EasyCV/easycv/models/ocr/heads/db_head.py

83 lines
2.6 KiB
Python

# Modified from https://github.com/PaddlePaddle/PaddleOCR/blob/release/2.6/ppocr/modeling/heads/det_db_head.py
import torch
import torch.nn as nn
import torch.nn.functional as F
from easycv.models.builder import HEADS
class DBBaseHead(nn.Module):
def __init__(self, in_channels, kernel_list=[3, 2, 2], **kwargs):
super(DBBaseHead, self).__init__()
self.conv1 = nn.Conv2d(
in_channels=in_channels,
out_channels=in_channels // 4,
kernel_size=kernel_list[0],
padding=int(kernel_list[0] // 2),
bias=False)
self.conv_bn1 = nn.BatchNorm2d(in_channels // 4)
self.relu1 = nn.ReLU(inplace=True)
self.conv2 = nn.ConvTranspose2d(
in_channels=in_channels // 4,
out_channels=in_channels // 4,
kernel_size=kernel_list[1],
stride=2)
self.conv_bn2 = nn.BatchNorm2d(in_channels // 4)
self.relu2 = nn.ReLU(inplace=True)
self.conv3 = nn.ConvTranspose2d(
in_channels=in_channels // 4,
out_channels=1,
kernel_size=kernel_list[2],
stride=2)
def forward(self, x):
x = self.conv1(x)
x = self.conv_bn1(x)
x = self.relu1(x)
x = self.conv2(x)
x = self.conv_bn2(x)
x = self.relu2(x)
x = self.conv3(x)
x = torch.sigmoid(x)
return x
@HEADS.register_module()
class DBHead(nn.Module):
"""
Differentiable Binarization (DB) for text detection:
see https://arxiv.org/abs/1911.08947
args:
params(dict): super parameters for build DB network
"""
def __init__(self, in_channels, k=50, **kwargs):
super(DBHead, self).__init__()
self.k = k
binarize_name_list = [
'conv2d_56', 'batch_norm_47', 'conv2d_transpose_0',
'batch_norm_48', 'conv2d_transpose_1', 'binarize'
]
thresh_name_list = [
'conv2d_57', 'batch_norm_49', 'conv2d_transpose_2',
'batch_norm_50', 'conv2d_transpose_3', 'thresh'
]
self.binarize = DBBaseHead(in_channels, **kwargs)
self.thresh = DBBaseHead(in_channels, **kwargs)
def step_function(self, x, y):
return torch.reciprocal(1 + torch.exp(-self.k * (x - y)))
def forward(self, x):
shrink_maps = self.binarize(x)
if not self.training:
return {'maps': shrink_maps}
threshold_maps = self.thresh(x)
binary_maps = self.step_function(shrink_maps, threshold_maps)
y = torch.cat([shrink_maps, threshold_maps, binary_maps], dim=1)
return {'maps': y}