PulseFocusPlatform/static/ppdet/modeling/losses/balanced_l1_loss.py

74 lines
2.6 KiB
Python

# 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