ED-Pose++: Enhanced Explicit Box Detection for Conventional and Interactive Multi-Object Keypoint Detection.

Detecting keypoints on diverse objects is essential for fine-grained visual understanding and analysis. This paper introduces Enhanced Explicit Box Detection (ED-Pose++), an end-to-end framework that leverages cascade box regression to realize both conventional and interactive multi-object keypoint detection. Unlike traditional one-stage methods, ED-Pose++ innovatively redefines multi-object keypoint detection as a dual-phase explicit box detection, achieving a unified representation and regression optimization process. Specifically, an object detection decoder first extracts each object's position and global features, establishing a good initialization for subsequent keypoint detection. To bring in contextual information near keypoints, we also regard each keypoint as a small box to learn both positions and their related local contents. In practice, an object-to-keypoint detection decoder adopts a collaborative learning strategy between object and keypoint features, facilitating efficient information propagation between global and local perspectives. Rooted on the architecture, we further equip dual-phase box detection with an interactive mechanism that enables the model to refine its predictions based on limited user feedback. During training, we incorporate an error correction scheme to equip the model with an adept self-correction capability for use during inference. The comprehensive experiments demonstrate ED-Pose++'s superior performance in conventional multi-object keypoint detection tasks. For the first time, ED-Pose++ outperforms heatmap-based top-down approaches across various benchmarks, despite operating within a fully end-to-end architecture. The interactive variant also dramatically reduces more than 10 times the labeling effort of 2D keypoint annotation compared with manual-only annotation.