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# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# The code is based on:
# https://github.com/dvlab-research/GridMask/blob/master/detection_grid/maskrcnn_benchmark/data/transforms/grid.py
from __future__ import absolute_import
from __future__ import print_function
from __future__ import division
import numpy as np
from PIL import Image
class Gridmask(object):
def __init__(self,
use_h=True,
use_w=True,
rotate=1,
offset=False,
ratio=0.5,
mode=1,
prob=0.7,
upper_iter=360000):
super(Gridmask, self).__init__()
self.use_h = use_h
self.use_w = use_w
self.rotate = rotate
self.offset = offset
self.ratio = ratio
self.mode = mode
self.prob = prob
self.st_prob = prob
self.upper_iter = upper_iter
def __call__(self, x, curr_iter):
self.prob = self.st_prob * min(1, 1.0 * curr_iter / self.upper_iter)
if np.random.rand() > self.prob:
return x
h, w, _ = x.shape
hh = int(1.5 * h)
ww = int(1.5 * w)
d = np.random.randint(2, h)
self.l = min(max(int(d * self.ratio + 0.5), 1), d - 1)
mask = np.ones((hh, ww), np.float32)
st_h = np.random.randint(d)
st_w = np.random.randint(d)
if self.use_h:
for i in range(hh // d):
s = d * i + st_h
t = min(s + self.l, hh)
mask[s:t, :] *= 0
if self.use_w:
for i in range(ww // d):
s = d * i + st_w
t = min(s + self.l, ww)
mask[:, s:t] *= 0
r = np.random.randint(self.rotate)
mask = Image.fromarray(np.uint8(mask))
mask = mask.rotate(r)
mask = np.asarray(mask)
mask = mask[(hh - h) // 2:(hh - h) // 2 + h, (ww - w) // 2:(ww - w) // 2
+ w].astype(np.float32)
if self.mode == 1:
mask = 1 - mask
mask = np.expand_dims(mask, axis=-1)
if self.offset:
offset = (2 * (np.random.rand(h, w) - 0.5)).astype(np.float32)
x = (x * mask + offset * (1 - mask)).astype(x.dtype)
else:
x = (x * mask).astype(x.dtype)
return x