Compressed Frequency-Division Multiplexing Sampling Technique for High-Density NearInfrared Brain Functional Imaging Photoelectric Array

Multi-channel and high-density fNIRS systems are crucial for providing detailed and comprehensive brain activity mapping, enhancing the understanding of neural processes. Currently, fNIRS primarily employs time-division multiplexing to sequentially collect data from each channel. However, as the number of channels increases, the time resolution significantly deteriorates. Therefore, maintaining high temporal resolution of fNIRS device represents the primary objective of this work. Therefore, this study introduces a compressed frequency-division multiplexing(FDM) sampling technique, considering the principle of light attenuation and the optoelectronic arrangement of the equipment, utilizing just four carrier frequencies to develop a multi-channel fNIRS system. This research verified the proposed solution through deployment on an FPGA platform and the measurement results ensures high temporal resolution of the device within highdensity fNIRS system photoelectric arrays.