Information processing apparatus, feature quantity extraction method, training data generation method, estimation model generation method, stress level estimation method, and storage medium

A feature quantity extraction method, comprising:

• identifying, as a time zone of interest by at least one processor, a time zone in which a chronic stress tendency is notably shown in biological signals which have been acquired from a subject over a predetermined time period;
• and
• extracting, by the at least one processor, one or more feature quantities from biological signals acquired in the time zone of interest which has been identified, the one or more feature quantities being used in machine learning of an estimation model for estimating a stress level or used in estimation of a stress level using the estimation model.

A computer-readable non-transitory storage medium storing a program for causing a computer to carry out:

• an identification process of identifying, as a time zone of interest, a time zone in which a chronic stress tendency is notably shown in biological signals which have been acquired from a subject over a predetermined time period;
• and
• an extraction process of extracting one or more feature quantities from biological signals acquired in the time zone of interest which has been identified, the one or more feature quantities being used in machine learning of an estimation model for estimating a stress level or used in estimation of a stress level using the estimation model.