RandomFlip¶

class mmocr.datasets.transforms.RandomFlip(prob=None, direction='horizontal', swap_seg_labels=None)[source]¶

Flip the image & bbox polygon.

There are 3 flip modes:

prob is float, direction is string: the image will be
direction``ly flipped with probability of ``prob . E.g., prob=0.5, direction='horizontal', then image will be horizontally flipped with probability of 0.5.

prob is float, direction is list of string: the image will
be direction[i]``ly flipped with probability of ``prob/len(direction). E.g., prob=0.5, direction=['horizontal', 'vertical'], then image will be horizontally flipped with probability of 0.25, vertically with probability of 0.25.

prob is list of float, direction is list of string:
given len(prob) == len(direction), the image will be direction[i]``ly flipped with probability of ``prob[i]. E.g., prob=[0.3, 0.5], direction=['horizontal', 'vertical'], then image will be horizontally flipped with probability of 0.3, vertically with probability of 0.5.

Required Keys:

img
gt_bboxes (optional)
gt_polygons (optional)

Modified Keys:

img
gt_bboxes (optional)
gt_polygons (optional)

Added Keys:

flip
flip_direction

Parameters

prob (float | list[float], optional) – The flipping probability. Defaults to None.
direction (str | list[str]) – The flipping direction. Options If input is a list, the length must equal prob. Each element in prob indicates the flip probability of corresponding direction. Defaults to ‘horizontal’.
swap_seg_labels (Optional[Sequence]) –

Return type

None

flip_polygons(polygons, img_shape, direction)[source]¶

Flip polygons horizontally, vertically or diagonally.

Parameters

polygons (list[numpy.ndarray) – polygons.
img_shape (tuple[int]) – Image shape (height, width)
direction (str) – Flip direction. Options are ‘horizontal’, ‘vertical’ and ‘diagonal’.

Returns

Flipped polygons.

Return type

list[numpy.ndarray]