SGE: Structured Light System Based on Gray Code with an Event Camera

2024-03-12

Optics Express

AI Summary

To address timestamp noise interference and the trade-off between depth accuracy and frame rate in event-camera-based structured-light systems, this paper proposes the first Gray-code-driven, event-triggered depth estimation method. By projecting high-speed Gray-code patterns via a DLP projector and leveraging the event camera’s asynchronous response, we design an event-pattern synchronization mechanism and a timestamp-free decoding scheme, eliminating timestamp jitter entirely. The system achieves 100% sensor bandwidth utilization, attains sub-millimeter depth accuracy at native spatial resolution—comparable to high-precision scanning systems—and boosts data acquisition speed by up to 41×. Our core contributions are: (i) the first integration of Gray coding into the event-camera structured-light framework; and (ii) the establishment of a robust, timestamp-free paradigm for dense depth reconstruction. This approach significantly advances real-time, high-fidelity 3D sensing under dynamic conditions.

Technology Category

• Computer Vision: 3D Computer Vision
• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Intelligent Robots: Multimodal Perception & Sensor Fusion

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation

Abstract

Fast and accurate depth sensing has long been a significant research challenge. Event camera, as a device that quickly responds to intensity changes, provides a new solution for structured light (SL) systems. In this paper, we introduce Gray code into event-based SL systems for the first time. Our setup includes an event camera and a Digital Light Processing (DLP) projector, enabling depth estimation through high-speed projection and decoding of Gray code patterns. By employing Gray code for point matching in event-based SL system, our method is immune to timestamp noise, realizing high-speed depth estimation without loss of accuracy and spatial resolution. The binary nature of events and Gray code minimizes data redundancy, enabling us to fully utilize sensor bandwidth at 100%. Experimental results show that our approach achieves accuracy comparable to state-of-the-art scanning methods while surpassing them in data acquisition speed (up to 41 times improvement) without sacrificing accuracy and spatial resolution. Our proposed approach offers a highly promising solution for ultra-fast, real-time, and high-precision dense depth estimation.

Problem

• Achieving fast, accurate depth sensing with event cameras
• Integrating Gray code into event-based structured light systems
• Enabling high-speed depth estimation without accuracy loss

Innovation

• Event camera with Gray code SL system
• High-speed Gray code pattern projection
• Immune to timestamp noise, high accuracy