Fig. 4.

Some recent examples of portable/wearable FD-NIRS systems. (a) The miniOptode integrated with the VCSEL source (top) and APD detector (bottom) for the FD-NIRS system described by Istfan et al. This figure is taken with permission from [50]. (b) The photograph of the handheld FD-NIRS system described by Stillwell et al. This figure is taken with permission from [58]. (c) The schematic and the chip micrograph of the CMOS-based system described by Miao and Koomson. This figure is taken with permission from [62]. (d) The schematic of the CMOS-based system described by Yazdi. This figure is taken with permission from [65].