动态光谱频域提取的FFT变换精度分析

近红外光谱无创血液成分检测因其测量方法的优越性，已经成为生物医学领域的研究热点之一。但除血氧饱和度外，目前还没有进入临床应用成果的报道，其关键在于个体差异和测量条件对检测精度的影响。文章先介绍一种可以消除个体差异的新的检测方法——动态光谱法，再从其原理出发，推导出基于傅里叶变换的动态光谱频域提取法。同时，文章通过实验，研究了采样率，采样周期个数，非同步采样对(快速傅里叶变换(FFT)精度的影响。分析结果表明：选择合适的采样率，采样信号周期个数、并利用现有的加窗和插值算法能够大幅度提高动态光谱数据的精度。

Discussion about the Prediction Accuracy for Dynamic Spectrum by Partial FFT

The development of near-infrared-based techniques for the noninvasive determination of blood component concentrations has attracted significant interest in recent years.But the noninvasive measurement of blood compositions has not yet been applied to the clinical field except blood oxygen saturation.The most important and also difficult problems are the effects of individual discrepancy and complicated measurement conditions.In the present article,the approach of dynamic spectrum(DS) is introduced,which is based on the principle of photoplethysmography.It is very difficult too to pick up DS with high precision in time domain.In order to extract the DS with high accuracy,the FFT method and it's leakage are discussed.The influences of sampling speed,sampling signal periodicity,window function and unsynchronized sample are analyzed by emulating experiments.The result of emulating experiments shows that choosing certain sampling speed,sampling signal periodicity,window function and interpolation arithmetic will improve accuracy observably.This provides necessary condition for the clinical application of DS.