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# Copyright (c) 2020 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.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
import sys
__dir__ = os.path.dirname(__file__)
sys.path.append(__dir__)
sys.path.append(os.path.join(__dir__, '..'))
import numpy as np
from .locality_aware_nms import nms_locality
import paddle
import cv2
import time
class SASTPostProcess(object):
"""
The post process for SAST.
"""
def __init__(self,
score_thresh=0.5,
nms_thresh=0.2,
sample_pts_num=2,
shrink_ratio_of_width=0.3,
expand_scale=1.0,
tcl_map_thresh=0.5,
**kwargs):
self.score_thresh = score_thresh
self.nms_thresh = nms_thresh
self.sample_pts_num = sample_pts_num
self.shrink_ratio_of_width = shrink_ratio_of_width
self.expand_scale = expand_scale
self.tcl_map_thresh = tcl_map_thresh
# c++ la-nms is faster, but only support python 3.5
self.is_python35 = False
if sys.version_info.major == 3 and sys.version_info.minor == 5:
self.is_python35 = True
def point_pair2poly(self, point_pair_list):
"""
Transfer vertical point_pairs into poly point in clockwise.
"""
# constract poly
point_num = len(point_pair_list) * 2
point_list = [0] * point_num
for idx, point_pair in enumerate(point_pair_list):
point_list[idx] = point_pair[0]
point_list[point_num - 1 - idx] = point_pair[1]
return np.array(point_list).reshape(-1, 2)
def shrink_quad_along_width(self,
quad,
begin_width_ratio=0.,
end_width_ratio=1.):
"""
Generate shrink_quad_along_width.
"""
ratio_pair = np.array(
[[begin_width_ratio], [end_width_ratio]], dtype=np.float32)
p0_1 = quad[0] + (quad[1] - quad[0]) * ratio_pair
p3_2 = quad[3] + (quad[2] - quad[3]) * ratio_pair
return np.array([p0_1[0], p0_1[1], p3_2[1], p3_2[0]])
def expand_poly_along_width(self, poly, shrink_ratio_of_width=0.3):
"""
expand poly along width.
"""
point_num = poly.shape[0]
left_quad = np.array(
[poly[0], poly[1], poly[-2], poly[-1]], dtype=np.float32)
left_ratio = -shrink_ratio_of_width * np.linalg.norm(left_quad[0] - left_quad[3]) / \
(np.linalg.norm(left_quad[0] - left_quad[1]) + 1e-6)
left_quad_expand = self.shrink_quad_along_width(left_quad, left_ratio,
1.0)
right_quad = np.array(
[
poly[point_num // 2 - 2], poly[point_num // 2 - 1],
poly[point_num // 2], poly[point_num // 2 + 1]
],
dtype=np.float32)
right_ratio = 1.0 + \
shrink_ratio_of_width * np.linalg.norm(right_quad[0] - right_quad[3]) / \
(np.linalg.norm(right_quad[0] - right_quad[1]) + 1e-6)
right_quad_expand = self.shrink_quad_along_width(right_quad, 0.0,
right_ratio)
poly[0] = left_quad_expand[0]
poly[-1] = left_quad_expand[-1]
poly[point_num // 2 - 1] = right_quad_expand[1]
poly[point_num // 2] = right_quad_expand[2]
return poly
def restore_quad(self, tcl_map, tcl_map_thresh, tvo_map):
"""Restore quad."""
xy_text = np.argwhere(tcl_map[:, :, 0] > tcl_map_thresh)
xy_text = xy_text[:, ::-1] # (n, 2)
# Sort the text boxes via the y axis
xy_text = xy_text[np.argsort(xy_text[:, 1])]
scores = tcl_map[xy_text[:, 1], xy_text[:, 0], 0]
scores = scores[:, np.newaxis]
# Restore
point_num = int(tvo_map.shape[-1] / 2)
assert point_num == 4
tvo_map = tvo_map[xy_text[:, 1], xy_text[:, 0], :]
xy_text_tile = np.tile(xy_text, (1, point_num)) # (n, point_num * 2)
quads = xy_text_tile - tvo_map
return scores, quads, xy_text
def quad_area(self, quad):
"""
compute area of a quad.
"""
edge = [(quad[1][0] - quad[0][0]) * (quad[1][1] + quad[0][1]),
(quad[2][0] - quad[1][0]) * (quad[2][1] + quad[1][1]),
(quad[3][0] - quad[2][0]) * (quad[3][1] + quad[2][1]),
(quad[0][0] - quad[3][0]) * (quad[0][1] + quad[3][1])]
return np.sum(edge) / 2.
def nms(self, dets):
if self.is_python35:
import lanms
dets = lanms.merge_quadrangle_n9(dets, self.nms_thresh)
else:
dets = nms_locality(dets, self.nms_thresh)
return dets
def cluster_by_quads_tco(self, tcl_map, tcl_map_thresh, quads, tco_map):
"""
Cluster pixels in tcl_map based on quads.
"""
instance_count = quads.shape[0] + 1 # contain background
instance_label_map = np.zeros(tcl_map.shape[:2], dtype=np.int32)
if instance_count == 1:
return instance_count, instance_label_map
# predict text center
xy_text = np.argwhere(tcl_map[:, :, 0] > tcl_map_thresh)
n = xy_text.shape[0]
xy_text = xy_text[:, ::-1] # (n, 2)
tco = tco_map[xy_text[:, 1], xy_text[:, 0], :] # (n, 2)
pred_tc = xy_text - tco
# get gt text center
m = quads.shape[0]
gt_tc = np.mean(quads, axis=1) # (m, 2)
pred_tc_tile = np.tile(pred_tc[:, np.newaxis, :],
(1, m, 1)) # (n, m, 2)
gt_tc_tile = np.tile(gt_tc[np.newaxis, :, :], (n, 1, 1)) # (n, m, 2)
dist_mat = np.linalg.norm(pred_tc_tile - gt_tc_tile, axis=2) # (n, m)
xy_text_assign = np.argmin(dist_mat, axis=1) + 1 # (n,)
instance_label_map[xy_text[:, 1], xy_text[:, 0]] = xy_text_assign
return instance_count, instance_label_map
def estimate_sample_pts_num(self, quad, xy_text):
"""
Estimate sample points number.
"""
eh = (np.linalg.norm(quad[0] - quad[3]) +
np.linalg.norm(quad[1] - quad[2])) / 2.0
ew = (np.linalg.norm(quad[0] - quad[1]) +
np.linalg.norm(quad[2] - quad[3])) / 2.0
dense_sample_pts_num = max(2, int(ew))
dense_xy_center_line = xy_text[np.linspace(
0,
xy_text.shape[0] - 1,
dense_sample_pts_num,
endpoint=True,
dtype=np.float32).astype(np.int32)]
dense_xy_center_line_diff = dense_xy_center_line[
1:] - dense_xy_center_line[:-1]
estimate_arc_len = np.sum(
np.linalg.norm(
dense_xy_center_line_diff, axis=1))
sample_pts_num = max(2, int(estimate_arc_len / eh))
return sample_pts_num
def detect_sast(self,
tcl_map,
tvo_map,
tbo_map,
tco_map,
ratio_w,
ratio_h,
src_w,
src_h,
shrink_ratio_of_width=0.3,
tcl_map_thresh=0.5,
offset_expand=1.0,
out_strid=4.0):
"""
first resize the tcl_map, tvo_map and tbo_map to the input_size, then restore the polys
"""
# restore quad
scores, quads, xy_text = self.restore_quad(tcl_map, tcl_map_thresh,
tvo_map)
dets = np.hstack((quads, scores)).astype(np.float32, copy=False)
dets = self.nms(dets)
if dets.shape[0] == 0:
return []
quads = dets[:, :-1].reshape(-1, 4, 2)
# Compute quad area
quad_areas = []
for quad in quads:
quad_areas.append(-self.quad_area(quad))
# instance segmentation
# instance_count, instance_label_map = cv2.connectedComponents(tcl_map.astype(np.uint8), connectivity=8)
instance_count, instance_label_map = self.cluster_by_quads_tco(
tcl_map, tcl_map_thresh, quads, tco_map)
# restore single poly with tcl instance.
poly_list = []
for instance_idx in range(1, instance_count):
xy_text = np.argwhere(instance_label_map == instance_idx)[:, ::-1]
quad = quads[instance_idx - 1]
q_area = quad_areas[instance_idx - 1]
if q_area < 5:
continue
#
len1 = float(np.linalg.norm(quad[0] - quad[1]))
len2 = float(np.linalg.norm(quad[1] - quad[2]))
min_len = min(len1, len2)
if min_len < 3:
continue
# filter small CC
if xy_text.shape[0] <= 0:
continue
# filter low confidence instance
xy_text_scores = tcl_map[xy_text[:, 1], xy_text[:, 0], 0]
if np.sum(xy_text_scores) / quad_areas[instance_idx - 1] < 0.1:
# if np.sum(xy_text_scores) / quad_areas[instance_idx - 1] < 0.05:
continue
# sort xy_text
left_center_pt = np.array(
[[(quad[0, 0] + quad[-1, 0]) / 2.0,
(quad[0, 1] + quad[-1, 1]) / 2.0]]) # (1, 2)
right_center_pt = np.array(
[[(quad[1, 0] + quad[2, 0]) / 2.0,
(quad[1, 1] + quad[2, 1]) / 2.0]]) # (1, 2)
proj_unit_vec = (right_center_pt - left_center_pt) / \
(np.linalg.norm(right_center_pt - left_center_pt) + 1e-6)
proj_value = np.sum(xy_text * proj_unit_vec, axis=1)
xy_text = xy_text[np.argsort(proj_value)]
# Sample pts in tcl map
if self.sample_pts_num == 0:
sample_pts_num = self.estimate_sample_pts_num(quad, xy_text)
else:
sample_pts_num = self.sample_pts_num
xy_center_line = xy_text[np.linspace(
0,
xy_text.shape[0] - 1,
sample_pts_num,
endpoint=True,
dtype=np.float32).astype(np.int32)]
point_pair_list = []
for x, y in xy_center_line:
# get corresponding offset
offset = tbo_map[y, x, :].reshape(2, 2)
if offset_expand != 1.0:
offset_length = np.linalg.norm(
offset, axis=1, keepdims=True)
expand_length = np.clip(
offset_length * (offset_expand - 1),
a_min=0.5,
a_max=3.0)
offset_detal = offset / offset_length * expand_length
offset = offset + offset_detal
# original point
ori_yx = np.array([y, x], dtype=np.float32)
point_pair = (ori_yx + offset)[:, ::-1] * out_strid / np.array(
[ratio_w, ratio_h]).reshape(-1, 2)
point_pair_list.append(point_pair)
# ndarry: (x, 2), expand poly along width
detected_poly = self.point_pair2poly(point_pair_list)
detected_poly = self.expand_poly_along_width(detected_poly,
shrink_ratio_of_width)
detected_poly[:, 0] = np.clip(
detected_poly[:, 0], a_min=0, a_max=src_w)
detected_poly[:, 1] = np.clip(
detected_poly[:, 1], a_min=0, a_max=src_h)
poly_list.append(detected_poly)
return poly_list
def __call__(self, outs_dict, shape_list):
score_list = outs_dict['f_score']
border_list = outs_dict['f_border']
tvo_list = outs_dict['f_tvo']
tco_list = outs_dict['f_tco']
if isinstance(score_list, paddle.Tensor):
score_list = score_list.numpy()
border_list = border_list.numpy()
tvo_list = tvo_list.numpy()
tco_list = tco_list.numpy()
img_num = len(shape_list)
poly_lists = []
for ino in range(img_num):
p_score = score_list[ino].transpose((1, 2, 0))
p_border = border_list[ino].transpose((1, 2, 0))
p_tvo = tvo_list[ino].transpose((1, 2, 0))
p_tco = tco_list[ino].transpose((1, 2, 0))
src_h, src_w, ratio_h, ratio_w = shape_list[ino]
poly_list = self.detect_sast(
p_score,
p_tvo,
p_border,
p_tco,
ratio_w,
ratio_h,
src_w,
src_h,
shrink_ratio_of_width=self.shrink_ratio_of_width,
tcl_map_thresh=self.tcl_map_thresh,
offset_expand=self.expand_scale)
poly_lists.append({'points': np.array(poly_list)})
return poly_lists