init

backend/ppocr/modeling/heads/det_fce_head.py

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+# copyright (c) 2022 PaddlePaddle Authors. All Rights Reserve.
+#
+# 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.
+"""
+This code is refer from:
+https://github.com/open-mmlab/mmocr/blob/main/mmocr/models/textdet/dense_heads/fce_head.py
+"""
+
+from paddle import nn
+from paddle import ParamAttr
+import paddle.nn.functional as F
+from paddle.nn.initializer import Normal
+import paddle
+from functools import partial
+
+
+def multi_apply(func, *args, **kwargs):
+    pfunc = partial(func, **kwargs) if kwargs else func
+    map_results = map(pfunc, *args)
+    return tuple(map(list, zip(*map_results)))
+
+
+class FCEHead(nn.Layer):
+    """The class for implementing FCENet head.
+    FCENet(CVPR2021): Fourier Contour Embedding for Arbitrary-shaped Text
+    Detection.
+
+    [https://arxiv.org/abs/2104.10442]
+
+    Args:
+        in_channels (int): The number of input channels.
+        scales (list[int]) : The scale of each layer.
+        fourier_degree (int) : The maximum Fourier transform degree k.
+    """
+
+    def __init__(self, in_channels, fourier_degree=5):
+        super().__init__()
+        assert isinstance(in_channels, int)
+
+        self.downsample_ratio = 1.0
+        self.in_channels = in_channels
+        self.fourier_degree = fourier_degree
+        self.out_channels_cls = 4
+        self.out_channels_reg = (2 * self.fourier_degree + 1) * 2
+
+        self.out_conv_cls = nn.Conv2D(
+            in_channels=self.in_channels,
+            out_channels=self.out_channels_cls,
+            kernel_size=3,
+            stride=1,
+            padding=1,
+            groups=1,
+            weight_attr=ParamAttr(
+                name='cls_weights',
+                initializer=Normal(
+                    mean=0., std=0.01)),
+            bias_attr=True)
+        self.out_conv_reg = nn.Conv2D(
+            in_channels=self.in_channels,
+            out_channels=self.out_channels_reg,
+            kernel_size=3,
+            stride=1,
+            padding=1,
+            groups=1,
+            weight_attr=ParamAttr(
+                name='reg_weights',
+                initializer=Normal(
+                    mean=0., std=0.01)),
+            bias_attr=True)
+
+    def forward(self, feats, targets=None):
+        cls_res, reg_res = multi_apply(self.forward_single, feats)
+        level_num = len(cls_res)
+        outs = {}
+        if not self.training:
+            for i in range(level_num):
+                tr_pred = F.softmax(cls_res[i][:, 0:2, :, :], axis=1)
+                tcl_pred = F.softmax(cls_res[i][:, 2:, :, :], axis=1)
+                outs['level_{}'.format(i)] = paddle.concat(
+                    [tr_pred, tcl_pred, reg_res[i]], axis=1)
+        else:
+            preds = [[cls_res[i], reg_res[i]] for i in range(level_num)]
+            outs['levels'] = preds
+        return outs
+
+    def forward_single(self, x):
+        cls_predict = self.out_conv_cls(x)
+        reg_predict = self.out_conv_reg(x)
+        return cls_predict, reg_predict