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1 month ago
import random
import cv2
import numpy as np
# random crop algorithm similar to https://github.com/argman/EAST
class EastRandomCropData:
def __init__(
self,
size=(640, 640),
max_tries=50,
min_crop_side_ratio=0.1,
require_original_image=False,
keep_ratio=True,
):
self.size = size
self.max_tries = max_tries
self.min_crop_side_ratio = min_crop_side_ratio
self.require_original_image = require_original_image
self.keep_ratio = keep_ratio
def __call__(self, data: dict) -> dict:
"""
从scales中随机选择一个尺度对图片和文本框进行缩放
:param data: {'img':,'text_polys':,'texts':,'ignore_tags':}
:return:
"""
im = data["img"]
text_polys = data["text_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]
# 计算crop区域
crop_x, crop_y, crop_w, crop_h = self.crop_area(im, all_care_polys)
# crop 图片 保持比例填充
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:
if len(im.shape) == 3:
padimg = np.zeros((self.size[1], self.size[0], im.shape[2]), im.dtype)
else:
padimg = np.zeros((self.size[1], self.size[0]), im.dtype)
padimg[:h, :w] = cv2.resize(
im[crop_y : crop_y + crop_h, crop_x : crop_x + crop_w], (w, h)
)
img = padimg
else:
img = cv2.resize(
im[crop_y : crop_y + crop_h, crop_x : crop_x + crop_w], tuple(self.size)
)
# crop 文本框
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 self.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["text_polys"] = np.float32(text_polys_crop)
data["ignore_tags"] = ignore_tags_crop
data["texts"] = texts_crop
return data
def is_poly_in_rect(self, 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(self, 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(self, 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(self, 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(self, 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(self, im, text_polys):
h, w = im.shape[:2]
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 = self.split_regions(h_axis)
w_regions = self.split_regions(w_axis)
for i in range(self.max_tries):
if len(w_regions) > 1:
xmin, xmax = self.region_wise_random_select(w_regions, w)
else:
xmin, xmax = self.random_select(w_axis, w)
if len(h_regions) > 1:
ymin, ymax = self.region_wise_random_select(h_regions, h)
else:
ymin, ymax = self.random_select(h_axis, h)
if (
xmax - xmin < self.min_crop_side_ratio * w
or ymax - ymin < self.min_crop_side_ratio * h
):
# area too small
continue
num_poly_in_rect = 0
for poly in text_polys:
if not self.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
class PSERandomCrop:
def __init__(self, size):
self.size = size
def __call__(self, data):
imgs = data["imgs"]
h, w = imgs[0].shape[0:2]
th, tw = self.size
if w == tw and h == th:
return imgs
# label中存在文本实例并且按照概率进行裁剪使用threshold_label_map控制
if np.max(imgs[2]) > 0 and random.random() > 3 / 8:
# 文本实例的左上角点
tl = np.min(np.where(imgs[2] > 0), axis=1) - self.size
tl[tl < 0] = 0
# 文本实例的右下角点
br = np.max(np.where(imgs[2] > 0), axis=1) - self.size
br[br < 0] = 0
# 保证选到右下角点时有足够的距离进行crop
br[0] = min(br[0], h - th)
br[1] = min(br[1], w - tw)
for _ in range(50000):
i = random.randint(tl[0], br[0])
j = random.randint(tl[1], br[1])
# 保证shrink_label_map有文本
if imgs[1][i : i + th, j : j + tw].sum() <= 0:
continue
else:
break
else:
i = random.randint(0, h - th)
j = random.randint(0, w - tw)
# return i, j, th, tw
for idx in range(len(imgs)):
if len(imgs[idx].shape) == 3:
imgs[idx] = imgs[idx][i : i + th, j : j + tw, :]
else:
imgs[idx] = imgs[idx][i : i + th, j : j + tw]
data["imgs"] = imgs
return data