Signal synthesis apparatus, signal synthesis method and program

A signal synthesis method executed by a signal synthesis device,

• the signal synthesis method comprising
• a waveform synthesis step of:
• setting a waveform in a time section of an R wave included in a waveform for one cycle indicating a cardiac cycle of a heart as a first target time waveform;
• setting a waveform in a time section of a T wave included in the waveform as a second target time waveform;
• setting a waveform obtained by inverting a time axis of the second target time waveform as a second target inverse time waveform;
• setting a set as a myocardial activity parameter set, the set including
• a value of a parameter specifying a first unimodal distribution or a value of a parameter specifying a first cumulative distribution function, a value of a parameter specifying a second unimodal distribution or a value of a parameter specifying a second cumulative distribution function, a value of a first weight parameter, a value of a second weight parameter, and a value of a first level parameter when the first target time waveform is approximated by a first approximate time waveform that is a time waveform represented by a function obtained by subtracting, from a function obtained by multiplying the first cumulative distribution function that is a cumulative distribution function of the first unimodal distribution by the value of the first weight parameter, a function obtained by multiplying the second cumulative distribution function that is a cumulative distribution function of the second unimodal distribution by the value of the second weight parameter, and adding the value of the first level parameter, and
• a value of a parameter specifying a third unimodal distribution or a value of a parameter specifying a third cumulative distribution function, a value of a parameter specifying a fourth unimodal distribution or a value of a parameter specifying a fourth cumulative distribution function, a value of a third weight parameter, a value of a fourth weight parameter, and a value of a second level parameter when the second target inverse time waveform is approximated by a second approximate inverse time waveform that is a waveform represented by a function obtained by subtracting, from a function obtained by multiplying the third cumulative distribution function that is a cumulative distribution function of the third unimodal distribution by the value of the third weight parameter, a function obtained by multiplying the fourth cumulative distribution function that is a cumulative distribution function of the fourth unimodal distribution by the value of the fourth weight parameter, and adding the value of the second level parameter;
• setting each of element values included in the myocardial activity parameter set as a myocardial activity parameter value;
• using each of myocardial activity parameter values included in the myocardial activity parameter set of a heart to be a target (Hereinafter, the heart is referred to as a “target heart”.);
• obtaining, as a synthesized waveform in the time section of the R wave, a time waveform represented by a function obtained by subtracting, from a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the first unimodal distribution or the first cumulative distribution function by the myocardial activity parameter value of the first weight parameter, a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the second unimodal distribution or the second cumulative distribution function by the myocardial activity parameter value of the second weight parameter, and adding the myocardial activity parameter value of the first level parameter;
• obtaining, as a synthesized waveform in the time section of the T wave, a waveform obtained by inverting a time axis of a waveform represented by a function obtained by subtracting, from a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the third unimodal distribution or the third cumulative distribution function by the myocardial activity parameter value of the third weight parameter, a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the fourth unimodal distribution or the fourth cumulative distribution function by the myocardial activity parameter value of the fourth weight parameter, and adding the myocardial activity parameter value of the second level parameter;
• and
• connecting the synthesized waveform in the time section of the R wave and the synthesized waveform in the time section of the T wave together to obtain a synthesized signal for a waveform indicating the cardiac cycle of the target heart.

A signal synthesis method executed by a signal synthesis device,

• the signal synthesis method comprising
• a waveform synthesis step of:
• setting a waveform in a time section of an R wave included in a waveform for one cycle indicating a cardiac cycle of a heart as a first target time waveform;
• setting a waveform in a time section of a T wave included in the waveform as a second target time waveform;
• setting a set as a myocardial activity parameter set, the set including a value of a parameter specifying a first unimodal distribution or a value of a parameter specifying a first cumulative distribution function, a value of a parameter specifying a second unimodal distribution or a value of a parameter specifying a second cumulative distribution function, a value of a first weight parameter, a value of a second weight parameter, and a value of a first level parameter when the first target time waveform is approximated by a first approximate time waveform that is a time waveform represented by a function obtained by subtracting, from a function obtained by multiplying the first cumulative distribution function that is a cumulative distribution function of the first unimodal distribution by the value of the first weight parameter, a function obtained by multiplying the second cumulative distribution function that is a cumulative distribution function of the second unimodal distribution by the value of the second weight parameter, and adding the value of the first level parameter, and
• a value of a parameter specifying a third unimodal distribution or a value of a parameter specifying a third cumulative distribution function, a value of a parameter specifying a fourth unimodal distribution or a value of a parameter specifying a fourth cumulative distribution function, a value of a third weight parameter, a value of a fourth weight parameter, and a value of a second level parameter when the second target time waveform is approximated by a second approximate time waveform that is a time waveform represented by a function obtained by subtracting, from a function obtained by subtracting, from 1, a function obtained by multiplying the third cumulative distribution function that is a cumulative distribution function of the third unimodal distribution by the value of the third weight parameter, a function obtained by subtracting, from 1, a function obtained by multiplying the fourth cumulative distribution function that is a cumulative distribution function of the fourth unimodal distribution by the value of the fourth weight parameter, and adding the value of the second level parameter;
• setting each of element values included in the myocardial activity parameter set as a myocardial activity parameter value;
• using each of myocardial activity parameter values included in the myocardial activity parameter set of a heart to be a target (Hereinafter, the heart is referred to as a “target heart”.);
• obtaining, as a synthesized waveform in the time section of the R wave, a time waveform represented by a function obtained by subtracting, from a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the first unimodal distribution or the first cumulative distribution function by the myocardial activity parameter value of the first weight parameter, a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the second unimodal distribution or the second cumulative distribution function by the myocardial activity parameter value of the second weight parameter, and adding the myocardial activity parameter value of the first level parameter;
• obtaining, as a synthesized waveform in the time section of the T wave, a time waveform represented by a function obtained by subtracting, from a function obtained by subtracting, from 1, a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the third unimodal distribution or the third cumulative distribution function by the myocardial activity parameter value of the third weight parameter, a function obtained by subtracting, from 1, a function obtained by multiplying a cumulative distribution function specified by the myocardial activity parameter value of the parameter specifying the fourth unimodal distribution or the fourth cumulative distribution function by the myocardial activity parameter value of the fourth weight parameter, and adding the myocardial activity parameter value of the second level parameter;
• and
• connecting the synthesized waveform in the time section of the R wave and the synthesized waveform in the time section of the T wave together to obtain a synthesized signal for a waveform indicating the cardiac cycle of the target heart.