[new api] add new api paddle.vision.ops.distribute_fpn_proposals (#43736)

* add distribute_fpn_proposals

* change to new dygraph

* fix doc and example code

* change fluid impl to current version

python/paddle/fluid/layers/detection.py

@@ -17,6 +17,8 @@ All layers just related to the detection neural network.
 
 from __future__ import print_function
 
+import paddle
+
 from .layer_function_generator import generate_layer_fn
 from .layer_function_generator import autodoc, templatedoc
 from ..layer_helper import LayerHelper
@@ -3774,52 +3776,13 @@ def distribute_fpn_proposals(fpn_rois,
                 refer_level=4,
                 refer_scale=224)
     """
-    num_lvl = max_level - min_level + 1
-
-    if _non_static_mode():
-        assert rois_num is not None, "rois_num should not be None in dygraph mode."
-        attrs = ('min_level', min_level, 'max_level', max_level, 'refer_level',
-                 refer_level, 'refer_scale', refer_scale)
-        multi_rois, restore_ind, rois_num_per_level = _C_ops.distribute_fpn_proposals(
-            fpn_rois, rois_num, num_lvl, num_lvl, *attrs)
-        return multi_rois, restore_ind, rois_num_per_level
-
-    check_variable_and_dtype(fpn_rois, 'fpn_rois', ['float32', 'float64'],
-                             'distribute_fpn_proposals')
-    helper = LayerHelper('distribute_fpn_proposals', **locals())
-    dtype = helper.input_dtype('fpn_rois')
-    multi_rois = [
-        helper.create_variable_for_type_inference(dtype) for i in range(num_lvl)
-    ]
-
-    restore_ind = helper.create_variable_for_type_inference(dtype='int32')
-
-    inputs = {'FpnRois': fpn_rois}
-    outputs = {
-        'MultiFpnRois': multi_rois,
-        'RestoreIndex': restore_ind,
-    }
-
-    if rois_num is not None:
-        inputs['RoisNum'] = rois_num
-        rois_num_per_level = [
-            helper.create_variable_for_type_inference(dtype='int32')
-            for i in range(num_lvl)
-        ]
-        outputs['MultiLevelRoIsNum'] = rois_num_per_level
-
-    helper.append_op(type='distribute_fpn_proposals',
-                     inputs=inputs,
-                     outputs=outputs,
-                     attrs={
-                         'min_level': min_level,
-                         'max_level': max_level,
-                         'refer_level': refer_level,
-                         'refer_scale': refer_scale
-                     })
-    if rois_num is not None:
-        return multi_rois, restore_ind, rois_num_per_level
-    return multi_rois, restore_ind
+    return paddle.vision.ops.distribute_fpn_proposals(fpn_rois=fpn_rois,
+                                                      min_level=min_level,
+                                                      max_level=max_level,
+                                                      refer_level=refer_level,
+                                                      refer_scale=refer_scale,
+                                                      rois_num=rois_num,
+                                                      name=name)
 
 
 @templatedoc()

python/paddle/fluid/tests/unittests/test_distribute_fpn_proposals_op.py

-#    Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
+# Copyright (c) 2019 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.
@@ -18,6 +18,8 @@ import unittest
 import numpy as np
 import math
 import sys
+import paddle
+
 from op_test import OpTest
 
 
@@ -164,5 +166,62 @@ class TestDistributeFPNProposalsOpNoOffset(
         self.pixel_offset = False
 
 
+class TestDistributeFpnProposalsAPI(unittest.TestCase):
+
+    def setUp(self):
+        np.random.seed(678)
+        self.rois_np = np.random.rand(10, 4).astype('float32')
+        self.rois_num_np = np.array([4, 6]).astype('int32')
+
+    def test_dygraph_with_static(self):
+        paddle.enable_static()
+        rois = paddle.static.data(name='rois', shape=[10, 4], dtype='float32')
+        rois_num = paddle.static.data(name='rois_num',
+                                      shape=[None],
+                                      dtype='int32')
+        multi_rois, restore_ind, rois_num_per_level = paddle.vision.ops.distribute_fpn_proposals(
+            fpn_rois=rois,
+            min_level=2,
+            max_level=5,
+            refer_level=4,
+            refer_scale=224,
+            rois_num=rois_num)
+        fetch_list = multi_rois + [restore_ind] + rois_num_per_level
+
+        exe = paddle.static.Executor()
+        output_stat = exe.run(paddle.static.default_main_program(),
+                              feed={
+                                  'rois': self.rois_np,
+                                  'rois_num': self.rois_num_np
+                              },
+                              fetch_list=fetch_list,
+                              return_numpy=False)
+        output_stat_np = []
+        for output in output_stat:
+            output_np = np.array(output)
+            if len(output_np) > 0:
+                output_stat_np.append(output_np)
+
+        paddle.disable_static()
+        rois_dy = paddle.to_tensor(self.rois_np)
+        rois_num_dy = paddle.to_tensor(self.rois_num_np)
+        multi_rois_dy, restore_ind_dy, rois_num_per_level_dy = paddle.vision.ops.distribute_fpn_proposals(
+            fpn_rois=rois_dy,
+            min_level=2,
+            max_level=5,
+            refer_level=4,
+            refer_scale=224,
+            rois_num=rois_num_dy)
+        output_dy = multi_rois_dy + [restore_ind_dy] + rois_num_per_level_dy
+        output_dy_np = []
+        for output in output_dy:
+            output_np = output.numpy()
+            if len(output_np) > 0:
+                output_dy_np.append(output_np)
+
+        for res_stat, res_dy in zip(output_stat_np, output_dy_np):
+            self.assertTrue(np.allclose(res_stat, res_dy))
+
+
 if __name__ == '__main__':
     unittest.main()

python/paddle/vision/ops.py

@@ -28,6 +28,7 @@ __all__ = [  #noqa
     'yolo_box',
     'deform_conv2d',
     'DeformConv2D',
+    'distribute_fpn_proposals',
     'read_file',
     'decode_jpeg',
     'roi_pool',
@@ -835,6 +836,123 @@ class DeformConv2D(Layer):
         return out
 
 
+def distribute_fpn_proposals(fpn_rois,
+                             min_level,
+                             max_level,
+                             refer_level,
+                             refer_scale,
+                             pixel_offset=False,
+                             rois_num=None,
+                             name=None):
+    r"""
+        In Feature Pyramid Networks (FPN) models, it is needed to distribute 
+    all proposals into different FPN level, with respect to scale of the proposals, 
+    the referring scale and the referring level. Besides, to restore the order of 
+    proposals, we return an array which indicates the original index of rois 
+    in current proposals. To compute FPN level for each roi, the formula is given as follows:
+    
+    .. math::
+        roi\_scale &= \sqrt{BBoxArea(fpn\_roi)}
+        level = floor(&\log(\\frac{roi\_scale}{refer\_scale}) + refer\_level)
+    where BBoxArea is a function to compute the area of each roi.
+
+    Args:
+        fpn_rois (Tensor): The input fpn_rois. 2-D Tensor with shape [N, 4] and data type can be
+            float32 or float64.
+        min_level (int): The lowest level of FPN layer where the proposals come 
+            from.
+        max_level (int): The highest level of FPN layer where the proposals
+            come from.
+        refer_level (int): The referring level of FPN layer with specified scale.
+        refer_scale (int): The referring scale of FPN layer with specified level.
+        pixel_offset (bool, optional): Whether there is pixel offset. If True, the offset of 
+            image shape will be 1. 'False' by default.
+        rois_num (Tensor, optional): 1-D Tensor contains the number of RoIs in each image. 
+            The shape is [B] and data type is int32. B is the number of images.
+            If rois_num not None, it will return a list of 1-D Tensor. Each element 
+            is the output RoIs' number of each image on the corresponding level
+            and the shape is [B]. None by default.
+        name (str, optional): For detailed information, please refer 
+            to :ref:`api_guide_Name`. Usually name is no need to set and 
+            None by default. 
+
+    Returns:
+        multi_rois (List) : The proposals in each FPN level. It is a list of 2-D Tensor with shape [M, 4], where M is
+            and data type is same as `fpn_rois` . The length is max_level-min_level+1.         
+        restore_ind (Tensor): The index used to restore the order of fpn_rois. It is a 2-D Tensor with shape [N, 1]
+            , where N is the number of total rois. The data type is int32. 
+        rois_num_per_level (List): A list of 1-D Tensor and each Tensor is 
+            the RoIs' number in each image on the corresponding level. The shape 
+            is [B] and data type of int32, where B is the number of images.
+
+    Examples:
+        .. code-block:: python
+
+            import paddle
+
+            fpn_rois = paddle.rand((10, 4))
+            rois_num = paddle.to_tensor([3, 1, 4, 2], dtype=paddle.int32)
+
+            multi_rois, restore_ind, rois_num_per_level = paddle.vision.ops.distribute_fpn_proposals(
+                fpn_rois=fpn_rois,
+                min_level=2,
+                max_level=5,
+                refer_level=4,
+                refer_scale=224,
+                rois_num=rois_num)
+    """
+    num_lvl = max_level - min_level + 1
+
+    if _non_static_mode():
+        assert rois_num is not None, "rois_num should not be None in dygraph mode."
+        attrs = ('min_level', min_level, 'max_level', max_level, 'refer_level',
+                 refer_level, 'refer_scale', refer_scale, 'pixel_offset',
+                 pixel_offset)
+        multi_rois, restore_ind, rois_num_per_level = _C_ops.distribute_fpn_proposals(
+            fpn_rois, rois_num, num_lvl, num_lvl, *attrs)
+        return multi_rois, restore_ind, rois_num_per_level
+
+    else:
+        check_variable_and_dtype(fpn_rois, 'fpn_rois', ['float32', 'float64'],
+                                 'distribute_fpn_proposals')
+        helper = LayerHelper('distribute_fpn_proposals', **locals())
+        dtype = helper.input_dtype('fpn_rois')
+        multi_rois = [
+            helper.create_variable_for_type_inference(dtype)
+            for i in range(num_lvl)
+        ]
+
+        restore_ind = helper.create_variable_for_type_inference(dtype='int32')
+
+        inputs = {'FpnRois': fpn_rois}
+        outputs = {
+            'MultiFpnRois': multi_rois,
+            'RestoreIndex': restore_ind,
+        }
+
+        if rois_num is not None:
+            inputs['RoisNum'] = rois_num
+            rois_num_per_level = [
+                helper.create_variable_for_type_inference(dtype='int32')
+                for i in range(num_lvl)
+            ]
+            outputs['MultiLevelRoIsNum'] = rois_num_per_level
+        else:
+            rois_num_per_level = None
+
+        helper.append_op(type='distribute_fpn_proposals',
+                         inputs=inputs,
+                         outputs=outputs,
+                         attrs={
+                             'min_level': min_level,
+                             'max_level': max_level,
+                             'refer_level': refer_level,
+                             'refer_scale': refer_scale,
+                             'pixel_offset': pixel_offset
+                         })
+        return multi_rois, restore_ind, rois_num_per_level
+
+
 def read_file(filename, name=None):
     """
     Reads and outputs the bytes contents of a file as a uint8 Tensor