Decoding visible light communication signals using image sensors

• Main Author: Ravichandrakumar, Dhuwaragish
• Other Authors: Arokiaswami Alphones
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/166847
• Institution: Nanyang Technological University

This report outlines a separate vision-based approach for indoor localization using Visible Light Communication (VLC) technology. The study aims to develop a decoding algorithm to extract encoded data from light waves captured by a smartphone camera. The encoded data is transmitted using On-Off-Keying (OOK) modulation and encoded with the Differential Manchester Encoding (DME) scheme. Image processing is performed with the in-built functions and tools from MATLAB programming to extract the encoded digital signal from the image. The algorithm is then executed on the encoded data sequence to retrieve the originally transmitted data. The performance of the algorithm is tested using BER analysis for various signal frequencies and distances between the LED transmitter and the smartphone camera. The results demonstrate that the algorithm works best for higher signal frequencies and for shorter distances. However, if the algorithm is utilized for indoor positioning services, it may encounter performance issues for lower signal frequencies with larger distances from the transmitter to the receiver, which may contain incomplete information at the receiver to perform the image processing. This study aims to provide an efficient indoor positioning service using VLC technology, which could be a viable alternative to the poor indoor navigation performance of GPS.