Crossing the Road Without Traffic Lights: An Android-based Safety Device

TL;DR

This paper introduces a low-cost, Android-based safety device that detects approaching vehicles using optical flow and provides pedestrians, especially those with visual impairments, with early warnings to cross safely without traffic lights.

Contribution

It presents a novel, infrastructure-free safety system using a smartphone camera and optical flow for real-time vehicle detection at crossings.

Findings

System operates in real-time on a smartphone.

Provides early warnings to pedestrians.

Can be deployed without existing traffic infrastructure.

Abstract

In the absence of pedestrian crossing lights, finding a safe moment to cross the road is often hazardous and challenging, especially for people with visual impairments. We present a reliable low-cost solution, an Android device attached to a traffic sign or lighting pole near the crossing, indicating whether it is safe to cross the road. The indication can be by sound, display, vibration, and various communication modalities provided by the Android device. The integral system camera is aimed at approaching traffic. Optical flow is computed from the incoming video stream, and projected onto an influx map, automatically acquired during a brief training period. The crossing safety is determined based on a 1-dimensional temporal signal derived from the projection. We implemented the complete system on a Samsung Galaxy K-Zoom Android smartphone, and obtained real-time operation. The system achieves promising experimental results, providing pedestrians with sufficiently early warning of approaching vehicles. The system can serve as a stand-alone safety device, that can be installed where pedestrian crossing lights are ruled out. Requiring no dedicated infrastructure, it can be powered by a solar panel and remotely maintained via the cellular network.