均值滤波算法研究

介绍了经典非局部均值滤波算法与Manjón非局部均值滤波算法,改进了非局部均值滤波方法的相似度权值,使算法在具有旋转平移不变性,保持时间复杂度的同时优化了视觉效果与信噪比。实验通过添加噪声标准差从10~100不等的高斯加性噪声,比较了改进后的算法与传统滤波算法以及Manjón非均值滤波算法,结果表明,改进后的算法无论从视觉上还是数值上都优于Manjón非均值滤波算法。     

面向脑血管分割的改进型非局部均值滤波算法研究

介绍了经典非局部均值滤波算法与Manjón非局部均值滤波算法,改进了非局部均值滤波方法的相似度权值,使算法在具有旋转平移不变性,保持时间复杂度的同时优化了视觉效果与信噪比。实验通过添加噪声标准差从10~100不等的高斯加性噪声,比较了改进后的算法与传统滤波算法以及Manjón非均值滤波算法,结果表明,改进后的算法无论从视觉上还是数值上都优于Manjón非均值滤波算法。     

Optical ammonia gas sensor based on a porous silicon rugate filter coated with polymer-supported dye

An ammonia gas sensor chip was prepared by coating an electrochemically-etched porous Si rugate filter with a chitosan film that is crosslinked by glycidoxypropyltrimethoxysilane (GPTMS). The bromothylmol blue (BTB), a pH indicator, was loaded in the film as ammonia-sensing molecules. White light reflected from the porous Si has a narrow bandwidth spectrum with a peak at 610 nm. Monitoring reflective optical intensity at the peak position allows for direct, real-time observation of changes in the concentration of ammonia gas in air samples. The reflective optical intensity decreased linearly with increasing concentrations of ammonia gas over the range of 0–100 ppm. The lowest detection limit was 0.5 ppm for ammonia gas. At optimum conditions, the full response time of the ammonia gas sensor was less than 15 s. The sensor chip also exhibited a good long-term stability over 1 year. Therefore, the simple sensor design has potential application in miniaturized optical measurement for online ammonia gas detection.     

Detection and characterization of ticlopidine conjugates in rat bile using high‐resolution mass spectrometry: applications of various data acquisition and processing tools

Ticlopidine, an antiplatelet drug, undergoes extensive oxidative metabolism to form S‐oxide, N‐oxide, hydroxylated and dealkylated metabolites. However, metabolism of ticlopidine via conjugation has not been thoroughly investigated. In this study, multiple data acquisition and processing tools were applied to the detection and characterization of ticlopidine conjugates in rat bile. Accurate full‐scan mass spectrometry (MS) and collision‐induced dissociation (CID) MS/MS data sets were recorded using isotope pattern‐dependent acquisition on an LTQ/Orbitrap system. In addition, mass spectral data from online H/D exchanging and high collision energy dissociation (HCD) were recorded. Data processes were carried out using extracted ion chromatography (EIC), mass defect filter (MDF) and isotope pattern filter (IPF). The total ion chromatogram displayed a few major conjugated metabolites and many endogenous components. Profiles from EIC and IPF processes exhibited multiple conjugates with no or minimal false positives. However, ticlopidine conjugates that were not predictable or lost a chorine atom were not found by EIC or IPF, respectively. MDF was able to detect almost all of ticlopidine conjugates although it led to a few more false positives. In addition to CID spectra, data from HCD, H/D exchanging experiments and isotope pattern simulation facilitated structural characterization of unknown conjugates. Consequently, 20 significant ticlopidine conjugates, including glucuronide, glutathione, cysteinylglycine, cysteine and N‐acetylcysteine conjugates, were identified in rat bile, a majority of which are associated with bioactivation and not previously reported. This study demonstrates the utility and limitation of various high‐resolution MS‐based data acquisition and processing techniques in detection and characterization of conjugated metabolites. Copyright © 2013 John Wiley & Sons, Ltd.     

Up‐and‐down shaker‐assisted ionic liquid‐based dispersive liquid—liquid microextraction of benzophenone‐type ultraviolet filters

Sun protection is an important part of our lives. UV filters are widely used to absorb solar radiation in sunscreens. However, excess UV filters constitute persistent groups of organic micropollutants present in the environment. An environmentally friendly ionic‐liquid‐based up‐and‐down shaker‐assisted dispersive liquid?liquid microextraction device combined with ultra‐performance liquid chromatography coupled with photodiode‐array detection has been developed to preconcentrate three UV filters (benzophenone, 2‐hydroxy‐4‐methoxybenzophenone, 2,2′‐dihydroxy‐4‐methoxybenzophenone) from field water samples. In this method, the optimal conditions for the proposed extraction method were: 40 μL [C₈MIM][PF₆] as extraction solvent and 200 μL methanol as disperser solvent were used to extract the UV filters. After up‐and‐down shaking for 3 min, the aqueous solution was centrifuged at 5000 rpm speed, then using microtube to collect the settled extraction solvent and using ultra‐performance liquid chromatography for further analysis. Quantification results indicated that the linear range was 2–1000 ng/mL. The LOD of this method was in the range 0.2–1.3 ng/mL with r² ≥ 0.9993. The relative recovery in studies of different types of field water samples was in the range 92–120%, and the RSD was 2.3–7.1%. The proposed method was also applied to the analysis of field samples.     

Liquid chromatography with diode array detection and multivariate curve resolution for the selective and sensitive quantification of estrogens in natural waters

Following the green analytical chemistry principles, an efficient strategy involving second-order data provided by liquid chromatography (LC) with diode array detection (DAD) was applied for the simultaneous determination of estriol, 17β-estradiol, 17α-ethinylestradiol and estrone in natural water samples. After a simple pre-concentration step, LC–DAD matrix data were rapidly obtained (in less than 5 min) with a chromatographic system operating isocratically. Applying a second-order calibration algorithm based on multivariate curve resolution with alternating least-squares (MCR-ALS), successful resolution was achieved in the presence of sample constituents that strongly coelute with the analytes. The flexibility of this multivariate model allowed the quantification of the four estrogens in tap, mineral, underground and river water samples. Limits of detection in the range between 3 and 13 ng L⁻¹, and relative prediction errors from 2 to 11% were achieved.     

窄带快照式多光谱成像色彩还原方法

由于兼具光谱分辨和空间分辨能力, 快照式窄带多光谱成像在资源遥感、精准农业、医疗检测等领域将有广泛应用。由于该方法使用窄带成像来提高光谱分辨率及图像对比度,所获得的图像是灰度信息,失去了场景的色彩信息,不便专家对图像鉴别、评价与赏析。已有的色彩还原算法主要针对光谱波段带宽较宽或者多个波段叠加基本覆盖整个可见光谱范围等两种光谱成像仪,不适合窄带多光谱成像方法的色彩还原。该研究适合于快照式窄带多光谱成像的色彩还原方法,提出建立窄带多光谱彩色相机的概念。首先,提出两种窄带多光谱色彩还原方法：(1)基于CIE色度系统三刺激值色的,(2)基于贝尔阵列插值算法的;其次,分别应用两种算法还原快照式窄带多光谱相机所获得的植物、手臂及宫颈组织等三种代表性场景窄带多光谱灰度图像;之后,计算并比较表征两种算法所得的代表性场景彩色图像的均值、方差、熵及梯度等表征图像质量的参数数值,确定出适合快照式窄带多光谱成像的色彩还原方法;最后,对所确定的色彩还原算法进行色偏校正。实验结果表明,基于CIE三刺激值色彩还原方法比贝尔阵列插值法更适用于窄带多光谱成像颜色复原。配合使用CIE三刺激值色彩还原方法及灰度图象校正算法,从窄带光谱成像所获得的植物、手臂皮肤及宫颈组织的灰度图像所还原出的近彩色图像逼近物体真实色彩,满足人眼观察习惯。介绍了仅覆盖可见光光谱范围30%的窄带多光谱图像进行色彩还原的方法,该方法证明快照式窄带多光谱成像可以兼具光谱分辨能力,同时保持可供人主观辨识的色彩信息。所提出实现快照式窄带多光谱彩色成像的方法,有望设计不同于传统RGB相机的彩色相机实施方案。     

The effect of Laplacian filter in adaptive unsharp masking for infrared image enhancement

Image processing, in particular image enhancement techniques have been the focal point of considerable research activity in the last decade. With the aid of an existing image enhancement technique, adaptive unsharp masking (AUM), we propose a novel kernel to be used in AUM filtering in order to enhance discontinuities which occur on the edges of targets of interest in infrared (IR) images. The proposed method uses an adaptive filter approach where an objective function is minimized by using descent algorithms. The output IR image has better sharpness and contrast adjustment for the detection of targets in terms of objective quality metrics. Hence, the proposed method ensures that the edges of the targets in IR images are sharper and that the quality of contrast adjustment has its optimum level in terms of peak signal-to-noise ratios.     

太阳能分光发电系统的光学薄膜滤波片设计与仿真

由于不同材料的禁带宽度不同,对太阳光谱的吸收曲线也各不相同,探讨了用等效折射概念设计滤光片的原理和计算方法.针对非晶硅、单晶硅和砷化镓的吸收谱线设计了一组短波通滤光片,滤波片A在波长380～800nm处,平均透射率T＞90％;在波长880～1100 nm处截止,平均透射率T＜1％;滤波片B在380～500 nm处T＞9...     

Radical of filters in BL‐algebras

In this paper, the notion of the radical of a filter in BL‐algebras is defined and several characterizations of the radical of a filter are given. Also we prove that A/F is an MV‐algebra if and only if D_s(A) ? F. After that we define the notion of semi maximal filter in BL‐algebras and we state and prove some theorems which determine the relationship between this notion and the other types of filters of a BL‐algebra. Moreover, we prove that A/F is a semi simple BL‐algebra if and only if F is a semi maximal filter of A. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim