add libra rcnn (#198)

add libra rcnn, including
  * libra loss
  * libra fpn(bfp)
  * libra sampling

.gitignore

@@ -4,6 +4,7 @@
 
 # Byte-compiled / optimized / DLL files
 __pycache__/
+.ipynb_checkpoints/
 *.py[cod]
 
 # C extensions

configs/libra_rcnn/README.md

+# Libra R-CNN: Towards Balanced Learning for Object Detection
+
+## Introduction
+
+- Libra R-CNN: Towards Balanced Learning for Object Detection
+: [https://arxiv.org/abs/1904.02701](https://arxiv.org/abs/1904.02701)
+
+```
+@inproceedings{pang2019libra,
+  title={Libra R-CNN: Towards Balanced Learning for Object Detection},
+  author={Pang, Jiangmiao and Chen, Kai and Shi, Jianping and Feng, Huajun and Ouyang, Wanli and Dahua Lin},
+  booktitle={IEEE Conference on Computer Vision and Pattern Recognition},
+  year={2019}
+}
+```
+
+
+## Model Zoo
+
+| Backbone                | Type     | Image/gpu | Lr schd | Inf time (fps) | Box AP | Mask AP |                           Download                           |
+| :---------------------- | :-------------:  | :-------: | :-----: | :------------: | :----: | :-----: | :----------------------------------------------------------: |
+| ResNet50-vd-BFP         | Faster     |     2     |   1x    |     18.247     |  40.5  |    -    | [model](https://paddlemodels.bj.bcebos.com/object_detection/libra_rcnn_r50_vd_fpn_1x.tar) |
+| ResNet101-vd-BFP         | Faster     |     2     |   1x    |     14.865     |  42.5  |    -    | [model](https://paddlemodels.bj.bcebos.com/object_detection/libra_rcnn_r101_vd_fpn_1x.tar) |

configs/libra_rcnn/libra_rcnn_r101_vd_fpn_1x.yml

+architecture: FasterRCNN
+max_iters: 90000
+snapshot_iter: 10000
+use_gpu: true
+log_smooth_window: 20
+save_dir: output
+pretrain_weights: https://paddle-imagenet-models-name.bj.bcebos.com/ResNet101_vd_pretrained.tar
+weights: output/libra_rcnn_r101_vd_fpn_1x/model_final
+metric: COCO
+num_classes: 81
+
+FasterRCNN:
+  backbone: ResNet
+  fpn: BFP
+  rpn_head: FPNRPNHead
+  roi_extractor: FPNRoIAlign
+  bbox_head: BBoxHead
+  bbox_assigner: LibraBBoxAssigner
+
+ResNet:
+  depth: 101
+  feature_maps: [2, 3, 4, 5]
+  freeze_at: 2
+  norm_type: bn
+  variant: d
+
+BFP:
+  base_neck:
+    max_level: 6
+    min_level: 2
+    num_chan: 256
+    spatial_scale: [0.03125, 0.0625, 0.125, 0.25]
+  refine_level: 2
+  refine_type: nonlocal
+  nonlocal_reduction: 1.0
+
+FPNRPNHead:
+  anchor_generator:
+    anchor_sizes: [32, 64, 128, 256, 512]
+    aspect_ratios: [0.5, 1.0, 2.0]
+    stride: [16.0, 16.0]
+    variance: [1.0, 1.0, 1.0, 1.0]
+  anchor_start_size: 32
+  max_level: 6
+  min_level: 2
+  num_chan: 256
+  rpn_target_assign:
+    rpn_batch_size_per_im: 256
+    rpn_fg_fraction: 0.5
+    rpn_negative_overlap: 0.3
+    rpn_positive_overlap: 0.7
+    rpn_straddle_thresh: 0.0
+  train_proposal:
+    min_size: 0.0
+    nms_thresh: 0.7
+    post_nms_top_n: 2000
+    pre_nms_top_n: 2000
+  test_proposal:
+    min_size: 0.0
+    nms_thresh: 0.7
+    post_nms_top_n: 1000
+    pre_nms_top_n: 1000
+
+FPNRoIAlign:
+  canconical_level: 4
+  canonical_size: 224
+  max_level: 5
+  min_level: 2
+  box_resolution: 7
+  sampling_ratio: 2
+
+LibraBBoxAssigner:
+  batch_size_per_im: 512
+  bbox_reg_weights: [0.1, 0.1, 0.2, 0.2]
+  bg_thresh_hi: 0.5
+  bg_thresh_lo: 0.0
+  fg_fraction: 0.25
+  fg_thresh: 0.5
+
+BBoxHead:
+  head: TwoFCHead
+  nms:
+    keep_top_k: 100
+    nms_threshold: 0.5
+    score_threshold: 0.05
+  bbox_loss: BalancedL1Loss
+
+BalancedL1Loss:
+  alpha: 0.5
+  gamma: 1.5
+  beta: 1.0
+  loss_weight: 1.0
+
+TwoFCHead:
+  mlp_dim: 1024
+
+LearningRate:
+  base_lr: 0.02
+  schedulers:
+  - !PiecewiseDecay
+    gamma: 0.1
+    milestones: [60000, 80000]
+  - !LinearWarmup
+    start_factor: 0.1
+    steps: 1000
+
+OptimizerBuilder:
+  optimizer:
+    momentum: 0.9
+    type: Momentum
+  regularizer:
+    factor: 0.0001
+    type: L2
+
+_READER_: '../faster_fpn_reader.yml'
+TrainReader:
+  batch_size: 2

configs/libra_rcnn/libra_rcnn_r50_vd_fpn_1x.yml

+architecture: FasterRCNN
+max_iters: 90000
+snapshot_iter: 10000
+use_gpu: true
+log_smooth_window: 20
+save_dir: output
+pretrain_weights: https://paddle-imagenet-models-name.bj.bcebos.com/ResNet50_vd_pretrained.tar
+weights: output/libra_rcnn_r50_vd_fpn_1x/model_final
+metric: COCO
+num_classes: 81
+
+FasterRCNN:
+  backbone: ResNet
+  fpn: BFP
+  rpn_head: FPNRPNHead
+  roi_extractor: FPNRoIAlign
+  bbox_head: BBoxHead
+  bbox_assigner: LibraBBoxAssigner
+
+ResNet:
+  depth: 50
+  feature_maps: [2, 3, 4, 5]
+  freeze_at: 2
+  norm_type: bn
+  variant: d
+
+BFP:
+  base_neck:
+    max_level: 6
+    min_level: 2
+    num_chan: 256
+    spatial_scale: [0.03125, 0.0625, 0.125, 0.25]
+  refine_level: 2
+  refine_type: nonlocal
+  nonlocal_reduction: 1.0
+
+FPNRPNHead:
+  anchor_generator:
+    anchor_sizes: [32, 64, 128, 256, 512]
+    aspect_ratios: [0.5, 1.0, 2.0]
+    stride: [16.0, 16.0]
+    variance: [1.0, 1.0, 1.0, 1.0]
+  anchor_start_size: 32
+  max_level: 6
+  min_level: 2
+  num_chan: 256
+  rpn_target_assign:
+    rpn_batch_size_per_im: 256
+    rpn_fg_fraction: 0.5
+    rpn_negative_overlap: 0.3
+    rpn_positive_overlap: 0.7
+    rpn_straddle_thresh: 0.0
+  train_proposal:
+    min_size: 0.0
+    nms_thresh: 0.7
+    post_nms_top_n: 2000
+    pre_nms_top_n: 2000
+  test_proposal:
+    min_size: 0.0
+    nms_thresh: 0.7
+    post_nms_top_n: 1000
+    pre_nms_top_n: 1000
+
+FPNRoIAlign:
+  canconical_level: 4
+  canonical_size: 224
+  max_level: 5
+  min_level: 2
+  box_resolution: 7
+  sampling_ratio: 2
+
+LibraBBoxAssigner:
+  batch_size_per_im: 512
+  bbox_reg_weights: [0.1, 0.1, 0.2, 0.2]
+  bg_thresh_hi: 0.5
+  bg_thresh_lo: 0.0
+  fg_fraction: 0.25
+  fg_thresh: 0.5
+
+BBoxHead:
+  head: TwoFCHead
+  nms:
+    keep_top_k: 100
+    nms_threshold: 0.5
+    score_threshold: 0.05
+  bbox_loss: BalancedL1Loss
+
+BalancedL1Loss:
+  alpha: 0.5
+  gamma: 1.5
+  beta: 1.0
+  loss_weight: 1.0
+
+TwoFCHead:
+  mlp_dim: 1024
+
+LearningRate:
+  base_lr: 0.02
+  schedulers:
+  - !PiecewiseDecay
+    gamma: 0.1
+    milestones: [60000, 80000]
+  - !LinearWarmup
+    start_factor: 0.1
+    steps: 1000
+
+OptimizerBuilder:
+  optimizer:
+    momentum: 0.9
+    type: Momentum
+  regularizer:
+    factor: 0.0001
+    type: L2
+
+_READER_: '../faster_fpn_reader.yml'
+TrainReader:
+  batch_size: 2

ppdet/modeling/backbones/__init__.py

@@ -27,6 +27,7 @@ from . import cb_resnet
 from . import res2net
 from . import hrnet
 from . import hrfpn
+from . import bfp
 
 from .resnet import *
 from .resnext import *
@@ -40,4 +41,5 @@ from .faceboxnet import *
 from .cb_resnet import *
 from .res2net import *
 from .hrnet import *
-from .hrfpn import *
\ No newline at end of file
+from .hrfpn import *
+from .bfp import *

ppdet/modeling/backbones/bfp.py

+# 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.
+# 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 sys
+
+from collections import OrderedDict
+
+from paddle import fluid
+from paddle.fluid.param_attr import ParamAttr
+from paddle.fluid.initializer import Xavier
+from paddle.fluid.regularizer import L2Decay
+
+from ppdet.core.workspace import register
+
+from .nonlocal_helper import add_space_nonlocal
+from .fpn import FPN
+
+__all__ = ['BFP']
+
+
+@register
+class BFP(object):
+    """
+    Libra R-CNN, see https://arxiv.org/abs/1904.02701
+    Args:
+        base_neck (dict): basic neck before balanced feature pyramid (bfp)
+        refine_level (int): index of integration and refine level of bfp
+        refine_type (str): refine type, None, conv or nonlocal
+        nonlocal_reduction (float): channel reduction level if refine_type is nonlocal
+        with_bias (bool): whether the nonlocal module contains bias
+        with_scale (bool): whether to scale feature in nonlocal module or not
+    """
+    __inject__ = ['base_neck']
+
+    def __init__(self,
+                 base_neck=FPN().__dict__,
+                 refine_level=2,
+                 refine_type="nonlocal",
+                 nonlocal_reduction=1,
+                 with_bias=True,
+                 with_scale=False):
+        if isinstance(base_neck, dict):
+            self.base_neck = FPN(**base_neck)
+        self.refine_level = refine_level
+        self.refine_type = refine_type
+        self.nonlocal_reduction = nonlocal_reduction
+        self.with_bias = with_bias
+        self.with_scale = with_scale
+
+    def get_output(self, body_dict):
+        # top-down order
+        res_dict, spatial_scale = self.base_neck.get_output(body_dict)
+        res_dict = self.get_output_bfp(res_dict)
+        return res_dict, spatial_scale
+
+    def get_output_bfp(self, body_dict):
+        body_name_list = list(body_dict.keys())
+        num_backbone_stages = len(body_name_list)
+
+        self.num_levels = len(body_dict)
+
+        # step 1: gather multi-level features by resize and average
+        feats = []
+        refine_level_name = body_name_list[self.refine_level]
+
+        for i in range(self.num_levels):
+            curr_fpn_name = body_name_list[i]
+            pool_stride = 2**(i - self.refine_level)
+            pool_size = [
+                body_dict[refine_level_name].shape[2],
+                body_dict[refine_level_name].shape[3]
+            ]
+            if i > self.refine_level:
+                gathered = fluid.layers.pool2d(
+                    input=body_dict[curr_fpn_name],
+                    pool_type='max',
+                    pool_size=pool_stride,
+                    pool_stride=pool_stride,
+                    ceil_mode=True, )
+            else:
+                gathered = self._resize_input_tensor(
+                    body_dict[curr_fpn_name], body_dict[refine_level_name],
+                    1.0 / pool_stride)
+            feats.append(gathered)
+
+        bsf = sum(feats) / len(feats)
+
+        # step 2: refine gathered features
+        if self.refine_type == "conv":
+            bsf = fluid.layers.conv2d(
+                bsf,
+                bsf.shape[1],
+                filter_size=3,
+                padding=1,
+                param_attr=ParamAttr(name="bsf_w"),
+                bias_attr=ParamAttr(name="bsf_b"),
+                name="bsf")
+        elif self.refine_type == "nonlocal":
+            dim_in = bsf.shape[1]
+            nonlocal_name = "nonlocal_bsf"
+            bsf = add_space_nonlocal(
+                bsf,
+                bsf.shape[1],
+                bsf.shape[1],
+                nonlocal_name,
+                int(bsf.shape[1] / self.nonlocal_reduction),
+                with_bias=self.with_bias,
+                with_scale=self.with_scale)
+
+        # step 3: scatter refined features to multi-levels by a residual path
+        fpn_dict = {}
+        fpn_name_list = []
+        for i in range(self.num_levels):
+            curr_fpn_name = body_name_list[i]
+            pool_stride = 2**(self.refine_level - i)
+            if i >= self.refine_level:
+                residual = self._resize_input_tensor(
+                    bsf, body_dict[curr_fpn_name], 1.0 / pool_stride)
+            else:
+                residual = fluid.layers.pool2d(
+                    input=bsf,
+                    pool_type='max',
+                    pool_size=pool_stride,
+                    pool_stride=pool_stride,
+                    ceil_mode=True, )
+
+            fpn_dict[curr_fpn_name] = residual + body_dict[curr_fpn_name]
+            fpn_name_list.append(curr_fpn_name)
+
+        res_dict = OrderedDict([(k, fpn_dict[k]) for k in fpn_name_list])
+        return res_dict
+
+    def _resize_input_tensor(self, body_input, ref_output, scale):
+        shape = fluid.layers.shape(ref_output)
+        shape_hw = fluid.layers.slice(shape, axes=[0], starts=[2], ends=[4])
+        out_shape_ = shape_hw
+        out_shape = fluid.layers.cast(out_shape_, dtype='int32')
+        out_shape.stop_gradient = True
+        body_output = fluid.layers.resize_nearest(
+            body_input, scale=scale, actual_shape=out_shape)
+        return body_output

ppdet/modeling/backbones/nonlocal_helper.py

@@ -5,95 +5,72 @@ from __future__ import unicode_literals
 
 import paddle.fluid as fluid
 from paddle.fluid import ParamAttr
+from paddle.fluid.initializer import ConstantInitializer
 
-                
-nonlocal_params = {
-    "use_zero_init_conv" : False,
-    "conv_init_std" : 0.01,
-    "no_bias"       : True,
-    "use_maxpool"   : False,
-    "use_softmax"   : True,
-    "use_bn"        : False,
-    "use_scale"     : True,  # vital for the model prformance!!!
-    "use_affine"    : False,
-    "bn_momentum"   : 0.9,
-    "bn_epsilon"    : 1.0000001e-5,
-    "bn_init_gamma" : 0.9,
-    "weight_decay_bn":1.e-4,
-    
-}
 
-
-def space_nonlocal(input, dim_in, dim_out, prefix, dim_inner, max_pool_stride = 2):
-    cur = input
-    theta = fluid.layers.conv2d(input = cur, num_filters = dim_inner, \
-                                filter_size = [1, 1], stride = [1, 1], \
-                                padding = [0, 0], \
-                                param_attr=ParamAttr(name = prefix + '_theta' + "_w", \
-                                    initializer = fluid.initializer.Normal(loc = 0.0, 
-                                    scale = nonlocal_params["conv_init_std"])), \
-                                bias_attr = ParamAttr(name = prefix + '_theta' + "_b", \
-                                    initializer = fluid.initializer.Constant(value = 0.)) \
-                                        if not nonlocal_params["no_bias"] else False, \
-                                name = prefix + '_theta')
+def space_nonlocal(input,
+                   dim_in,
+                   dim_out,
+                   prefix,
+                   dim_inner,
+                   with_bias=False,
+                   with_scale=True):
+    theta = fluid.layers.conv2d(
+        input=input,
+        num_filters=dim_inner,
+        filter_size=1,
+        stride=1,
+        padding=0,
+        param_attr=ParamAttr(name=prefix + '_theta_w'),
+        bias_attr=ParamAttr(
+            name=prefix + '_theta_b', initializer=ConstantInitializer(value=0.))
+        if with_bias else False)
     theta_shape = theta.shape
-    theta_shape_op = fluid.layers.shape( theta )
+    theta_shape_op = fluid.layers.shape(theta)
     theta_shape_op.stop_gradient = True
-    
-    if nonlocal_params["use_maxpool"]:
-        max_pool = fluid.layers.pool2d(input = cur, \
-                                        pool_size = [max_pool_stride, max_pool_stride], \
-                                        pool_type = 'max', \
-                                        pool_stride = [max_pool_stride, max_pool_stride], \
-                                        pool_padding = [0, 0], \
-                                        name = prefix + '_pool')
-    else:
-        max_pool = cur
-    
-    phi = fluid.layers.conv2d(input = max_pool, num_filters = dim_inner, \
-                             filter_size = [1, 1], stride = [1, 1], \
-                             padding = [0, 0], \
-                             param_attr = ParamAttr(name = prefix + '_phi' + "_w", \
-                                 initializer = fluid.initializer.Normal(loc = 0.0, 
-                                 scale = nonlocal_params["conv_init_std"])), \
-                             bias_attr = ParamAttr(name = prefix + '_phi' + "_b", \
-                                 initializer = fluid.initializer.Constant(value = 0.)) \
-                                      if (nonlocal_params["no_bias"] == 0) else False, \
-                             name = prefix + '_phi')
-    phi_shape = phi.shape
-    
-    g = fluid.layers.conv2d(input = max_pool, num_filters = dim_inner, \
-                 filter_size = [1, 1], stride = [1, 1], \
-                 padding = [0, 0], \
-                 param_attr = ParamAttr(name = prefix + '_g' + "_w", \
-                     initializer = fluid.initializer.Normal(loc = 0.0, scale = nonlocal_params["conv_init_std"])), \
-                 bias_attr = ParamAttr(name = prefix + '_g' + "_b", \
-                     initializer = fluid.initializer.Constant(value = 0.)) if (nonlocal_params["no_bias"] == 0) else False, \
-                 name = prefix + '_g')
-    g_shape = g.shape
+
     # we have to use explicit batch size (to support arbitrary spacetime size)
     # e.g. (8, 1024, 4, 14, 14) => (8, 1024, 784)
-    theta = fluid.layers.reshape(theta, shape=(0, 0, -1) )
+    theta = fluid.layers.reshape(theta, shape=(0, 0, -1))
     theta = fluid.layers.transpose(theta, [0, 2, 1])
+
+    phi = fluid.layers.conv2d(
+        input=input,
+        num_filters=dim_inner,
+        filter_size=1,
+        stride=1,
+        padding=0,
+        param_attr=ParamAttr(name=prefix + '_phi_w'),
+        bias_attr=ParamAttr(
+            name=prefix + '_phi_b', initializer=ConstantInitializer(value=0.))
+        if with_bias else False,
+        name=prefix + '_phi')
     phi = fluid.layers.reshape(phi, [0, 0, -1])
-    theta_phi = fluid.layers.matmul(theta, phi, name = prefix + '_affinity')
+
+    theta_phi = fluid.layers.matmul(theta, phi)
+
+    g = fluid.layers.conv2d(
+        input=input,
+        num_filters=dim_inner,
+        filter_size=1,
+        stride=1,
+        padding=0,
+        param_attr=ParamAttr(name=prefix + '_g_w'),
+        bias_attr=ParamAttr(
+            name=prefix + '_g_b', initializer=ConstantInitializer(value=0.))
+        if with_bias else False,
+        name=prefix + '_g')
     g = fluid.layers.reshape(g, [0, 0, -1])
-    
-    if nonlocal_params["use_softmax"]:
-        if nonlocal_params["use_scale"]:
-            theta_phi_sc = fluid.layers.scale(theta_phi, scale = dim_inner**-.5)
-        else:
-            theta_phi_sc = theta_phi
-        p = fluid.layers.softmax(theta_phi_sc, name = prefix + '_affinity' + '_prob')
-    else:
-        # not clear about what is doing in xlw's code
-        p = None  # not implemented
-        raise "Not implemented when not use softmax"
+
+    # scale
+    if with_scale:
+        theta_phi = fluid.layers.scale(theta_phi, scale=dim_inner**-.5)
+    p = fluid.layers.softmax(theta_phi)
 
     # note g's axis[2] corresponds to p's axis[2]
     # e.g. g(8, 1024, 784_2) * p(8, 784_1, 784_2) => (8, 1024, 784_1)
     p = fluid.layers.transpose(p, [0, 2, 1])
-    t = fluid.layers.matmul(g, p, name = prefix + '_y')
+    t = fluid.layers.matmul(g, p)
 
     # reshape back
     # e.g. (8, 1024, 784) => (8, 1024, 4, 14, 14)
@@ -104,56 +81,40 @@ def space_nonlocal(input, dim_in, dim_out, prefix, dim_inner, max_pool_stride =
 
     t_re = fluid.layers.reshape(t, shape=[n, ch, h, w])
     blob_out = t_re
-    blob_out = fluid.layers.conv2d(input = blob_out, num_filters = dim_out, \
-                                  filter_size = [1, 1], stride = [1, 1], padding = [0, 0], \
-                                  param_attr = ParamAttr(name = prefix + '_out' + "_w", \
-                                      initializer = fluid.initializer.Constant(value = 0.) \
-                                        if nonlocal_params["use_zero_init_conv"] \
-                                        else fluid.initializer.Normal(loc = 0.0, 
-                                            scale = nonlocal_params["conv_init_std"])), \
-                                  bias_attr = ParamAttr(name = prefix + '_out' + "_b", \
-                                          initializer = fluid.initializer.Constant(value = 0.)) \
-                                           if (nonlocal_params["no_bias"] == 0) else False, \
-                                  name = prefix + '_out')
+    blob_out = fluid.layers.conv2d(
+        input=blob_out,
+        num_filters=dim_out,
+        filter_size=1,
+        stride=1,
+        padding=0,
+        param_attr=ParamAttr(
+            name=prefix + '_out_w', initializer=ConstantInitializer(value=0.0)),
+        bias_attr=ParamAttr(
+            name=prefix + '_out_b', initializer=ConstantInitializer(value=0.0))
+        if with_bias else False,
+        name=prefix + '_out')
     blob_out_shape = blob_out.shape
-    
-
-    if nonlocal_params["use_bn"]:
-        bn_name = prefix + "_bn"
-        blob_out = fluid.layers.batch_norm(blob_out, \
-                      # is_test = test_mode, \
-                      momentum = nonlocal_params["bn_momentum"], \
-                      epsilon = nonlocal_params["bn_epsilon"], \
-                      name = bn_name, \
-                      param_attr = ParamAttr(name = bn_name + "_s", \
-                      initializer = fluid.initializer.Constant(value = nonlocal_params["bn_init_gamma"]), \
-                      regularizer = fluid.regularizer.L2Decay(nonlocal_params["weight_decay_bn"])), \
-                      bias_attr = ParamAttr(name = bn_name + "_b", \
-                      regularizer = fluid.regularizer.L2Decay(nonlocal_params["weight_decay_bn"])), \
-                      moving_mean_name = bn_name + "_rm", \
-                      moving_variance_name = bn_name + "_riv") # add bn
-    
-    if nonlocal_params["use_affine"]:
-        affine_scale = fluid.layers.create_parameter(\
-                       shape=[blob_out_shape[1]], dtype = blob_out.dtype, \
-                       attr=ParamAttr(name=prefix + '_affine' + '_s'), \
-                       default_initializer = fluid.initializer.Constant(value = 1.))
-        affine_bias = fluid.layers.create_parameter(\
-                      shape=[blob_out_shape[1]], dtype = blob_out.dtype, \
-                      attr=ParamAttr(name=prefix + '_affine' + '_b'), \
-                      default_initializer = fluid.initializer.Constant(value = 0.))
-        blob_out = fluid.layers.affine_channel(blob_out, scale = affine_scale, \
-                      bias = affine_bias, name = prefix + '_affine')   # add affine
-    
     return blob_out
 
 
-def add_space_nonlocal(input, dim_in, dim_out, prefix, dim_inner ):
+def add_space_nonlocal(input,
+                       dim_in,
+                       dim_out,
+                       prefix,
+                       dim_inner,
+                       with_bias=False,
+                       with_scale=True):
     '''
     add_space_nonlocal: 
         Non-local Neural Networks: see https://arxiv.org/abs/1711.07971
     '''
-    conv = space_nonlocal(input, dim_in, dim_out, prefix, dim_inner)
-    output = fluid.layers.elementwise_add(input, conv, name = prefix + '_sum')
+    conv = space_nonlocal(
+        input,
+        dim_in,
+        dim_out,
+        prefix,
+        dim_inner,
+        with_bias=with_bias,
+        with_scale=with_scale)
+    output = input + conv
     return output
-

ppdet/modeling/losses/__init__.py

@@ -19,9 +19,11 @@ from . import smooth_l1_loss
 from . import giou_loss
 from . import diou_loss
 from . import iou_loss
+from . import balanced_l1_loss
 
 from .yolo_loss import *
 from .smooth_l1_loss import *
 from .giou_loss import *
 from .diou_loss import *
 from .iou_loss import *
+from .balanced_l1_loss import *

ppdet/modeling/losses/balanced_l1_loss.py

+# 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.
+# 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 paddle import fluid
+from ppdet.core.workspace import register, serializable
+
+__all__ = ['BalancedL1Loss']
+
+
+@register
+@serializable
+class BalancedL1Loss(object):
+    """
+    Balanced L1 Loss, see https://arxiv.org/abs/1904.02701
+    Args:
+        alpha (float): hyper parameter of BalancedL1Loss, see more details in the paper
+        gamma (float): hyper parameter of BalancedL1Loss, see more details in the paper
+        beta  (float): hyper parameter of BalancedL1Loss, see more details in the paper
+        loss_weights (float): loss weight
+    """
+
+    def __init__(self, alpha=0.5, gamma=1.5, beta=1.0, loss_weight=1.0):
+        super(BalancedL1Loss, self).__init__()
+        self.alpha = alpha
+        self.gamma = gamma
+        self.beta = beta
+        self.loss_weight = loss_weight
+
+    def __call__(
+            self,
+            x,
+            y,
+            inside_weight=None,
+            outside_weight=None, ):
+        alpha = self.alpha
+        gamma = self.gamma
+        beta = self.beta
+        loss_weight = self.loss_weight
+        diff = fluid.layers.abs(x - y)
+        b = np.e**(gamma / alpha) - 1
+        less_beta = diff < beta
+        ge_beta = diff >= beta
+        less_beta = fluid.layers.cast(x=less_beta, dtype='float32')
+        ge_beta = fluid.layers.cast(x=ge_beta, dtype='float32')
+        less_beta.stop_gradient = True
+        ge_beta.stop_gradient = True
+        loss_1 = less_beta * (
+            alpha / b * (b * diff + 1) * fluid.layers.log(b * diff / beta + 1) -
+            alpha * diff)
+        loss_2 = ge_beta * (gamma * diff + gamma / b - alpha * beta)
+        iou_weights = 1.0
+        if inside_weight is not None and outside_weight is not None:
+            iou_weights = inside_weight * outside_weight
+        loss = (loss_1 + loss_2) * iou_weights
+        loss = fluid.layers.reduce_sum(loss, dim=-1) * loss_weight
+        return loss

ppdet/utils/bbox_utils.py

+# 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.
+# 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 logging
+import numpy as np
+
+import paddle.fluid as fluid
+
+__all__ = ["bbox_overlaps", "box_to_delta"]
+
+logger = logging.getLogger(__name__)
+
+
+def bbox_overlaps(boxes_1, boxes_2):
+    '''
+    bbox_overlaps
+        boxes_1: x1, y, x2, y2
+        boxes_2: x1, y, x2, y2
+    '''
+    assert boxes_1.shape[1] == 4 and boxes_2.shape[1] == 4
+
+    num_1 = boxes_1.shape[0]
+    num_2 = boxes_2.shape[0]
+
+    x1_1 = boxes_1[:, 0:1]
+    y1_1 = boxes_1[:, 1:2]
+    x2_1 = boxes_1[:, 2:3]
+    y2_1 = boxes_1[:, 3:4]
+    area_1 = (x2_1 - x1_1 + 1) * (y2_1 - y1_1 + 1)
+
+    x1_2 = boxes_2[:, 0].transpose()
+    y1_2 = boxes_2[:, 1].transpose()
+    x2_2 = boxes_2[:, 2].transpose()
+    y2_2 = boxes_2[:, 3].transpose()
+    area_2 = (x2_2 - x1_2 + 1) * (y2_2 - y1_2 + 1)
+
+    xx1 = np.maximum(x1_1, x1_2)
+    yy1 = np.maximum(y1_1, y1_2)
+    xx2 = np.minimum(x2_1, x2_2)
+    yy2 = np.minimum(y2_1, y2_2)
+
+    w = np.maximum(0.0, xx2 - xx1 + 1)
+    h = np.maximum(0.0, yy2 - yy1 + 1)
+    inter = w * h
+
+    ovr = inter / (area_1 + area_2 - inter)
+    return ovr
+
+
+def box_to_delta(ex_boxes, gt_boxes, weights):
+    """ box_to_delta """
+    ex_w = ex_boxes[:, 2] - ex_boxes[:, 0] + 1
+    ex_h = ex_boxes[:, 3] - ex_boxes[:, 1] + 1
+    ex_ctr_x = ex_boxes[:, 0] + 0.5 * ex_w
+    ex_ctr_y = ex_boxes[:, 1] + 0.5 * ex_h
+
+    gt_w = gt_boxes[:, 2] - gt_boxes[:, 0] + 1
+    gt_h = gt_boxes[:, 3] - gt_boxes[:, 1] + 1
+    gt_ctr_x = gt_boxes[:, 0] + 0.5 * gt_w
+    gt_ctr_y = gt_boxes[:, 1] + 0.5 * gt_h
+
+    dx = (gt_ctr_x - ex_ctr_x) / ex_w / weights[0]
+    dy = (gt_ctr_y - ex_ctr_y) / ex_h / weights[1]
+    dw = (np.log(gt_w / ex_w)) / weights[2]
+    dh = (np.log(gt_h / ex_h)) / weights[3]
+
+    targets = np.vstack([dx, dy, dw, dh]).transpose()
+    return targets

tools/eval.py

@@ -87,6 +87,8 @@ def main():
     reader = create_reader(cfg.EvalReader)
     loader.set_sample_list_generator(reader, place)
 
+    dataset = cfg['EvalReader']['dataset']
+
     # eval already exists json file
     if FLAGS.json_eval:
         logger.info(
@@ -123,8 +125,6 @@ def main():
             callable(model.is_bbox_normalized):
         is_bbox_normalized = model.is_bbox_normalized()
 
-    dataset = cfg['EvalReader']['dataset']
-
     sub_eval_prog = None
     sub_keys = None
     sub_values = None