This repository maintains an organized collection of academic studies on imbalance problems in object detection. It follows the taxonomy from a TPAMI review paper covering class imbalance (foreground-background and foreground-foreground), scale imbalance (object-level and feature-level), spatial imbalance (regression loss, IoU distribution, object location), and objective imbalance. Researchers can request additions via pull requests, and the collection is limited to generic object detection datasets like ILSVRC, Pascal VOC, and MS-COCO.