FETAL ULTRASOUND PROCESSING UNIT FOR SEPARATING HEART RATE SIGNALS

A processing unit and method are provided for processing fetal Doppler ultrasound data to extract a set of signals representative of different distinct heart rate signal sources, e.g. for detecting two fetal heart rate sources (22a, 22b) in a twin pregnancy. Doppler data is received from a plurality of different transducer sources (12a, 12b), corresponding to different (but potentially overlapping) tissue regions within the maternal abdomen. From the multiple sources of Doppler ultrasound data a single set of input signal channels is compiled (53), each corresponding to a different tissue region within the maternal abdomen. These are then processed successively by a PCA algorithm (54) followed by an ICA algorithm (58), which work to unmix the multiple heart rate sources present in each of the input channels, and derive a set of output signals from the ICA which can be taken as representative of the separate heart rate sources (22a, 22b).