as float if less than 1 minute.30    if seconds < 10:31        return f'{seconds:7.3f} s'32    if seconds < 60:33        return f'{seconds:7.2f} s'34 35    seconds = int(seconds + 0.5)36    days, seconds = divmod(seconds, 86400)37    hours, seconds = divmod(seconds, 3600)38    minutes, seconds = divmod(seconds, 60)39    if days:40        return f'{days:2d} d {hours:02d} h'41    if hours:42        return f'{hours:2d} h {minutes:02d} m'43    return f'{minutes:2d} m {seconds:02d} s'44 45 46def format_range(obj, min_val=None, max_val=None):47    """Formats the given object to a valid range.48 49    If `min_val` or `max_val` is provided, both the starting value and the end50    value will be clamped to range `[min_val, max_val]`.51 52    NOTE: (a, b) is regarded as a valid range if and only if `a <= b`.53 54    Args:55        obj: The input object to format.56        min_val: The minimum value to cut off the input range. If not provided,57            the default minimum value is negative infinity. (default: None)58        max_val: The maximum value to cut off the input range. If not provided,59            the default maximum value is infinity. (default: None)60 61    Returns:62        A two-elements tuple, indicating the start and the end of the range.63 64    Raises:65        ValueError: If the input object is an invalid range.66    """67    if not isinstance(obj, (tuple, list)):68        raise ValueError(f'Input object must be a tuple or a list, '69                         f'but `{type(obj)}` received!')70    if len(obj) != 2:71        raise ValueError(f'Input object is expected to contain two elements, '72                         f'but `{len(obj)}` received!')73    if obj[0] > obj[1]:74        raise ValueError(f'The second element is expected to be equal to or '75                         f'greater than the first one, '76                         f'but `({obj[0]}, {obj[1]})` received!')77 78    obj = list(obj)79    if min_val is not None:80        obj[0] = max(obj[0], min_val)81        obj[1] = max(obj[1], min_val)82    if max_val is not None:83        obj[0] = min(obj[0], max_val)84        obj[1] = min(obj[1], max_val)85    return tuple(obj)86 87 88def format_image_size(size):89    """Formats the given image size to a two-element tuple.90 91    A valid image size can be an integer, indicating both the height and the92    width, OR can be a two-element list or tuple. Both height and width are93    assumed to be positive integer.94 95    Args:96        size: The input size to format.97 98    Returns:99        A two-elements tuple, indicating the height and the width, respectively.100 101    Raises:102        ValueError: If the input size is invalid.103    """104    if not isinstance(size, (int, tuple, list)):105        raise ValueError(f'Input size must be an integer, a tuple, or a list, '106                         f'but `{type(size)}` received!')107    if isinstance(size, int):108        size = (size, size)109    else:110        if len(size) == 1:111            size = (size[0], size[0])112        if not len(size) == 2:113            raise ValueError(f'Input size is expected to have two numbers at '114                             f'most, but `{len(size)}` numbers received!')115    if not isinstance(size[0], int) or size[0] < 0:116        raise ValueError(f'The height is expected to be a non-negative '117                         f'integer, but `{size[0]}` received!')118    if not isinstance(size[1], int) or size[1] < 0:119        raise ValueError(f'The width is expected to be a non-negative '120                         f'integer, but `{size[1]}` received!')121    return tuple(size)122 123 124def format_image(image):125    """Formats an image read from `cv2`.126 127    NOTE: This function will always return a 3-dimensional image (i.e., with128    shape [H, W, C]) in pixel range [0, 255]. For color images, the channel129    order of the input is expected to be with `BGR` or `BGRA`, which is the130    raw image decoded by `cv2`; while the channel order of the output is set to131    `RGB` or `RGBA` by default.132 133    Args:134        image: `np.ndarray`, an image read by `cv2.imread()` or135            `cv2.imdecode()`.136 137    Returns:138        An image with shape [H, W, C] (where `C = 1` for grayscale image).139    """140    if image.ndim == 2:  # add additional axis if given a grayscale image141        image = image[:, :, np.newaxis]142 143    assert isinstance(image, np.ndarray)144    assert image.dtype == np.uint8145    assert image.ndim == 3 and image.shape[2] in [1, 3, 4]146 147    if image.shape[2] == 3:  # BGR image148        return cv2.cvtColor(image, cv2.COLOR_BGR2RGB)149    if image.shape[2] == 4:  # BGRA image150        return cv2.cvtColor(image, cv2.COLOR_BGRA2RGBA)151    return image152 153 154def raw_label_to_one_hot(raw_label, num_classes):155    """Converts a single label into one-hot vector.156 157    Args:158        raw_label: The raw label.159        num_classes: Total number of classes.160 161    Returns:162        one-hot vector of the given raw label.163    """164    one_hot = np.zeros(num_classes, dtype=np.float32)165    one_hot[raw_label] = 1.0166    return one_hot167 168 169def one_hot_to_raw_label(one_hot):170    """Converts a one-hot vector to a single value label.171 172    Args:173        one_hot: `np.ndarray`, a one-hot encoded vector.174 175    Returns:176        A single integer to represent the category.177    """178    return np.argmax(one_hot)179