Activity meter and sleep/awake state recording system

1. An activity meter attachable to a target person whose activity amount is measured, comprising:

an acceleration sensor configured to detect acceleration in at least three axis directions;

an acceleration energy detection section configured to detect acceleration energy based on an acceleration signal of the acceleration sensor;

a first determining section configured to determine removal of the activity meter from the target person based on whether the acceleration energy detected by the acceleration enemy detection section is equal to or less than a first predetermined value and an acceleration component in a direction of gravity in the acceleration signal of the acceleration sensor exceeds a second predetermined value;

a second determining section configured to detect whether the acceleration energy is equal to or greater than a third predetermined value, and to detect whether a change in the acceleration energy is equal to or less than a fourth predetermined value when the acceleration energy is equal to or greater than the third predetermined value; and

a control section configured to:

detect that the target person is in an awake state, when the first determining section determines that the activity meter is removed from the target person,

detect that the target person is in a sleep state, when the second determining section determines that the acceleration energy is not equal to or greater than the third predetermined value in a case where the first determining section determines that the activity meter is not removed from the target person,

determine that the target person is in the sleep state when the second determining section determines that the acceleration energy is equal to or greater than the third predetermined value and the change in the acceleration energy is equal to or less than the fourth predetermined value in the case where the first determining section determines that the activity meter is not removed from the target person, and

determine that the target person is in the awake state when the second determining section determines that the acceleration energy is equal to or greater than the third predetermined value and the change in the acceleration energy is not equal to or less than the fourth predetermined value in the case where the first determining section determines that the activity meter is not removed from the target person.

2. The activity meter according to claim 1 , further comprising a sleep/awake state storage section configured to record information on the sleep state and the awake state.

3. The activity meter according to claim 2 , further comprising an information transmitting section configured to transmit information on the sleep state and the awake state stored in the sleep/awake state storage section.

4. A sleep/awake state recording system comprising:

an activity meter attachable to a target person whose activity amount is measured; and

a terminal communicable with the activity meter,

wherein the activity meter includes:

an acceleration sensor configured to detect acceleration in at least three axis directions;

an acceleration energy detection section configured to detect acceleration energy based on an acceleration signal of the acceleration sensor;

a first determining section configured to determine removal of the activity meter from the target person based on whether the acceleration energy detected by the acceleration energy detection section is equal to or less than a first predetermined value and an acceleration component in a direction of gravity in the acceleration signal of the acceleration sensor exceeds a second predetermined value;

a second determining section configured to detect whether the acceleration energy is equal to or greater than a third predetermined value, and to detect whether a change in the acceleration energy is equal to or less than a fourth predetermined value when the acceleration energy is equal to or greater than the third predetermined value,

a control section configured to:

detect that the target person is in an awake state, when the first determining section determines that the activity meter is removed from the target person,

detect that the target person is in a sleep state, when the second determining section determines that the acceleration energy is not equal to or greater than the third predetermined value in a case where the first determining section determines that the activity meter is not removed from the target person,

determine that the target person is in the sleep state when the second determining section determines that the acceleration energy is equal to or greater than the third predetermined value and the change in the acceleration energy is equal to or less than the fourth predetermined value in the case where the first determining section determines that the activity meter is not removed from the target person, and

determine that the target person is in the awake state when the second determining section determines that the acceleration energy is equal to or greater than the third predetermined value and the change in the acceleration energy is not equal to or less than the fourth predetermined value in the case where the first determining section determines that the activity meter is not removed from the target person;

a sleep/awake state storage section configured to record information on the sleep state and the awake state; and

an information transmitting section configured to transmit information on the sleep state and the awake state stored in the sleep/awake state storage section, and

wherein the terminal includes:

a correction section configured to correct the information on the sleep state and the awake state received from the activity meter; and

a storage section configured to store the corrected information.