PDL: Regularizing Multiple Instance Learning with Progressive Dropout Layers

PDL: Regularizing Multiple Instance Learning with Progressive Dropout Layers

Reference MIL methods github repo: DSMIL TransMIl DTFD-MIL ABMIL

Abstract Multiple instance learning (MIL) was a weakly supervised learning approach that sought to assign binary class labels to collections of instances known as bags. However, due to their weak supervision nature, the MIL methods were susceptible to overfitting and required assistance in developing comprehensive representations of target instances. While regularization typically effectively combated overfitting, its integration with the MIL model has been frequently overlooked in prior studies. Meanwhile, current regularization methods for MIL have shown limitations in their capacity to uncover a diverse array of representations. In this study, we delve into the realm of regularization within the MIL model, presenting a novel approach in the form of a Progressive Dropout Layer (PDL). We aim to not only address overfitting but also empower the MIL model in uncovering intricate and impactful feature representations. The proposed method was orthogonal to existing MIL methods and could be easily integrated into them to boost performance. Our extensive evaluation across a range of MIL benchmark datasets demonstrated that the incorporation of the PDL into multiple MIL methods not only elevated their classification performance but also augmented their potential for weakly-supervised feature localizations.

Framework

Experiment Result

How to use

In Network.py

from models.dropout import Pdropout
.......
class TransMIL(nn.Module):
    def __init__(self, input_size, n_classes, mDim=512):
        super(TransMIL, self).__init__()
        self.pos_layer = PPEG(dim=mDim)
        self._fc1 = nn.Sequential(nn.Linear(input_size, mDim), nn.ReLU(), nn.Dropout(0.2))
        # the fc1 as the middle layer
        self._fc1 = nn.Sequential(
          nn.Linear(input_size, 256),
          nn.ReLU(),
          # append the PDL after Relu activation function
          Pdropout(0.35),
          nn.Linear(256, 128),
          nn.ReLU(),
          Pdropout(0.35),
          nn.Linear(128, mDim),
          nn.ReLU(),
          Pdropout(0.35)
        )
        self.cls_token = nn.Parameter(torch.randn(1, 1, mDim))
        self.n_classes = n_classes
        self.layer1 = TransLayer(dim=mDim)
        self.layer2 = TransLayer(dim=mDim)
        self.norm = nn.LayerNorm(mDim)
        self._fc2 = nn.Linear(mDim, self.n_classes)
........

IN train.py

from models.dropout import LinearScheduler
.......
milnet = TransMIL(args.feats_size, args.num_classes, mDim=args.L).cuda()
progressive_schedule = LinearScheduler(milnet,start_value=0,stop_value=P_max,nr_steps=args.num_epochs)

for epoch in range(1, args.num_epochs + 1):
        progressive_schedule.step()
........

The interpolation methods in dropout.py. (You could custom the interpolation based on number of instance, number of epoch, size of dataset)

    # For dropout layers
    def non_linear_interpolation(self,max,min,num):
        e_base = 20
        log_e = 1.5
        res = (max - min)/log_e* np.log10((np.linspace(0, np.power(10,(log_e)) - 1, num)+ 1)) + min
        #res = (max-min)/e_base *(np.power(10,(np.linspace(0, np.log10(e_base+1), num))) - 1) + min
        #res = (max - min)*(0.5*(1-np.cos(np.linspace(0, math.pi, num)))) + min
        res = torch.from_numpy(res).float()
        return res

    # For progressive processing function
    def dropvalue_sampler(self,min,max,num):
        e_base = 20
        log_e = 1.5
        res = (max - min)/log_e* np.log10((np.linspace(0, np.power(10,(log_e)) - 1, num)+ 1)) + min
        #res =  (max - min)*(0.5*(1-np.cos(np.linspace(0, math.pi, num)))) + min
        #res = (max-min)/e_base *(np.power(10,(np.linspace(0, np.log10(e_base+1), num))) - 1) + min

Citation

@misc{zhu2023pdl,
      title={PDL: Regularizing Multiple Instance Learning with Progressive Dropout Layers}, 
      author={Wenhui Zhu and Peijie Qiu and Oana M. Dumitrascu and Yalin Wang},
      year={2023},
      eprint={2308.10112},
      archivePrefix={arXiv},
      primaryClass={cs.CV}
}