PaddleSeg模型开发规范

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import os

import numpy as np
import paddle.nn as nn
import paddle.nn.functional as F

from paddleseg.cvlibs import manager
from paddleseg.models import layers
from paddleseg.utils import utils

@manager.MODELS.add_component
class PSPNet(nn.Layer):
    """
    The PSPNet implementation based on PaddlePaddle.

    The original article refers to
    Zhao, Hengshuang, et al. "Pyramid scene parsing network"
    (https://openaccess.thecvf.com/content_cvpr_2017/papers/Zhao_Pyramid_Scene_Parsing_CVPR_2017_paper.pdf).

    Args:
        num_classes (int): The unique number of target classes.
        backbone (Paddle.nn.Layer): Backbone network, currently support Resnet50/101.
        backbone_indices (tuple, optional): Two values in the tuple indicate the indices of output of backbone.
        pp_out_channels (int, optional): The output channels after Pyramid Pooling Module. Default: 1024.
        bin_sizes (tuple, optional): The out size of pooled feature maps. Default: (1,2,3,6).
        enable_auxiliary_loss (bool, optional): A bool value indicates whether adding auxiliary loss. Default: True.
        align_corners (bool, optional): An argument of F.interpolate. It should be set to False when the feature size is even,
            e.g. 1024x512, otherwise it is True, e.g. 769x769. Default: False.
        pretrained (str, optional): The path or url of pretrained model. Default: None.
    """

def __init__(self,
             num_classes,
             backbone,
             backbone_indices=(2, 3),
             pp_out_channels=1024,
             bin_sizes=(1, 2, 3, 6),
             enable_auxiliary_loss=True,
             align_corners=False,
             pretrained=None):
    super().__init__()
    ...
    self.init_weight()

def forward(self, x):
    feat_list = self.backbone(x)
    logit_list = self.head(feat_list)
    return [
        F.interpolate(
            logit,
            x.shape[2:],
            mode='bilinear',
            align_corners=self.align_corners) for logit in logit_list
    ]

# 带有 backbone 的对整个模型进行加载
def init_weight(self):
    if self.pretrained is not None:
        utils.load_entire_model(self, self.pretrained)
# 不带 backbone 的自身模型初始化
def init_weight(self):
      """Initialize the parameters of model parts."""
      for sublayer in self.sublayers():
        if isinstance(sublayer, nn.Conv2D):
          param_init.normal_init(sublayer.weight, std=0.001)
        elif isinstance(sublayer, (nn.BatchNorm, nn.SyncBatchNorm)):
          param_init.constant_init(sublayer.weight, value=1.0)
          param_init.constant_init(sublayer.bias, value=0.0)

class PSPNetHead(nn.Layer):

from .pspnet import *

@manager.LOSSES.add_component
class CrossEntropyLoss(nn.Layer):
    """
    Implements the cross entropy loss function.

    Args:
        weight (tuple|list|ndarray|Tensor, optional): A manual rescaling weight
            given to each class. Its length must be equal to the number of classes.
            Default ``None``.
        ignore_index (int64, optional): Specifies a target value that is ignored
            and does not contribute to the input gradient. Default ``255``.
        top_k_percent_pixels (float, optional): the value lies in [0.0, 1.0]. When its value < 1.0, only compute the loss for
            the top k percent pixels (e.g., the top 20% pixels). This is useful for hard pixel mining. Default ``1.0``.
        data_format (str, optional): The tensor format to use, 'NCHW' or 'NHWC'. Default ``'NCHW'``.
    """

from paddleseg.dataset import Dataset

@manager.DATASETS.add_component
class Cityscapes(Dataset):
      """
    Cityscapes dataset `https://www.cityscapes-dataset.com/`.
    The folder structure is as follow:
        cityscapes
        |
        |--leftImg8bit
        |  |--train
        |  |--val
        |  |--test
        |
        |--gtFine
        |  |--train
        |  |--val
        |  |--test
    Make sure there are **labelTrainIds.png in gtFine directory. If not, please run the conver_cityscapes.py in tools.
    Args:
        transforms (list): Transforms for image.
        dataset_root (str): Cityscapes dataset directory.
        mode (str, optional): Which part of dataset to use. it is one of ('train', 'val', 'test'). Default: 'train'.
        edge (bool, optional): Whether to compute edge while training. Default: False
    """