自适应中值滤波用于色谱信号去噪的研究

在分析化学领域中，如何从被干扰的信号中有效去除噪声并恢复有用信号，具有重要的意义。此文从中值滤波基本概念出发，针对经典中值滤波器滑动窗口长度固定对信号去噪的影响，提出了自适应中值滤波器，通过对某元素色谱曲线进行去噪处理，并与移动均值法和小波变换法进行比较表明，此方法不仅能有效地滤除脉冲和高斯噪声，而且使色谱峰的边缘得到良好保护，从而提高了色谱数据分析的精确性。     

基于分形维数的分析信号自适应中值滤波

提出一种面向分析仪器谱图信号处理的分形维自适应中值波方法（AMeFFD）。该法延拓运用分形理论，定义了相对点盒维数概念，由此建立建立判定脉冲型噪声的特异性指标，从而可自动调节中值滤波窗口宽度，有效地滤除脉冲型噪声及其它类噪声。对仿真色谱信号及实测色谱图的处理结果表明：AMeFFD法克服了经典中值滤波算法的缺陷，无论在信号的均方根偏差还是谱峰差等指标上，均明显优于后者，能在确保谱峰不畸变的同时更有效地滤除脉冲型常见噪声，是处理化学谱图信号的有力工具。     

模式滤波器在色谱信号除噪中的应用

提出一种模式滤波器方法,用于解决色谱信号中宽带噪声的除噪问题。模式滤波器的应用原理是基于色谱信号与宽带噪声之间的形态差异。工作过程：先采用模式匹配方法识别宽带噪声,再识别各种噪声的起始点与终止点,最后采用线性插值方法重构含噪声的色谱信号。方法具有实现简单、运算速度快、去除噪声能力强等特点。由实际采集的色谱信号经除噪处理后所得的结果表明：模式滤波器比一般滤波器具有更好的除噪效果。     

用分段训练的Elman递归神经网络滤除色谱数据中的噪声

分析了色谱信号噪声的分形特征,采用分段训练的Elman递归神经网络除噪.实验结果表明,此方法在滤除噪声时具有一般神经网络和中值滤波器所没有的优点,精度明显提高.     

卡尔曼滤波法分辨呋喃妥因和呋喃唑酮未分离液相色谱峰

高效液相色谱法对色谱峰进行定量分析时,通常需要测量峰高和峰面积,但有时由于未分离色谱峰(如重迭峰、肩峰等)的存在,使测得的数据产生较大偏差。卡尔曼滤波理论是解决这一难题的可靠方法,它是一种最佳滤波法,能滤除噪声与干扰,获得真实信号与参数估计值,本文选取呋喃妥因和呋喃唑酮进行实验,结果表明用卡尔曼滤波法能定量分析未分离高效液相色谱峰,其分辨结果明显优     

分析化学信号在多尺度空间的滤噪

从多分辨率分析出发，结合离散正交小波变换(DWT)的理论，通过对各尺度下未抽取前的小波系数进行非线性滤波处理，达到在保护信号边缘的同时，有效实现白噪声及脉冲噪声的滤除。实验数据仿真结果研究也证明了该方法的可行性。     

强噪声背景中微弱信号检测的初步研究

为了提高信噪比,以往大都设法滤除噪声。根据随机共振理论,本文对用添加噪声来提高测量信号信噪比的方法进行了初步的尝试,并将此方法应用于强噪声背景中微弱信号的检测,得出了一些有意义的初步结构。     

一种基于光谱信息计算解析的液相色谱滤噪新方法

提出一种基于光谱信息计算解析的高效液相色谱滤噪新方法.对于HPLC/DAD所获得的二维量测数据,取半峰高以上色谱数据点所对应的各列光谱数据进行计算处理,求得在检测波长下的单位标准光谱,并根据光谱维数据与单位标准光谱的关系,采用最小二乘法重构计算求出色谱维数据,从而去除色谱噪声.仿真实验和实测谱图的滤噪结果表明,该方法能有效滤除常见噪声,与中值滤波算法相比较,滤噪性能明显优于后者,是提高色谱定量分析准确度的有力工具.     

集成滤波器在谱图信号除噪中的应用

本文提出了一种由神经元网络与线性自适应滤波器组成的集成滤波器的实现方法，用于谱图信号除噪处理。     

分析信号处理方法的比较研究

研究了高效液相色谱－火焰原子吸收光谱联用系统分析信号处理方法，比较了各种处理方法的优缺点，用积分与适应平滑法综合处理色谱峰分析信号，不仅能有效地消除噪声，而且能使分析信号得到加强，以测定镍为例，经积分与适应平滑法综合处理后，检出限改善了２．７倍。     

Adaptive numerical morphological filter for identifying chromatographic signals.

A morphological algorithm has been proposed to filter away impulsive noises confounded in the chromatographic signal. Compared with the conventional median filtering method, the results showed that the proposed method has the advantages of a better filtering effect and less distortion. In particular, the morphological filter with adaptive scale gives very good results.     

Parametric studies of matched filters to enhance the signal-to-noise ratios of LC-MS-MS peaks

Chromatographic parameters of reference signals employed in matched filter methods have been studied using numerical experiments to improve the signal-to-noise (S/N) ratios of small liquid chromatography (LC) peaks obtained with electrospray tandem mass spectrometers (MS-MS). These parameters include the width, shape, and S/N ratios of chromatographic peaks used as the reference signal profiles. Our results show the effect of reference peak widths on improving the S/N ratio of chromatographic peaks; the influence of reference peak shapes is negligible. To verify simulation results, various reference signals, including analyte peaks of high concentration standards, internal standard peaks, and artificial Gaussian peaks of different widths, have been employed to enhance signal peaks on real liquid chromatography-tandem mass spectrometry (LC-MS-MS) chromatograms via matched filter methods. Our experimental results demonstrate that the S/N ratio enhancement of chromatographic peaks agree with the simulation predictions. These findings, therefore, suggest that regardless of peak shape, a well-smooth peak with a width close to that of the analyte peak is an adequate reference signal, when matched filter methods are used to improve LC-MS-MS chromatograms. Nevertheless, all methods processed LC-MS-MS peaks in this study do not achieve the ideal improvement ratios estimated with simulation results. We attribute this deficiency to spike-like noise, which have considerable low frequency components riding on LC-MS-MS chromatograms. Matched filtering, which works as a low-pass filter in the frequency domain, cannot effectively eliminate low frequency flicker noise contributed by these spikes. In addition, simple median filtering does not provide adequate improvement despite being able to smooth out most spikes in the chromatograms.     

卡尔曼滤波荧光光度法用于混合萤光染料的同时测定

根据常规与同步荧光方法的特点,提出了卡尔曼滤波荧光分光光度分析法,对多组分萤光染料混合物进行同时测定,结果良好。该法既具有优良的选择性和较高的灵敏度,又具有一定的通用性,适于推广应用。     

Kalman滤波用于荧光,吸收,导数与同步光谱的研究

将Ｋａｌｍａｎ滤波用于常规荧光、同步荧光、导数荧光、吸收光谱及导数光谱，实现了不经分离对苯酚与间苯二酚混合物及复方药物制剂的同时测定。结果良好，操作简便。     

Filtering and integration of chromatographic data: a tool to improve calibration?

The effect of filtering and automated integration of chromatographic data on the calibration curve and detection limit was assessed. In a first approach simulated chromatograms were used to quantify the effects of data processing. Three types of filters were used: Savitzky-Golay, Fourier and Wavelet filter. The filter parameters chosen have been optimized in a previous study. The simulated data have been integrated by a commercial software package. The use of applying the DIN 32645 concept for the determination of the detection limit of chromatographic data is discussed and opposed to the concept of the method detection limit. Under the conditions investigated, filtering can improve the limit of detection up to a factor of three. This can be explained by the fact that filtering reduces the variance of the peak area and height and the limit of detection is mainly determined by their variance. However, the integration algorithm practically limits the possible improvements by filtering the data.