An embodiment includes a functional near infrared (fNIR) system comprising: first, second, and third light emitting diodes (LED) and a photo detector； and at least one storage medium having instructions stored thereon for causing the system to: (a) emit photo energy at first, second, and third wavelengths from the first, second, and third LEDs during first and second time periods, (b) determine first, second, and third optical density changes and changes in first and second chromophore concentrations based on the emitted photo energy； and (c) determine and fit first, second, and third absorption values to a first absorption spectra curve based on the determined changes in first and second chromophore concentrations. Other embodiments are described herein.一實施例包含一種功能性近紅外(fNIR)系統，包含：第一、第二、及第三發光二極體(LED)及一光偵測器；及具有指令儲存於其中以造成該系統進行下列操作之至少一儲存媒體：(a)在第一及第二時間期間以第一、第二、及第三波長自該第一、第二、及第三LED發射光能量；(b)基於經發射的該光能量來決定第一、第二、及第三光密度改變及於第一及第二發色團濃度中之改變；及(c)基於於該第一及第二發色團濃度中經決定的改變來決定及適配該第一、第二、及第三吸收值至一第一吸收頻譜曲線。其他實施例係說明於此。
