A Survey on Event-based Optical Marker Systems

TL;DR

The paper surveys Event-Based Optical Marker Systems (EBOMS), exploring how asynchronous event cameras synergize with optical markers to deliver low-latency tracking, precise pose estimation, and high-rate optical communication in dynamic and adverse lighting. It provides a taxonomy of marker types—active, geometric, passive, and hybrid—and reviews representative methods across object detection, pose estimation, and communication, highlighting concrete pipelines, decoding schemes, and performance metrics. Key contributions include a structured synthesis of EBOMS methodologies, a comparative lens on sensing and marker design, and insights into end-to-end pipelines that integrate detection, localization, and data transmission. The authors also discuss open challenges such as datasets, encoding schemes, hardware-software co-design, multi-agent scalability, and marker innovation needed to advance EBOMS toward practical deployments in robotics, AR, and beyond.

Abstract

The advent of event-based cameras, with their low latency, high dynamic range, and reduced power consumption, marked a significant change in robotic vision and machine perception. In particular, the combination of these neuromorphic sensors with widely-available passive or active optical markers (e.g. AprilTags, arrays of blinking LEDs), has recently opened up a wide field of possibilities. This survey paper provides a comprehensive review on Event-Based Optical Marker Systems (EBOMS). We analyze the basic principles and technologies on which these systems are based, with a special focus on their asynchronous operation and robustness against adverse lighting conditions. We also describe the most relevant applications of EBOMS, including object detection and tracking, pose estimation, and optical communication. The article concludes with a discussion of possible future research directions in this rapidly-emerging and multidisciplinary field.

Figures (6)

• Figure 1: Number of publications on event cameras per year, based on Scopus Scopus_web (data collected in March 2025).
• Figure 2: Core components of Event-Based Optical Marker Systems (EBOMS): (a) Optical-marker system, which may include different types of markers (e.g. LEDs) depending on the specific application; (b) Event-based camera, where each pixel operates independently and generates events asynchronously in response to brightness changes, encoding spatial, temporal and polarity information.
• Figure 3: Classification of optical markers used in EBOMS into four categories: (Left) Active markers emit modulated light signals, typically using LEDs; (Center left) Geometric markers, such as ArUco or AprilTag, encode information through distinct visual patterns; (Center right) Passive markers depend on ambient or external light sources; (Right) Hybrid markers combine active, geometric, or passive elements to capitalize on their respective strengths, in challenging environments.
• Figure 4: The EBOMS proposed in wang2022smart relies on LED-light encoding, LED detection and asynchronous data decoding. The microcontroller modulates the light signals based on input data, which are then captured as events by the neuromorphic camera. The detection algorithm processes these events, followed by asynchronous demodulation, decoding, and error checking, to reconstruct the transmitted message.
• Figure 5: Overview of Selene EBOMS proposed in wang2024towards. The system consists of an event camera and a DMD (Digital Micromirror Device).