File size: 24,031 Bytes
2366e36
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
# 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