[PaddlePaddle Hackathon] Task 66 (#4317)

* allow forwarding for multi scale inputs

* fixed PadBatch not working with multi scale input

* add faster_rcnn_r34_fpn_multiscaletest_1x_coco.yml

* fixed multi scale input checking for batch transforms (PadBatch)

* less scales and faster inference for multi scale test configuration file

* fixed retrieving im_id from multi-scale inputs

* add multi scale prediction boxes merging

* allow multi scale testing for tools/infer.py (actually trainer.predict method)

* add MultiscaleTestResize setting for TestReader

* use BBoxPostProcess.nms parameter for multi scale prediction NMS of CascadeRCNN

* add documentation for multi scale testing

* raise exception if the network architecture is not supported in multi scale test mode

* move documentation file

* add test case for multi scale test

* load pretrained weights from URL

* add image files for testing. use relative path for input images

* update documentation

* use isinstance for sequence type checking. add empty checking for samples sequence

configs/faster_rcnn/faster_rcnn_r34_fpn_multiscaletest_1x_coco.yml

+_BASE_: [
+  'faster_rcnn_r34_fpn_1x_coco.yml',
+]
+
+pretrain_weights: https://paddledet.bj.bcebos.com/models/pretrained/ResNet34_pretrained.pdparams
+weights: output/faster_rcnn_r34_fpn_multiscaletest_1x_coco/model_final
+
+EvalReader:
+  sample_transforms:
+  - Decode: {}
+#  - Resize: {interp: 2, target_size: [800, 1333], keep_ratio: True}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900], use_flip: False}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
+
+TestReader:
+  sample_transforms:
+  - Decode: {}
+#  - Resize: {interp: 2, target_size: [800, 1333], keep_ratio: True}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900], use_flip: False}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
\ No newline at end of file

docs/tutorials/config_annotation/multi_scale_test_config.md

+# Multi Scale Test Configuration
+
+Tags: Configuration
+
+---
+```yaml
+
+##################################### Multi scale test configuration #####################################
+
+EvalReader:
+  sample_transforms:
+  - Decode: {}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900]}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
+
+TestReader:
+  sample_transforms:
+  - Decode: {}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900]}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
+```
+
+---
+
+Multi Scale Test is a TTA (Test Time Augmentation) method, it can improve object detection performance. 
+
+The input image will be scaled into different scales, then model generated predictions (bboxes) at different scales, finally all the predictions will be combined to generate final prediction. (Here **NMS** is used to aggregate the predictions.)
+
+## _MultiscaleTestResize_ option
+
+`MultiscaleTestResize` option is used to enable multi scale test prediction. 
+
+`origin_target_size: [800, 1333]` means the input image will be scaled to 800 (for short edge) and 1333 (max edge length cannot be greater than 1333) at first
+
+`target_size: [700 , 900]` property is used to specify different scales. 
+
+It can be plugged into evaluation process or test (inference) process, by adding `MultiscaleTestResize` entry to `EvalReader.sample_transforms` or `TestReader.sample_transforms`
+
+---
+
+###Note
+
+Now only CascadeRCNN, FasterRCNN and MaskRCNN are supported for multi scale testing. And batch size must be 1.
\ No newline at end of file

docs/tutorials/config_annotation/multi_scale_test_config_cn.md

+# 多尺度测试的配置
+
+标签: 配置
+
+---
+```yaml
+
+##################################### 多尺度测试的配置 #####################################
+
+EvalReader:
+  sample_transforms:
+  - Decode: {}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900]}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
+
+TestReader:
+  sample_transforms:
+  - Decode: {}
+  - MultiscaleTestResize: {origin_target_size: [800, 1333], target_size: [700 , 900]}
+  - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]}
+  - Permute: {}
+```
+
+---
+
+多尺度测试是一种TTA方法（测试时增强），可以用于提高目标检测的准确率
+
+输入图像首先被缩放为不同尺度的图像，然后模型对这些不同尺度的图像进行预测，最后将这些不同尺度上的预测结果整合为最终预测结果。（这里使用了**NMS**来整合不同尺度的预测结果）
+
+## _MultiscaleTestResize_ 选项
+
+`MultiscaleTestResize` 选项用于开启多尺度测试. 
+
+`origin_target_size: [800, 1333]` 项代表输入图像首先缩放为短边为800，最长边不超过1333.
+
+`target_size: [700 , 900]` 项设置不同的预测尺度。
+
+通过在`EvalReader.sample_transforms`或`TestReader.sample_transforms`中设置`MultiscaleTestResize`项，可以在评估过程或预测过程中开启多尺度测试。
+
+---
+
+###注意
+
+目前多尺度测试只支持CascadeRCNN, FasterRCNN and MaskRCNN网络, 并且batch size需要是1.
\ No newline at end of file

ppdet/data/transform/batch_operators.py

@@ -16,6 +16,8 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import typing
+
 try:
     from collections.abc import Sequence
 except Exception:
@@ -58,7 +60,13 @@ class PadBatch(BaseOperator):
         """
         coarsest_stride = self.pad_to_stride
 
-        max_shape = np.array([data['image'].shape for data in samples]).max(
+        # multi scale input is nested list
+        if isinstance(samples, typing.Sequence) and len(samples) > 0 and isinstance(samples[0], typing.Sequence):
+            inner_samples = samples[0]
+        else:
+            inner_samples = samples
+
+        max_shape = np.array([data['image'].shape for data in inner_samples]).max(
             axis=0)
         if coarsest_stride > 0:
             max_shape[1] = int(
@@ -66,7 +74,7 @@ class PadBatch(BaseOperator):
             max_shape[2] = int(
                 np.ceil(max_shape[2] / coarsest_stride) * coarsest_stride)
 
-        for data in samples:
+        for data in inner_samples:
             im = data['image']
             im_c, im_h, im_w = im.shape[:]
             padding_im = np.zeros(

ppdet/engine/trainer.py

@@ -22,6 +22,7 @@ import copy
 import time
 
 import numpy as np
+import typing
 from PIL import Image
 
 import paddle
@@ -428,7 +429,11 @@ class Trainer(object):
             for metric in self._metrics:
                 metric.update(data, outs)
 
-            sample_num += data['im_id'].numpy().shape[0]
+            # multi-scale inputs: all inputs have same im_id
+            if isinstance(data, typing.Sequence):
+                sample_num += data[0]['im_id'].numpy().shape[0]
+            else:
+                sample_num += data['im_id'].numpy().shape[0]
             self._compose_callback.on_step_end(self.status)
 
         self.status['sample_num'] = sample_num
@@ -471,7 +476,10 @@ class Trainer(object):
             outs = self.model(data)
 
             for key in ['im_shape', 'scale_factor', 'im_id']:
-                outs[key] = data[key]
+                if isinstance(data, typing.Sequence):
+                    outs[key] = data[0][key]
+                else:
+                    outs[key] = data[key]
             for key, value in outs.items():
                 if hasattr(value, 'numpy'):
                     outs[key] = value.numpy()

ppdet/metrics/metrics.py

@@ -21,6 +21,7 @@ import sys
 import json
 import paddle
 import numpy as np
+import typing
 
 from .map_utils import prune_zero_padding, DetectionMAP
 from .coco_utils import get_infer_results, cocoapi_eval
@@ -97,7 +98,11 @@ class COCOMetric(Metric):
         for k, v in outputs.items():
             outs[k] = v.numpy() if isinstance(v, paddle.Tensor) else v
 
-        im_id = inputs['im_id']
+        # multi-scale inputs: all inputs have same im_id
+        if isinstance(inputs, typing.Sequence):
+            im_id = inputs[0]['im_id']
+        else:
+            im_id = inputs['im_id']
         outs['im_id'] = im_id.numpy() if isinstance(im_id,
                                                     paddle.Tensor) else im_id
 

ppdet/modeling/architectures/meta_arch.py

@@ -2,9 +2,13 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
+import numpy as np
 import paddle
 import paddle.nn as nn
+import typing
+
 from ppdet.core.workspace import register
+from static.ppdet.utils.post_process import nms
 
 __all__ = ['BaseArch']
 
@@ -25,7 +29,53 @@ class BaseArch(nn.Layer):
         if self.training:
             out = self.get_loss()
         else:
-            out = self.get_pred()
+            inputs_list = []
+            # multi-scale input
+            if not isinstance(inputs, typing.Sequence):
+                inputs_list.append(inputs)
+            else:
+                inputs_list.extend(inputs)
+
+            outs = []
+            for inp in inputs_list:
+                self.inputs = inp
+                outs.append(self.get_pred())
+
+            # multi-scale test
+            if len(outs)>1:
+                out = self.merge_multi_scale_predictions(outs)
+            else:
+                out = outs[0]
+        return out
+
+    def merge_multi_scale_predictions(self, outs):
+        # default values for architectures not included in following list
+        num_classes = 80
+        nms_threshold = 0.5
+        keep_top_k = 100
+
+        if self.__class__.__name__ in ('CascadeRCNN', 'FasterRCNN', 'MaskRCNN'):
+            num_classes = self.bbox_head.num_classes
+            keep_top_k = self.bbox_post_process.nms.keep_top_k
+            nms_threshold = self.bbox_post_process.nms.nms_threshold
+        else:
+            raise Exception("Multi scale test only supports CascadeRCNN, FasterRCNN and MaskRCNN for now")
+
+        final_boxes = []
+        all_scale_outs = paddle.concat([o['bbox'] for o in outs]).numpy()
+        for c in range(num_classes):
+            idxs = all_scale_outs[:, 0] == c
+            if np.count_nonzero(idxs) == 0:
+                continue
+            r = nms(all_scale_outs[idxs, 1:], nms_threshold)
+            final_boxes.append(np.concatenate([np.full((r.shape[0], 1), c), r], 1))
+        out = np.concatenate(final_boxes)
+        out = np.concatenate(sorted(out, key=lambda e: e[1])[-keep_top_k:]).reshape((-1, 6))
+        out = {
+            'bbox': paddle.to_tensor(out),
+            'bbox_num': paddle.to_tensor(np.array([out.shape[0], ]))
+        }
+
         return out
 
     def build_inputs(self, data, input_def):

ppdet/modeling/tests/test_mstest.py

+#   Copyright (c) 2021 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 unittest
+from ppdet.core.workspace import load_config
+from ppdet.engine import Trainer
+
+class TestMultiScaleInference(unittest.TestCase):
+    def setUp(self):
+        self.set_config()
+
+    def set_config(self):
+        self.mstest_cfg_file = 'configs/faster_rcnn/faster_rcnn_r34_fpn_multiscaletest_1x_coco.yml'
+
+    # test evaluation with multi scale test
+    def test_eval_mstest(self):
+        cfg = load_config(self.mstest_cfg_file)
+        trainer = Trainer(cfg, mode='eval')
+
+        cfg.weights = 'https://paddledet.bj.bcebos.com/models/faster_rcnn_r34_fpn_1x_coco.pdparams'
+        trainer.load_weights(cfg.weights)
+
+        trainer.evaluate()
+
+    # test inference with multi scale test
+    def test_infer_mstest(self):
+        cfg = load_config(self.mstest_cfg_file)
+        trainer = Trainer(cfg, mode='test')
+
+        cfg.weights = 'https://paddledet.bj.bcebos.com/models/faster_rcnn_r34_fpn_1x_coco.pdparams'
+        trainer.load_weights(cfg.weights)
+        tests_img_root = os.path.join(os.path.dirname(__file__), 'imgs')
+
+        # input images to predict
+        imgs = ['coco2017_val2017_000000000139.jpg', 'coco2017_val2017_000000000724.jpg']
+        imgs = [os.path.join(tests_img_root, img) for img in imgs]
+        trainer.predict(imgs,
+                        draw_threshold=0.5,
+                        output_dir='output',
+                        save_txt=True)
+
+
+if __name__ == '__main__':
+    unittest.main()