init

backend/ppocr/postprocess/east_postprocess.py

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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 numpy as np
+from .locality_aware_nms import nms_locality
+import cv2
+import paddle
+
+import os
+import sys
+
+
+class EASTPostProcess(object):
+    """
+    The post process for EAST.
+    """
+
+    def __init__(self,
+                 score_thresh=0.8,
+                 cover_thresh=0.1,
+                 nms_thresh=0.2,
+                 **kwargs):
+
+        self.score_thresh = score_thresh
+        self.cover_thresh = cover_thresh
+        self.nms_thresh = nms_thresh
+
+    def restore_rectangle_quad(self, origin, geometry):
+        """
+        Restore rectangle from quadrangle.
+        """
+        # quad
+        origin_concat = np.concatenate(
+            (origin, origin, origin, origin), axis=1)  # (n, 8)
+        pred_quads = origin_concat - geometry
+        pred_quads = pred_quads.reshape((-1, 4, 2))  # (n, 4, 2)
+        return pred_quads
+
+    def detect(self,
+               score_map,
+               geo_map,
+               score_thresh=0.8,
+               cover_thresh=0.1,
+               nms_thresh=0.2):
+        """
+        restore text boxes from score map and geo map
+        """
+
+        score_map = score_map[0]
+        geo_map = np.swapaxes(geo_map, 1, 0)
+        geo_map = np.swapaxes(geo_map, 1, 2)
+        # filter the score map
+        xy_text = np.argwhere(score_map > score_thresh)
+        if len(xy_text) == 0:
+            return []
+        # sort the text boxes via the y axis
+        xy_text = xy_text[np.argsort(xy_text[:, 0])]
+        #restore quad proposals
+        text_box_restored = self.restore_rectangle_quad(
+            xy_text[:, ::-1] * 4, geo_map[xy_text[:, 0], xy_text[:, 1], :])
+        boxes = np.zeros((text_box_restored.shape[0], 9), dtype=np.float32)
+        boxes[:, :8] = text_box_restored.reshape((-1, 8))
+        boxes[:, 8] = score_map[xy_text[:, 0], xy_text[:, 1]]
+
+        try:
+            import lanms
+            boxes = lanms.merge_quadrangle_n9(boxes, nms_thresh)
+        except:
+            print(
+                'you should install lanms by pip3 install lanms-nova to speed up nms_locality'
+            )
+            boxes = nms_locality(boxes.astype(np.float64), nms_thresh)
+        if boxes.shape[0] == 0:
+            return []
+        # Here we filter some low score boxes by the average score map, 
+        #   this is different from the orginal paper.
+        for i, box in enumerate(boxes):
+            mask = np.zeros_like(score_map, dtype=np.uint8)
+            cv2.fillPoly(mask, box[:8].reshape(
+                (-1, 4, 2)).astype(np.int32) // 4, 1)
+            boxes[i, 8] = cv2.mean(score_map, mask)[0]
+        boxes = boxes[boxes[:, 8] > cover_thresh]
+        return boxes
+
+    def sort_poly(self, p):
+        """
+        Sort polygons.
+        """
+        min_axis = np.argmin(np.sum(p, axis=1))
+        p = p[[min_axis, (min_axis + 1) % 4,\
+            (min_axis + 2) % 4, (min_axis + 3) % 4]]
+        if abs(p[0, 0] - p[1, 0]) > abs(p[0, 1] - p[1, 1]):
+            return p
+        else:
+            return p[[0, 3, 2, 1]]
+
+    def __call__(self, outs_dict, shape_list):
+        score_list = outs_dict['f_score']
+        geo_list = outs_dict['f_geo']
+        if isinstance(score_list, paddle.Tensor):
+            score_list = score_list.numpy()
+            geo_list = geo_list.numpy()
+        img_num = len(shape_list)
+        dt_boxes_list = []
+        for ino in range(img_num):
+            score = score_list[ino]
+            geo = geo_list[ino]
+            boxes = self.detect(
+                score_map=score,
+                geo_map=geo,
+                score_thresh=self.score_thresh,
+                cover_thresh=self.cover_thresh,
+                nms_thresh=self.nms_thresh)
+            boxes_norm = []
+            if len(boxes) > 0:
+                h, w = score.shape[1:]
+                src_h, src_w, ratio_h, ratio_w = shape_list[ino]
+                boxes = boxes[:, :8].reshape((-1, 4, 2))
+                boxes[:, :, 0] /= ratio_w
+                boxes[:, :, 1] /= ratio_h
+                for i_box, box in enumerate(boxes):
+                    box = self.sort_poly(box.astype(np.int32))
+                    if np.linalg.norm(box[0] - box[1]) < 5 \
+                        or np.linalg.norm(box[3] - box[0]) < 5:
+                        continue
+                    boxes_norm.append(box)
+            dt_boxes_list.append({'points': np.array(boxes_norm)})
+        return dt_boxes_list