Unbalanced Optimal Transport: A Unified Framework for Object Detection
This provides a more flexible and efficient approach for object detection researchers and practitioners, though it is incremental as it builds on existing matching strategies.
The paper tackles the problem of matching predicted bounding boxes to ground truth in object detection by introducing Unbalanced Optimal Transport as a unified framework, achieving state-of-the-art results in Average Precision and Average Recall with faster initial convergence.
During training, supervised object detection tries to correctly match the predicted bounding boxes and associated classification scores to the ground truth. This is essential to determine which predictions are to be pushed towards which solutions, or to be discarded. Popular matching strategies include matching to the closest ground truth box (mostly used in combination with anchors), or matching via the Hungarian algorithm (mostly used in anchor-free methods). Each of these strategies comes with its own properties, underlying losses, and heuristics. We show how Unbalanced Optimal Transport unifies these different approaches and opens a whole continuum of methods in between. This allows for a finer selection of the desired properties. Experimentally, we show that training an object detection model with Unbalanced Optimal Transport is able to reach the state-of-the-art both in terms of Average Precision and Average Recall as well as to provide a faster initial convergence. The approach is well suited for GPU implementation, which proves to be an advantage for large-scale models.