Abstract:
fNIRS is a non-invasive, portable & easy to use brain imaging modality. It can estimate the hemodynamic response of the brain by measuring the absorption of IR light with respect to time. The standard channel separation between source & detector in fNIRS is 3cm but this distance has a disadvantage of higher channel noise. To resolve the issue, we have presented a new fNIRS design with small channel separation to minimize the channel noise. In this research, we have designed the fNIRS device using 2 sources & 14 detectors in a circular configuration. The detectors are placed in two circles each circle having 7 LEDs with a radius of 1.5cm & 2.25cm respectively. After the software design, we implemented it on a hardware & tested the device using occlusion. Once the device got tested through occlusion, we acquired the brain signals by placing it on the left frontal cortex. After placing the device on the frontal cortex, we reverse counted for 200sec with rest & count intervals. The whole experimental design is described in the sections below. We applied Modified Beer Lambert Law (MBLL) to deduce results. The results proved to be promising as the channel noise reduced & we got better signals. The results can be improved further by using the high-power IR LEDs having better penetrating ability.
