PROBLEM TO BE SOLVED: To provide a technology to acquire a waveform of a pulse wave whose influence by a change in disturbance light is suppressed.SOLUTION: A control part 3 outputs, as a pulse wave signal, a differential value indicating a difference between irradiation intensity and disturbance light intensity when a variation of the disturbance light intensity is a disturbance threshold or less in S46. The control part 3 acquires an initial value indicating a differential value when a disturbance variation changes from the disturbance threshold or less to a value larger than the disturbance threshold in S52. The control part 3 outputs, as a pulse wave signal, a correction value indicating a value acquired by adding an interpolation value indicating a value multiplying a lapsed time indicating a time that has elapsed since the disturbance variation exceeds the disturbance threshold by a difference change rate indicating a change rate of the differential value when the disturbance variation is the disturbance threshold or less, to the initial value when the disturbance variation is larger than the disturbance threshold in S56.SELECTED DRAWING: Figure 4BCOPYRIGHT: (C)2018,JPO&INPIT【課題】外乱光の変化による影響が抑制された脈波の波形を得る技術を提供する。【解決手段】制御部3は、S46では、外乱光強度の変化量が外乱閾値以下である場合に、照射強度と外乱光強度との差を示す差分値を脈波信号として出力する。制御部3は、S52では、外乱変化量が外乱閾値以下から外乱閾値よりも大きい値に変化したときの差分値を表す初期値を取得する。制御部3は、S56では、外乱変化量が外乱閾値よりも大きい場合に、外乱変化量が外乱閾値を超えてからの時間を示す経過時間に外乱変化量が外乱閾値以下であるときの差分値の変化率を表す差分変化率を乗じた値を表す補間値、を初期値に加算して得られる値を表す補正値、を脈波信号として出力する。【選択図】図4B
