Fast fetal heart rate estimation for multi-channel FHR measurement

The fetal heart signal obtained using ultrasonic Doppler effect measurements is generally quasi-periodic. Its autocorrelation function (ACF) has been successfully applied in the estimation of fetal heart rate (FHR). To overcome the massive computations incurred in the estimation, the authors developed a fast strategy involving two-pass process to estimate FHR via normalized ACF. The algorithm has enabled up to four-channel simultaneous FHR measurement based on a general purpose PC.