Filtering a pressure signal from a medical apparatus

A computer-implemented signal filtering method comprising:

• receiving, in a processor from a pressure sensor, a pressure signal (p) comprising a time-sequence of data samples representing fluid pressure in a medical apparatus;
• operating, using the processor, a digital filter on the pressure signal (p) to produce a filtered pressure signal (y), wherein the digital filter is operated to, at each current time point, compute a current filtered data sample (ym) of the filtered pressure signal (y) as a function of a preceding state vector (Z*) of the digital filter and a current data sample (pm) in the pressure signal (p), and compute a current state vector (Zm) of the digital filter as a function of the preceding state vector (Z*), the current data sample (pm) and, optionally, the current filtered data sample (ym);
• detecting or predicting, using the processor, a disturbance in the pressure signal (p);
• and
• selectively modifying, using the processor, the preceding state vector (Z*) of the digital filter at a selected time point (t2) subsequent to the disturbance in the pressure signal (p), so as to suppress influence of the disturbance on the filtered pressure signal (y).

A signal filtering device comprising:

• a memory;
• and
• a processor in communication with the memory, the processor configured to:
• obtain a pressure signal (p) comprising a time-sequence of data samples representing fluid pressure in a medical apparatus;
• operate a digital filter on the pressure signal (p) to produce a filtered pressure signal (y), wherein the digital filter is configured to, at each current time point, compute a current filtered data sample (ym) of the filtered pressure signal (y) as a function of a preceding state vector (Z*) of the digital filter and a current data sample (pm) in the pressure signal (p), and compute a current state vector (Zm) of the digital filter as a function of the preceding state vector (Z*), the current data sample (pm) and, optionally, the current filtered data sample (ym);
• detect or predict a disturbance in the pressure signal (p);
• and
• selectively modify the preceding state vector (Z*) of the digital filter at a selected time point (t2) subsequent to the disturbance in the pressure signal (p), so as to suppress influence of the disturbance on the filtered pressure signal (y).

A medical system comprising:

• a medical apparatus;
• a pressure sensor arranged to be responsive to fluid pressure in the medical apparatus;
• and
• a signal filtering device including a processor in communication with a memory, the processor configured to:
• obtain a pressure signal (p) comprising a time-sequence of data samples representing fluid pressure in a medical apparatus;
• operate a digital filter on the pressure signal (p) to produce a filtered pressure signal (y), wherein the digital filter is configured to, at each current time point, compute a current filtered data sample (ym) of the filtered pressure signal (y) as a function of a preceding state vector (Z*) of the digital filter and a current data sample (pm) in the pressure signal (p), and compute a current state vector (Zm) of the digital filter as a function of the preceding state vector (Z*), the current data sample (pm) and, optionally, the current filtered data sample (ym);
• detect or predict a disturbance in the pressure signal (p);
• and
• selectively modify the preceding state vector (Z*) of the digital filter at a selected time point (t2) subsequent to the disturbance in the pressure signal (p), so as to suppress influence of the disturbance on the filtered pressure signal (y),
• wherein the signal filtering device is connected to the pressure sensor and is configured to obtain the pressure signal (p) from the pressure sensor.