Computer-implemented method and system for direct photoplethysmography (PPG) with multiple sensors

A computer-implemented method for direct photoplethysmography or direct PPG comprising:

• obtaining during a time interval wherein a continuous direct PPG measurement is carried out, plural PPG signals by respective plural sensors in a wearable device, said plural sensors corresponding to plural cameras or plural photodiodes or a combination thereof;
• and
• combining said plural PPG signals to thereby obtain a multi-sensor PPG signal,
• wherein said method for direct PPG comprises:
• segmenting said plural PPG signals identically such that for each segment in a PPG signal obtained by a sensor of the plural sensors temporally corresponding segments exist in the PPG signals obtained by other sensors of the plural sensors;
• processing each PPG signal of said plural PPG signals to identify good quality segments of said PPG signal wherein a quality measure of said PPG signal is above a threshold and bad quality segments of said PPG signal wherein said quality measure of said PPG signal is below said threshold;
• removing said bad quality segments from each PPG signal of said plural PPG signals;
• and
• combining temporally corresponding good quality segments from each PPG signal of said plural PPG signals to obtain said multi-sensor PPG signal.