Non-linear characteristic of human blood NIR spectra

In order to investigate the non-linear characteristic in the human blood spectra, the NIR spectra of the human blood in changeable optical path length (from 0.20 mm to 1.25 mm) is measured in this paper. The production, quantization and positive factors of the non-linear characteristic are discussed. It has been revealed that there is a remarkable non-linear characteristic in the human blood spectra with the thickness of the blood layer raising. The discussion deduced that the non-liner characteristic of the spectra mainly caused by the scatter of the blood samples. The non-liner characteristic of the human blood will raise the prediction resolution of the calibration model of blood compositions.