Bio-information estimating apparatus and bio-information estimating method

A wearable device comprising:

• a main body;
• a strap;
• a sensor part disposed in the main body, and configured to measure a pulse wave signal from an object, a contact force that is applied by the object to the sensor part, and a contact area of the object that is applied to the sensor part;
• and
• a processor configured to:
• obtain a first feature value of a contact area change graph representing a first change in the contact area with respect to a second change in the contact force;
• obtain a contact pressure between the object and the sensor part, based on the contact force and the contact area;
• obtain an oscillometric envelope representing the contact pressure versus the pulse wave signal;
• obtain a second feature value of the oscillometric envelope;
• and
• estimate bio-information, based on the first feature value and the second feature value.