PROBLEM TO BE SOLVED: To realize higher S/N by reducing only a measuring error without weakening signal strength even in using two wavelengths a difference of Hb absorptivity of which is large.SOLUTION: (a) An Hb signal the measuring error of which decreases by combination of certain two wavelengths is measured by using light of more than three wavelengths, simultaneously, (b) an Hb signal strength of an active signal of which does not weaken by combination of two wavelengths different from the combination of (a) is measured, and (c) the signal strength of the Hb signal small in the measuring error is corrected to be equal to the signal strength of the Hb signal measured so as not to weaken the signal strength. Otherwise, the measuring data is corrected so that the signal strength comes to meet proportion of the previously specified estimated signal strength by measuring it by using only two wavelengths of the combination considered to make the S/N better.COPYRIGHT: (C)2008,JPO&INPIT【課題】Hb吸光係数の差が大きい2波長を用いた場合でも,信号強度を弱めることなく計測誤差だけ低減させ,より高いS/Nを実現する。【解決手段】(a)3波長以上の光を用いて,ある2波長の組み合わせで計測誤差が小さくなるHb信号を計測すると同時に,(b)その組み合わせとは異なる2波長の組み合わせで活動信号の強度が弱まらないHb信号を計測し,(c)計測誤差が小さいHb信号における信号強度が,信号強度が弱まらないよう計測したHb信号の信号強度と等しくなるよう補正する。あるいは,S/Nがよくなると考えられる組み合わせの2波長だけを用いて計測を行い,事前に定めた予想される信号強度の割合に合うよう,計測データを補正する。【選択図】図6
