2019

Bridging the Gap Between Anchor-based and Anchor-free Detection via Adaptive Training Sample Selection

Zhang, Shifeng, Chi, Cheng, Yao, Yongqiang et al.

Understand

Object detection has been dominated by anchor-based detectors for several years.

  • Recently, anchor-free detectors have become popular due to the proposal of FPN and Focal Loss.
  • In this paper, we first point out that the essential difference between anchor-based and anchor-free detection is actually how to define positive and negative training samples, which leads to the performance gap between them.
  • If they adopt the same definition of positive and negative samples during training, there is no obvious difference in the final performance, no matter regressing from a box or a point.

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