from abc import ABCMeta, abstractmethod
import cv2
import mmcv
import numpy as np
import pycocotools.mask as maskUtils
import torch
from mmcv.ops.roi_align import roi_align
[文档]class BaseInstanceMasks(metaclass=ABCMeta):
"""Base class for instance masks."""
[文档] @abstractmethod
def rescale(self, scale, interpolation='nearest'):
"""Rescale masks as large as possible while keeping the aspect ratio.
For details can refer to `mmcv.imrescale`.
Args:
scale (tuple[int]): The maximum size (h, w) of rescaled mask.
interpolation (str): Same as :func:`mmcv.imrescale`.
Returns:
BaseInstanceMasks: The rescaled masks.
"""
[文档] @abstractmethod
def resize(self, out_shape, interpolation='nearest'):
"""Resize masks to the given out_shape.
Args:
out_shape: Target (h, w) of resized mask.
interpolation (str): See :func:`mmcv.imresize`.
Returns:
BaseInstanceMasks: The resized masks.
"""
[文档] @abstractmethod
def flip(self, flip_direction='horizontal'):
"""Flip masks alone the given direction.
Args:
flip_direction (str): Either 'horizontal' or 'vertical'.
Returns:
BaseInstanceMasks: The flipped masks.
"""
[文档] @abstractmethod
def pad(self, out_shape, pad_val):
"""Pad masks to the given size of (h, w).
Args:
out_shape (tuple[int]): Target (h, w) of padded mask.
pad_val (int): The padded value.
Returns:
BaseInstanceMasks: The padded masks.
"""
[文档] @abstractmethod
def crop(self, bbox):
"""Crop each mask by the given bbox.
Args:
bbox (ndarray): Bbox in format [x1, y1, x2, y2], shape (4, ).
Return:
BaseInstanceMasks: The cropped masks.
"""
[文档] @abstractmethod
def crop_and_resize(self,
bboxes,
out_shape,
inds,
device,
interpolation='bilinear',
binarize=True):
"""Crop and resize masks by the given bboxes.
This function is mainly used in mask targets computation.
It firstly align mask to bboxes by assigned_inds, then crop mask by the
assigned bbox and resize to the size of (mask_h, mask_w)
Args:
bboxes (Tensor): Bboxes in format [x1, y1, x2, y2], shape (N, 4)
out_shape (tuple[int]): Target (h, w) of resized mask
inds (ndarray): Indexes to assign masks to each bbox,
shape (N,) and values should be between [0, num_masks - 1].
device (str): Device of bboxes
interpolation (str): See `mmcv.imresize`
binarize (bool): if True fractional values are rounded to 0 or 1
after the resize operation. if False and unsupported an error
will be raised. Defaults to True.
Return:
BaseInstanceMasks: the cropped and resized masks.
"""
[文档] @abstractmethod
def expand(self, expanded_h, expanded_w, top, left):
"""see :class:`Expand`."""
@property
@abstractmethod
def areas(self):
"""ndarray: areas of each instance."""
[文档] @abstractmethod
def to_ndarray(self):
"""Convert masks to the format of ndarray.
Return:
ndarray: Converted masks in the format of ndarray.
"""
[文档] @abstractmethod
def to_tensor(self, dtype, device):
"""Convert masks to the format of Tensor.
Args:
dtype (str): Dtype of converted mask.
device (torch.device): Device of converted masks.
Returns:
Tensor: Converted masks in the format of Tensor.
"""
[文档] @abstractmethod
def translate(self,
out_shape,
offset,
direction='horizontal',
fill_val=0,
interpolation='bilinear'):
"""Translate the masks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
offset (int | float): The offset for translate.
direction (str): The translate direction, either "horizontal"
or "vertical".
fill_val (int | float): Border value. Default 0.
interpolation (str): Same as :func:`mmcv.imtranslate`.
Returns:
Translated masks.
"""
[文档] def shear(self,
out_shape,
magnitude,
direction='horizontal',
border_value=0,
interpolation='bilinear'):
"""Shear the masks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
magnitude (int | float): The magnitude used for shear.
direction (str): The shear direction, either "horizontal"
or "vertical".
border_value (int | tuple[int]): Value used in case of a
constant border. Default 0.
interpolation (str): Same as in :func:`mmcv.imshear`.
Returns:
ndarray: Sheared masks.
"""
[文档] @abstractmethod
def rotate(self, out_shape, angle, center=None, scale=1.0, fill_val=0):
"""Rotate the masks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
angle (int | float): Rotation angle in degrees. Positive values
mean counter-clockwise rotation.
center (tuple[float], optional): Center point (w, h) of the
rotation in source image. If not specified, the center of
the image will be used.
scale (int | float): Isotropic scale factor.
fill_val (int | float): Border value. Default 0 for masks.
Returns:
Rotated masks.
"""
[文档]class BitmapMasks(BaseInstanceMasks):
"""This class represents masks in the form of bitmaps.
Args:
masks (ndarray): ndarray of masks in shape (N, H, W), where N is
the number of objects.
height (int): height of masks
width (int): width of masks
Example:
>>> from mmdet.core.mask.structures import * # NOQA
>>> num_masks, H, W = 3, 32, 32
>>> rng = np.random.RandomState(0)
>>> masks = (rng.rand(num_masks, H, W) > 0.1).astype(np.int)
>>> self = BitmapMasks(masks, height=H, width=W)
>>> # demo crop_and_resize
>>> num_boxes = 5
>>> bboxes = np.array([[0, 0, 30, 10.0]] * num_boxes)
>>> out_shape = (14, 14)
>>> inds = torch.randint(0, len(self), size=(num_boxes,))
>>> device = 'cpu'
>>> interpolation = 'bilinear'
>>> new = self.crop_and_resize(
... bboxes, out_shape, inds, device, interpolation)
>>> assert len(new) == num_boxes
>>> assert new.height, new.width == out_shape
"""
def __init__(self, masks, height, width):
self.height = height
self.width = width
if len(masks) == 0:
self.masks = np.empty((0, self.height, self.width), dtype=np.uint8)
else:
assert isinstance(masks, (list, np.ndarray))
if isinstance(masks, list):
assert isinstance(masks[0], np.ndarray)
assert masks[0].ndim == 2 # (H, W)
else:
assert masks.ndim == 3 # (N, H, W)
self.masks = np.stack(masks).reshape(-1, height, width)
assert self.masks.shape[1] == self.height
assert self.masks.shape[2] == self.width
def __getitem__(self, index):
"""Index the BitmapMask.
Args:
index (int | ndarray): Indices in the format of integer or ndarray.
Returns:
:obj:`BitmapMasks`: Indexed bitmap masks.
"""
masks = self.masks[index].reshape(-1, self.height, self.width)
return BitmapMasks(masks, self.height, self.width)
def __iter__(self):
return iter(self.masks)
def __repr__(self):
s = self.__class__.__name__ + '('
s += f'num_masks={len(self.masks)}, '
s += f'height={self.height}, '
s += f'width={self.width})'
return s
def __len__(self):
"""Number of masks."""
return len(self.masks)
[文档] def rescale(self, scale, interpolation='nearest'):
"""See :func:`BaseInstanceMasks.rescale`."""
if len(self.masks) == 0:
new_w, new_h = mmcv.rescale_size((self.width, self.height), scale)
rescaled_masks = np.empty((0, new_h, new_w), dtype=np.uint8)
else:
rescaled_masks = np.stack([
mmcv.imrescale(mask, scale, interpolation=interpolation)
for mask in self.masks
])
height, width = rescaled_masks.shape[1:]
return BitmapMasks(rescaled_masks, height, width)
[文档] def resize(self, out_shape, interpolation='nearest'):
"""See :func:`BaseInstanceMasks.resize`."""
if len(self.masks) == 0:
resized_masks = np.empty((0, *out_shape), dtype=np.uint8)
else:
resized_masks = np.stack([
mmcv.imresize(
mask, out_shape[::-1], interpolation=interpolation)
for mask in self.masks
])
return BitmapMasks(resized_masks, *out_shape)
[文档] def flip(self, flip_direction='horizontal'):
"""See :func:`BaseInstanceMasks.flip`."""
assert flip_direction in ('horizontal', 'vertical', 'diagonal')
if len(self.masks) == 0:
flipped_masks = self.masks
else:
flipped_masks = np.stack([
mmcv.imflip(mask, direction=flip_direction)
for mask in self.masks
])
return BitmapMasks(flipped_masks, self.height, self.width)
[文档] def pad(self, out_shape, pad_val=0):
"""See :func:`BaseInstanceMasks.pad`."""
if len(self.masks) == 0:
padded_masks = np.empty((0, *out_shape), dtype=np.uint8)
else:
padded_masks = np.stack([
mmcv.impad(mask, shape=out_shape, pad_val=pad_val)
for mask in self.masks
])
return BitmapMasks(padded_masks, *out_shape)
[文档] def crop(self, bbox):
"""See :func:`BaseInstanceMasks.crop`."""
assert isinstance(bbox, np.ndarray)
assert bbox.ndim == 1
# clip the boundary
bbox = bbox.copy()
bbox[0::2] = np.clip(bbox[0::2], 0, self.width)
bbox[1::2] = np.clip(bbox[1::2], 0, self.height)
x1, y1, x2, y2 = bbox
w = np.maximum(x2 - x1, 1)
h = np.maximum(y2 - y1, 1)
if len(self.masks) == 0:
cropped_masks = np.empty((0, h, w), dtype=np.uint8)
else:
cropped_masks = self.masks[:, y1:y1 + h, x1:x1 + w]
return BitmapMasks(cropped_masks, h, w)
[文档] def crop_and_resize(self,
bboxes,
out_shape,
inds,
device='cpu',
interpolation='bilinear',
binarize=True):
"""See :func:`BaseInstanceMasks.crop_and_resize`."""
if len(self.masks) == 0:
empty_masks = np.empty((0, *out_shape), dtype=np.uint8)
return BitmapMasks(empty_masks, *out_shape)
# convert bboxes to tensor
if isinstance(bboxes, np.ndarray):
bboxes = torch.from_numpy(bboxes).to(device=device)
if isinstance(inds, np.ndarray):
inds = torch.from_numpy(inds).to(device=device)
num_bbox = bboxes.shape[0]
fake_inds = torch.arange(
num_bbox, device=device).to(dtype=bboxes.dtype)[:, None]
rois = torch.cat([fake_inds, bboxes], dim=1) # Nx5
rois = rois.to(device=device)
if num_bbox > 0:
gt_masks_th = torch.from_numpy(self.masks).to(device).index_select(
0, inds).to(dtype=rois.dtype)
targets = roi_align(gt_masks_th[:, None, :, :], rois, out_shape,
1.0, 0, 'avg', True).squeeze(1)
if binarize:
resized_masks = (targets >= 0.5).cpu().numpy()
else:
resized_masks = targets.cpu().numpy()
else:
resized_masks = []
return BitmapMasks(resized_masks, *out_shape)
[文档] def expand(self, expanded_h, expanded_w, top, left):
"""See :func:`BaseInstanceMasks.expand`."""
if len(self.masks) == 0:
expanded_mask = np.empty((0, expanded_h, expanded_w),
dtype=np.uint8)
else:
expanded_mask = np.zeros((len(self), expanded_h, expanded_w),
dtype=np.uint8)
expanded_mask[:, top:top + self.height,
left:left + self.width] = self.masks
return BitmapMasks(expanded_mask, expanded_h, expanded_w)
[文档] def translate(self,
out_shape,
offset,
direction='horizontal',
fill_val=0,
interpolation='bilinear'):
"""Translate the BitmapMasks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
offset (int | float): The offset for translate.
direction (str): The translate direction, either "horizontal"
or "vertical".
fill_val (int | float): Border value. Default 0 for masks.
interpolation (str): Same as :func:`mmcv.imtranslate`.
Returns:
BitmapMasks: Translated BitmapMasks.
Example:
>>> from mmdet.core.mask.structures import BitmapMasks
>>> self = BitmapMasks.random(dtype=np.uint8)
>>> out_shape = (32, 32)
>>> offset = 4
>>> direction = 'horizontal'
>>> fill_val = 0
>>> interpolation = 'bilinear'
>>> # Note, There seem to be issues when:
>>> # * out_shape is different than self's shape
>>> # * the mask dtype is not supported by cv2.AffineWarp
>>> new = self.translate(out_shape, offset, direction, fill_val,
>>> interpolation)
>>> assert len(new) == len(self)
>>> assert new.height, new.width == out_shape
"""
if len(self.masks) == 0:
translated_masks = np.empty((0, *out_shape), dtype=np.uint8)
else:
translated_masks = mmcv.imtranslate(
self.masks.transpose((1, 2, 0)),
offset,
direction,
border_value=fill_val,
interpolation=interpolation)
if translated_masks.ndim == 2:
translated_masks = translated_masks[:, :, None]
translated_masks = translated_masks.transpose(
(2, 0, 1)).astype(self.masks.dtype)
return BitmapMasks(translated_masks, *out_shape)
[文档] def shear(self,
out_shape,
magnitude,
direction='horizontal',
border_value=0,
interpolation='bilinear'):
"""Shear the BitmapMasks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
magnitude (int | float): The magnitude used for shear.
direction (str): The shear direction, either "horizontal"
or "vertical".
border_value (int | tuple[int]): Value used in case of a
constant border.
interpolation (str): Same as in :func:`mmcv.imshear`.
Returns:
BitmapMasks: The sheared masks.
"""
if len(self.masks) == 0:
sheared_masks = np.empty((0, *out_shape), dtype=np.uint8)
else:
sheared_masks = mmcv.imshear(
self.masks.transpose((1, 2, 0)),
magnitude,
direction,
border_value=border_value,
interpolation=interpolation)
if sheared_masks.ndim == 2:
sheared_masks = sheared_masks[:, :, None]
sheared_masks = sheared_masks.transpose(
(2, 0, 1)).astype(self.masks.dtype)
return BitmapMasks(sheared_masks, *out_shape)
[文档] def rotate(self, out_shape, angle, center=None, scale=1.0, fill_val=0):
"""Rotate the BitmapMasks.
Args:
out_shape (tuple[int]): Shape for output mask, format (h, w).
angle (int | float): Rotation angle in degrees. Positive values
mean counter-clockwise rotation.
center (tuple[float], optional): Center point (w, h) of the
rotation in source image. If not specified, the center of
the image will be used.
scale (int | float): Isotropic scale factor.
fill_val (int | float): Border value. Default 0 for masks.
Returns:
BitmapMasks: Rotated BitmapMasks.
"""
if len(self.masks) == 0:
rotated_masks = np.empty((0, *out_shape), dtype=self.masks.dtype)
else:
rotated_masks = mmcv.imrotate(
self.masks.transpose((1, 2, 0)),
angle,
center=center,
scale=scale,
border_value=fill_val)
if rotated_masks.ndim == 2:
# case when only one mask, (h, w)
rotated_masks = rotated_masks[:, :, None] # (h, w, 1)
rotated_masks = rotated_masks.transpose(
(2, 0, 1)).astype(self.masks.dtype)
return BitmapMasks(rotated_masks, *out_shape)
@property
def areas(self):
"""See :py:attr:`BaseInstanceMasks.areas`."""
return self.masks.sum((1, 2))
[文档] def to_ndarray(self):
"""See :func:`BaseInstanceMasks.to_ndarray`."""
return self.masks
[文档] def to_tensor(self, dtype, device):
"""See :func:`BaseInstanceMasks.to_tensor`."""
return torch.tensor(self.masks, dtype=dtype, device=device)
[文档] @classmethod
def random(cls,
num_masks=3,
height=32,
width=32,
dtype=np.uint8,
rng=None):
"""Generate random bitmap masks for demo / testing purposes.
Example:
>>> from mmdet.core.mask.structures import BitmapMasks
>>> self = BitmapMasks.random()
>>> print('self = {}'.format(self))
self = BitmapMasks(num_masks=3, height=32, width=32)
"""
from mmdet.utils.util_random import ensure_rng
rng = ensure_rng(rng)
masks = (rng.rand(num_masks, height, width) > 0.1).astype(dtype)
self = cls(masks, height=height, width=width)
return self
[文档]class PolygonMasks(BaseInstanceMasks):
"""This class represents masks in the form of polygons.
Polygons is a list of three levels. The first level of the list
corresponds to objects, the second level to the polys that compose the
object, the third level to the poly coordinates
Args:
masks (list[list[ndarray]]): The first level of the list
corresponds to objects, the second level to the polys that
compose the object, the third level to the poly coordinates
height (int): height of masks
width (int): width of masks
Example:
>>> from mmdet.core.mask.structures import * # NOQA
>>> masks = [
>>> [ np.array([0, 0, 10, 0, 10, 10., 0, 10, 0, 0]) ]
>>> ]
>>> height, width = 16, 16
>>> self = PolygonMasks(masks, height, width)
>>> # demo translate
>>> new = self.translate((16, 16), 4., direction='horizontal')
>>> assert np.all(new.masks[0][0][1::2] == masks[0][0][1::2])
>>> assert np.all(new.masks[0][0][0::2] == masks[0][0][0::2] + 4)
>>> # demo crop_and_resize
>>> num_boxes = 3
>>> bboxes = np.array([[0, 0, 30, 10.0]] * num_boxes)
>>> out_shape = (16, 16)
>>> inds = torch.randint(0, len(self), size=(num_boxes,))
>>> device = 'cpu'
>>> interpolation = 'bilinear'
>>> new = self.crop_and_resize(
... bboxes, out_shape, inds, device, interpolation)
>>> assert len(new) == num_boxes
>>> assert new.height, new.width == out_shape
"""
def __init__(self, masks, height, width):
assert isinstance(masks, list)
if len(masks) > 0:
assert isinstance(masks[0], list)
assert isinstance(masks[0][0], np.ndarray)
self.height = height
self.width = width
self.masks = masks
def __getitem__(self, index):
"""Index the polygon masks.
Args:
index (ndarray | List): The indices.
Returns:
:obj:`PolygonMasks`: The indexed polygon masks.
"""
if isinstance(index, np.ndarray):
index = index.tolist()
if isinstance(index, list):
masks = [self.masks[i] for i in index]
else:
try:
masks = self.masks[index]
except Exception:
raise ValueError(
f'Unsupported input of type {type(index)} for indexing!')
if len(masks) and isinstance(masks[0], np.ndarray):
masks = [masks] # ensure a list of three levels
return PolygonMasks(masks, self.height, self.width)
def __iter__(self):
return iter(self.masks)
def __repr__(self):
s = self.__class__.__name__ + '('
s += f'num_masks={len(self.masks)}, '
s += f'height={self.height}, '
s += f'width={self.width})'
return s
def __len__(self):
"""Number of masks."""
return len(self.masks)
[文档] def rescale(self, scale, interpolation=None):
"""see :func:`BaseInstanceMasks.rescale`"""
new_w, new_h = mmcv.rescale_size((self.width, self.height), scale)
if len(self.masks) == 0:
rescaled_masks = PolygonMasks([], new_h, new_w)
else:
rescaled_masks = self.resize((new_h, new_w))
return rescaled_masks
[文档] def resize(self, out_shape, interpolation=None):
"""see :func:`BaseInstanceMasks.resize`"""
if len(self.masks) == 0:
resized_masks = PolygonMasks([], *out_shape)
else:
h_scale = out_shape[0] / self.height
w_scale = out_shape[1] / self.width
resized_masks = []
for poly_per_obj in self.masks:
resized_poly = []
for p in poly_per_obj:
p = p.copy()
p[0::2] *= w_scale
p[1::2] *= h_scale
resized_poly.append(p)
resized_masks.append(resized_poly)
resized_masks = PolygonMasks(resized_masks, *out_shape)
return resized_masks
[文档] def flip(self, flip_direction='horizontal'):
"""see :func:`BaseInstanceMasks.flip`"""
assert flip_direction in ('horizontal', 'vertical', 'diagonal')
if len(self.masks) == 0:
flipped_masks = PolygonMasks([], self.height, self.width)
else:
flipped_masks = []
for poly_per_obj in self.masks:
flipped_poly_per_obj = []
for p in poly_per_obj:
p = p.copy()
if flip_direction == 'horizontal':
p[0::2] = self.width - p[0::2]
elif flip_direction == 'vertical':
p[1::2] = self.height - p[1::2]
else:
p[0::2] = self.width - p[0::2]
p[1::2] = self.height - p[1::2]
flipped_poly_per_obj.append(p)
flipped_masks.append(flipped_poly_per_obj)
flipped_masks = PolygonMasks(flipped_masks, self.height,
self.width)
return flipped_masks
[文档] def crop(self, bbox):
"""see :func:`BaseInstanceMasks.crop`"""
assert isinstance(bbox, np.ndarray)
assert bbox.ndim == 1
# clip the boundary
bbox = bbox.copy()
bbox[0::2] = np.clip(bbox[0::2], 0, self.width)
bbox[1::2] = np.clip(bbox[1::2], 0, self.height)
x1, y1, x2, y2 = bbox
w = np.maximum(x2 - x1, 1)
h = np.maximum(y2 - y1, 1)
if len(self.masks) == 0:
cropped_masks = PolygonMasks([], h, w)
else:
cropped_masks = []
for poly_per_obj in self.masks:
cropped_poly_per_obj = []
for p in poly_per_obj:
# pycocotools will clip the boundary
p = p.copy()
p[0::2] -= bbox[0]
p[1::2] -= bbox[1]
cropped_poly_per_obj.append(p)
cropped_masks.append(cropped_poly_per_obj)
cropped_masks = PolygonMasks(cropped_masks, h, w)
return cropped_masks
[文档] def pad(self, out_shape, pad_val=0):
"""padding has no effect on polygons`"""
return PolygonMasks(self.masks, *out_shape)
[文档] def expand(self, *args, **kwargs):
"""TODO: Add expand for polygon"""
raise NotImplementedError
[文档] def crop_and_resize(self,
bboxes,
out_shape,
inds,
device='cpu',
interpolation='bilinear',
binarize=True):
"""see :func:`BaseInstanceMasks.crop_and_resize`"""
out_h, out_w = out_shape
if len(self.masks) == 0:
return PolygonMasks([], out_h, out_w)
if not binarize:
raise ValueError('Polygons are always binary, '
'setting binarize=False is unsupported')
resized_masks = []
for i in range(len(bboxes)):
mask = self.masks[inds[i]]
bbox = bboxes[i, :]
x1, y1, x2, y2 = bbox
w = np.maximum(x2 - x1, 1)
h = np.maximum(y2 - y1, 1)
h_scale = out_h / max(h, 0.1) # avoid too large scale
w_scale = out_w / max(w, 0.1)
resized_mask = []
for p in mask:
p = p.copy()
# crop
# pycocotools will clip the boundary
p[0::2] -= bbox[0]
p[1::2] -= bbox[1]
# resize
p[0::2] *= w_scale
p[1::2] *= h_scale
resized_mask.append(p)
resized_masks.append(resized_mask)
return PolygonMasks(resized_masks, *out_shape)
[文档] def translate(self,
out_shape,
offset,
direction='horizontal',
fill_val=None,
interpolation=None):
"""Translate the PolygonMasks.
Example:
>>> self = PolygonMasks.random(dtype=np.int)
>>> out_shape = (self.height, self.width)
>>> new = self.translate(out_shape, 4., direction='horizontal')
>>> assert np.all(new.masks[0][0][1::2] == self.masks[0][0][1::2])
>>> assert np.all(new.masks[0][0][0::2] == self.masks[0][0][0::2] + 4) # noqa: E501
"""
assert fill_val is None or fill_val == 0, 'Here fill_val is not '\
f'used, and defaultly should be None or 0. got {fill_val}.'
if len(self.masks) == 0:
translated_masks = PolygonMasks([], *out_shape)
else:
translated_masks = []
for poly_per_obj in self.masks:
translated_poly_per_obj = []
for p in poly_per_obj:
p = p.copy()
if direction == 'horizontal':
p[0::2] = np.clip(p[0::2] + offset, 0, out_shape[1])
elif direction == 'vertical':
p[1::2] = np.clip(p[1::2] + offset, 0, out_shape[0])
translated_poly_per_obj.append(p)
translated_masks.append(translated_poly_per_obj)
translated_masks = PolygonMasks(translated_masks, *out_shape)
return translated_masks
[文档] def shear(self,
out_shape,
magnitude,
direction='horizontal',
border_value=0,
interpolation='bilinear'):
"""See :func:`BaseInstanceMasks.shear`."""
if len(self.masks) == 0:
sheared_masks = PolygonMasks([], *out_shape)
else:
sheared_masks = []
if direction == 'horizontal':
shear_matrix = np.stack([[1, magnitude],
[0, 1]]).astype(np.float32)
elif direction == 'vertical':
shear_matrix = np.stack([[1, 0], [magnitude,
1]]).astype(np.float32)
for poly_per_obj in self.masks:
sheared_poly = []
for p in poly_per_obj:
p = np.stack([p[0::2], p[1::2]], axis=0) # [2, n]
new_coords = np.matmul(shear_matrix, p) # [2, n]
new_coords[0, :] = np.clip(new_coords[0, :], 0,
out_shape[1])
new_coords[1, :] = np.clip(new_coords[1, :], 0,
out_shape[0])
sheared_poly.append(
new_coords.transpose((1, 0)).reshape(-1))
sheared_masks.append(sheared_poly)
sheared_masks = PolygonMasks(sheared_masks, *out_shape)
return sheared_masks
[文档] def rotate(self, out_shape, angle, center=None, scale=1.0, fill_val=0):
"""See :func:`BaseInstanceMasks.rotate`."""
if len(self.masks) == 0:
rotated_masks = PolygonMasks([], *out_shape)
else:
rotated_masks = []
rotate_matrix = cv2.getRotationMatrix2D(center, -angle, scale)
for poly_per_obj in self.masks:
rotated_poly = []
for p in poly_per_obj:
p = p.copy()
coords = np.stack([p[0::2], p[1::2]], axis=1) # [n, 2]
# pad 1 to convert from format [x, y] to homogeneous
# coordinates format [x, y, 1]
coords = np.concatenate(
(coords, np.ones((coords.shape[0], 1), coords.dtype)),
axis=1) # [n, 3]
rotated_coords = np.matmul(
rotate_matrix[None, :, :],
coords[:, :, None])[..., 0] # [n, 2, 1] -> [n, 2]
rotated_coords[:, 0] = np.clip(rotated_coords[:, 0], 0,
out_shape[1])
rotated_coords[:, 1] = np.clip(rotated_coords[:, 1], 0,
out_shape[0])
rotated_poly.append(rotated_coords.reshape(-1))
rotated_masks.append(rotated_poly)
rotated_masks = PolygonMasks(rotated_masks, *out_shape)
return rotated_masks
[文档] def to_bitmap(self):
"""convert polygon masks to bitmap masks."""
bitmap_masks = self.to_ndarray()
return BitmapMasks(bitmap_masks, self.height, self.width)
@property
def areas(self):
"""Compute areas of masks.
This func is modified from `detectron2
<https://github.com/facebookresearch/detectron2/blob/ffff8acc35ea88ad1cb1806ab0f00b4c1c5dbfd9/detectron2/structures/masks.py#L387>`_.
The function only works with Polygons using the shoelace formula.
Return:
ndarray: areas of each instance
""" # noqa: W501
area = []
for polygons_per_obj in self.masks:
area_per_obj = 0
for p in polygons_per_obj:
area_per_obj += self._polygon_area(p[0::2], p[1::2])
area.append(area_per_obj)
return np.asarray(area)
def _polygon_area(self, x, y):
"""Compute the area of a component of a polygon.
Using the shoelace formula:
https://stackoverflow.com/questions/24467972/calculate-area-of-polygon-given-x-y-coordinates
Args:
x (ndarray): x coordinates of the component
y (ndarray): y coordinates of the component
Return:
float: the are of the component
""" # noqa: 501
return 0.5 * np.abs(
np.dot(x, np.roll(y, 1)) - np.dot(y, np.roll(x, 1)))
[文档] def to_ndarray(self):
"""Convert masks to the format of ndarray."""
if len(self.masks) == 0:
return np.empty((0, self.height, self.width), dtype=np.uint8)
bitmap_masks = []
for poly_per_obj in self.masks:
bitmap_masks.append(
polygon_to_bitmap(poly_per_obj, self.height, self.width))
return np.stack(bitmap_masks)
[文档] def to_tensor(self, dtype, device):
"""See :func:`BaseInstanceMasks.to_tensor`."""
if len(self.masks) == 0:
return torch.empty((0, self.height, self.width),
dtype=dtype,
device=device)
ndarray_masks = self.to_ndarray()
return torch.tensor(ndarray_masks, dtype=dtype, device=device)
[文档] @classmethod
def random(cls,
num_masks=3,
height=32,
width=32,
n_verts=5,
dtype=np.float32,
rng=None):
"""Generate random polygon masks for demo / testing purposes.
Adapted from [1]_
References:
.. [1] https://gitlab.kitware.com/computer-vision/kwimage/-/blob/928cae35ca8/kwimage/structs/polygon.py#L379 # noqa: E501
Example:
>>> from mmdet.core.mask.structures import PolygonMasks
>>> self = PolygonMasks.random()
>>> print('self = {}'.format(self))
"""
from mmdet.utils.util_random import ensure_rng
rng = ensure_rng(rng)
def _gen_polygon(n, irregularity, spikeyness):
"""Creates the polygon by sampling points on a circle around the
centre. Random noise is added by varying the angular spacing
between sequential points, and by varying the radial distance of
each point from the centre.
Based on original code by Mike Ounsworth
Args:
n (int): number of vertices
irregularity (float): [0,1] indicating how much variance there
is in the angular spacing of vertices. [0,1] will map to
[0, 2pi/numberOfVerts]
spikeyness (float): [0,1] indicating how much variance there is
in each vertex from the circle of radius aveRadius. [0,1]
will map to [0, aveRadius]
Returns:
a list of vertices, in CCW order.
"""
from scipy.stats import truncnorm
# Generate around the unit circle
cx, cy = (0.0, 0.0)
radius = 1
tau = np.pi * 2
irregularity = np.clip(irregularity, 0, 1) * 2 * np.pi / n
spikeyness = np.clip(spikeyness, 1e-9, 1)
# generate n angle steps
lower = (tau / n) - irregularity
upper = (tau / n) + irregularity
angle_steps = rng.uniform(lower, upper, n)
# normalize the steps so that point 0 and point n+1 are the same
k = angle_steps.sum() / (2 * np.pi)
angles = (angle_steps / k).cumsum() + rng.uniform(0, tau)
# Convert high and low values to be wrt the standard normal range
# https://docs.scipy.org/doc/scipy/reference/generated/scipy.stats.truncnorm.html
low = 0
high = 2 * radius
mean = radius
std = spikeyness
a = (low - mean) / std
b = (high - mean) / std
tnorm = truncnorm(a=a, b=b, loc=mean, scale=std)
# now generate the points
radii = tnorm.rvs(n, random_state=rng)
x_pts = cx + radii * np.cos(angles)
y_pts = cy + radii * np.sin(angles)
points = np.hstack([x_pts[:, None], y_pts[:, None]])
# Scale to 0-1 space
points = points - points.min(axis=0)
points = points / points.max(axis=0)
# Randomly place within 0-1 space
points = points * (rng.rand() * .8 + .2)
min_pt = points.min(axis=0)
max_pt = points.max(axis=0)
high = (1 - max_pt)
low = (0 - min_pt)
offset = (rng.rand(2) * (high - low)) + low
points = points + offset
return points
def _order_vertices(verts):
"""
References:
https://stackoverflow.com/questions/1709283/how-can-i-sort-a-coordinate-list-for-a-rectangle-counterclockwise
"""
mlat = verts.T[0].sum() / len(verts)
mlng = verts.T[1].sum() / len(verts)
tau = np.pi * 2
angle = (np.arctan2(mlat - verts.T[0], verts.T[1] - mlng) +
tau) % tau
sortx = angle.argsort()
verts = verts.take(sortx, axis=0)
return verts
# Generate a random exterior for each requested mask
masks = []
for _ in range(num_masks):
exterior = _order_vertices(_gen_polygon(n_verts, 0.9, 0.9))
exterior = (exterior * [(width, height)]).astype(dtype)
masks.append([exterior.ravel()])
self = cls(masks, height, width)
return self
def polygon_to_bitmap(polygons, height, width):
"""Convert masks from the form of polygons to bitmaps.
Args:
polygons (list[ndarray]): masks in polygon representation
height (int): mask height
width (int): mask width
Return:
ndarray: the converted masks in bitmap representation
"""
rles = maskUtils.frPyObjects(polygons, height, width)
rle = maskUtils.merge(rles)
bitmap_mask = maskUtils.decode(rle).astype(np.bool)
return bitmap_mask