Removing motion-related artifacts in heart rate measurement systems using iterative mask estimation in frequency-domain

An apparatus for assisting separation of a heartbeat signal present in a first signal generated by a heartbeat sensor, the apparatus comprising:

• at least one memory configured to store computer executable instructions, and
• at least one processor coupled to the at least one memory and configured, when executing the instructions, to:
• process the first signal to compute a time-frequency-domain representation (pobs(f,t)) of the first signal;
• process a second signal to compute a time-frequency-domain representation (paccx(f,t)) of the second signal, the second signal indicative of a motion of the heartbeat sensor with respect to a first direction (x);
• initialize a first source model for a first source (s1), the first source representing a source of the heartbeat signal;
• initialize a second source model for a second source (s2), the second source representing a source of a contribution to the first signal due to the motion of the heartbeat sensor with respect to the first direction, wherein the second source model is initialized based on the time-frequency-domain representation (paccx(f,t)) of the second signal;
• perform a plurality of iterations of modifying one or more parameters of the first source model and/or one or more parameters of the second source model based on the time-frequency-domain representation of the first signal;
• and
• following the plurality of iterations, compute an estimate of the heartbeat signal based on the one or more parameters of the first source model and/or the one or more parameters of the second source model.

A non-transitory computer readable storage medium storing software code portions configured, when executed on a processor, to:

• process the first signal to compute a time-frequency-domain representation (pobs(f,t)) of the first signal;
• process a second signal to compute a time-frequency-domain representation (paccx(f,t)) of the second signal, the second signal indicative of a motion of the heartbeat sensor with respect to a first direction (x);
• initialize a first source model for a first source (s1), the first source representing a source of the heartbeat signal;
• initialize a second source model for a second source (s2), the second source representing a source of a contribution to the first signal due to the motion of the heartbeat sensor with respect to the first direction, wherein the second source model is initialized based on the time-frequency-domain representation (paccx(f,t)) of the second signal;
• perform a plurality of iterations of modifying one or more parameters of the first source model and/or one or more parameters of the second source model based on the time-frequency-domain representation of the first signal;
• and
• following the plurality of iterations, compute an estimate of the heartbeat signal based on the one or more parameters of the first source model and/or the one or more parameters of the second source model.