Compensation schemes for uneven illumination and LED light-emitting instability in optical camera communication system

In order to increase the data rate of the optical camera communication (OCC) system, the 8 -composite -amplitude -shift -keying modulation (8CASK) OCC system is used in this work. However, if the static decision thresholds are employed to demodulate multi -level ASK signal, uneven illumination of LED lamps and LED light -emitting instability lead to the fluctuation of the gray range in the picture and degrade the bit -error -rate (BER) performance. In this work, we propose and demonstrate a demodulation scheme, using the uneven illumination compensation algorithm, the pixel matrix threshold overall update algorithm and the secondary decision algorithm, to mitigate the impact of illumination unevenness and LED light -emitting instability. The BER performance is evaluated and compared with other demodulation schemes. The experimental results demonstrate that the communication rate of our proposed scheme can reach 9kbit/s at a distance of 250 cm where the illumination is 135lux, and the BER is 8.01 x 10 - 5 . (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement