Remote foetal heart rate acquisition and analysis

The remote foetal monitoring and analysis is part of INTERCARE project-an integrated healthcare system applied to Electrocardiography and Cardiotocography. Its aim is to provide low cost and wide spread technological infrastructure that supports an integrated healthcare system to users and healthcare providers. This paper illustrates the work done in the cardiotocography area. The authors have developed a system for remote acquisition and analysis of FHER. The system uses a portable “foetal detector” which can be used by the pregnant woman to acquire the heart beats. This detector sends a modulated audio signal via the telephone line or a computer connected to the Internet. At the processing end the signal received by the telephone can be switched to the computer sound acquisition board. The signal is then processed by an application that reads from the soundcard. Due to the noise added by devices and telephone lines, the signal is filtered using optimal FIR filters and is decimated until its band of interest covers the peaks of the heart sounds. Next the signal is processed by a specially developed adaptive correlation algorithm in order to obtain the heart beat instants. The whole process operates in real time. The adaptive correlation algorithm performs a continuous adjustment of the heart beat template and threshold detection levels