Sleep monitoring method and apparatus, sleep aid device and method

A sleep monitoring apparatus, comprising:

• a signal acquisition sub-circuit configured to acquire an electroencephalogram (EEG) signal of a user;
• a first processing sub-circuit configured to process the EEG signal by at least one of wavelet packet decomposition, wavelet transform, or Fourier transform to obtain energy values of the EEG signal in a plurality of set frequency bands;
• a second processing sub-circuit configured to calculate relative energy values of the EEG signal in the plurality of set frequency bands;
• and
• a state determination sub-circuit configured to determine sleep state, mental stress, and fatigue level according to the relative energy values,
• wherein the plurality of set frequency bands comprises a first frequency band, a second frequency band, a third frequency band, and a fourth frequency band;
• and
• the first frequency band is greater than or equal to 0.5 Hz and less than 4 Hz, the second frequency band is greater than or equal to 4 Hz and less than 8 Hz, the third frequency band is greater than or equal to 8 Hz and less than 12 Hz, and the fourth frequency band is greater than or equal to 12 Hz and less than or equal to 30 Hz,
• wherein the second processing sub-circuit is further configured to:
• calculate a sum of the energy values of the EEG signal;
• and
• determine each of the relative energy values as a ratio of the energy value of the EEG signal in a respective set frequency band to the sum,
• wherein the state determination sub-circuit is further configured to:
• calculate a sleep index SI by formulas of:
• SI=(K1*E1+K2*E2)/(K3*E3+K4*E4),
• K1+K2=1, and
• K3+K4=1,
• where, K1 has a value range of 0.3-0.5, K3 has a value range of 0.7-1, E1 is the relative energy value of the EEG signal in the first frequency band, E2 is the relative energy value of the EEG signal in the second frequency band, E3 is the relative energy value of the EEG signal in the third frequency band, and E4 is the relative energy value of the EEG signal in the fourth frequency band;
• and
• calculate a deep sleep index DI by a formula of:
• DI=E1/E2,
• wherein, if SI<TH1, it is determined to be an awake period;
• if SI>TH1 and DI<TH2, it is determined to be a light sleep period;
• and if SI>TH1 and DI>TH2, it is determined to be a deep sleep period, and
• wherein, TH1 is a constant having a value range of 1.5-4, and TH2 is a constant having a value range of 0.8-2;
• and
• an output device,
• wherein the output device comprises at least one of a heater and a music player electrically connected to the state determination sub-circuit and is configured to operate according to a control signal output by the state determination sub-circuit indicative of the sleep state.