Readout Time Measurement in Optical Camera Communication using Commercial LED Light Source

The rolling shutter mechanism makes the CMOS image sensor (CIS) suitable for optical camera communication by linking the periodicity of the image to the blinking frequency of the light source, where the readout time of CIS plays a pivot role in period estimation and information demodulation algorithms. However, in practice, the readout time is an intrinsic but unknown parameter and varied for different CISs, which should be measured and calibrated before data demodulation for different receiver devices. In this paper, a complete measurement system based on commercial LED lights is proposed to estimate the readout time of the CIS in different smart phones. Experiment results justify the feasibility of commercial LED lights in measurement and the differences in readout time for different smart phones.