Design and implementation of a cascaded camera switching system for drone-based multi-camera perception

Abstract

This project introduces the design and implementation of a multi-camera expansion system based on Raspberry Pi. The goal is to extend the Raspberry Pi’s CSI interface, enabling multiple camera modules to share a single CSI interface. Compared to existing commercial solutions, the core contribution of this research is the design of a lighter and more compact expansion board to meet the miniaturization requirements of UAV platforms. The system achieves multiplexing switching through an I2C multiplexer and GPIO control of MIPI. On the hardware side, a custom four-layer PCB was designed and fabricated. On the software side, a dedicated device tree overlay layer was defined to describe its hardware topology. During the verification phase, software tools such as libcamera and media-ctl, as well as custom control scripts, were used for system integration and verification. Experimental results show that the system successfully implemented I2C communication, GPIO-based channel selection, device driver registration, camera enumeration, and media pipeline creation. However, in system-level testing, stable image stream transmission failed to be established. Further testing revealed that the fault lies in the high-speed MIPI CSI-2 transmission path. Although complete image streaming was not achieved, the project successfully validated the control architecture and software integration of the proposed multi-camera system, and the troubleshooting process provided a reference for subsequent development and optimization.