yolov6 / yolov6 /layers /common.py
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#!/usr/bin/env python3
# -*- coding:utf-8 -*-
import warnings
from pathlib import Path
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from yolov6.layers.dbb_transforms import *
class SiLU(nn.Module):
'''Activation of SiLU'''
@staticmethod
def forward(x):
return x * torch.sigmoid(x)
class Conv(nn.Module):
'''Normal Conv with SiLU activation'''
def __init__(self, in_channels, out_channels, kernel_size, stride, groups=1, bias=False):
super().__init__()
padding = kernel_size // 2
self.conv = nn.Conv2d(
in_channels,
out_channels,
kernel_size=kernel_size,
stride=stride,
padding=padding,
groups=groups,
bias=bias,
)
self.bn = nn.BatchNorm2d(out_channels)
self.act = nn.SiLU()
def forward(self, x):
return self.act(self.bn(self.conv(x)))
def forward_fuse(self, x):
return self.act(self.conv(x))
class SimConv(nn.Module):
'''Normal Conv with ReLU activation'''
def __init__(self, in_channels, out_channels, kernel_size, stride, groups=1, bias=False):
super().__init__()
padding = kernel_size // 2
self.conv = nn.Conv2d(
in_channels,
out_channels,
kernel_size=kernel_size,
stride=stride,
padding=padding,
groups=groups,
bias=bias,
)
self.bn = nn.BatchNorm2d(out_channels)
self.act = nn.ReLU()
def forward(self, x):
return self.act(self.bn(self.conv(x)))
def forward_fuse(self, x):
return self.act(self.conv(x))
class SimSPPF(nn.Module):
'''Simplified SPPF with ReLU activation'''
def __init__(self, in_channels, out_channels, kernel_size=5):
super().__init__()
c_ = in_channels // 2 # hidden channels
self.cv1 = SimConv(in_channels, c_, 1, 1)
self.cv2 = SimConv(c_ * 4, out_channels, 1, 1)
self.m = nn.MaxPool2d(kernel_size=kernel_size, stride=1, padding=kernel_size // 2)
def forward(self, x):
x = self.cv1(x)
with warnings.catch_warnings():
warnings.simplefilter('ignore')
y1 = self.m(x)
y2 = self.m(y1)
return self.cv2(torch.cat([x, y1, y2, self.m(y2)], 1))
class Transpose(nn.Module):
'''Normal Transpose, default for upsampling'''
def __init__(self, in_channels, out_channels, kernel_size=2, stride=2):
super().__init__()
self.upsample_transpose = torch.nn.ConvTranspose2d(
in_channels=in_channels,
out_channels=out_channels,
kernel_size=kernel_size,
stride=stride,
bias=True
)
def forward(self, x):
return self.upsample_transpose(x)
class Concat(nn.Module):
def __init__(self, dimension=1):
super().__init__()
self.d = dimension
def forward(self, x):
return torch.cat(x, self.d)
def conv_bn(in_channels, out_channels, kernel_size, stride, padding, groups=1):
'''Basic cell for rep-style block, including conv and bn'''
result = nn.Sequential()
result.add_module('conv', nn.Conv2d(in_channels=in_channels, out_channels=out_channels,
kernel_size=kernel_size, stride=stride, padding=padding, groups=groups, bias=False))
result.add_module('bn', nn.BatchNorm2d(num_features=out_channels))
return result
class RepBlock(nn.Module):
'''
RepBlock is a stage block with rep-style basic block
'''
def __init__(self, in_channels, out_channels, n=1):
super().__init__()
self.conv1 = RepVGGBlock(in_channels, out_channels)
self.block = nn.Sequential(*(RepVGGBlock(out_channels, out_channels) for _ in range(n - 1))) if n > 1 else None
def forward(self, x):
x = self.conv1(x)
if self.block is not None:
x = self.block(x)
return x
class RepVGGBlock(nn.Module):
'''RepVGGBlock is a basic rep-style block, including training and deploy status
This code is based on https://github.com/DingXiaoH/RepVGG/blob/main/repvgg.py
'''
def __init__(self, in_channels, out_channels, kernel_size=3,
stride=1, padding=1, dilation=1, groups=1, padding_mode='zeros', deploy=False, use_se=False):
super(RepVGGBlock, self).__init__()
""" Initialization of the class.
Args:
in_channels (int): Number of channels in the input image
out_channels (int): Number of channels produced by the convolution
kernel_size (int or tuple): Size of the convolving kernel
stride (int or tuple, optional): Stride of the convolution. Default: 1
padding (int or tuple, optional): Zero-padding added to both sides of
the input. Default: 1
dilation (int or tuple, optional): Spacing between kernel elements. Default: 1
groups (int, optional): Number of blocked connections from input
channels to output channels. Default: 1
padding_mode (string, optional): Default: 'zeros'
deploy: Whether to be deploy status or training status. Default: False
use_se: Whether to use se. Default: False
"""
self.deploy = deploy
self.groups = groups
self.in_channels = in_channels
self.out_channels = out_channels
assert kernel_size == 3
assert padding == 1
padding_11 = padding - kernel_size // 2
self.nonlinearity = nn.ReLU()
if use_se:
raise NotImplementedError("se block not supported yet")
else:
self.se = nn.Identity()
if deploy:
self.rbr_reparam = nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, stride=stride,
padding=padding, dilation=dilation, groups=groups, bias=True, padding_mode=padding_mode)
else:
self.rbr_identity = nn.BatchNorm2d(num_features=in_channels) if out_channels == in_channels and stride == 1 else None
self.rbr_dense = conv_bn(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, stride=stride, padding=padding, groups=groups)
self.rbr_1x1 = conv_bn(in_channels=in_channels, out_channels=out_channels, kernel_size=1, stride=stride, padding=padding_11, groups=groups)
def forward(self, inputs):
'''Forward process'''
if hasattr(self, 'rbr_reparam'):
return self.nonlinearity(self.se(self.rbr_reparam(inputs)))
if self.rbr_identity is None:
id_out = 0
else:
id_out = self.rbr_identity(inputs)
return self.nonlinearity(self.se(self.rbr_dense(inputs) + self.rbr_1x1(inputs) + id_out))
def get_equivalent_kernel_bias(self):
kernel3x3, bias3x3 = self._fuse_bn_tensor(self.rbr_dense)
kernel1x1, bias1x1 = self._fuse_bn_tensor(self.rbr_1x1)
kernelid, biasid = self._fuse_bn_tensor(self.rbr_identity)
return kernel3x3 + self._pad_1x1_to_3x3_tensor(kernel1x1) + kernelid, bias3x3 + bias1x1 + biasid
def _pad_1x1_to_3x3_tensor(self, kernel1x1):
if kernel1x1 is None:
return 0
else:
return torch.nn.functional.pad(kernel1x1, [1, 1, 1, 1])
def _fuse_bn_tensor(self, branch):
if branch is None:
return 0, 0
if isinstance(branch, nn.Sequential):
kernel = branch.conv.weight
running_mean = branch.bn.running_mean
running_var = branch.bn.running_var
gamma = branch.bn.weight
beta = branch.bn.bias
eps = branch.bn.eps
else:
assert isinstance(branch, nn.BatchNorm2d)
if not hasattr(self, 'id_tensor'):
input_dim = self.in_channels // self.groups
kernel_value = np.zeros((self.in_channels, input_dim, 3, 3), dtype=np.float32)
for i in range(self.in_channels):
kernel_value[i, i % input_dim, 1, 1] = 1
self.id_tensor = torch.from_numpy(kernel_value).to(branch.weight.device)
kernel = self.id_tensor
running_mean = branch.running_mean
running_var = branch.running_var
gamma = branch.weight
beta = branch.bias
eps = branch.eps
std = (running_var + eps).sqrt()
t = (gamma / std).reshape(-1, 1, 1, 1)
return kernel * t, beta - running_mean * gamma / std
def switch_to_deploy(self):
if hasattr(self, 'rbr_reparam'):
return
kernel, bias = self.get_equivalent_kernel_bias()
self.rbr_reparam = nn.Conv2d(in_channels=self.rbr_dense.conv.in_channels, out_channels=self.rbr_dense.conv.out_channels,
kernel_size=self.rbr_dense.conv.kernel_size, stride=self.rbr_dense.conv.stride,
padding=self.rbr_dense.conv.padding, dilation=self.rbr_dense.conv.dilation, groups=self.rbr_dense.conv.groups, bias=True)
self.rbr_reparam.weight.data = kernel
self.rbr_reparam.bias.data = bias
for para in self.parameters():
para.detach_()
self.__delattr__('rbr_dense')
self.__delattr__('rbr_1x1')
if hasattr(self, 'rbr_identity'):
self.__delattr__('rbr_identity')
if hasattr(self, 'id_tensor'):
self.__delattr__('id_tensor')
self.deploy = True
def conv_bn_v2(in_channels, out_channels, kernel_size, stride=1, padding=0, dilation=1, groups=1,
padding_mode='zeros'):
conv_layer = nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size,
stride=stride, padding=padding, dilation=dilation, groups=groups,
bias=False, padding_mode=padding_mode)
bn_layer = nn.BatchNorm2d(num_features=out_channels, affine=True)
se = nn.Sequential()
se.add_module('conv', conv_layer)
se.add_module('bn', bn_layer)
return se
class IdentityBasedConv1x1(nn.Conv2d):
def __init__(self, channels, groups=1):
super(IdentityBasedConv1x1, self).__init__(in_channels=channels, out_channels=channels, kernel_size=1, stride=1, padding=0, groups=groups, bias=False)
assert channels % groups == 0
input_dim = channels // groups
id_value = np.zeros((channels, input_dim, 1, 1))
for i in range(channels):
id_value[i, i % input_dim, 0, 0] = 1
self.id_tensor = torch.from_numpy(id_value).type_as(self.weight)
nn.init.zeros_(self.weight)
def forward(self, input):
kernel = self.weight + self.id_tensor.to(self.weight.device)
result = F.conv2d(input, kernel, None, stride=1, padding=0, dilation=self.dilation, groups=self.groups)
return result
def get_actual_kernel(self):
return self.weight + self.id_tensor.to(self.weight.device)
class BNAndPadLayer(nn.Module):
def __init__(self,
pad_pixels,
num_features,
eps=1e-5,
momentum=0.1,
affine=True,
track_running_stats=True):
super(BNAndPadLayer, self).__init__()
self.bn = nn.BatchNorm2d(num_features, eps, momentum, affine, track_running_stats)
self.pad_pixels = pad_pixels
def forward(self, input):
output = self.bn(input)
if self.pad_pixels > 0:
if self.bn.affine:
pad_values = self.bn.bias.detach() - self.bn.running_mean * self.bn.weight.detach() / torch.sqrt(self.bn.running_var + self.bn.eps)
else:
pad_values = - self.bn.running_mean / torch.sqrt(self.bn.running_var + self.bn.eps)
output = F.pad(output, [self.pad_pixels] * 4)
pad_values = pad_values.view(1, -1, 1, 1)
output[:, :, 0:self.pad_pixels, :] = pad_values
output[:, :, -self.pad_pixels:, :] = pad_values
output[:, :, :, 0:self.pad_pixels] = pad_values
output[:, :, :, -self.pad_pixels:] = pad_values
return output
@property
def bn_weight(self):
return self.bn.weight
@property
def bn_bias(self):
return self.bn.bias
@property
def running_mean(self):
return self.bn.running_mean
@property
def running_var(self):
return self.bn.running_var
@property
def eps(self):
return self.bn.eps
class DBBBlock(nn.Module):
'''
RepBlock is a stage block with rep-style basic block
'''
def __init__(self, in_channels, out_channels, n=1):
super().__init__()
self.conv1 = DiverseBranchBlock(in_channels, out_channels)
self.block = nn.Sequential(*(DiverseBranchBlock(out_channels, out_channels) for _ in range(n - 1))) if n > 1 else None
def forward(self, x):
x = self.conv1(x)
if self.block is not None:
x = self.block(x)
return x
class DiverseBranchBlock(nn.Module):
def __init__(self, in_channels, out_channels, kernel_size=3,
stride=1, padding=1, dilation=1, groups=1,
internal_channels_1x1_3x3=None,
deploy=False, nonlinear=nn.ReLU(), single_init=False):
super(DiverseBranchBlock, self).__init__()
self.deploy = deploy
if nonlinear is None:
self.nonlinear = nn.Identity()
else:
self.nonlinear = nonlinear
self.kernel_size = kernel_size
self.out_channels = out_channels
self.groups = groups
assert padding == kernel_size // 2
if deploy:
self.dbb_reparam = nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, stride=stride,
padding=padding, dilation=dilation, groups=groups, bias=True)
else:
self.dbb_origin = conv_bn_v2(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, stride=stride, padding=padding, dilation=dilation, groups=groups)
self.dbb_avg = nn.Sequential()
if groups < out_channels:
self.dbb_avg.add_module('conv',
nn.Conv2d(in_channels=in_channels, out_channels=out_channels, kernel_size=1,
stride=1, padding=0, groups=groups, bias=False))
self.dbb_avg.add_module('bn', BNAndPadLayer(pad_pixels=padding, num_features=out_channels))
self.dbb_avg.add_module('avg', nn.AvgPool2d(kernel_size=kernel_size, stride=stride, padding=0))
self.dbb_1x1 = conv_bn_v2(in_channels=in_channels, out_channels=out_channels, kernel_size=1, stride=stride,
padding=0, groups=groups)
else:
self.dbb_avg.add_module('avg', nn.AvgPool2d(kernel_size=kernel_size, stride=stride, padding=padding))
self.dbb_avg.add_module('avgbn', nn.BatchNorm2d(out_channels))
if internal_channels_1x1_3x3 is None:
internal_channels_1x1_3x3 = in_channels if groups < out_channels else 2 * in_channels # For mobilenet, it is better to have 2X internal channels
self.dbb_1x1_kxk = nn.Sequential()
if internal_channels_1x1_3x3 == in_channels:
self.dbb_1x1_kxk.add_module('idconv1', IdentityBasedConv1x1(channels=in_channels, groups=groups))
else:
self.dbb_1x1_kxk.add_module('conv1', nn.Conv2d(in_channels=in_channels, out_channels=internal_channels_1x1_3x3,
kernel_size=1, stride=1, padding=0, groups=groups, bias=False))
self.dbb_1x1_kxk.add_module('bn1', BNAndPadLayer(pad_pixels=padding, num_features=internal_channels_1x1_3x3, affine=True))
self.dbb_1x1_kxk.add_module('conv2', nn.Conv2d(in_channels=internal_channels_1x1_3x3, out_channels=out_channels,
kernel_size=kernel_size, stride=stride, padding=0, groups=groups, bias=False))
self.dbb_1x1_kxk.add_module('bn2', nn.BatchNorm2d(out_channels))
# The experiments reported in the paper used the default initialization of bn.weight (all as 1). But changing the initialization may be useful in some cases.
if single_init:
# Initialize the bn.weight of dbb_origin as 1 and others as 0. This is not the default setting.
self.single_init()
def get_equivalent_kernel_bias(self):
k_origin, b_origin = transI_fusebn(self.dbb_origin.conv.weight, self.dbb_origin.bn)
if hasattr(self, 'dbb_1x1'):
k_1x1, b_1x1 = transI_fusebn(self.dbb_1x1.conv.weight, self.dbb_1x1.bn)
k_1x1 = transVI_multiscale(k_1x1, self.kernel_size)
else:
k_1x1, b_1x1 = 0, 0
if hasattr(self.dbb_1x1_kxk, 'idconv1'):
k_1x1_kxk_first = self.dbb_1x1_kxk.idconv1.get_actual_kernel()
else:
k_1x1_kxk_first = self.dbb_1x1_kxk.conv1.weight
k_1x1_kxk_first, b_1x1_kxk_first = transI_fusebn(k_1x1_kxk_first, self.dbb_1x1_kxk.bn1)
k_1x1_kxk_second, b_1x1_kxk_second = transI_fusebn(self.dbb_1x1_kxk.conv2.weight, self.dbb_1x1_kxk.bn2)
k_1x1_kxk_merged, b_1x1_kxk_merged = transIII_1x1_kxk(k_1x1_kxk_first, b_1x1_kxk_first, k_1x1_kxk_second, b_1x1_kxk_second, groups=self.groups)
k_avg = transV_avg(self.out_channels, self.kernel_size, self.groups)
k_1x1_avg_second, b_1x1_avg_second = transI_fusebn(k_avg.to(self.dbb_avg.avgbn.weight.device), self.dbb_avg.avgbn)
if hasattr(self.dbb_avg, 'conv'):
k_1x1_avg_first, b_1x1_avg_first = transI_fusebn(self.dbb_avg.conv.weight, self.dbb_avg.bn)
k_1x1_avg_merged, b_1x1_avg_merged = transIII_1x1_kxk(k_1x1_avg_first, b_1x1_avg_first, k_1x1_avg_second, b_1x1_avg_second, groups=self.groups)
else:
k_1x1_avg_merged, b_1x1_avg_merged = k_1x1_avg_second, b_1x1_avg_second
return transII_addbranch((k_origin, k_1x1, k_1x1_kxk_merged, k_1x1_avg_merged), (b_origin, b_1x1, b_1x1_kxk_merged, b_1x1_avg_merged))
def switch_to_deploy(self):
if hasattr(self, 'dbb_reparam'):
return
kernel, bias = self.get_equivalent_kernel_bias()
self.dbb_reparam = nn.Conv2d(in_channels=self.dbb_origin.conv.in_channels, out_channels=self.dbb_origin.conv.out_channels,
kernel_size=self.dbb_origin.conv.kernel_size, stride=self.dbb_origin.conv.stride,
padding=self.dbb_origin.conv.padding, dilation=self.dbb_origin.conv.dilation, groups=self.dbb_origin.conv.groups, bias=True)
self.dbb_reparam.weight.data = kernel
self.dbb_reparam.bias.data = bias
for para in self.parameters():
para.detach_()
self.__delattr__('dbb_origin')
self.__delattr__('dbb_avg')
if hasattr(self, 'dbb_1x1'):
self.__delattr__('dbb_1x1')
self.__delattr__('dbb_1x1_kxk')
def forward(self, inputs):
if hasattr(self, 'dbb_reparam'):
return self.nonlinear(self.dbb_reparam(inputs))
out = self.dbb_origin(inputs)
if hasattr(self, 'dbb_1x1'):
out += self.dbb_1x1(inputs)
out += self.dbb_avg(inputs)
out += self.dbb_1x1_kxk(inputs)
return self.nonlinear(out)
def init_gamma(self, gamma_value):
if hasattr(self, "dbb_origin"):
torch.nn.init.constant_(self.dbb_origin.bn.weight, gamma_value)
if hasattr(self, "dbb_1x1"):
torch.nn.init.constant_(self.dbb_1x1.bn.weight, gamma_value)
if hasattr(self, "dbb_avg"):
torch.nn.init.constant_(self.dbb_avg.avgbn.weight, gamma_value)
if hasattr(self, "dbb_1x1_kxk"):
torch.nn.init.constant_(self.dbb_1x1_kxk.bn2.weight, gamma_value)
def single_init(self):
self.init_gamma(0.0)
if hasattr(self, "dbb_origin"):
torch.nn.init.constant_(self.dbb_origin.bn.weight, 1.0)
class DetectBackend(nn.Module):
def __init__(self, weights='yolov6s.pt', device=None, dnn=True):
super().__init__()
assert isinstance(weights, str) and Path(weights).suffix == '.pt', f'{Path(weights).suffix} format is not supported.'
from yolov6.utils.checkpoint import load_checkpoint
model = load_checkpoint(weights, map_location=device)
stride = int(model.stride.max())
self.__dict__.update(locals()) # assign all variables to self
def forward(self, im, val=False):
y = self.model(im)
if isinstance(y, np.ndarray):
y = torch.tensor(y, device=self.device)
return y