P2RBox: A Single Point is All You Need for Oriented Object Detection
Guangming Cao Xuehui Yu Wenwen Yu Xumeng Han Xue Yang Guorong Li Jianbin Jiao Zhenjun Han
Oriented object detection, a specialized subfield in computer vision, finds
applications across diverse scenarios, excelling particularly when dealing with
objects of arbitrary orientations. Conversely, point annotation, which treats
objects as single points, offers a cost-effective alternative to rotated and
horizontal bounding boxes but sacrifices performance due to the loss of size
and orientation information. In this study, we introduce the P2RBox network,
which leverages point annotations and a mask generator to create mask
proposals, followed by filtration through our Inspector Module and Constrainer
Module. This process selects high-quality masks, which are subsequently
converted into rotated box annotations for training a fully supervised
detector. Specifically, we've thoughtfully crafted an Inspector Module rooted
in multi-instance learning principles to evaluate the semantic score of masks.
We've also proposed a more robust mask quality assessment in conjunction with
the Constrainer Module. Furthermore, we've introduced a Symmetry Axis
Estimation (SAE) Module inspired by the spectral theorem for symmetric matrices
to transform the top-performing mask proposal into rotated bounding boxes.
P2RBox performs well with three fully supervised rotated object detectors:
RetinaNet, Rotated FCOS, and Oriented R-CNN. By combining with Oriented R-CNN,
P2RBox achieves 62.26% on DOTA-v1.0 test dataset. As far as we know, this is
the first attempt at training an oriented object detector with point
supervision.