Fig. 2.

(a) First wearable CW fNIRS system following a modular design.³³ Reproduced with permission, courtesy of Frontiers Media. (b) $\mu \mathrm{NTS}$: first wearable modular CW HD-DOT system.^34,35 Reproduced with permission, courtesy of OPTICA Publishing Group. (c) LUMO: first commercially available wearable modular CW HD-DOT system.^13,36 Reproduced with permission, courtesy of SPIE. (d) In-house CW wearable HD-DOT system.³⁷ Reproduced with permission, courtesy of SPIE. (e) Kernel flow: first wearable time-domain DOT system.³⁸ Reproduced with permission, courtesy of Kernel, USA. (f) NINJANirs 2021.³⁹ Reproduced with permission, courtesy of OPTICA Publishing Group.