Height material for substance in determination is disclosed. This method comprises: obtain the first measure spectrum from the first Nichtinvasives sensor, the first elastomeric material involved in the first measure spectrum Obtain the second measure spectrum and the second Nichtinvasives sensor, the spectrum of the second measurement and the characteristic about the second material The concentration for calculating the chemical component of the first estimation x is based on first measure spectrum The concentration for calculating the chemical component of estimation 2 among second is based on second spectrum Determine the first and second residual spectras r1, r2, the deviation definition between remaining spectrum is the frequency spectrum of measured Power estimation, and estimated frequency spectrum is the chemical component for the concentration that component corresponds to intermediate estimation measure spectrum The concentration of the chemical component of computed improved is based on estimation 1 among first, the second estimation 2 and remaining spectrum r1, r2.
