Method and apparatus for the non-invasive determination of the concentration of a component

A method of determining the concentration of a component from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by human tissue or transmitted through human tissue, said method comprising the following steps:

• 7.1 converting the intensities of received electromagnetic waves into at least one first and one second electric signal;
• 7.2 forming a continuous first temporal average value of the first signal;
• 7.3 forming a continuous second temporal average value of the second signal;
• 7. 4 continuously determining a first alternating component from said first signal and said first average value;
• 7.5 continuously determining a second alternating component from said second signal and said second average value;
• 7.6 determining a continuous differential value of the two alternating components;
• 7.7 determining a first integrated average value by integrating the first average value over a subperiod of said continuous differential value;
• 7.8 determining a second integrated average value by integrating the second average value over said subperiod;
• 7.9 determining an integrated alternating component by integrating the first or the second alternating component over said subperiod;
• 7.10 determining a first integrated differential value by integrating said differential value over said subperiod;
• 7.11 determining an integrated ratio value on the basis of the integrated differential value, the integrated alternating component and the two integrated average values;
• and
• 7.12 deriving the concentration of the component from the integrated ratio value.

A method of determining a pulse rate of a flow of blood through human tissue from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by said human tissue or transmitted through said human tissue, said method comprising the following steps:

• 13.1 converting the intensities of received electromagnetic waves into at least one first and one second electric signal;
• 13.2 forming a continuous first temporal average value of the first signal;
• 13.3 forming a continuous second temporal average value of the second signal;
• 13.4 continuously determining a first alternating component from said first signal and said first average value;
• 13.5 continuously determining a second alternating component from said second signal and said second average value;
• 13.6 determining a continuous differential value of the two alternating components;
• and
• 13.7 determining the pulse rate of the flow of blood on the basis of the zero passages of said differential value.

An apparatus for determining the concentration of a component from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by human tissue or transmitted through human tissue, comprising:

• means for converting the intensities of received electromagnetic waves into at least one first and one second electric signal;
• means for forming a continuous first temporal average value of the first signal;
• means for forming a continuous second temporal average value of the second signal;
• means for determining a continuous ratio from said first and second signals as well as from said first and second continuous temporal average values with the exception of regions lying close to the zero passages of alternating components of said first signal and said first average value, and said second signal and said second average value;
• and
• means for deriving the concentration of the component from said continuous ratio.

An apparatus for determining the concentration of a component from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by human tissue or transmitted through human tissue, comprising:

• means for converting the intensities of received electromagnetic waves into at least one first and one second electric signal;
• means for forming a continuous first temporal average value of the first signal;
• means for forming a continuous second temporal average value of the second signal;
• means for continuously determining a first alternating component from said first signal and said first average value;
• means for continuously determining a second alternating component from said second signal and said second average value;
• means for determining a continuous differential value of the two alternating components;
• means for determining a first integrated average value by integrating the first average value over a subperiod of said continuous differential value;
• means for determining a second integrated average value by integrating the second average value over said subperiod;
• means for determining an integrated alternating component by integrating the first or the second alternating component over said subperiod;
• means for determining a first integrated differential value by integrating said differential value over said subperiod;
• means for determining a first integrated ratio value on the basis of the integrated differential value, the integrated alternating component and the two integrated average values;
• and
• means for deriving the concentration of the component from the first integrated ratio value.

An apparatus for determining a pulse rate of a flow of blood through human tissue from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by said human tissue or transmitted through said human tissue, comprising:

• means for converting the intensities of received electromagnetic waves into at least one first and one second electric signal;
• means for forming a continuous first temporal average value of the first signal;
• means for forming a continuous second temporal average value of the second signal;
• means for continuously determining a first alternating component from said first signal and said first average value;
• means for continuously determining a second alternating component from said second signal and said second average value;
• means for determining a continuous differential value of the two alternating components;
• and
• means for determining the pulse rate of the flow of blood on the basis of the zero passages of said differential value.