Fig. 1. General model of optical camera communication system

Fig. 2. Low-pass filter characteristics of image sensor’s exposure effect and its impacts on rolling-shutter-FSK (RS-FSK) modulation waveform. (a) Unit impulse response and frequency response; (b) inter-symbol interference and frequency selective attenuation for RS-FSK modulation waveform

Fig. 3. Constellation diagram and modulation waveform schematic of phase-frequency joint modulation scheme (N=M=4, f₁=200 Hz, ϕ1=π/2, T_s=5 ms). (a) Constellation diagram; (b) modulated waveform for each constellation point

Fig. 4. Structure diagram of data frame

Fig. 5. Structure diagram of demodulator

Fig. 6. Structure diagram of frequency domain equalizer

Fig. 7. Structure diagram of demodulation for joint phase-frequency shift keying modulated symbols

Fig. 8. Example of modulated waveform, pixel vector from image, and equalized vector for a data frame (N=M=2, Q=4, T_e=2^-10 s, signal-to-noise ratio is 10 dB, N_pps=250)

Fig. 9. Average SER curves for different exposure times given (N_pps=250)

Fig. 10. Average SER curves for constellation diagrams under different modulation frequencies and phase modulation orders (T_e=2^-10 s)

Fig. 11. Average SER curves for image sensor with different readout time (T_e=2^-10 s,T_s=5 ms)

Fig. 12. Average SER curves for 4 different 16-ary modulation schemes with same symbol rate (T_e=2^-10 s,T_s=5 ms)