Biological signal processing device, watching system, and watching method

A watching system comprising:

• a body-worn sensor configured to calculate RRIs of a biological signal of a target to be watched;
• a processor configured to communicate with the body-worn sensor and for executing a program;
• and
• a memory or a hard disk for storing the program, wherein upon execution of the program, the processor is configured to:
• i. acquire first RRI information composed of a plurality of first RRIs arranged in time series;
• ii. group a plurality of first points about a straight line indicating a state where the first RRIs are constant in a feature space, the plurality of first points having positions that are determined on the basis of values of the first RRIs among the first RRIs constituting the first RRI information, and generate a map from the feature space on the basis of a grouping result of the plurality of first points, wherein each first point includes a coordinate based on dimensions of the feature space and defined by a subset of the plurality of first RRIs in a normal state;
• iii. store a grouping result of the first RRI information in the memory;
• iv. acquire second RRI information composed of a plurality of second RRIs arranged in time series;
• v. compare a second point whose coordinates are determined by a value of a subset of second RRI to be evaluated with the grouping result of the first RRIs in the feature space, and calculate a first index indicating resemblance to heart rate variability of each second RRI to be evaluated on the basis of a relationship between the second point and the with the grouping result of the first RRIs to determine a deviation amount;
• vi. calculate a second index indicating a reliability of each second RRI to be evaluated based on an average of first indexes within a specified range of each second RRI;
• vii. correct a target second RRI of the plurality of second RRIs when the second index of the target second RRI falls below a predetermined reliability threshold a specified number of times;
• viii. actively monitor a heart rate variability of the target to be watched by iteratively performing steps iv to vii to determine the target's biological state;
• and
• ix. issuing a notification to an external device based on an active monitoring result of the target to be watched.

A watching method comprising:

• a step of acquiring first RRIs of a biological signal of a target to be watched, by a body-worn sensor, and acquiring RRI information composed of a plurality of the RRIs arranged in time series;
• a step of grouping a plurality of first points whose positions are determined on the basis of values of the first RRIs among the plurality of the first RRIs, on a feature space, and generating a map from the feature space on the basis of the plurality of first points, wherein each first point includes a coordinate based on dimensions of the feature space and defined by a subset of the plurality of first RRIs in a normal state;
• a step of acquiring second RRIs of a biological signal of a target to be watched, by the body-worn sensor, and acquiring second RRI information composed of a plurality of the second RRIs arranged in time series;
• a step of comparing a second point whose coordinates are determined by a value of a subset of second RRI to be evaluated with a grouping result of the first RRIs in the feature space, and calculating a first index indicating resemblance to heart rate variability of each second RRI to be evaluated, on the basis of a relationship between the second point and the the grouping result of the first RRIs to determine a deviation amount;
• a step of calculating a second index of each second RRI to be evaluated based on an average of the grouping of first indexes within a specified range of each second RRI;
• a step of correcting a target second RRI of the plurality of second RRIs a target second RRI when the second index of the target second RRI falls below a predetermined reliability threshold a specified number of times;
• a step of actively monitoring a heart rate variability of the target to be watched by iteratively performing steps iv to vii to determine the target's biological state;
• and
• a step of issuing a notification to an external device based on an active monitoring result of the target to be watched.