Mask Encoding for Single Shot Instance Segmentation
It addresses the performance gap for researchers and practitioners needing efficient instance segmentation, though it is incremental as it builds on existing one-stage detectors.
The paper tackles the challenge of one-stage instance segmentation by proposing MEInst, which encodes masks into compact vectors to integrate with bounding-box detectors, achieving 36.4% mask AP on MS-COCO with a ResNeXt-101-FPN backbone.
To date, instance segmentation is dominated by twostage methods, as pioneered by Mask R-CNN. In contrast, one-stage alternatives cannot compete with Mask R-CNN in mask AP, mainly due to the difficulty of compactly representing masks, making the design of one-stage methods very challenging. In this work, we propose a simple singleshot instance segmentation framework, termed mask encoding based instance segmentation (MEInst). Instead of predicting the two-dimensional mask directly, MEInst distills it into a compact and fixed-dimensional representation vector, which allows the instance segmentation task to be incorporated into one-stage bounding-box detectors and results in a simple yet efficient instance segmentation framework. The proposed one-stage MEInst achieves 36.4% in mask AP with single-model (ResNeXt-101-FPN backbone) and single-scale testing on the MS-COCO benchmark. We show that the much simpler and flexible one-stage instance segmentation method, can also achieve competitive performance. This framework can be easily adapted for other instance-level recognition tasks. Code is available at: https://git.io/AdelaiDet