File size: 11,392 Bytes
5de2f8f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
import numpy as np
import json
import cv2

np.seterr(divide='ignore', invalid='ignore')
import pyclipper
from shapely.geometry import Polygon
import warnings

warnings.simplefilter('ignore')


class DetLabelEncode(object):

    def __init__(self, **kwargs):
        pass

    def __call__(self, data):
        label = data['label']
        label = json.loads(label)
        nBox = len(label)
        boxes, txts, txt_tags = [], [], []
        for bno in range(0, nBox):
            box = label[bno]['points']
            txt = label[bno]['transcription']
            boxes.append(box)
            txts.append(txt)
            if txt in ['*', '###']:
                txt_tags.append(True)
            else:
                txt_tags.append(False)
        if len(boxes) == 0:
            return None
        boxes = self.expand_points_num(boxes)
        boxes = np.array(boxes, dtype=np.float32)
        txt_tags = np.array(txt_tags, dtype=np.bool_)

        data['polys'] = boxes
        data['texts'] = txts
        data['ignore_tags'] = txt_tags
        return data

    def order_points_clockwise(self, pts):
        rect = np.zeros((4, 2), dtype='float32')
        s = pts.sum(axis=1)
        rect[0] = pts[np.argmin(s)]
        rect[2] = pts[np.argmax(s)]
        tmp = np.delete(pts, (np.argmin(s), np.argmax(s)), axis=0)
        diff = np.diff(np.array(tmp), axis=1)
        rect[1] = tmp[np.argmin(diff)]
        rect[3] = tmp[np.argmax(diff)]
        return rect

    def expand_points_num(self, boxes):
        max_points_num = 0
        for box in boxes:
            if len(box) > max_points_num:
                max_points_num = len(box)
        ex_boxes = []
        for box in boxes:
            ex_box = box + [box[-1]] * (max_points_num - len(box))
            ex_boxes.append(ex_box)
        return ex_boxes


class MakeBorderMap(object):

    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
        if 'total_epoch' in kwargs and 'epoch' in kwargs and kwargs[
                'epoch'] != 'None':
            self.shrink_ratio = self.shrink_ratio + 0.2 * kwargs[
                'epoch'] / float(kwargs['total_epoch'])

    def __call__(self, data):
        img = data['image']
        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


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
        if 'total_epoch' in kwargs and 'epoch' in kwargs and kwargs[
                'epoch'] != 'None':
            self.shrink_ratio = self.shrink_ratio + 0.2 * kwargs[
                'epoch'] / float(kwargs['total_epoch'])

    def __call__(self, data):
        image = data['image']
        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)
                shrunk = []

                # 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)
                    shrunk = padding.Execute(-distance)
                    if len(shrunk) == 1:
                        break

                if shrunk == []:
                    cv2.fillPoly(mask,
                                 polygon.astype(np.int32)[np.newaxis, :, :], 0)
                    ignore_tags[i] = True
                    continue

                for each_shrink in shrunk:
                    shrink = np.array(each_shrink).reshape(-1, 2)
                    cv2.fillPoly(gt, [shrink.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