TY - JOUR
T1 - Rearrangeable and exchangeable optical module with system-on-chip for wearable functional near-infrared spectroscopy system
AU - Funane, Tsukasa
AU - Numata, Takashi
AU - Sato, Hiroki
AU - Hiraizumi, Shinsuke
AU - Hasegawa, Yuichi
AU - Kuwabara, Hidenobu
AU - Hasegawa, Kiyoshi
AU - Kiguchi, Masashi
N1 - Funding Information:
This work was supported by Hitachi, Ltd. and Hitachi High-Technologies Corporation.
Publisher Copyright:
© 2017 The Authors.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photodiode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying +3.3V of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.
AB - We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photodiode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying +3.3V of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.
KW - functional near-infrared spectroscopy
KW - module-based system
KW - system-on-chip
KW - wearable
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U2 - 10.1117/1.NPh.5.1.011007
DO - 10.1117/1.NPh.5.1.011007
M3 - Article
AN - SCOPUS:85029797409
VL - 5
JO - Neurophotonics
JF - Neurophotonics
SN - 2329-4248
IS - 1
M1 - 011007
ER -