SIGNAL-PROCESSING FOR A LASER-DOPPLER BLOOD PERFUSION METER

Two signal processing methods for laser-Doppler perfusion velocimetry are presented. The methods are based on the calculation of the moments of the frequency power spectrum. The first uses square-root omega-filtering (omega is the frequency) with analogous electronics, the second uses signal autocorrelation with digital electronics. Comparison is made with a third instrument: a spectrum analyzer coupled to a computer, using Fourier transform techniques. The performance of these setups (sensitivity, limit sensitivity and accuracy) are investigated. We propose a calibration standard for signal processors to be used for blood perfusion measurements. The analogous instrument proved to be the cheapest but the digital instrument had the best performance.