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add yolo v10 and modify pipeline

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王庆刚
2025-03-28 13:19:54 +08:00
parent 183299c06b
commit 798c596acc
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ultralytics/nn/modules/head.py
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@ -1,7 +1,5 @@
# Ultralytics YOLO 🚀, AGPL-3.0 license
"""
Model head modules
"""
"""Model head modules."""
import math
@ -9,25 +7,28 @@ import torch
import torch.nn as nn
from torch.nn.init import constant_, xavier_uniform_
from ultralytics.utils.tal import TORCH_1_10, dist2bbox, make_anchors
from .block import DFL, Proto
from ultralytics.utils.tal import TORCH_1_10, dist2bbox, dist2rbox, make_anchors
from .block import DFL, Proto, ContrastiveHead, BNContrastiveHead
from .conv import Conv
from .transformer import MLP, DeformableTransformerDecoder, DeformableTransformerDecoderLayer
from .utils import bias_init_with_prob, linear_init_
from .utils import bias_init_with_prob, linear_init
import copy
from ultralytics.utils import ops
__all__ = 'Detect', 'Segment', 'Pose', 'Classify', 'RTDETRDecoder'
__all__ = "Detect", "Segment", "Pose", "Classify", "OBB", "RTDETRDecoder"
class Detect(nn.Module):
"""YOLOv8 Detect head for detection models."""
dynamic = False # force grid reconstruction
export = False # export mode
shape = None
anchors = torch.empty(0) # init
strides = torch.empty(0) # init
def __init__(self, nc=80, ch=()): # detection layer
def __init__(self, nc=80, ch=()):
"""Initializes the YOLOv8 detection layer with specified number of classes and channels."""
super().__init__()
self.nc = nc # number of classes
self.nl = len(ch) # number of detection layers
@ -36,41 +37,54 @@ class Detect(nn.Module):
self.stride = torch.zeros(self.nl) # strides computed during build
c2, c3 = max((16, ch[0] // 4, self.reg_max * 4)), max(ch[0], min(self.nc, 100)) # channels
self.cv2 = nn.ModuleList(
nn.Sequential(Conv(x, c2, 3), Conv(c2, c2, 3), nn.Conv2d(c2, 4 * self.reg_max, 1)) for x in ch)
nn.Sequential(Conv(x, c2, 3), Conv(c2, c2, 3), nn.Conv2d(c2, 4 * self.reg_max, 1)) for x in ch
)
self.cv3 = nn.ModuleList(nn.Sequential(Conv(x, c3, 3), Conv(c3, c3, 3), nn.Conv2d(c3, self.nc, 1)) for x in ch)
self.dfl = DFL(self.reg_max) if self.reg_max > 1 else nn.Identity()
def forward(self, x):
"""Concatenates and returns predicted bounding boxes and class probabilities."""
def inference(self, x):
# Inference path
shape = x[0].shape # BCHW
for i in range(self.nl):
x[i] = torch.cat((self.cv2[i](x[i]), self.cv3[i](x[i])), 1)
if self.training:
return x
elif self.dynamic or self.shape != shape:
x_cat = torch.cat([xi.view(shape[0], self.no, -1) for xi in x], 2)
if self.dynamic or self.shape != shape:
self.anchors, self.strides = (x.transpose(0, 1) for x in make_anchors(x, self.stride, 0.5))
self.shape = shape
x_cat = torch.cat([xi.view(shape[0], self.no, -1) for xi in x], 2)
if self.export and self.format in ('saved_model', 'pb', 'tflite', 'edgetpu', 'tfjs'): # avoid TF FlexSplitV ops
box = x_cat[:, :self.reg_max * 4]
cls = x_cat[:, self.reg_max * 4:]
if self.export and self.format in ("saved_model", "pb", "tflite", "edgetpu", "tfjs"): # avoid TF FlexSplitV ops
box = x_cat[:, : self.reg_max * 4]
cls = x_cat[:, self.reg_max * 4 :]
else:
box, cls = x_cat.split((self.reg_max * 4, self.nc), 1)
dbox = dist2bbox(self.dfl(box), self.anchors.unsqueeze(0), xywh=True, dim=1) * self.strides
if self.export and self.format in ('tflite', 'edgetpu'):
# Normalize xywh with image size to mitigate quantization error of TFLite integer models as done in YOLOv5:
# https://github.com/ultralytics/yolov5/blob/0c8de3fca4a702f8ff5c435e67f378d1fce70243/models/tf.py#L307-L309
# See this PR for details: https://github.com/ultralytics/ultralytics/pull/1695
img_h = shape[2] * self.stride[0]
img_w = shape[3] * self.stride[0]
img_size = torch.tensor([img_w, img_h, img_w, img_h], device=dbox.device).reshape(1, 4, 1)
dbox /= img_size
if self.export and self.format in ("tflite", "edgetpu"):
# Precompute normalization factor to increase numerical stability
# See https://github.com/ultralytics/ultralytics/issues/7371
grid_h = shape[2]
grid_w = shape[3]
grid_size = torch.tensor([grid_w, grid_h, grid_w, grid_h], device=box.device).reshape(1, 4, 1)
norm = self.strides / (self.stride[0] * grid_size)
dbox = self.decode_bboxes(self.dfl(box) * norm, self.anchors.unsqueeze(0) * norm[:, :2])
else:
dbox = self.decode_bboxes(self.dfl(box), self.anchors.unsqueeze(0)) * self.strides
y = torch.cat((dbox, cls.sigmoid()), 1)
return y if self.export else (y, x)
def forward_feat(self, x, cv2, cv3):
y = []
for i in range(self.nl):
y.append(torch.cat((cv2[i](x[i]), cv3[i](x[i])), 1))
return y
def forward(self, x):
"""Concatenates and returns predicted bounding boxes and class probabilities."""
y = self.forward_feat(x, self.cv2, self.cv3)
if self.training:
return y
return self.inference(y)
def bias_init(self):
"""Initialize Detect() biases, WARNING: requires stride availability."""
m = self # self.model[-1] # Detect() module
@ -78,7 +92,13 @@ class Detect(nn.Module):
# ncf = math.log(0.6 / (m.nc - 0.999999)) if cf is None else torch.log(cf / cf.sum()) # nominal class frequency
for a, b, s in zip(m.cv2, m.cv3, m.stride): # from
a[-1].bias.data[:] = 1.0 # box
b[-1].bias.data[:m.nc] = math.log(5 / m.nc / (640 / s) ** 2) # cls (.01 objects, 80 classes, 640 img)
b[-1].bias.data[: m.nc] = math.log(5 / m.nc / (640 / s) ** 2) # cls (.01 objects, 80 classes, 640 img)
def decode_bboxes(self, bboxes, anchors):
"""Decode bounding boxes."""
if self.export:
return dist2bbox(bboxes, anchors, xywh=False, dim=1)
return dist2bbox(bboxes, anchors, xywh=True, dim=1)
class Segment(Detect):
@ -107,6 +127,37 @@ class Segment(Detect):
return (torch.cat([x, mc], 1), p) if self.export else (torch.cat([x[0], mc], 1), (x[1], mc, p))
class OBB(Detect):
"""YOLOv8 OBB detection head for detection with rotation models."""
def __init__(self, nc=80, ne=1, ch=()):
"""Initialize OBB with number of classes `nc` and layer channels `ch`."""
super().__init__(nc, ch)
self.ne = ne # number of extra parameters
self.detect = Detect.forward
c4 = max(ch[0] // 4, self.ne)
self.cv4 = nn.ModuleList(nn.Sequential(Conv(x, c4, 3), Conv(c4, c4, 3), nn.Conv2d(c4, self.ne, 1)) for x in ch)
def forward(self, x):
"""Concatenates and returns predicted bounding boxes and class probabilities."""
bs = x[0].shape[0] # batch size
angle = torch.cat([self.cv4[i](x[i]).view(bs, self.ne, -1) for i in range(self.nl)], 2) # OBB theta logits
# NOTE: set `angle` as an attribute so that `decode_bboxes` could use it.
angle = (angle.sigmoid() - 0.25) * math.pi # [-pi/4, 3pi/4]
# angle = angle.sigmoid() * math.pi / 2 # [0, pi/2]
if not self.training:
self.angle = angle
x = self.detect(self, x)
if self.training:
return x, angle
return torch.cat([x, angle], 1) if self.export else (torch.cat([x[0], angle], 1), (x[1], angle))
def decode_bboxes(self, bboxes, anchors):
"""Decode rotated bounding boxes."""
return dist2rbox(bboxes, self.angle, anchors, dim=1)
class Pose(Detect):
"""YOLOv8 Pose head for keypoints models."""
@ -142,7 +193,7 @@ class Pose(Detect):
else:
y = kpts.clone()
if ndim == 3:
y[:, 2::3].sigmoid_() # inplace sigmoid
y[:, 2::3] = y[:, 2::3].sigmoid() # sigmoid (WARNING: inplace .sigmoid_() Apple MPS bug)
y[:, 0::ndim] = (y[:, 0::ndim] * 2.0 + (self.anchors[0] - 0.5)) * self.strides
y[:, 1::ndim] = (y[:, 1::ndim] * 2.0 + (self.anchors[1] - 0.5)) * self.strides
return y
@ -151,7 +202,10 @@ class Pose(Detect):
class Classify(nn.Module):
"""YOLOv8 classification head, i.e. x(b,c1,20,20) to x(b,c2)."""
def __init__(self, c1, c2, k=1, s=1, p=None, g=1): # ch_in, ch_out, kernel, stride, padding, groups
def __init__(self, c1, c2, k=1, s=1, p=None, g=1):
"""Initializes YOLOv8 classification head with specified input and output channels, kernel size, stride,
padding, and groups.
"""
super().__init__()
c_ = 1280 # efficientnet_b0 size
self.conv = Conv(c1, c_, k, s, p, g)
@ -167,27 +221,99 @@ class Classify(nn.Module):
return x if self.training else x.softmax(1)
class WorldDetect(Detect):
def __init__(self, nc=80, embed=512, with_bn=False, ch=()):
"""Initialize YOLOv8 detection layer with nc classes and layer channels ch."""
super().__init__(nc, ch)
c3 = max(ch[0], min(self.nc, 100))
self.cv3 = nn.ModuleList(nn.Sequential(Conv(x, c3, 3), Conv(c3, c3, 3), nn.Conv2d(c3, embed, 1)) for x in ch)
self.cv4 = nn.ModuleList(BNContrastiveHead(embed) if with_bn else ContrastiveHead() for _ in ch)
def forward(self, x, text):
"""Concatenates and returns predicted bounding boxes and class probabilities."""
for i in range(self.nl):
x[i] = torch.cat((self.cv2[i](x[i]), self.cv4[i](self.cv3[i](x[i]), text)), 1)
if self.training:
return x
# Inference path
shape = x[0].shape # BCHW
x_cat = torch.cat([xi.view(shape[0], self.nc + self.reg_max * 4, -1) for xi in x], 2)
if self.dynamic or self.shape != shape:
self.anchors, self.strides = (x.transpose(0, 1) for x in make_anchors(x, self.stride, 0.5))
self.shape = shape
if self.export and self.format in ("saved_model", "pb", "tflite", "edgetpu", "tfjs"): # avoid TF FlexSplitV ops
box = x_cat[:, : self.reg_max * 4]
cls = x_cat[:, self.reg_max * 4 :]
else:
box, cls = x_cat.split((self.reg_max * 4, self.nc), 1)
if self.export and self.format in ("tflite", "edgetpu"):
# Precompute normalization factor to increase numerical stability
# See https://github.com/ultralytics/ultralytics/issues/7371
grid_h = shape[2]
grid_w = shape[3]
grid_size = torch.tensor([grid_w, grid_h, grid_w, grid_h], device=box.device).reshape(1, 4, 1)
norm = self.strides / (self.stride[0] * grid_size)
dbox = self.decode_bboxes(self.dfl(box) * norm, self.anchors.unsqueeze(0) * norm[:, :2])
else:
dbox = self.decode_bboxes(self.dfl(box), self.anchors.unsqueeze(0)) * self.strides
y = torch.cat((dbox, cls.sigmoid()), 1)
return y if self.export else (y, x)
class RTDETRDecoder(nn.Module):
"""
Real-Time Deformable Transformer Decoder (RTDETRDecoder) module for object detection.
This decoder module utilizes Transformer architecture along with deformable convolutions to predict bounding boxes
and class labels for objects in an image. It integrates features from multiple layers and runs through a series of
Transformer decoder layers to output the final predictions.
"""
export = False # export mode
def __init__(
self,
nc=80,
ch=(512, 1024, 2048),
hd=256, # hidden dim
nq=300, # num queries
ndp=4, # num decoder points
nh=8, # num head
ndl=6, # num decoder layers
d_ffn=1024, # dim of feedforward
dropout=0.,
act=nn.ReLU(),
eval_idx=-1,
# training args
nd=100, # num denoising
label_noise_ratio=0.5,
box_noise_scale=1.0,
learnt_init_query=False):
self,
nc=80,
ch=(512, 1024, 2048),
hd=256, # hidden dim
nq=300, # num queries
ndp=4, # num decoder points
nh=8, # num head
ndl=6, # num decoder layers
d_ffn=1024, # dim of feedforward
dropout=0.0,
act=nn.ReLU(),
eval_idx=-1,
# Training args
nd=100, # num denoising
label_noise_ratio=0.5,
box_noise_scale=1.0,
learnt_init_query=False,
):
"""
Initializes the RTDETRDecoder module with the given parameters.
Args:
nc (int): Number of classes. Default is 80.
ch (tuple): Channels in the backbone feature maps. Default is (512, 1024, 2048).
hd (int): Dimension of hidden layers. Default is 256.
nq (int): Number of query points. Default is 300.
ndp (int): Number of decoder points. Default is 4.
nh (int): Number of heads in multi-head attention. Default is 8.
ndl (int): Number of decoder layers. Default is 6.
d_ffn (int): Dimension of the feed-forward networks. Default is 1024.
dropout (float): Dropout rate. Default is 0.
act (nn.Module): Activation function. Default is nn.ReLU.
eval_idx (int): Evaluation index. Default is -1.
nd (int): Number of denoising. Default is 100.
label_noise_ratio (float): Label noise ratio. Default is 0.5.
box_noise_scale (float): Box noise scale. Default is 1.0.
learnt_init_query (bool): Whether to learn initial query embeddings. Default is False.
"""
super().__init__()
self.hidden_dim = hd
self.nhead = nh
@ -196,7 +322,7 @@ class RTDETRDecoder(nn.Module):
self.num_queries = nq
self.num_decoder_layers = ndl
# backbone feature projection
# Backbone feature projection
self.input_proj = nn.ModuleList(nn.Sequential(nn.Conv2d(x, hd, 1, bias=False), nn.BatchNorm2d(hd)) for x in ch)
# NOTE: simplified version but it's not consistent with .pt weights.
# self.input_proj = nn.ModuleList(Conv(x, hd, act=False) for x in ch)
@ -205,58 +331,61 @@ class RTDETRDecoder(nn.Module):
decoder_layer = DeformableTransformerDecoderLayer(hd, nh, d_ffn, dropout, act, self.nl, ndp)
self.decoder = DeformableTransformerDecoder(hd, decoder_layer, ndl, eval_idx)
# denoising part
# Denoising part
self.denoising_class_embed = nn.Embedding(nc, hd)
self.num_denoising = nd
self.label_noise_ratio = label_noise_ratio
self.box_noise_scale = box_noise_scale
# decoder embedding
# Decoder embedding
self.learnt_init_query = learnt_init_query
if learnt_init_query:
self.tgt_embed = nn.Embedding(nq, hd)
self.query_pos_head = MLP(4, 2 * hd, hd, num_layers=2)
# encoder head
# Encoder head
self.enc_output = nn.Sequential(nn.Linear(hd, hd), nn.LayerNorm(hd))
self.enc_score_head = nn.Linear(hd, nc)
self.enc_bbox_head = MLP(hd, hd, 4, num_layers=3)
# decoder head
# Decoder head
self.dec_score_head = nn.ModuleList([nn.Linear(hd, nc) for _ in range(ndl)])
self.dec_bbox_head = nn.ModuleList([MLP(hd, hd, 4, num_layers=3) for _ in range(ndl)])
self._reset_parameters()
def forward(self, x, batch=None):
"""Runs the forward pass of the module, returning bounding box and classification scores for the input."""
from ultralytics.models.utils.ops import get_cdn_group
# input projection and embedding
# Input projection and embedding
feats, shapes = self._get_encoder_input(x)
# prepare denoising training
dn_embed, dn_bbox, attn_mask, dn_meta = \
get_cdn_group(batch,
self.nc,
self.num_queries,
self.denoising_class_embed.weight,
self.num_denoising,
self.label_noise_ratio,
self.box_noise_scale,
self.training)
# Prepare denoising training
dn_embed, dn_bbox, attn_mask, dn_meta = get_cdn_group(
batch,
self.nc,
self.num_queries,
self.denoising_class_embed.weight,
self.num_denoising,
self.label_noise_ratio,
self.box_noise_scale,
self.training,
)
embed, refer_bbox, enc_bboxes, enc_scores = \
self._get_decoder_input(feats, shapes, dn_embed, dn_bbox)
embed, refer_bbox, enc_bboxes, enc_scores = self._get_decoder_input(feats, shapes, dn_embed, dn_bbox)
# decoder
dec_bboxes, dec_scores = self.decoder(embed,
refer_bbox,
feats,
shapes,
self.dec_bbox_head,
self.dec_score_head,
self.query_pos_head,
attn_mask=attn_mask)
# Decoder
dec_bboxes, dec_scores = self.decoder(
embed,
refer_bbox,
feats,
shapes,
self.dec_bbox_head,
self.dec_score_head,
self.query_pos_head,
attn_mask=attn_mask,
)
x = dec_bboxes, dec_scores, enc_bboxes, enc_scores, dn_meta
if self.training:
return x
@ -264,29 +393,31 @@ class RTDETRDecoder(nn.Module):
y = torch.cat((dec_bboxes.squeeze(0), dec_scores.squeeze(0).sigmoid()), -1)
return y if self.export else (y, x)
def _generate_anchors(self, shapes, grid_size=0.05, dtype=torch.float32, device='cpu', eps=1e-2):
def _generate_anchors(self, shapes, grid_size=0.05, dtype=torch.float32, device="cpu", eps=1e-2):
"""Generates anchor bounding boxes for given shapes with specific grid size and validates them."""
anchors = []
for i, (h, w) in enumerate(shapes):
sy = torch.arange(end=h, dtype=dtype, device=device)
sx = torch.arange(end=w, dtype=dtype, device=device)
grid_y, grid_x = torch.meshgrid(sy, sx, indexing='ij') if TORCH_1_10 else torch.meshgrid(sy, sx)
grid_y, grid_x = torch.meshgrid(sy, sx, indexing="ij") if TORCH_1_10 else torch.meshgrid(sy, sx)
grid_xy = torch.stack([grid_x, grid_y], -1) # (h, w, 2)
valid_WH = torch.tensor([h, w], dtype=dtype, device=device)
valid_WH = torch.tensor([w, h], dtype=dtype, device=device)
grid_xy = (grid_xy.unsqueeze(0) + 0.5) / valid_WH # (1, h, w, 2)
wh = torch.ones_like(grid_xy, dtype=dtype, device=device) * grid_size * (2.0 ** i)
wh = torch.ones_like(grid_xy, dtype=dtype, device=device) * grid_size * (2.0**i)
anchors.append(torch.cat([grid_xy, wh], -1).view(-1, h * w, 4)) # (1, h*w, 4)
anchors = torch.cat(anchors, 1) # (1, h*w*nl, 4)
valid_mask = ((anchors > eps) * (anchors < 1 - eps)).all(-1, keepdim=True) # 1, h*w*nl, 1
valid_mask = ((anchors > eps) & (anchors < 1 - eps)).all(-1, keepdim=True) # 1, h*w*nl, 1
anchors = torch.log(anchors / (1 - anchors))
anchors = anchors.masked_fill(~valid_mask, float('inf'))
anchors = anchors.masked_fill(~valid_mask, float("inf"))
return anchors, valid_mask
def _get_encoder_input(self, x):
# get projection features
"""Processes and returns encoder inputs by getting projection features from input and concatenating them."""
# Get projection features
x = [self.input_proj[i](feat) for i, feat in enumerate(x)]
# get encoder inputs
# Get encoder inputs
feats = []
shapes = []
for feat in x:
@ -301,14 +432,15 @@ class RTDETRDecoder(nn.Module):
return feats, shapes
def _get_decoder_input(self, feats, shapes, dn_embed=None, dn_bbox=None):
bs = len(feats)
# prepare input for decoder
"""Generates and prepares the input required for the decoder from the provided features and shapes."""
bs = feats.shape[0]
# Prepare input for decoder
anchors, valid_mask = self._generate_anchors(shapes, dtype=feats.dtype, device=feats.device)
features = self.enc_output(valid_mask * feats) # bs, h*w, 256
enc_outputs_scores = self.enc_score_head(features) # (bs, h*w, nc)
# query selection
# Query selection
# (bs, num_queries)
topk_ind = torch.topk(enc_outputs_scores.max(-1).values, self.num_queries, dim=1).indices.view(-1)
# (bs, num_queries)
@ -319,7 +451,7 @@ class RTDETRDecoder(nn.Module):
# (bs, num_queries, 4)
top_k_anchors = anchors[:, topk_ind].view(bs, self.num_queries, -1)
# dynamic anchors + static content
# Dynamic anchors + static content
refer_bbox = self.enc_bbox_head(top_k_features) + top_k_anchors
enc_bboxes = refer_bbox.sigmoid()
@ -339,20 +471,21 @@ class RTDETRDecoder(nn.Module):
# TODO
def _reset_parameters(self):
# class and bbox head init
"""Initializes or resets the parameters of the model's various components with predefined weights and biases."""
# Class and bbox head init
bias_cls = bias_init_with_prob(0.01) / 80 * self.nc
# NOTE: the weight initialization in `linear_init_` would cause NaN when training with custom datasets.
# linear_init_(self.enc_score_head)
# NOTE: the weight initialization in `linear_init` would cause NaN when training with custom datasets.
# linear_init(self.enc_score_head)
constant_(self.enc_score_head.bias, bias_cls)
constant_(self.enc_bbox_head.layers[-1].weight, 0.)
constant_(self.enc_bbox_head.layers[-1].bias, 0.)
constant_(self.enc_bbox_head.layers[-1].weight, 0.0)
constant_(self.enc_bbox_head.layers[-1].bias, 0.0)
for cls_, reg_ in zip(self.dec_score_head, self.dec_bbox_head):
# linear_init_(cls_)
# linear_init(cls_)
constant_(cls_.bias, bias_cls)
constant_(reg_.layers[-1].weight, 0.)
constant_(reg_.layers[-1].bias, 0.)
constant_(reg_.layers[-1].weight, 0.0)
constant_(reg_.layers[-1].bias, 0.0)
linear_init_(self.enc_output[0])
linear_init(self.enc_output[0])
xavier_uniform_(self.enc_output[0].weight)
if self.learnt_init_query:
xavier_uniform_(self.tgt_embed.weight)
@ -360,3 +493,43 @@ class RTDETRDecoder(nn.Module):
xavier_uniform_(self.query_pos_head.layers[1].weight)
for layer in self.input_proj:
xavier_uniform_(layer[0].weight)
class v10Detect(Detect):
max_det = 300
def __init__(self, nc=80, ch=()):
super().__init__(nc, ch)
c3 = max(ch[0], min(self.nc, 100)) # channels
self.cv3 = nn.ModuleList(nn.Sequential(nn.Sequential(Conv(x, x, 3, g=x), Conv(x, c3, 1)), \
nn.Sequential(Conv(c3, c3, 3, g=c3), Conv(c3, c3, 1)), \
nn.Conv2d(c3, self.nc, 1)) for i, x in enumerate(ch))
self.one2one_cv2 = copy.deepcopy(self.cv2)
self.one2one_cv3 = copy.deepcopy(self.cv3)
def forward(self, x):
one2one = self.forward_feat([xi.detach() for xi in x], self.one2one_cv2, self.one2one_cv3)
if not self.export:
one2many = super().forward(x)
if not self.training:
one2one = self.inference(one2one)
if not self.export:
return {"one2many": one2many, "one2one": one2one}
else:
assert(self.max_det != -1)
boxes, scores, labels = ops.v10postprocess(one2one.permute(0, 2, 1), self.max_det, self.nc)
return torch.cat([boxes, scores.unsqueeze(-1), labels.unsqueeze(-1).to(boxes.dtype)], dim=-1)
else:
return {"one2many": one2many, "one2one": one2one}
def bias_init(self):
super().bias_init()
"""Initialize Detect() biases, WARNING: requires stride availability."""
m = self # self.model[-1] # Detect() module
# cf = torch.bincount(torch.tensor(np.concatenate(dataset.labels, 0)[:, 0]).long(), minlength=nc) + 1
# ncf = math.log(0.6 / (m.nc - 0.999999)) if cf is None else torch.log(cf / cf.sum()) # nominal class frequency
for a, b, s in zip(m.one2one_cv2, m.one2one_cv3, m.stride): # from
a[-1].bias.data[:] = 1.0 # box
b[-1].bias.data[: m.nc] = math.log(5 / m.nc / (640 / s) ** 2) # cls (.01 objects, 80 classes, 640 img)