Single-image crowd counting: a comparative survey on deep learning-based approaches

Crowd counting is an attracting computer vision problem. Solutions to crowd counting hold high adaptability to other counting problems such as traffic counting and cell counting. Numerous methods have been proposed for the problem. Deep learning-based methods play a significant role in recent advancement. However, no existing literature reviews capture their sophisticated development by challenges. In this paper, we discuss and categorize recent deep learning works in crowd counting by considering how they address the challenges.