MJPNet-S*: Multistyle Joint-Perception Network with Knowledge Distillation for Drone RGB-Thermal Crowd Density Estimation in Smart Cities

Crowd density estimation has gained significant research interest owing to its potential in various industries and social applications. Therefore, this paper proposes a multistyle joint-perception network based on a knowledge distillation-trained student network (MJPNet-S*) for drone-based red–green–blue, thermal/depth (RGB-T/D) crowd density estimation tasks. To provide superior accuracy and efficiency, a novel trimodal working module effectively combines the modalities to facilitate comprehensive extraction and utilization. A two-step strategy comprising high-and low-level fusion is employed in which the high-level features capture relational reasoning and a one-dimensional projection relationship module captures multisensory field information with high-quality semantics. A shallow injection fusion module leverages the multiscale and channel relationships at the low level to combine full-text information interactively. Finally, to reduce resource consumption, a neighboring collaborative distillation method enables the lightweight student network to achieve superior performance by increasing the speed by 92 reducing the number of parameters by 83 of the teacher. Extensive experiments demonstrate that the proposed MJPNet-S* performs remarkably well on two RGB-T datasets. The code will be made public at https://github.com/WBangG/MJPNet.