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# Copyright (c) OpenMMLab. All rights reserved.
import cv2
import numpy as np
from lanms import merge_quadrangle_n9 as la_nms
from mmdet.core import BitmapMasks
from mmdet.datasets.builder import PIPELINES
from numpy.linalg import norm
import mmocr.utils.check_argument as check_argument
from .textsnake_targets import TextSnakeTargets
@PIPELINES.register_module()
class DRRGTargets(TextSnakeTargets):
"""Generate the ground truth targets of DRRG: Deep Relational Reasoning
Graph Network for Arbitrary Shape Text Detection.
[https://arxiv.org/abs/2003.07493]. This code was partially adapted from
https://github.com/GXYM/DRRG licensed under the MIT license.
Args:
orientation_thr (float): The threshold for distinguishing between
head edge and tail edge among the horizontal and vertical edges
of a quadrangle.
resample_step (float): The step size for resampling the text center
line.
num_min_comps (int): The minimum number of text components, which
should be larger than k_hop1 mentioned in paper.
num_max_comps (int): The maximum number of text components.
min_width (float): The minimum width of text components.
max_width (float): The maximum width of text components.
center_region_shrink_ratio (float): The shrink ratio of text center
regions.
comp_shrink_ratio (float): The shrink ratio of text components.
comp_w_h_ratio (float): The width to height ratio of text components.
min_rand_half_height(float): The minimum half-height of random text
components.
max_rand_half_height (float): The maximum half-height of random
text components.
jitter_level (float): The jitter level of text component geometric
features.
"""
def __init__(self,
orientation_thr=2.0,
resample_step=8.0,
num_min_comps=9,
num_max_comps=600,
min_width=8.0,
max_width=24.0,
center_region_shrink_ratio=0.3,
comp_shrink_ratio=1.0,
comp_w_h_ratio=0.3,
text_comp_nms_thr=0.25,
min_rand_half_height=8.0,
max_rand_half_height=24.0,
jitter_level=0.2):
super().__init__()
self.orientation_thr = orientation_thr
self.resample_step = resample_step
self.num_max_comps = num_max_comps
self.num_min_comps = num_min_comps
self.min_width = min_width
self.max_width = max_width
self.center_region_shrink_ratio = center_region_shrink_ratio
self.comp_shrink_ratio = comp_shrink_ratio
self.comp_w_h_ratio = comp_w_h_ratio
self.text_comp_nms_thr = text_comp_nms_thr
self.min_rand_half_height = min_rand_half_height
self.max_rand_half_height = max_rand_half_height
self.jitter_level = jitter_level
def dist_point2line(self, point, line):
assert isinstance(line, tuple)
point1, point2 = line
d = abs(np.cross(point2 - point1, point - point1)) / (
norm(point2 - point1) + 1e-8)
return d
def draw_center_region_maps(self, top_line, bot_line, center_line,
center_region_mask, top_height_map,
bot_height_map, sin_map, cos_map,
region_shrink_ratio):
"""Draw attributes of text components on text center regions.
Args:
top_line (ndarray): The points composing the top side lines of text
polygons.
bot_line (ndarray): The points composing bottom side lines of text
polygons.
center_line (ndarray): The points composing the center lines of
text instances.
center_region_mask (ndarray): The text center region mask.
top_height_map (ndarray): The map on which the distance from points
to top side lines will be drawn for each pixel in text center
regions.
bot_height_map (ndarray): The map on which the distance from points
to bottom side lines will be drawn for each pixel in text
center regions.
sin_map (ndarray): The map of vector_sin(top_point - bot_point)
that will be drawn on text center regions.
cos_map (ndarray): The map of vector_cos(top_point - bot_point)
will be drawn on text center regions.
region_shrink_ratio (float): The shrink ratio of text center
regions.
"""
assert top_line.shape == bot_line.shape == center_line.shape
assert (center_region_mask.shape == top_height_map.shape ==
bot_height_map.shape == sin_map.shape == cos_map.shape)
assert isinstance(region_shrink_ratio, float)
h, w = center_region_mask.shape
for i in range(0, len(center_line) - 1):
top_mid_point = (top_line[i] + top_line[i + 1]) / 2
bot_mid_point = (bot_line[i] + bot_line[i + 1]) / 2
sin_theta = self.vector_sin(top_mid_point - bot_mid_point)
cos_theta = self.vector_cos(top_mid_point - bot_mid_point)
tl = center_line[i] + (top_line[i] -
center_line[i]) * region_shrink_ratio
tr = center_line[i + 1] + (
top_line[i + 1] - center_line[i + 1]) * region_shrink_ratio
br = center_line[i + 1] + (
bot_line[i + 1] - center_line[i + 1]) * region_shrink_ratio
bl = center_line[i] + (bot_line[i] -
center_line[i]) * region_shrink_ratio
current_center_box = np.vstack([tl, tr, br, bl]).astype(np.int32)
cv2.fillPoly(center_region_mask, [current_center_box], color=1)
cv2.fillPoly(sin_map, [current_center_box], color=sin_theta)
cv2.fillPoly(cos_map, [current_center_box], color=cos_theta)
current_center_box[:, 0] = np.clip(current_center_box[:, 0], 0,
w - 1)
current_center_box[:, 1] = np.clip(current_center_box[:, 1], 0,
h - 1)
min_coord = np.min(current_center_box, axis=0).astype(np.int32)
max_coord = np.max(current_center_box, axis=0).astype(np.int32)
current_center_box = current_center_box - min_coord
box_sz = (max_coord - min_coord + 1)
center_box_mask = np.zeros((box_sz[1], box_sz[0]), dtype=np.uint8)
cv2.fillPoly(center_box_mask, [current_center_box], color=1)
inds = np.argwhere(center_box_mask > 0)
inds = inds + (min_coord[1], min_coord[0])
inds_xy = np.fliplr(inds)
top_height_map[(inds[:, 0], inds[:, 1])] = self.dist_point2line(
inds_xy, (top_line[i], top_line[i + 1]))
bot_height_map[(inds[:, 0], inds[:, 1])] = self.dist_point2line(
inds_xy, (bot_line[i], bot_line[i + 1]))
def generate_center_mask_attrib_maps(self, img_size, text_polys):
"""Generate text center region masks and geometric attribute maps.
Args:
img_size (tuple): The image size (height, width).
text_polys (list[list[ndarray]]): The list of text polygons.
Returns:
center_lines (list): The list of text center lines.
center_region_mask (ndarray): The text center region mask.
top_height_map (ndarray): The map on which the distance from points
to top side lines will be drawn for each pixel in text center
regions.
bot_height_map (ndarray): The map on which the distance from points
to bottom side lines will be drawn for each pixel in text
center regions.
sin_map (ndarray): The sin(theta) map where theta is the angle
between vector (top point - bottom point) and vector (1, 0).
cos_map (ndarray): The cos(theta) map where theta is the angle
between vector (top point - bottom point) and vector (1, 0).
"""
assert isinstance(img_size, tuple)
assert check_argument.is_2dlist(text_polys)
h, w = img_size
center_lines = []
center_region_mask = np.zeros((h, w), np.uint8)
top_height_map = np.zeros((h, w), dtype=np.float32)
bot_height_map = np.zeros((h, w), dtype=np.float32)
sin_map = np.zeros((h, w), dtype=np.float32)
cos_map = np.zeros((h, w), dtype=np.float32)
for poly in text_polys:
assert len(poly) == 1
polygon_points = poly[0].reshape(-1, 2)
_, _, top_line, bot_line = self.reorder_poly_edge(polygon_points)
resampled_top_line, resampled_bot_line = self.resample_sidelines(
top_line, bot_line, self.resample_step)
resampled_bot_line = resampled_bot_line[::-1]
center_line = (resampled_top_line + resampled_bot_line) / 2
if self.vector_slope(center_line[-1] - center_line[0]) > 2:
if (center_line[-1] - center_line[0])[1] < 0:
center_line = center_line[::-1]
resampled_top_line = resampled_top_line[::-1]
resampled_bot_line = resampled_bot_line[::-1]
else:
if (center_line[-1] - center_line[0])[0] < 0:
center_line = center_line[::-1]
resampled_top_line = resampled_top_line[::-1]
resampled_bot_line = resampled_bot_line[::-1]
line_head_shrink_len = np.clip(
(norm(top_line[0] - bot_line[0]) * self.comp_w_h_ratio),
self.min_width, self.max_width) / 2
line_tail_shrink_len = np.clip(
(norm(top_line[-1] - bot_line[-1]) * self.comp_w_h_ratio),
self.min_width, self.max_width) / 2
num_head_shrink = int(line_head_shrink_len // self.resample_step)
num_tail_shrink = int(line_tail_shrink_len // self.resample_step)
if len(center_line) > num_head_shrink + num_tail_shrink + 2:
center_line = center_line[num_head_shrink:len(center_line) -
num_tail_shrink]
resampled_top_line = resampled_top_line[
num_head_shrink:len(resampled_top_line) - num_tail_shrink]
resampled_bot_line = resampled_bot_line[
num_head_shrink:len(resampled_bot_line) - num_tail_shrink]
center_lines.append(center_line.astype(np.int32))
self.draw_center_region_maps(resampled_top_line,
resampled_bot_line, center_line,
center_region_mask, top_height_map,
bot_height_map, sin_map, cos_map,
self.center_region_shrink_ratio)
return (center_lines, center_region_mask, top_height_map,
bot_height_map, sin_map, cos_map)
def generate_rand_comp_attribs(self, num_rand_comps, center_sample_mask):
"""Generate random text components and their attributes to ensure the
the number of text components in an image is larger than k_hop1, which
is the number of one hop neighbors in KNN graph.
Args:
num_rand_comps (int): The number of random text components.
center_sample_mask (ndarray): The region mask for sampling text
component centers .
Returns:
rand_comp_attribs (ndarray): The random text component attributes
(x, y, h, w, cos, sin, comp_label=0).
"""
assert isinstance(num_rand_comps, int)
assert num_rand_comps > 0
assert center_sample_mask.ndim == 2
h, w = center_sample_mask.shape
max_rand_half_height = self.max_rand_half_height
min_rand_half_height = self.min_rand_half_height
max_rand_height = max_rand_half_height * 2
max_rand_width = np.clip(max_rand_height * self.comp_w_h_ratio,
self.min_width, self.max_width)
margin = int(
np.sqrt((max_rand_height / 2)**2 + (max_rand_width / 2)**2)) + 1
if 2 * margin + 1 > min(h, w):
assert min(h, w) > (np.sqrt(2) * (self.min_width + 1))
max_rand_half_height = max(min(h, w) / 4, self.min_width / 2 + 1)
min_rand_half_height = max(max_rand_half_height / 4,
self.min_width / 2)
max_rand_height = max_rand_half_height * 2
max_rand_width = np.clip(max_rand_height * self.comp_w_h_ratio,
self.min_width, self.max_width)
margin = int(
np.sqrt((max_rand_height / 2)**2 +
(max_rand_width / 2)**2)) + 1
inner_center_sample_mask = np.zeros_like(center_sample_mask)
inner_center_sample_mask[margin:h - margin, margin:w - margin] = \
center_sample_mask[margin:h - margin, margin:w - margin]
kernel_size = int(np.clip(max_rand_half_height, 7, 21))
inner_center_sample_mask = cv2.erode(
inner_center_sample_mask,
np.ones((kernel_size, kernel_size), np.uint8))
center_candidates = np.argwhere(inner_center_sample_mask > 0)
num_center_candidates = len(center_candidates)
sample_inds = np.random.choice(num_center_candidates, num_rand_comps)
rand_centers = center_candidates[sample_inds]
rand_top_height = np.random.randint(
min_rand_half_height,
max_rand_half_height,
size=(len(rand_centers), 1))
rand_bot_height = np.random.randint(
min_rand_half_height,
max_rand_half_height,
size=(len(rand_centers), 1))
rand_cos = 2 * np.random.random(size=(len(rand_centers), 1)) - 1
rand_sin = 2 * np.random.random(size=(len(rand_centers), 1)) - 1
scale = np.sqrt(1.0 / (rand_cos**2 + rand_sin**2 + 1e-8))
rand_cos = rand_cos * scale
rand_sin = rand_sin * scale
height = (rand_top_height + rand_bot_height)
width = np.clip(height * self.comp_w_h_ratio, self.min_width,
self.max_width)
rand_comp_attribs = np.hstack([
rand_centers[:, ::-1], height, width, rand_cos, rand_sin,
np.zeros_like(rand_sin)
]).astype(np.float32)
return rand_comp_attribs
def jitter_comp_attribs(self, comp_attribs, jitter_level):
"""Jitter text components attributes.
Args:
comp_attribs (ndarray): The text component attributes.
jitter_level (float): The jitter level of text components
attributes.
Returns:
jittered_comp_attribs (ndarray): The jittered text component
attributes (x, y, h, w, cos, sin, comp_label).
"""
assert comp_attribs.shape[1] == 7
assert comp_attribs.shape[0] > 0
assert isinstance(jitter_level, float)
x = comp_attribs[:, 0].reshape((-1, 1))
y = comp_attribs[:, 1].reshape((-1, 1))
h = comp_attribs[:, 2].reshape((-1, 1))
w = comp_attribs[:, 3].reshape((-1, 1))
cos = comp_attribs[:, 4].reshape((-1, 1))
sin = comp_attribs[:, 5].reshape((-1, 1))
comp_labels = comp_attribs[:, 6].reshape((-1, 1))
x += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * (h * np.abs(cos) + w * np.abs(sin)) * jitter_level
y += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * (h * np.abs(sin) + w * np.abs(cos)) * jitter_level
h += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * h * jitter_level
w += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * w * jitter_level
cos += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * 2 * jitter_level
sin += (np.random.random(size=(len(comp_attribs), 1)) -
0.5) * 2 * jitter_level
scale = np.sqrt(1.0 / (cos**2 + sin**2 + 1e-8))
cos = cos * scale
sin = sin * scale
jittered_comp_attribs = np.hstack([x, y, h, w, cos, sin, comp_labels])
return jittered_comp_attribs
def generate_comp_attribs(self, center_lines, text_mask,
center_region_mask, top_height_map,
bot_height_map, sin_map, cos_map):
"""Generate text component attributes.
Args:
center_lines (list[ndarray]): The list of text center lines .
text_mask (ndarray): The text region mask.
center_region_mask (ndarray): The text center region mask.
top_height_map (ndarray): The map on which the distance from points
to top side lines will be drawn for each pixel in text center
regions.
bot_height_map (ndarray): The map on which the distance from points
to bottom side lines will be drawn for each pixel in text
center regions.
sin_map (ndarray): The sin(theta) map where theta is the angle
between vector (top point - bottom point) and vector (1, 0).
cos_map (ndarray): The cos(theta) map where theta is the angle
between vector (top point - bottom point) and vector (1, 0).
Returns:
pad_comp_attribs (ndarray): The padded text component attributes
of a fixed size.
"""
assert isinstance(center_lines, list)
assert (text_mask.shape == center_region_mask.shape ==
top_height_map.shape == bot_height_map.shape == sin_map.shape
== cos_map.shape)
center_lines_mask = np.zeros_like(center_region_mask)
cv2.polylines(center_lines_mask, center_lines, 0, 1, 1)
center_lines_mask = center_lines_mask * center_region_mask
comp_centers = np.argwhere(center_lines_mask > 0)
y = comp_centers[:, 0]
x = comp_centers[:, 1]
top_height = top_height_map[y, x].reshape(
(-1, 1)) * self.comp_shrink_ratio
bot_height = bot_height_map[y, x].reshape(
(-1, 1)) * self.comp_shrink_ratio
sin = sin_map[y, x].reshape((-1, 1))
cos = cos_map[y, x].reshape((-1, 1))
top_mid_points = comp_centers + np.hstack(
[top_height * sin, top_height * cos])
bot_mid_points = comp_centers - np.hstack(
[bot_height * sin, bot_height * cos])
width = (top_height + bot_height) * self.comp_w_h_ratio
width = np.clip(width, self.min_width, self.max_width)
r = width / 2
tl = top_mid_points[:, ::-1] - np.hstack([-r * sin, r * cos])
tr = top_mid_points[:, ::-1] + np.hstack([-r * sin, r * cos])
br = bot_mid_points[:, ::-1] + np.hstack([-r * sin, r * cos])
bl = bot_mid_points[:, ::-1] - np.hstack([-r * sin, r * cos])
text_comps = np.hstack([tl, tr, br, bl]).astype(np.float32)
score = np.ones((text_comps.shape[0], 1), dtype=np.float32)
text_comps = np.hstack([text_comps, score])
text_comps = la_nms(text_comps, self.text_comp_nms_thr)
if text_comps.shape[0] >= 1:
img_h, img_w = center_region_mask.shape
text_comps[:, 0:8:2] = np.clip(text_comps[:, 0:8:2], 0, img_w - 1)
text_comps[:, 1:8:2] = np.clip(text_comps[:, 1:8:2], 0, img_h - 1)
comp_centers = np.mean(
text_comps[:, 0:8].reshape((-1, 4, 2)),
axis=1).astype(np.int32)
x = comp_centers[:, 0]
y = comp_centers[:, 1]
height = (top_height_map[y, x] + bot_height_map[y, x]).reshape(
(-1, 1))
width = np.clip(height * self.comp_w_h_ratio, self.min_width,
self.max_width)
cos = cos_map[y, x].reshape((-1, 1))
sin = sin_map[y, x].reshape((-1, 1))
_, comp_label_mask = cv2.connectedComponents(
center_region_mask, connectivity=8)
comp_labels = comp_label_mask[y, x].reshape(
(-1, 1)).astype(np.float32)
x = x.reshape((-1, 1)).astype(np.float32)
y = y.reshape((-1, 1)).astype(np.float32)
comp_attribs = np.hstack(
[x, y, height, width, cos, sin, comp_labels])
comp_attribs = self.jitter_comp_attribs(comp_attribs,
self.jitter_level)
if comp_attribs.shape[0] < self.num_min_comps:
num_rand_comps = self.num_min_comps - comp_attribs.shape[0]
rand_comp_attribs = self.generate_rand_comp_attribs(
num_rand_comps, 1 - text_mask)
comp_attribs = np.vstack([comp_attribs, rand_comp_attribs])
else:
comp_attribs = self.generate_rand_comp_attribs(
self.num_min_comps, 1 - text_mask)
num_comps = (
np.ones((comp_attribs.shape[0], 1), dtype=np.float32) *
comp_attribs.shape[0])
comp_attribs = np.hstack([num_comps, comp_attribs])
if comp_attribs.shape[0] > self.num_max_comps:
comp_attribs = comp_attribs[:self.num_max_comps, :]
comp_attribs[:, 0] = self.num_max_comps
pad_comp_attribs = np.zeros(
(self.num_max_comps, comp_attribs.shape[1]), dtype=np.float32)
pad_comp_attribs[:comp_attribs.shape[0], :] = comp_attribs
return pad_comp_attribs
def generate_targets(self, results):
"""Generate the gt targets for DRRG.
Args:
results (dict): The input result dictionary.
Returns:
results (dict): The output result dictionary.
"""
assert isinstance(results, dict)
polygon_masks = results['gt_masks'].masks
polygon_masks_ignore = results['gt_masks_ignore'].masks
h, w, _ = results['img_shape']
gt_text_mask = self.generate_text_region_mask((h, w), polygon_masks)
gt_mask = self.generate_effective_mask((h, w), polygon_masks_ignore)
(center_lines, gt_center_region_mask, gt_top_height_map,
gt_bot_height_map, gt_sin_map,
gt_cos_map) = self.generate_center_mask_attrib_maps((h, w),
polygon_masks)
gt_comp_attribs = self.generate_comp_attribs(center_lines,
gt_text_mask,
gt_center_region_mask,
gt_top_height_map,
gt_bot_height_map,
gt_sin_map, gt_cos_map)
results['mask_fields'].clear() # rm gt_masks encoded by polygons
mapping = {
'gt_text_mask': gt_text_mask,
'gt_center_region_mask': gt_center_region_mask,
'gt_mask': gt_mask,
'gt_top_height_map': gt_top_height_map,
'gt_bot_height_map': gt_bot_height_map,
'gt_sin_map': gt_sin_map,
'gt_cos_map': gt_cos_map
}
for key, value in mapping.items():
value = value if isinstance(value, list) else [value]
results[key] = BitmapMasks(value, h, w)
results['mask_fields'].append(key)
results['gt_comp_attribs'] = gt_comp_attribs
return results