  Keypoint-based methods are a relatively new paradigm in object detection,
eliminating the need for anchor boxes and offering a simplified detection
framework. Keypoint-based CornerNet achieves state of the art accuracy among
single-stage detectors. However, this accuracy comes at high processing cost.
In this work, we tackle the problem of efficient keypoint-based object
detection and introduce CornerNet-Lite. CornerNet-Lite is a combination of two
efficient variants of CornerNet: CornerNet-Saccade, which uses an attention
mechanism to eliminate the need for exhaustively processing all pixels of the
image, and CornerNet-Squeeze, which introduces a new compact backbone
architecture. Together these two variants address the two critical use cases in
efficient object detection: improving efficiency without sacrificing accuracy,
and improving accuracy at real-time efficiency. CornerNet-Saccade is suitable
for offline processing, improving the efficiency of CornerNet by 6.0x and the
AP by 1.0% on COCO. CornerNet-Squeeze is suitable for real-time detection,
improving both the efficiency and accuracy of the popular real-time detector
YOLOv3 (34.4% AP at 30ms for CornerNet-Squeeze compared to 33.0% AP at 39ms for
YOLOv3 on COCO). Together these contributions for the first time reveal the
potential of keypoint-based detection to be useful for applications requiring
processing efficiency.
