build.py 2.0 KB

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  1. #!/usr/bin/env python3
  2. # -*- coding:utf-8 -*-
  3. import torch
  4. import torch.nn as nn
  5. from .loss import build_criterion
  6. from .yolov3 import YOLOv3
  7. # build object detector
  8. def build_yolov3(args, cfg, device, num_classes=80, trainable=False, deploy=False):
  9. print('==============================')
  10. print('Build {} ...'.format(args.model.upper()))
  11. print('==============================')
  12. print('Model Configuration: \n', cfg)
  13. # -------------- Build YOLO --------------
  14. model = YOLOv3(
  15. cfg=cfg,
  16. device=device,
  17. num_classes=num_classes,
  18. trainable=trainable,
  19. conf_thresh=args.conf_thresh,
  20. nms_thresh=args.nms_thresh,
  21. topk=args.topk,
  22. deploy = deploy,
  23. nms_class_agnostic = args.nms_class_agnostic
  24. )
  25. # -------------- Initialize YOLO --------------
  26. for m in model.modules():
  27. if isinstance(m, nn.BatchNorm2d):
  28. m.eps = 1e-3
  29. m.momentum = 0.03
  30. # Init bias
  31. init_prob = 0.01
  32. bias_value = -torch.log(torch.tensor((1. - init_prob) / init_prob))
  33. # obj pred
  34. for obj_pred in model.obj_preds:
  35. b = obj_pred.bias.view(1, -1)
  36. b.data.fill_(bias_value.item())
  37. obj_pred.bias = torch.nn.Parameter(b.view(-1), requires_grad=True)
  38. # cls pred
  39. for cls_pred in model.cls_preds:
  40. b = cls_pred.bias.view(1, -1)
  41. b.data.fill_(bias_value.item())
  42. cls_pred.bias = torch.nn.Parameter(b.view(-1), requires_grad=True)
  43. # reg pred
  44. for reg_pred in model.reg_preds:
  45. b = reg_pred.bias.view(-1, )
  46. b.data.fill_(1.0)
  47. reg_pred.bias = torch.nn.Parameter(b.view(-1), requires_grad=True)
  48. w = reg_pred.weight
  49. w.data.fill_(0.)
  50. reg_pred.weight = torch.nn.Parameter(w, requires_grad=True)
  51. # -------------- Build criterion --------------
  52. criterion = None
  53. if trainable:
  54. # build criterion for training
  55. criterion = build_criterion(cfg, device, num_classes)
  56. return model, criterion