ONNX, BCEBlurWithLogitsLoss, plot_study updates

models/onnx_export.py

-# Exports a pytorch *.pt model to *.onnx format
-# Example usage (run from ./yolov5 directory):
-# $ export PYTHONPATH="$PWD" && python models/onnx_export.py --weights ./weights/yolov5s.pt --img 640 --batch 1
+"""Exports a pytorch *.pt model to *.onnx format
+
+Usage:
+    import torch
+    $ export PYTHONPATH="$PWD" && python models/onnx_export.py --weights ./weights/yolov5s.pt --img 640 --batch 1
+"""
 
 import argparse
 

utils/utils.py

@@ -339,6 +339,23 @@ def smooth_BCE(eps=0.1):  # https://github.com/ultralytics/yolov3/issues/238#iss
     return 1.0 - 0.5 * eps, 0.5 * eps
 
 
+class BCEBlurWithLogitsLoss(nn.Module):
+    # BCEwithLogitLoss() with reduced missing label effects.
+    def __init__(self, alpha=0.05):
+        super(BCEBlurWithLogitsLoss, self).__init__()
+        self.loss_fcn = nn.BCEWithLogitsLoss(reduction='none')  # must be nn.BCEWithLogitsLoss()
+        self.alpha = alpha
+
+    def forward(self, pred, true):
+        loss = self.loss_fcn(pred, true)
+        pred = torch.sigmoid(pred)  # prob from logits
+        dx = pred - true  # reduce only missing label effects
+        # dx = (pred - true).abs()  # reduce missing label and false label effects
+        alpha_factor = 1 - torch.exp((dx - 1) / (self.alpha + 1e-4))
+        loss *= alpha_factor
+        return loss.mean()
+
+
 def compute_loss(p, targets, model):  # predictions, targets, model
     ft = torch.cuda.FloatTensor if p[0].is_cuda else torch.Tensor
     lcls, lbox, lobj = ft([0]), ft([0]), ft([0])
@@ -1009,7 +1026,7 @@ def plot_study_txt(f='study.txt', x=None):  # from utils.utils import *; plot_st
     ax2.plot(1E3 / np.array([209, 140, 97, 58, 35, 18]), [33.5, 39.1, 42.5, 45.9, 49., 50.5],
              'k.-', linewidth=2, markersize=8, alpha=.25, label='EfficientDet')
     ax2.set_xlim(0, 30)
-    ax2.set_ylim(23, 50)
+    ax2.set_ylim(25, 50)
     ax2.set_xlabel('GPU Latency (ms)')
     ax2.set_ylabel('COCO AP val')
     ax2.legend(loc='lower right')