Thresholding schemes for visible light communications with CMOS camera using entropy-based algorithms.

Abstract

Recent visible light communication (VLC) studies mainly used positive-intrinsic-negative (PIN) and avalanche photodiode (APD). VLC using embedded complementary-metal-oxide-semiconductor (CMOS) camera is attractive. Using the rolling shutter effect of CMOS camera can increase the VLC data rate; and different techniques have been proposed for improving the demodulation of the rolling shutter pattern. Important steps to demodulate the rolling shutter pattern are the smoothing and the application of efficient thresholding to distinguish data logic. Here, we propose and demonstrate for the first time two entropy thresholding algorithms, including maximum entropy thresholding and minimum cross entropy thresholding. Experimental evaluation to compare their bit-error-rate (BER) performances and efficiencies are also performed.