EasyCV/easycv/datasets/ocr/pipelines/det_transform.py

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# Modified from https://github.com/PaddlePaddle/PaddleOCR/tree/release/2.6/ppocr/data/imaug
import math
import random
import sys
import cv2
import imgaug
import imgaug.augmenters as iaa
import numpy as np
import pyclipper
from shapely.geometry import Polygon
from easycv.datasets.registry import PIPELINES
from easycv.framework.errors import RuntimeError
class AugmenterBuilder(object):
def __init__(self):
pass
def build(self, args, root=True):
if args is None or len(args) == 0:
return None
elif isinstance(args, list):
if root:
sequence = [self.build(value, root=False) for value in args]
return iaa.Sequential(sequence)
else:
return getattr(
iaa,
args[0])(*[self.to_tuple_if_list(a) for a in args[1:]])
elif isinstance(args, dict):
cls = getattr(iaa, args['type'])
return cls(
**
{k: self.to_tuple_if_list(v)
for k, v in args['args'].items()})
else:
raise RuntimeError('unknown augmenter arg: ' + str(args))
def to_tuple_if_list(self, obj):
if isinstance(obj, list):
return tuple(obj)
return obj
@PIPELINES.register_module()
class IaaAugment():
def __init__(self, augmenter_args=None, **kwargs):
if augmenter_args is None:
augmenter_args = [{
'type': 'Fliplr',
'args': {
'p': 0.5
}
}, {
'type': 'Affine',
'args': {
'rotate': [-10, 10]
}
}, {
'type': 'Resize',
'args': {
'size': [0.5, 3]
}
}]
self.augmenter = AugmenterBuilder().build(augmenter_args)
def __call__(self, data):
image = data['img']
shape = image.shape
if self.augmenter:
aug = self.augmenter.to_deterministic()
data['img'] = aug.augment_image(image)
data = self.may_augment_annotation(aug, data, shape)
return data
def may_augment_annotation(self, aug, data, shape):
if aug is None:
return data
line_polys = []
for poly in data['polys']:
new_poly = self.may_augment_poly(aug, shape, poly)
line_polys.append(new_poly)
data['polys'] = np.array(line_polys)
return data
def may_augment_poly(self, aug, img_shape, poly):
keypoints = [imgaug.Keypoint(p[0], p[1]) for p in poly]
keypoints = aug.augment_keypoints(
[imgaug.KeypointsOnImage(keypoints, shape=img_shape)])[0].keypoints
poly = [(p.x, p.y) for p in keypoints]
return poly
def is_poly_in_rect(poly, x, y, w, h):
poly = np.array(poly)
if poly[:, 0].min() < x or poly[:, 0].max() > x + w:
return False
if poly[:, 1].min() < y or poly[:, 1].max() > y + h:
return False
return True
def is_poly_outside_rect(poly, x, y, w, h):
poly = np.array(poly)
if poly[:, 0].max() < x or poly[:, 0].min() > x + w:
return True
if poly[:, 1].max() < y or poly[:, 1].min() > y + h:
return True
return False
def split_regions(axis):
regions = []
min_axis = 0
for i in range(1, axis.shape[0]):
if axis[i] != axis[i - 1] + 1:
region = axis[min_axis:i]
min_axis = i
regions.append(region)
return regions
def random_select(axis, max_size):
xx = np.random.choice(axis, size=2)
xmin = np.min(xx)
xmax = np.max(xx)
xmin = np.clip(xmin, 0, max_size - 1)
xmax = np.clip(xmax, 0, max_size - 1)
return xmin, xmax
def region_wise_random_select(regions, max_size):
selected_index = list(np.random.choice(len(regions), 2))
selected_values = []
for index in selected_index:
axis = regions[index]
xx = int(np.random.choice(axis, size=1))
selected_values.append(xx)
xmin = min(selected_values)
xmax = max(selected_values)
return xmin, xmax
def crop_area(im, text_polys, min_crop_side_ratio, max_tries):
h, w, _ = im.shape
h_array = np.zeros(h, dtype=np.int32)
w_array = np.zeros(w, dtype=np.int32)
for points in text_polys:
points = np.round(points, decimals=0).astype(np.int32)
minx = np.min(points[:, 0])
maxx = np.max(points[:, 0])
w_array[minx:maxx] = 1
miny = np.min(points[:, 1])
maxy = np.max(points[:, 1])
h_array[miny:maxy] = 1
# ensure the cropped area not across a text
h_axis = np.where(h_array == 0)[0]
w_axis = np.where(w_array == 0)[0]
if len(h_axis) == 0 or len(w_axis) == 0:
return 0, 0, w, h
h_regions = split_regions(h_axis)
w_regions = split_regions(w_axis)
for i in range(max_tries):
if len(w_regions) > 1:
xmin, xmax = region_wise_random_select(w_regions, w)
else:
xmin, xmax = random_select(w_axis, w)
if len(h_regions) > 1:
ymin, ymax = region_wise_random_select(h_regions, h)
else:
ymin, ymax = random_select(h_axis, h)
if xmax - xmin < min_crop_side_ratio * w or ymax - ymin < min_crop_side_ratio * h:
# area too small
continue
num_poly_in_rect = 0
for poly in text_polys:
if not is_poly_outside_rect(poly, xmin, ymin, xmax - xmin,
ymax - ymin):
num_poly_in_rect += 1
break
if num_poly_in_rect > 0:
return xmin, ymin, xmax - xmin, ymax - ymin
return 0, 0, w, h
@PIPELINES.register_module()
class EastRandomCropData(object):
"""
crop method for ocr detection, ensure the cropped area not across a text,
and keep min side larger than min_crop_side_ratio
"""
def __init__(self,
size=(640, 640),
max_tries=10,
min_crop_side_ratio=0.1,
keep_ratio=True,
**kwargs):
"""
Args:
size (tuple, optional): target size to crop. Defaults to (640, 640).
max_tries (int, optional): max try times. Defaults to 10.
min_crop_side_ratio (float, optional): min side should larger than this. Defaults to 0.1.
keep_ratio (bool, optional): whether to keep ratio. Defaults to True.
"""
self.size = size
self.max_tries = max_tries
self.min_crop_side_ratio = min_crop_side_ratio
self.keep_ratio = keep_ratio
def __call__(self, data):
img = data['img']
text_polys = data['polys']
ignore_tags = data['ignore_tags']
texts = data['texts']
all_care_polys = [
text_polys[i] for i, tag in enumerate(ignore_tags) if not tag
]
# compute crop area
crop_x, crop_y, crop_w, crop_h = crop_area(img, all_care_polys,
self.min_crop_side_ratio,
self.max_tries)
# crop img
scale_w = self.size[0] / crop_w
scale_h = self.size[1] / crop_h
scale = min(scale_w, scale_h)
h = int(crop_h * scale)
w = int(crop_w * scale)
if self.keep_ratio:
padimg = np.zeros((self.size[1], self.size[0], img.shape[2]),
img.dtype)
padimg[:h, :w] = cv2.resize(
img[crop_y:crop_y + crop_h, crop_x:crop_x + crop_w], (w, h))
img = padimg
else:
img = cv2.resize(
img[crop_y:crop_y + crop_h, crop_x:crop_x + crop_w],
tuple(self.size))
# crop text
text_polys_crop = []
ignore_tags_crop = []
texts_crop = []
for poly, text, tag in zip(text_polys, texts, ignore_tags):
poly = ((poly - (crop_x, crop_y)) * scale).tolist()
if not is_poly_outside_rect(poly, 0, 0, w, h):
text_polys_crop.append(poly)
ignore_tags_crop.append(tag)
texts_crop.append(text)
data['img'] = img
data['polys'] = np.array(text_polys_crop)
data['ignore_tags'] = ignore_tags_crop
data['texts'] = texts_crop
return data
@PIPELINES.register_module()
class MakeBorderMap(object):
"""
Making Border binary mask from DBNet algorithm
"""
def __init__(self,
shrink_ratio=0.4,
thresh_min=0.3,
thresh_max=0.7,
**kwargs):
self.shrink_ratio = shrink_ratio
self.thresh_min = thresh_min
self.thresh_max = thresh_max
def __call__(self, data):
img = data['img']
text_polys = data['polys']
ignore_tags = data['ignore_tags']
canvas = np.zeros(img.shape[:2], dtype=np.float32)
mask = np.zeros(img.shape[:2], dtype=np.float32)
for i in range(len(text_polys)):
if ignore_tags[i]:
continue
self.draw_border_map(text_polys[i], canvas, mask=mask)
canvas = canvas * (self.thresh_max - self.thresh_min) + self.thresh_min
data['threshold_map'] = canvas
data['threshold_mask'] = mask
return data
def draw_border_map(self, polygon, canvas, mask):
polygon = np.array(polygon)
assert polygon.ndim == 2
assert polygon.shape[1] == 2
polygon_shape = Polygon(polygon)
if polygon_shape.area <= 0:
return
distance = polygon_shape.area * (
1 - np.power(self.shrink_ratio, 2)) / polygon_shape.length
subject = [tuple(l) for l in polygon]
padding = pyclipper.PyclipperOffset()
padding.AddPath(subject, pyclipper.JT_ROUND,
pyclipper.ET_CLOSEDPOLYGON)
padded_polygon = np.array(padding.Execute(distance)[0])
cv2.fillPoly(mask, [padded_polygon.astype(np.int32)], 1.0)
xmin = padded_polygon[:, 0].min()
xmax = padded_polygon[:, 0].max()
ymin = padded_polygon[:, 1].min()
ymax = padded_polygon[:, 1].max()
width = xmax - xmin + 1
height = ymax - ymin + 1
polygon[:, 0] = polygon[:, 0] - xmin
polygon[:, 1] = polygon[:, 1] - ymin
xs = np.broadcast_to(
np.linspace(0, width - 1, num=width).reshape(1, width),
(height, width))
ys = np.broadcast_to(
np.linspace(0, height - 1, num=height).reshape(height, 1),
(height, width))
distance_map = np.zeros((polygon.shape[0], height, width),
dtype=np.float32)
for i in range(polygon.shape[0]):
j = (i + 1) % polygon.shape[0]
absolute_distance = self._distance(xs, ys, polygon[i], polygon[j])
distance_map[i] = np.clip(absolute_distance / distance, 0, 1)
distance_map = distance_map.min(axis=0)
xmin_valid = min(max(0, xmin), canvas.shape[1] - 1)
xmax_valid = min(max(0, xmax), canvas.shape[1] - 1)
ymin_valid = min(max(0, ymin), canvas.shape[0] - 1)
ymax_valid = min(max(0, ymax), canvas.shape[0] - 1)
canvas[ymin_valid:ymax_valid + 1, xmin_valid:xmax_valid + 1] = np.fmax(
1 - distance_map[ymin_valid - ymin:ymax_valid - ymax + height,
xmin_valid - xmin:xmax_valid - xmax + width],
canvas[ymin_valid:ymax_valid + 1, xmin_valid:xmax_valid + 1])
def _distance(self, xs, ys, point_1, point_2):
'''
compute the distance from point to a line
ys: coordinates in the first axis
xs: coordinates in the second axis
point_1, point_2: (x, y), the end of the line
'''
height, width = xs.shape[:2]
square_distance_1 = np.square(xs - point_1[0]) + np.square(ys -
point_1[1])
square_distance_2 = np.square(xs - point_2[0]) + np.square(ys -
point_2[1])
square_distance = np.square(point_1[0] -
point_2[0]) + np.square(point_1[1] -
point_2[1])
cosin = (square_distance - square_distance_1 - square_distance_2) / (
2 * np.sqrt(square_distance_1 * square_distance_2))
square_sin = 1 - np.square(cosin)
square_sin = np.nan_to_num(square_sin)
result = np.sqrt(square_distance_1 * square_distance_2 * square_sin /
square_distance)
result[cosin < 0] = np.sqrt(
np.fmin(square_distance_1, square_distance_2))[cosin < 0]
# self.extend_line(point_1, point_2, result)
return result
def extend_line(self, point_1, point_2, result, shrink_ratio):
ex_point_1 = (int(
round(point_1[0] + (point_1[0] - point_2[0]) *
(1 + shrink_ratio))),
int(
round(point_1[1] + (point_1[1] - point_2[1]) *
(1 + shrink_ratio))))
cv2.line(
result,
tuple(ex_point_1),
tuple(point_1),
4096.0,
1,
lineType=cv2.LINE_AA,
shift=0)
ex_point_2 = (int(
round(point_2[0] + (point_2[0] - point_1[0]) *
(1 + shrink_ratio))),
int(
round(point_2[1] + (point_2[1] - point_1[1]) *
(1 + shrink_ratio))))
cv2.line(
result,
tuple(ex_point_2),
tuple(point_2),
4096.0,
1,
lineType=cv2.LINE_AA,
shift=0)
return ex_point_1, ex_point_2
@PIPELINES.register_module()
class MakeShrinkMap(object):
r'''
Making binary mask from detection data with ICDAR format.
Typically following the process of class `MakeICDARData`.
'''
def __init__(self, min_text_size=8, shrink_ratio=0.4, **kwargs):
self.min_text_size = min_text_size
self.shrink_ratio = shrink_ratio
def __call__(self, data):
image = data['img']
text_polys = data['polys']
ignore_tags = data['ignore_tags']
h, w = image.shape[:2]
text_polys, ignore_tags = self.validate_polygons(
text_polys, ignore_tags, h, w)
gt = np.zeros((h, w), dtype=np.float32)
mask = np.ones((h, w), dtype=np.float32)
for i in range(len(text_polys)):
polygon = text_polys[i]
height = max(polygon[:, 1]) - min(polygon[:, 1])
width = max(polygon[:, 0]) - min(polygon[:, 0])
if ignore_tags[i] or min(height, width) < self.min_text_size:
cv2.fillPoly(mask,
polygon.astype(np.int32)[np.newaxis, :, :], 0)
ignore_tags[i] = True
else:
polygon_shape = Polygon(polygon)
subject = [tuple(l) for l in polygon]
padding = pyclipper.PyclipperOffset()
padding.AddPath(subject, pyclipper.JT_ROUND,
pyclipper.ET_CLOSEDPOLYGON)
shrinked = []
# Increase the shrink ratio every time we get multiple polygon returned back
possible_ratios = np.arange(self.shrink_ratio, 1,
self.shrink_ratio)
np.append(possible_ratios, 1)
# print(possible_ratios)
for ratio in possible_ratios:
# print(f"Change shrink ratio to {ratio}")
distance = polygon_shape.area * (
1 - np.power(ratio, 2)) / polygon_shape.length
shrinked = padding.Execute(-distance)
if len(shrinked) == 1:
break
if shrinked == []:
cv2.fillPoly(mask,
polygon.astype(np.int32)[np.newaxis, :, :], 0)
ignore_tags[i] = True
continue
for each_shirnk in shrinked:
shirnk = np.array(each_shirnk).reshape(-1, 2)
cv2.fillPoly(gt, [shirnk.astype(np.int32)], 1)
data['shrink_map'] = gt
data['shrink_mask'] = mask
return data
def validate_polygons(self, polygons, ignore_tags, h, w):
'''
polygons (numpy.array, required): of shape (num_instances, num_points, 2)
'''
if len(polygons) == 0:
return polygons, ignore_tags
assert len(polygons) == len(ignore_tags)
for polygon in polygons:
polygon[:, 0] = np.clip(polygon[:, 0], 0, w - 1)
polygon[:, 1] = np.clip(polygon[:, 1], 0, h - 1)
for i in range(len(polygons)):
area = self.polygon_area(polygons[i])
if abs(area) < 1:
ignore_tags[i] = True
if area > 0:
polygons[i] = polygons[i][::-1, :]
return polygons, ignore_tags
def polygon_area(self, polygon):
"""
compute polygon area
"""
area = 0
q = polygon[-1]
for p in polygon:
area += p[0] * q[1] - p[1] * q[0]
q = p
return area / 2.0
@PIPELINES.register_module()
class OCRDetResize(object):
"""resize function for ocr det test
"""
def __init__(self, **kwargs):
super(OCRDetResize, self).__init__()
self.resize_type = 0
if 'image_shape' in kwargs:
self.image_shape = kwargs['image_shape']
self.resize_type = 1
elif 'limit_side_len' in kwargs:
self.limit_side_len = kwargs['limit_side_len']
self.limit_type = kwargs.get('limit_type', 'min')
elif 'resize_long' in kwargs:
self.resize_type = 2
self.resize_long = kwargs.get('resize_long', 960)
else:
self.limit_side_len = 736
self.limit_type = 'min'
def __call__(self, data):
img = data['img']
src_h, src_w, _ = img.shape
if self.resize_type == 0:
# img, shape = self.resize_image_type0(img)
img, [ratio_h, ratio_w] = self.resize_image_type0(img)
elif self.resize_type == 2:
img, [ratio_h, ratio_w] = self.resize_image_type2(img)
else:
# img, shape = self.resize_image_type1(img)
img, [ratio_h, ratio_w] = self.resize_image_type1(img)
data['img'] = img
# data['shape'] = np.array([src_h, src_w, ratio_h, ratio_w])
return data
def resize_image_type1(self, img):
resize_h, resize_w = self.image_shape
ori_h, ori_w = img.shape[:2] # (h, w, c)
ratio_h = float(resize_h) / ori_h
ratio_w = float(resize_w) / ori_w
img = cv2.resize(img, (int(resize_w), int(resize_h)))
return img, [ratio_h, ratio_w]
def resize_image_type0(self, img):
"""
resize image to a size multiple of 32 which is required by the network
args:
img(array): array with shape [h, w, c]
return(tuple):
img, (ratio_h, ratio_w)
"""
limit_side_len = self.limit_side_len
h, w, c = img.shape
# limit the max side
if self.limit_type == 'max':
if max(h, w) > limit_side_len:
if h > w:
ratio = float(limit_side_len) / h
else:
ratio = float(limit_side_len) / w
else:
ratio = 1.
elif self.limit_type == 'min':
if min(h, w) < limit_side_len:
if h < w:
ratio = float(limit_side_len) / h
else:
ratio = float(limit_side_len) / w
else:
ratio = 1.
elif self.limit_type == 'resize_long':
ratio = float(limit_side_len) / max(h, w)
else:
raise Exception('not support limit type, image ')
resize_h = int(h * ratio)
resize_w = int(w * ratio)
resize_h = max(int(round(resize_h / 32) * 32), 32)
resize_w = max(int(round(resize_w / 32) * 32), 32)
try:
if int(resize_w) <= 0 or int(resize_h) <= 0:
return None, (None, None)
img = cv2.resize(img, (int(resize_w), int(resize_h)))
except:
print(img.shape, resize_w, resize_h)
sys.exit(0)
ratio_h = resize_h / float(h)
ratio_w = resize_w / float(w)
return img, [ratio_h, ratio_w]
def resize_image_type2(self, img):
h, w, _ = img.shape
resize_w = w
resize_h = h
if resize_h > resize_w:
ratio = float(self.resize_long) / resize_h
else:
ratio = float(self.resize_long) / resize_w
resize_h = int(resize_h * ratio)
resize_w = int(resize_w * ratio)
max_stride = 128
resize_h = (resize_h + max_stride - 1) // max_stride * max_stride
resize_w = (resize_w + max_stride - 1) // max_stride * max_stride
img = cv2.resize(img, (int(resize_w), int(resize_h)))
ratio_h = resize_h / float(h)
ratio_w = resize_w / float(w)
return img, [ratio_h, ratio_w]