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465
network/yolo_training.py
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465
network/yolo_training.py
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import math
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from copy import deepcopy
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from functools import partial
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import numpy as np
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import torch
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import torch.nn as nn
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class YOLOLoss(nn.Module):
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def __init__(self, anchors, num_classes, input_shape, cuda, anchors_mask = [[6,7,8], [3,4,5], [0,1,2]], label_smoothing = 0):
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super(YOLOLoss, self).__init__()
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#-----------------------------------------------------------#
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# 20x20的特征层对应的anchor是[116,90],[156,198],[373,326]
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# 40x40的特征层对应的anchor是[30,61],[62,45],[59,119]
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# 80x80的特征层对应的anchor是[10,13],[16,30],[33,23]
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#-----------------------------------------------------------#
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self.anchors = anchors
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self.num_classes = num_classes
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self.bbox_attrs = 5 + num_classes
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self.input_shape = input_shape
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self.anchors_mask = anchors_mask
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self.label_smoothing = label_smoothing
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self.threshold = 4
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self.balance = [0.4, 1.0, 4]
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self.box_ratio = 0.05
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self.obj_ratio = 1 * (input_shape[0] * input_shape[1]) / (640 ** 2)
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self.cls_ratio = 0.5 * (num_classes / 80)
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self.cuda = cuda
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def clip_by_tensor(self, t, t_min, t_max):
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t = t.float()
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result = (t >= t_min).float() * t + (t < t_min).float() * t_min
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result = (result <= t_max).float() * result + (result > t_max).float() * t_max
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return result
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def MSELoss(self, pred, target):
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return torch.pow(pred - target, 2)
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def BCELoss(self, pred, target):
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epsilon = 1e-7
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pred = self.clip_by_tensor(pred, epsilon, 1.0 - epsilon)
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output = - target * torch.log(pred) - (1.0 - target) * torch.log(1.0 - pred)
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return output
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def box_giou(self, b1, b2):
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"""
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输入为：
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----------
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b1: tensor, shape=(batch, feat_w, feat_h, anchor_num, 4), xywh
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b2: tensor, shape=(batch, feat_w, feat_h, anchor_num, 4), xywh
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返回为：
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-------
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giou: tensor, shape=(batch, feat_w, feat_h, anchor_num, 1)
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"""
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#----------------------------------------------------#
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# 求出预测框左上角右下角
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#----------------------------------------------------#
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b1_xy = b1[..., :2]
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b1_wh = b1[..., 2:4]
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b1_wh_half = b1_wh/2.
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b1_mins = b1_xy - b1_wh_half
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b1_maxes = b1_xy + b1_wh_half
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#----------------------------------------------------#
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# 求出真实框左上角右下角
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#----------------------------------------------------#
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b2_xy = b2[..., :2]
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b2_wh = b2[..., 2:4]
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b2_wh_half = b2_wh/2.
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b2_mins = b2_xy - b2_wh_half
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b2_maxes = b2_xy + b2_wh_half
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#----------------------------------------------------#
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# 求真实框和预测框所有的iou
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#----------------------------------------------------#
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intersect_mins = torch.max(b1_mins, b2_mins)
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intersect_maxes = torch.min(b1_maxes, b2_maxes)
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intersect_wh = torch.max(intersect_maxes - intersect_mins, torch.zeros_like(intersect_maxes))
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intersect_area = intersect_wh[..., 0] * intersect_wh[..., 1]
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b1_area = b1_wh[..., 0] * b1_wh[..., 1]
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b2_area = b2_wh[..., 0] * b2_wh[..., 1]
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union_area = b1_area + b2_area - intersect_area
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iou = intersect_area / union_area
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#----------------------------------------------------#
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# 找到包裹两个框的最小框的左上角和右下角
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#----------------------------------------------------#
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enclose_mins = torch.min(b1_mins, b2_mins)
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enclose_maxes = torch.max(b1_maxes, b2_maxes)
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enclose_wh = torch.max(enclose_maxes - enclose_mins, torch.zeros_like(intersect_maxes))
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#----------------------------------------------------#
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# 计算对角线距离
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#----------------------------------------------------#
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enclose_area = enclose_wh[..., 0] * enclose_wh[..., 1]
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giou = iou - (enclose_area - union_area) / enclose_area
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return giou
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#---------------------------------------------------#
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# 平滑标签
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#---------------------------------------------------#
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def smooth_labels(self, y_true, label_smoothing, num_classes):
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return y_true * (1.0 - label_smoothing) + label_smoothing / num_classes
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def forward(self, l, input, targets=None, y_true=None):
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#----------------------------------------------------#
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# l 代表使用的是第几个有效特征层
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# input的shape为 bs, 3*(5+num_classes), 20, 20
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# bs, 3*(5+num_classes), 40, 40
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# bs, 3*(5+num_classes), 80, 80
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# targets 真实框的标签情况 [batch_size, num_gt, 5]
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#----------------------------------------------------#
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#--------------------------------#
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# 获得图片数量，特征层的高和宽
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# 20, 20
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#--------------------------------#
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bs = input.size(0)
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in_h = input.size(2)
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in_w = input.size(3)
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#-----------------------------------------------------------------------#
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# 计算步长
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# 每一个特征点对应原来的图片上多少个像素点
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# [640, 640] 高的步长为640 / 20 = 32，宽的步长为640 / 20 = 32
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# 如果特征层为20x20的话，一个特征点就对应原来的图片上的32个像素点
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# 如果特征层为40x40的话，一个特征点就对应原来的图片上的16个像素点
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# 如果特征层为80x80的话，一个特征点就对应原来的图片上的8个像素点
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# stride_h = stride_w = 32、16、8
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#-----------------------------------------------------------------------#
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stride_h = self.input_shape[0] / in_h
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stride_w = self.input_shape[1] / in_w
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#-------------------------------------------------#
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# 此时获得的scaled_anchors大小是相对于特征层的
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#-------------------------------------------------#
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scaled_anchors = [(a_w / stride_w, a_h / stride_h) for a_w, a_h in self.anchors]
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#-----------------------------------------------#
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# 输入的input一共有三个，他们的shape分别是
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# bs, 3 * (5+num_classes), 20, 20 => bs, 3, 5 + num_classes, 20, 20 => batch_size, 3, 20, 20, 5 + num_classes
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# batch_size, 3, 20, 20, 5 + num_classes
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# batch_size, 3, 40, 40, 5 + num_classes
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# batch_size, 3, 80, 80, 5 + num_classes
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#-----------------------------------------------#
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prediction = input.view(bs, len(self.anchors_mask[l]), self.bbox_attrs, in_h, in_w).permute(0, 1, 3, 4, 2).contiguous()
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#-----------------------------------------------#
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# 先验框的中心位置的调整参数
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#-----------------------------------------------#
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x = torch.sigmoid(prediction[..., 0])
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y = torch.sigmoid(prediction[..., 1])
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#-----------------------------------------------#
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# 先验框的宽高调整参数
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#-----------------------------------------------#
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w = torch.sigmoid(prediction[..., 2])
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h = torch.sigmoid(prediction[..., 3])
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#-----------------------------------------------#
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# 获得置信度，是否有物体
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#-----------------------------------------------#
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conf = torch.sigmoid(prediction[..., 4])
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#-----------------------------------------------#
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# 种类置信度
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#-----------------------------------------------#
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pred_cls = torch.sigmoid(prediction[..., 5:])
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#-----------------------------------------------#
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# self.get_target已经合并到dataloader中
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# 原因是在这里执行过慢，会大大延长训练时间
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#-----------------------------------------------#
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# y_true, noobj_mask = self.get_target(l, targets, scaled_anchors, in_h, in_w)
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#---------------------------------------------------------------#
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# 将预测结果进行解码，判断预测结果和真实值的重合程度
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# 如果重合程度过大则忽略，因为这些特征点属于预测比较准确的特征点
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# 作为负样本不合适
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#----------------------------------------------------------------#
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pred_boxes = self.get_pred_boxes(l, x, y, h, w, targets, scaled_anchors, in_h, in_w)
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if self.cuda:
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y_true = y_true.type_as(x)
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loss = 0
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n = torch.sum(y_true[..., 4] == 1)
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if n != 0:
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#---------------------------------------------------------------#
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# 计算预测结果和真实结果的giou，计算对应有真实框的先验框的giou损失
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# loss_cls计算对应有真实框的先验框的分类损失
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#----------------------------------------------------------------#
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giou = self.box_giou(pred_boxes, y_true[..., :4]).type_as(x)
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loss_loc = torch.mean((1 - giou)[y_true[..., 4] == 1])
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loss_cls = torch.mean(self.BCELoss(pred_cls[y_true[..., 4] == 1], self.smooth_labels(y_true[..., 5:][y_true[..., 4] == 1], self.label_smoothing, self.num_classes)))
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loss += loss_loc * self.box_ratio + loss_cls * self.cls_ratio
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#-----------------------------------------------------------#
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# 计算置信度的loss
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# 也就意味着先验框对应的预测框预测的更准确
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# 它才是用来预测这个物体的。
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#-----------------------------------------------------------#
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tobj = torch.where(y_true[..., 4] == 1, giou.detach().clamp(0), torch.zeros_like(y_true[..., 4]))
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else:
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tobj = torch.zeros_like(y_true[..., 4])
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loss_conf = torch.mean(self.BCELoss(conf, tobj))
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loss += loss_conf * self.balance[l] * self.obj_ratio
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# if n != 0:
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# print(loss_loc * self.box_ratio, loss_cls * self.cls_ratio, loss_conf * self.balance[l] * self.obj_ratio)
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return loss
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def get_near_points(self, x, y, i, j):
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sub_x = x - i
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sub_y = y - j
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if sub_x > 0.5 and sub_y > 0.5:
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return [[0, 0], [1, 0], [0, 1]]
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elif sub_x < 0.5 and sub_y > 0.5:
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return [[0, 0], [-1, 0], [0, 1]]
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elif sub_x < 0.5 and sub_y < 0.5:
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return [[0, 0], [-1, 0], [0, -1]]
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else:
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return [[0, 0], [1, 0], [0, -1]]
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def get_target(self, l, targets, anchors, in_h, in_w):
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#-----------------------------------------------------#
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# 计算一共有多少张图片
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#-----------------------------------------------------#
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bs = len(targets)
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#-----------------------------------------------------#
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# 用于选取哪些先验框不包含物体
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# bs, 3, 20, 20
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#-----------------------------------------------------#
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noobj_mask = torch.ones(bs, len(self.anchors_mask[l]), in_h, in_w, requires_grad = False)
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#-----------------------------------------------------#
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# 帮助找到每一个先验框最对应的真实框
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#-----------------------------------------------------#
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box_best_ratio = torch.zeros(bs, len(self.anchors_mask[l]), in_h, in_w, requires_grad = False)
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#-----------------------------------------------------#
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# batch_size, 3, 20, 20, 5 + num_classes
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#-----------------------------------------------------#
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y_true = torch.zeros(bs, len(self.anchors_mask[l]), in_h, in_w, self.bbox_attrs, requires_grad = False)
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for b in range(bs):
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if len(targets[b])==0:
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continue
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batch_target = torch.zeros_like(targets[b])
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#-------------------------------------------------------#
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# 计算出正样本在特征层上的中心点
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# 获得真实框相对于特征层的大小
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#-------------------------------------------------------#
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batch_target[:, [0,2]] = targets[b][:, [0,2]] * in_w
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batch_target[:, [1,3]] = targets[b][:, [1,3]] * in_h
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batch_target[:, 4] = targets[b][:, 4]
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batch_target = batch_target.cpu()
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#-----------------------------------------------------------------------------#
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# batch_target : num_true_box, 5
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# batch_target[:, 2:4] : num_true_box, 2
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# torch.unsqueeze(batch_target[:, 2:4], 1) : num_true_box, 1, 2
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# anchors : 9, 2
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# torch.unsqueeze(torch.FloatTensor(anchors), 0) : 1, 9, 2
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# ratios_of_gt_anchors : num_true_box, 9, 2
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# ratios_of_anchors_gt : num_true_box, 9, 2
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#
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# ratios : num_true_box, 9, 4
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# max_ratios : num_true_box, 9
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# max_ratios每一个真实框和每一个先验框的最大宽高比！
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#------------------------------------------------------------------------------#
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ratios_of_gt_anchors = torch.unsqueeze(batch_target[:, 2:4], 1) / torch.unsqueeze(torch.FloatTensor(anchors), 0)
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ratios_of_anchors_gt = torch.unsqueeze(torch.FloatTensor(anchors), 0) / torch.unsqueeze(batch_target[:, 2:4], 1)
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ratios = torch.cat([ratios_of_gt_anchors, ratios_of_anchors_gt], dim = -1)
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max_ratios, _ = torch.max(ratios, dim = -1)
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for t, ratio in enumerate(max_ratios):
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#-------------------------------------------------------#
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# ratio : 9
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#-------------------------------------------------------#
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over_threshold = ratio < self.threshold
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over_threshold[torch.argmin(ratio)] = True
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for k, mask in enumerate(self.anchors_mask[l]):
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if not over_threshold[mask]:
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continue
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#----------------------------------------#
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# 获得真实框属于哪个网格点
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# x 1.25 => 1
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# y 3.75 => 3
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#----------------------------------------#
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i = torch.floor(batch_target[t, 0]).long()
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j = torch.floor(batch_target[t, 1]).long()
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offsets = self.get_near_points(batch_target[t, 0], batch_target[t, 1], i, j)
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for offset in offsets:
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local_i = i + offset[0]
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local_j = j + offset[1]
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if local_i >= in_w or local_i < 0 or local_j >= in_h or local_j < 0:
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continue
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if box_best_ratio[b, k, local_j, local_i] != 0:
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if box_best_ratio[b, k, local_j, local_i] > ratio[mask]:
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y_true[b, k, local_j, local_i, :] = 0
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else:
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continue
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#----------------------------------------#
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# 取出真实框的种类
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#----------------------------------------#
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c = batch_target[t, 4].long()
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#----------------------------------------#
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# noobj_mask代表无目标的特征点
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#----------------------------------------#
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noobj_mask[b, k, local_j, local_i] = 0
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#----------------------------------------#
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# tx、ty代表中心调整参数的真实值
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#----------------------------------------#
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y_true[b, k, local_j, local_i, 0] = batch_target[t, 0]
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y_true[b, k, local_j, local_i, 1] = batch_target[t, 1]
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y_true[b, k, local_j, local_i, 2] = batch_target[t, 2]
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y_true[b, k, local_j, local_i, 3] = batch_target[t, 3]
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y_true[b, k, local_j, local_i, 4] = 1
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y_true[b, k, local_j, local_i, c + 5] = 1
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#----------------------------------------#
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# 获得当前先验框最好的比例
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#----------------------------------------#
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box_best_ratio[b, k, local_j, local_i] = ratio[mask]
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return y_true, noobj_mask
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def get_pred_boxes(self, l, x, y, h, w, targets, scaled_anchors, in_h, in_w):
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#-----------------------------------------------------#
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# 计算一共有多少张图片
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#-----------------------------------------------------#
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bs = len(targets)
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#-----------------------------------------------------#
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# 生成网格，先验框中心，网格左上角
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#-----------------------------------------------------#
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grid_x = torch.linspace(0, in_w - 1, in_w).repeat(in_h, 1).repeat(
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int(bs * len(self.anchors_mask[l])), 1, 1).view(x.shape).type_as(x)
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grid_y = torch.linspace(0, in_h - 1, in_h).repeat(in_w, 1).t().repeat(
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int(bs * len(self.anchors_mask[l])), 1, 1).view(y.shape).type_as(x)
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# 生成先验框的宽高
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scaled_anchors_l = np.array(scaled_anchors)[self.anchors_mask[l]]
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anchor_w = torch.Tensor(scaled_anchors_l).index_select(1, torch.LongTensor([0])).type_as(x)
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anchor_h = torch.Tensor(scaled_anchors_l).index_select(1, torch.LongTensor([1])).type_as(x)
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anchor_w = anchor_w.repeat(bs, 1).repeat(1, 1, in_h * in_w).view(w.shape)
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anchor_h = anchor_h.repeat(bs, 1).repeat(1, 1, in_h * in_w).view(h.shape)
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#-------------------------------------------------------#
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# 计算调整后的先验框中心与宽高
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#-------------------------------------------------------#
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pred_boxes_x = torch.unsqueeze(x * 2. - 0.5 + grid_x, -1)
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pred_boxes_y = torch.unsqueeze(y * 2. - 0.5 + grid_y, -1)
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pred_boxes_w = torch.unsqueeze((w * 2) ** 2 * anchor_w, -1)
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pred_boxes_h = torch.unsqueeze((h * 2) ** 2 * anchor_h, -1)
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pred_boxes = torch.cat([pred_boxes_x, pred_boxes_y, pred_boxes_w, pred_boxes_h], dim = -1)
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return pred_boxes
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def is_parallel(model):
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# Returns True if model is of type DP or DDP
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return type(model) in (nn.parallel.DataParallel, nn.parallel.DistributedDataParallel)
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def de_parallel(model):
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# De-parallelize a model: returns single-GPU model if model is of type DP or DDP
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return model.module if is_parallel(model) else model
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def copy_attr(a, b, include=(), exclude=()):
|
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# Copy attributes from b to a, options to only include [...] and to exclude [...]
|
||||
for k, v in b.__dict__.items():
|
||||
if (len(include) and k not in include) or k.startswith('_') or k in exclude:
|
||||
continue
|
||||
else:
|
||||
setattr(a, k, v)
|
||||
|
||||
class ModelEMA:
|
||||
""" Updated Exponential Moving Average (EMA) from https://github.com/rwightman/pytorch-image-models
|
||||
Keeps a moving average of everything in the model state_dict (parameters and buffers)
|
||||
For EMA details see https://www.tensorflow.org/api_docs/python/tf/train/ExponentialMovingAverage
|
||||
"""
|
||||
|
||||
def __init__(self, model, decay=0.9999, tau=2000, updates=0):
|
||||
# Create EMA
|
||||
self.ema = deepcopy(de_parallel(model)).eval() # FP32 EMA
|
||||
# if next(model.parameters()).device.type != 'cpu':
|
||||
# self.ema.half() # FP16 EMA
|
||||
self.updates = updates # number of EMA updates
|
||||
self.decay = lambda x: decay * (1 - math.exp(-x / tau)) # decay exponential ramp (to help early epochs)
|
||||
for p in self.ema.parameters():
|
||||
p.requires_grad_(False)
|
||||
|
||||
def update(self, model):
|
||||
# Update EMA parameters
|
||||
with torch.no_grad():
|
||||
self.updates += 1
|
||||
d = self.decay(self.updates)
|
||||
|
||||
msd = de_parallel(model).state_dict() # model state_dict
|
||||
for k, v in self.ema.state_dict().items():
|
||||
if v.dtype.is_floating_point:
|
||||
v *= d
|
||||
v += (1 - d) * msd[k].detach()
|
||||
|
||||
def update_attr(self, model, include=(), exclude=('process_group', 'reducer')):
|
||||
# Update EMA attributes
|
||||
copy_attr(self.ema, model, include, exclude)
|
||||
|
||||
def weights_init(net, init_type='normal', init_gain = 0.02):
|
||||
def init_func(m):
|
||||
classname = m.__class__.__name__
|
||||
if hasattr(m, 'weight') and classname.find('Conv') != -1:
|
||||
if init_type == 'normal':
|
||||
torch.nn.init.normal_(m.weight.data, 0.0, init_gain)
|
||||
elif init_type == 'xavier':
|
||||
torch.nn.init.xavier_normal_(m.weight.data, gain=init_gain)
|
||||
elif init_type == 'kaiming':
|
||||
torch.nn.init.kaiming_normal_(m.weight.data, a=0, mode='fan_in')
|
||||
elif init_type == 'orthogonal':
|
||||
torch.nn.init.orthogonal_(m.weight.data, gain=init_gain)
|
||||
else:
|
||||
raise NotImplementedError('initialization method [%s] is not implemented' % init_type)
|
||||
elif classname.find('BatchNorm2d') != -1:
|
||||
torch.nn.init.normal_(m.weight.data, 1.0, 0.02)
|
||||
torch.nn.init.constant_(m.bias.data, 0.0)
|
||||
print('initialize network with %s type' % init_type)
|
||||
net.apply(init_func)
|
||||
|
||||
def get_lr_scheduler(lr_decay_type, lr, min_lr, total_iters, warmup_iters_ratio = 0.05, warmup_lr_ratio = 0.1, no_aug_iter_ratio = 0.05, step_num = 10):
|
||||
def yolox_warm_cos_lr(lr, min_lr, total_iters, warmup_total_iters, warmup_lr_start, no_aug_iter, iters):
|
||||
if iters <= warmup_total_iters:
|
||||
# lr = (lr - warmup_lr_start) * iters / float(warmup_total_iters) + warmup_lr_start
|
||||
lr = (lr - warmup_lr_start) * pow(iters / float(warmup_total_iters), 2
|
||||
) + warmup_lr_start
|
||||
elif iters >= total_iters - no_aug_iter:
|
||||
lr = min_lr
|
||||
else:
|
||||
lr = min_lr + 0.5 * (lr - min_lr) * (
|
||||
1.0
|
||||
+ math.cos(
|
||||
math.pi
|
||||
* (iters - warmup_total_iters)
|
||||
/ (total_iters - warmup_total_iters - no_aug_iter)
|
||||
)
|
||||
)
|
||||
return lr
|
||||
|
||||
def step_lr(lr, decay_rate, step_size, iters):
|
||||
if step_size < 1:
|
||||
raise ValueError("step_size must above 1.")
|
||||
n = iters // step_size
|
||||
out_lr = lr * decay_rate ** n
|
||||
return out_lr
|
||||
|
||||
if lr_decay_type == "cos":
|
||||
warmup_total_iters = min(max(warmup_iters_ratio * total_iters, 1), 3)
|
||||
warmup_lr_start = max(warmup_lr_ratio * lr, 1e-6)
|
||||
no_aug_iter = min(max(no_aug_iter_ratio * total_iters, 1), 15)
|
||||
func = partial(yolox_warm_cos_lr ,lr, min_lr, total_iters, warmup_total_iters, warmup_lr_start, no_aug_iter)
|
||||
else:
|
||||
decay_rate = (min_lr / lr) ** (1 / (step_num - 1))
|
||||
step_size = total_iters / step_num
|
||||
func = partial(step_lr, lr, decay_rate, step_size)
|
||||
|
||||
return func
|
||||
|
||||
def set_optimizer_lr(optimizer, lr_scheduler_func, epoch):
|
||||
lr = lr_scheduler_func(epoch)
|
||||
for param_group in optimizer.param_groups:
|
||||
param_group['lr'] = lr
|
||||
Reference in New Issue
Block a user