bytetrack / yolox /models /yolo_head.py
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#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
from loguru import logger
import torch
import torch.nn as nn
import torch.nn.functional as F
from yolox.utils import bboxes_iou
import math
from .losses import IOUloss
from .network_blocks import BaseConv, DWConv
class YOLOXHead(nn.Module):
def __init__(
self,
num_classes,
width=1.0,
strides=[8, 16, 32],
in_channels=[256, 512, 1024],
act="silu",
depthwise=False,
):
"""
Args:
act (str): activation type of conv. Defalut value: "silu".
depthwise (bool): wheather apply depthwise conv in conv branch. Defalut value: False.
"""
super().__init__()
self.n_anchors = 1
self.num_classes = num_classes
self.decode_in_inference = True # for deploy, set to False
self.cls_convs = nn.ModuleList()
self.reg_convs = nn.ModuleList()
self.cls_preds = nn.ModuleList()
self.reg_preds = nn.ModuleList()
self.obj_preds = nn.ModuleList()
self.stems = nn.ModuleList()
Conv = DWConv if depthwise else BaseConv
for i in range(len(in_channels)):
self.stems.append(
BaseConv(
in_channels=int(in_channels[i] * width),
out_channels=int(256 * width),
ksize=1,
stride=1,
act=act,
)
)
self.cls_convs.append(
nn.Sequential(
*[
Conv(
in_channels=int(256 * width),
out_channels=int(256 * width),
ksize=3,
stride=1,
act=act,
),
Conv(
in_channels=int(256 * width),
out_channels=int(256 * width),
ksize=3,
stride=1,
act=act,
),
]
)
)
self.reg_convs.append(
nn.Sequential(
*[
Conv(
in_channels=int(256 * width),
out_channels=int(256 * width),
ksize=3,
stride=1,
act=act,
),
Conv(
in_channels=int(256 * width),
out_channels=int(256 * width),
ksize=3,
stride=1,
act=act,
),
]
)
)
self.cls_preds.append(
nn.Conv2d(
in_channels=int(256 * width),
out_channels=self.n_anchors * self.num_classes,
kernel_size=1,
stride=1,
padding=0,
)
)
self.reg_preds.append(
nn.Conv2d(
in_channels=int(256 * width),
out_channels=4,
kernel_size=1,
stride=1,
padding=0,
)
)
self.obj_preds.append(
nn.Conv2d(
in_channels=int(256 * width),
out_channels=self.n_anchors * 1,
kernel_size=1,
stride=1,
padding=0,
)
)
self.use_l1 = False
self.l1_loss = nn.L1Loss(reduction="none")
self.bcewithlog_loss = nn.BCEWithLogitsLoss(reduction="none")
self.iou_loss = IOUloss(reduction="none")
self.strides = strides
self.grids = [torch.zeros(1)] * len(in_channels)
self.expanded_strides = [None] * len(in_channels)
def initialize_biases(self, prior_prob):
for conv in self.cls_preds:
b = conv.bias.view(self.n_anchors, -1)
b.data.fill_(-math.log((1 - prior_prob) / prior_prob))
conv.bias = torch.nn.Parameter(b.view(-1), requires_grad=True)
for conv in self.obj_preds:
b = conv.bias.view(self.n_anchors, -1)
b.data.fill_(-math.log((1 - prior_prob) / prior_prob))
conv.bias = torch.nn.Parameter(b.view(-1), requires_grad=True)
def forward(self, xin, labels=None, imgs=None):
outputs = []
origin_preds = []
x_shifts = []
y_shifts = []
expanded_strides = []
for k, (cls_conv, reg_conv, stride_this_level, x) in enumerate(
zip(self.cls_convs, self.reg_convs, self.strides, xin)
):
x = self.stems[k](x)
cls_x = x
reg_x = x
cls_feat = cls_conv(cls_x)
cls_output = self.cls_preds[k](cls_feat)
reg_feat = reg_conv(reg_x)
reg_output = self.reg_preds[k](reg_feat)
obj_output = self.obj_preds[k](reg_feat)
if self.training:
output = torch.cat([reg_output, obj_output, cls_output], 1)
output, grid = self.get_output_and_grid(
output, k, stride_this_level, xin[0].type()
)
x_shifts.append(grid[:, :, 0])
y_shifts.append(grid[:, :, 1])
expanded_strides.append(
torch.zeros(1, grid.shape[1])
.fill_(stride_this_level)
.type_as(xin[0])
)
if self.use_l1:
batch_size = reg_output.shape[0]
hsize, wsize = reg_output.shape[-2:]
reg_output = reg_output.view(
batch_size, self.n_anchors, 4, hsize, wsize
)
reg_output = reg_output.permute(0, 1, 3, 4, 2).reshape(
batch_size, -1, 4
)
origin_preds.append(reg_output.clone())
else:
output = torch.cat(
[reg_output, obj_output.sigmoid(), cls_output.sigmoid()], 1
)
outputs.append(output)
if self.training:
return self.get_losses(
imgs,
x_shifts,
y_shifts,
expanded_strides,
labels,
torch.cat(outputs, 1),
origin_preds,
dtype=xin[0].dtype,
)
else:
self.hw = [x.shape[-2:] for x in outputs]
# [batch, n_anchors_all, 85]
outputs = torch.cat(
[x.flatten(start_dim=2) for x in outputs], dim=2
).permute(0, 2, 1)
if self.decode_in_inference:
return self.decode_outputs(outputs, dtype=xin[0].type())
else:
return outputs
def get_output_and_grid(self, output, k, stride, dtype):
grid = self.grids[k]
batch_size = output.shape[0]
n_ch = 5 + self.num_classes
hsize, wsize = output.shape[-2:]
if grid.shape[2:4] != output.shape[2:4]:
yv, xv = torch.meshgrid([torch.arange(hsize), torch.arange(wsize)])
grid = torch.stack((xv, yv), 2).view(1, 1, hsize, wsize, 2).type(dtype)
self.grids[k] = grid
output = output.view(batch_size, self.n_anchors, n_ch, hsize, wsize)
output = output.permute(0, 1, 3, 4, 2).reshape(
batch_size, self.n_anchors * hsize * wsize, -1
)
grid = grid.view(1, -1, 2)
output[..., :2] = (output[..., :2] + grid) * stride
output[..., 2:4] = torch.exp(output[..., 2:4]) * stride
return output, grid
def decode_outputs(self, outputs, dtype):
grids = []
strides = []
for (hsize, wsize), stride in zip(self.hw, self.strides):
yv, xv = torch.meshgrid([torch.arange(hsize), torch.arange(wsize)])
grid = torch.stack((xv, yv), 2).view(1, -1, 2)
grids.append(grid)
shape = grid.shape[:2]
strides.append(torch.full((*shape, 1), stride))
grids = torch.cat(grids, dim=1).type(dtype)
strides = torch.cat(strides, dim=1).type(dtype)
outputs[..., :2] = (outputs[..., :2] + grids) * strides
outputs[..., 2:4] = torch.exp(outputs[..., 2:4]) * strides
return outputs
def get_losses(
self,
imgs,
x_shifts,
y_shifts,
expanded_strides,
labels,
outputs,
origin_preds,
dtype,
):
bbox_preds = outputs[:, :, :4] # [batch, n_anchors_all, 4]
obj_preds = outputs[:, :, 4].unsqueeze(-1) # [batch, n_anchors_all, 1]
cls_preds = outputs[:, :, 5:] # [batch, n_anchors_all, n_cls]
# calculate targets
mixup = labels.shape[2] > 5
if mixup:
label_cut = labels[..., :5]
else:
label_cut = labels
nlabel = (label_cut.sum(dim=2) > 0).sum(dim=1) # number of objects
total_num_anchors = outputs.shape[1]
x_shifts = torch.cat(x_shifts, 1) # [1, n_anchors_all]
y_shifts = torch.cat(y_shifts, 1) # [1, n_anchors_all]
expanded_strides = torch.cat(expanded_strides, 1)
if self.use_l1:
origin_preds = torch.cat(origin_preds, 1)
cls_targets = []
reg_targets = []
l1_targets = []
obj_targets = []
fg_masks = []
num_fg = 0.0
num_gts = 0.0
for batch_idx in range(outputs.shape[0]):
num_gt = int(nlabel[batch_idx])
num_gts += num_gt
if num_gt == 0:
cls_target = outputs.new_zeros((0, self.num_classes))
reg_target = outputs.new_zeros((0, 4))
l1_target = outputs.new_zeros((0, 4))
obj_target = outputs.new_zeros((total_num_anchors, 1))
fg_mask = outputs.new_zeros(total_num_anchors).bool()
else:
gt_bboxes_per_image = labels[batch_idx, :num_gt, 1:5]
gt_classes = labels[batch_idx, :num_gt, 0]
bboxes_preds_per_image = bbox_preds[batch_idx]
try:
(
gt_matched_classes,
fg_mask,
pred_ious_this_matching,
matched_gt_inds,
num_fg_img,
) = self.get_assignments( # noqa
batch_idx,
num_gt,
total_num_anchors,
gt_bboxes_per_image,
gt_classes,
bboxes_preds_per_image,
expanded_strides,
x_shifts,
y_shifts,
cls_preds,
bbox_preds,
obj_preds,
labels,
imgs,
)
except RuntimeError:
logger.info(
"OOM RuntimeError is raised due to the huge memory cost during label assignment. \
CPU mode is applied in this batch. If you want to avoid this issue, \
try to reduce the batch size or image size."
)
print("OOM RuntimeError is raised due to the huge memory cost during label assignment. \
CPU mode is applied in this batch. If you want to avoid this issue, \
try to reduce the batch size or image size.")
torch.cuda.empty_cache()
(
gt_matched_classes,
fg_mask,
pred_ious_this_matching,
matched_gt_inds,
num_fg_img,
) = self.get_assignments( # noqa
batch_idx,
num_gt,
total_num_anchors,
gt_bboxes_per_image,
gt_classes,
bboxes_preds_per_image,
expanded_strides,
x_shifts,
y_shifts,
cls_preds,
bbox_preds,
obj_preds,
labels,
imgs,
"cpu",
)
torch.cuda.empty_cache()
num_fg += num_fg_img
cls_target = F.one_hot(
gt_matched_classes.to(torch.int64), self.num_classes
) * pred_ious_this_matching.unsqueeze(-1)
obj_target = fg_mask.unsqueeze(-1)
reg_target = gt_bboxes_per_image[matched_gt_inds]
if self.use_l1:
l1_target = self.get_l1_target(
outputs.new_zeros((num_fg_img, 4)),
gt_bboxes_per_image[matched_gt_inds],
expanded_strides[0][fg_mask],
x_shifts=x_shifts[0][fg_mask],
y_shifts=y_shifts[0][fg_mask],
)
cls_targets.append(cls_target)
reg_targets.append(reg_target)
obj_targets.append(obj_target.to(dtype))
fg_masks.append(fg_mask)
if self.use_l1:
l1_targets.append(l1_target)
cls_targets = torch.cat(cls_targets, 0)
reg_targets = torch.cat(reg_targets, 0)
obj_targets = torch.cat(obj_targets, 0)
fg_masks = torch.cat(fg_masks, 0)
if self.use_l1:
l1_targets = torch.cat(l1_targets, 0)
num_fg = max(num_fg, 1)
loss_iou = (
self.iou_loss(bbox_preds.view(-1, 4)[fg_masks], reg_targets)
).sum() / num_fg
loss_obj = (
self.bcewithlog_loss(obj_preds.view(-1, 1), obj_targets)
).sum() / num_fg
loss_cls = (
self.bcewithlog_loss(
cls_preds.view(-1, self.num_classes)[fg_masks], cls_targets
)
).sum() / num_fg
if self.use_l1:
loss_l1 = (
self.l1_loss(origin_preds.view(-1, 4)[fg_masks], l1_targets)
).sum() / num_fg
else:
loss_l1 = 0.0
reg_weight = 5.0
loss = reg_weight * loss_iou + loss_obj + loss_cls + loss_l1
return (
loss,
reg_weight * loss_iou,
loss_obj,
loss_cls,
loss_l1,
num_fg / max(num_gts, 1),
)
def get_l1_target(self, l1_target, gt, stride, x_shifts, y_shifts, eps=1e-8):
l1_target[:, 0] = gt[:, 0] / stride - x_shifts
l1_target[:, 1] = gt[:, 1] / stride - y_shifts
l1_target[:, 2] = torch.log(gt[:, 2] / stride + eps)
l1_target[:, 3] = torch.log(gt[:, 3] / stride + eps)
return l1_target
@torch.no_grad()
def get_assignments(
self,
batch_idx,
num_gt,
total_num_anchors,
gt_bboxes_per_image,
gt_classes,
bboxes_preds_per_image,
expanded_strides,
x_shifts,
y_shifts,
cls_preds,
bbox_preds,
obj_preds,
labels,
imgs,
mode="gpu",
):
if mode == "cpu":
print("------------CPU Mode for This Batch-------------")
gt_bboxes_per_image = gt_bboxes_per_image.cpu().float()
bboxes_preds_per_image = bboxes_preds_per_image.cpu().float()
gt_classes = gt_classes.cpu().float()
expanded_strides = expanded_strides.cpu().float()
x_shifts = x_shifts.cpu()
y_shifts = y_shifts.cpu()
img_size = imgs.shape[2:]
fg_mask, is_in_boxes_and_center = self.get_in_boxes_info(
gt_bboxes_per_image,
expanded_strides,
x_shifts,
y_shifts,
total_num_anchors,
num_gt,
img_size
)
bboxes_preds_per_image = bboxes_preds_per_image[fg_mask]
cls_preds_ = cls_preds[batch_idx][fg_mask]
obj_preds_ = obj_preds[batch_idx][fg_mask]
num_in_boxes_anchor = bboxes_preds_per_image.shape[0]
if mode == "cpu":
gt_bboxes_per_image = gt_bboxes_per_image.cpu()
bboxes_preds_per_image = bboxes_preds_per_image.cpu()
pair_wise_ious = bboxes_iou(gt_bboxes_per_image, bboxes_preds_per_image, False)
gt_cls_per_image = (
F.one_hot(gt_classes.to(torch.int64), self.num_classes)
.float()
.unsqueeze(1)
.repeat(1, num_in_boxes_anchor, 1)
)
pair_wise_ious_loss = -torch.log(pair_wise_ious + 1e-8)
if mode == "cpu":
cls_preds_, obj_preds_ = cls_preds_.cpu(), obj_preds_.cpu()
with torch.cuda.amp.autocast(enabled=False):
cls_preds_ = (
cls_preds_.float().unsqueeze(0).repeat(num_gt, 1, 1).sigmoid_()
* obj_preds_.float().unsqueeze(0).repeat(num_gt, 1, 1).sigmoid_()
)
pair_wise_cls_loss = F.binary_cross_entropy(
cls_preds_.sqrt_(), gt_cls_per_image, reduction="none"
).sum(-1)
del cls_preds_
cost = (
pair_wise_cls_loss
+ 3.0 * pair_wise_ious_loss
+ 100000.0 * (~is_in_boxes_and_center)
)
(
num_fg,
gt_matched_classes,
pred_ious_this_matching,
matched_gt_inds,
) = self.dynamic_k_matching(cost, pair_wise_ious, gt_classes, num_gt, fg_mask)
del pair_wise_cls_loss, cost, pair_wise_ious, pair_wise_ious_loss
if mode == "cpu":
gt_matched_classes = gt_matched_classes.cuda()
fg_mask = fg_mask.cuda()
pred_ious_this_matching = pred_ious_this_matching.cuda()
matched_gt_inds = matched_gt_inds.cuda()
return (
gt_matched_classes,
fg_mask,
pred_ious_this_matching,
matched_gt_inds,
num_fg,
)
def get_in_boxes_info(
self,
gt_bboxes_per_image,
expanded_strides,
x_shifts,
y_shifts,
total_num_anchors,
num_gt,
img_size
):
expanded_strides_per_image = expanded_strides[0]
x_shifts_per_image = x_shifts[0] * expanded_strides_per_image
y_shifts_per_image = y_shifts[0] * expanded_strides_per_image
x_centers_per_image = (
(x_shifts_per_image + 0.5 * expanded_strides_per_image)
.unsqueeze(0)
.repeat(num_gt, 1)
) # [n_anchor] -> [n_gt, n_anchor]
y_centers_per_image = (
(y_shifts_per_image + 0.5 * expanded_strides_per_image)
.unsqueeze(0)
.repeat(num_gt, 1)
)
gt_bboxes_per_image_l = (
(gt_bboxes_per_image[:, 0] - 0.5 * gt_bboxes_per_image[:, 2])
.unsqueeze(1)
.repeat(1, total_num_anchors)
)
gt_bboxes_per_image_r = (
(gt_bboxes_per_image[:, 0] + 0.5 * gt_bboxes_per_image[:, 2])
.unsqueeze(1)
.repeat(1, total_num_anchors)
)
gt_bboxes_per_image_t = (
(gt_bboxes_per_image[:, 1] - 0.5 * gt_bboxes_per_image[:, 3])
.unsqueeze(1)
.repeat(1, total_num_anchors)
)
gt_bboxes_per_image_b = (
(gt_bboxes_per_image[:, 1] + 0.5 * gt_bboxes_per_image[:, 3])
.unsqueeze(1)
.repeat(1, total_num_anchors)
)
b_l = x_centers_per_image - gt_bboxes_per_image_l
b_r = gt_bboxes_per_image_r - x_centers_per_image
b_t = y_centers_per_image - gt_bboxes_per_image_t
b_b = gt_bboxes_per_image_b - y_centers_per_image
bbox_deltas = torch.stack([b_l, b_t, b_r, b_b], 2)
is_in_boxes = bbox_deltas.min(dim=-1).values > 0.0
is_in_boxes_all = is_in_boxes.sum(dim=0) > 0
# in fixed center
center_radius = 2.5
# clip center inside image
gt_bboxes_per_image_clip = gt_bboxes_per_image[:, 0:2].clone()
gt_bboxes_per_image_clip[:, 0] = torch.clamp(gt_bboxes_per_image_clip[:, 0], min=0, max=img_size[1])
gt_bboxes_per_image_clip[:, 1] = torch.clamp(gt_bboxes_per_image_clip[:, 1], min=0, max=img_size[0])
gt_bboxes_per_image_l = (gt_bboxes_per_image_clip[:, 0]).unsqueeze(1).repeat(
1, total_num_anchors
) - center_radius * expanded_strides_per_image.unsqueeze(0)
gt_bboxes_per_image_r = (gt_bboxes_per_image_clip[:, 0]).unsqueeze(1).repeat(
1, total_num_anchors
) + center_radius * expanded_strides_per_image.unsqueeze(0)
gt_bboxes_per_image_t = (gt_bboxes_per_image_clip[:, 1]).unsqueeze(1).repeat(
1, total_num_anchors
) - center_radius * expanded_strides_per_image.unsqueeze(0)
gt_bboxes_per_image_b = (gt_bboxes_per_image_clip[:, 1]).unsqueeze(1).repeat(
1, total_num_anchors
) + center_radius * expanded_strides_per_image.unsqueeze(0)
c_l = x_centers_per_image - gt_bboxes_per_image_l
c_r = gt_bboxes_per_image_r - x_centers_per_image
c_t = y_centers_per_image - gt_bboxes_per_image_t
c_b = gt_bboxes_per_image_b - y_centers_per_image
center_deltas = torch.stack([c_l, c_t, c_r, c_b], 2)
is_in_centers = center_deltas.min(dim=-1).values > 0.0
is_in_centers_all = is_in_centers.sum(dim=0) > 0
# in boxes and in centers
is_in_boxes_anchor = is_in_boxes_all | is_in_centers_all
is_in_boxes_and_center = (
is_in_boxes[:, is_in_boxes_anchor] & is_in_centers[:, is_in_boxes_anchor]
)
del gt_bboxes_per_image_clip
return is_in_boxes_anchor, is_in_boxes_and_center
def dynamic_k_matching(self, cost, pair_wise_ious, gt_classes, num_gt, fg_mask):
# Dynamic K
# ---------------------------------------------------------------
matching_matrix = torch.zeros_like(cost)
ious_in_boxes_matrix = pair_wise_ious
n_candidate_k = min(10, ious_in_boxes_matrix.size(1))
topk_ious, _ = torch.topk(ious_in_boxes_matrix, n_candidate_k, dim=1)
dynamic_ks = torch.clamp(topk_ious.sum(1).int(), min=1)
for gt_idx in range(num_gt):
_, pos_idx = torch.topk(
cost[gt_idx], k=dynamic_ks[gt_idx].item(), largest=False
)
matching_matrix[gt_idx][pos_idx] = 1.0
del topk_ious, dynamic_ks, pos_idx
anchor_matching_gt = matching_matrix.sum(0)
if (anchor_matching_gt > 1).sum() > 0:
cost_min, cost_argmin = torch.min(cost[:, anchor_matching_gt > 1], dim=0)
matching_matrix[:, anchor_matching_gt > 1] *= 0.0
matching_matrix[cost_argmin, anchor_matching_gt > 1] = 1.0
fg_mask_inboxes = matching_matrix.sum(0) > 0.0
num_fg = fg_mask_inboxes.sum().item()
fg_mask[fg_mask.clone()] = fg_mask_inboxes
matched_gt_inds = matching_matrix[:, fg_mask_inboxes].argmax(0)
gt_matched_classes = gt_classes[matched_gt_inds]
pred_ious_this_matching = (matching_matrix * pair_wise_ious).sum(0)[
fg_mask_inboxes
]
return num_fg, gt_matched_classes, pred_ious_this_matching, matched_gt_inds