Apparatus and method for measuring bio-information

An apparatus for measuring bio-information, the apparatus comprising:

• a pulse wave sensor configured to emit light of multiple wavelengths onto an object, and detect the light to obtain multi-wavelength pulse wave signals when the light is reflected or scattered from the object;
• and
• a processor configured to:
• obtain a conversion signal that estimates a contact pressure between the object and the pulse wave sensor, based on differences between the multi-wavelength pulse wave signals, without using a force sensor or a pressure sensor to measure the contact pressure,
• obtain an oscillometric envelope based on the multi-wavelength pulse wave signals and the conversion signal, and
• obtain bio-information based on the oscillometric envelope,
• wherein the bio-information comprises at least one of a blood pressure, a vascular age, an arterial stiffness, an aortic pressure waveform, a vascular compliance, a stress index, and a degree of fatigue.