Combining a Multispectral Camera and Spectrometer for Spectral Data Acquisition and Noninvasive Blood Composition Measurement

The dynamic spectroscopic method, as a noninvasive blood component measurement method, currently uses spectrometers as the main measurement instrument. However, spectrometers have limited accuracy in measuring light intensity at each wavelength, which restricts the measurement accuracy of the dynamic spectrum method. In this paper, a combination of a multispectral camera and a spectrometer is utilized for the first time to measure spectral photoplethysmography (PPG) signals. Both the high amplitude resolution and high accuracy of the multispectral camera in terms of sampling values and the advantage of the spectrometer in terms of the number of wavelengths are exploited. According to the experimental data, this method effectively improves the measurement results. In particular, when measuring for hemoglobin, the mean absolute percentage error (MAPE) decreased by 25.3% and 22.9%, respectively compared with a single spectrometer and a multispectral camera. For platelet measurements, the MAPE decreased by 28.9% and 22.8%, respectively. For total bilirubin measurements, the MAPE decreased by 14.5 and 26.3%, respectively. It demonstrates that the noninvasive blood component measurement method of a combined multispectral camera and spectrometer can effectively reduce the interference of non-target components and improve measurement accuracy.