  In this paper, we present a comprehensive review of the imbalance problems in
object detection. To analyze the problems in a systematic manner, we introduce
a problem-based taxonomy. Following this taxonomy, we discuss each problem in
depth and present a unifying yet critical perspective on the solutions in the
literature. In addition, we identify major open issues regarding the existing
imbalance problems as well as imbalance problems that have not been discussed
before. Moreover, in order to keep our review up to date, we provide an
accompanying webpage which catalogs papers addressing imbalance problems,
according to our problem-based taxonomy. Researchers can track newer studies on
this webpage available at:
https://github.com/kemaloksuz/ObjectDetectionImbalance .
