🤖 AI Summary
This work addresses the challenge of time synchronization among heterogeneous sensors in roadside and vehicle-mounted multi-LiDAR–multi-camera systems by proposing an open-source, modular, and scalable hardware synchronization solution. Using the LiDAR synchronization pulse as a reference, the system employs programmable delay circuits to generate independent trigger signals for each camera, enabling flexible and precise spatiotemporal alignment. The architecture supports arbitrary combinations of sensor counts and has been validated on both a three-camera roadside platform and a seven-camera vehicular setup. Experimental results demonstrate significantly improved spatial consistency between point clouds and images, while the design ensures robustness, reproducibility, and ease of deployment.
📝 Abstract
Accurate temporal alignment of heterogeneous sensors is necessary for reliable environment perception in roadside multi-lidar, multi-camera systems, particularly in dense urban traffic. For this purpose, an open-source, simple, modular, and configurable hardware-triggered time-synchronization circuit is presented in this work to perform temporal alignment or accurate time synchronization between a lidar and multiple cameras. In the designed circuit, a lidar synchronization pulse is used as a reference input, and independently programmable, time-delayed trigger pulses are generated for each camera, allowing flexible adaptation to varying sensor setups and mounting geometries. A series of experiments is conducted on a roadside-mounted perception system comprised of lidar and three cameras, in which the trigger delay is systematically varied, and its impact on spatial-temporal alignment is evaluated. For different classes of road users, the overlap between lidar point cloud measurements and camera measurements is quantified to identify delay configurations that maximize cross-sensor consistency. The proposed circuit is shown to achieve robust and repeatable synchronization while remaining straightforward to deploy, reconfigure, and extend due to its simple and open-source design. Following validation on a three-camera roadside system, the circuit is extended to a vehicle platform with seven cameras and a lidar, providing a low-cost, extensible solution for multi-sensor synchronization across infrastructure and vehicle setups. All hardware circuit design files and source codes are available at https://github.com/shiva-THI/hardware-trigger-time-sync-lidar-cameras.