focal loss for multi-class classification 转自:https://blog.csdn.net/Umi_you/article/details/80982190 Focal loss 出自何恺明团队Focal Loss for Dense Object Detection一文,用于解决分类问题中数据类别不平衡以及判别难易程度差别的问题。文章中因用于目标检测区分前景和背景的二分类问题,公式以二分类问题为例。
import torch import torch.nn as nn import torch.nn.functional as F class FocalLoss(nn.Module): def __init__(self, alpha=0.25, gamma=2, num_classes=3, size_average=True): super(FocalLoss, self).__init__() self.size_average = size_average if isinstance(alpha, list): assert len(al...
An (unofficial) implementation of Focal Loss, as described in the RetinaNet paper, generalized to the multi-class case. - AdeelH/pytorch-multi-class-focal-loss
The focal loss was proposed for dense object detection task early this year. It enablestraining highly accurate dense object detectors with an imbalance between foreground and background classes at1:1000scale. This tutorial will show you how to apply focal loss to train a multi-class classifier mo...
In this paper, we propose a convolutional neural networks model based on the multi-class focal loss function. Specifically, our approach is designed to address the class imbalance via reshaping the standard cross entropy loss that it down-weights the loss assigned to well-classified examples. We ...
We selected four representative loss functions: (1) Categorical Cross-entropy loss, (2) Focal loss29, (3) Bi-tempered loss23 and (4) Lovasz-softmax loss26. We report an experimental comparison using a multi-centric dataset of CRC cases from five different centers, as well as two publicly...
In this paper, we propose a new form of focal loss by re-designing the re-weighting scheme that can calculate the weight according to the probability as well as widen the weight difference of the examples. Besides, we introduce the extended focal loss to multi-class classification task by ...
首先我们定义给定类的在focal loss [17] 中的基本项: (2) 其中是焦点参数,调节容易样本的衰减率。然后,我们对部分标注损失的定义如下: (3) 其中,和分别是正标签,负标签和未标注标签的焦点参数。是selectivity参数将在4.1节介绍。我们通常设置以比负标签更低的比例衰减正项,因为与负标签相比,正标签的频率较低...
Implementation of binary and categorical/multiclass focal loss using Keras with TensorFlow backend - aldi-dimara/keras-focal-loss
focal_for_multiclass Introduction Focal loss is proposed in the paperFocal Loss for Dense Object Detection. This paper was facing a task for binary classification, however there are other tasks need multiple class classification. There were few implementation about this task, so I implemented it wi...