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101.
针对如何提取纸币图像特征和提高识别率的问题,综合利用退化四元小波变换具有的相位特性,提出一种基于退化四元小波变换的纸币识别方法.该方法首先对采集的纸币图像进行倾斜校正和边缘检测,然后运用退化四元小波对纸币图像进行分解操作,并对分解系数进行统计分析,将每个分解子带系数的能量和标准差作为该纸币图像的特征向量,最后将支持向量机作为分类器对纸币图像进行识别.本文方法在资源约束的嵌入式清分系统上实现,实验结果表明采用本文提出的算法突破了传统纸币识别系统识别率很难再提高的瓶颈,同时能够满足清分系统的实时性要求. 相似文献
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基于级联迭代傅里叶(CIFT)变换算法提出了一种新的光学图像的加密方法,该方法通过输入和4-F相关的傅里叶域的模糊设计和定位,从而实现光学加密以及真实性验证。与以往的方法有所不同,新算法采用改进的搜索策略:修改两个阶段的同步分布,同时扩大搜索空间。计算机模拟实验表明其快速的收敛算法能够更好地恢复图像的质量,密钥会被分配到不同的方面,用户只有在得到这些密钥的授权之后才能得到解密后的图像,这种密钥分配策略可以极大减少被入侵的风险。 相似文献
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《Journal of Great Lakes research》2022,48(1):143-158
Variability of phytoplankton in the Caspian Sea (CS) is related to the complex orography, the variety of physical and chemical processes, and climatic indices. Here, interannual and intra-annual variability of satellite-derived chlorophyll-a concentrations (Chl-a) were studied using wavelet analysis during 2002–2019 in different regions of the CS. Self-Organizing Maps (SOM) analysis performed to classify the CS into the areas of similar variability of satellite-derived Chl-a. Wavelet spectral analysis showed that the Chl-a variability regulated by four primary periodic cycles: 0.5-year, 1-year, 2 to 2.5-year, and 3 to 5-year. The 0.5 and 1-year wavelet cycles mostly depicted the intensity of seasonality patterns. The 2–2.5-year and 3–5-year cycles of Chl-a showed non-stationary coherence with corresponding low-frequency cycles of NAO and ENSO. The 3–5-year wavelet amplitudes of Chl-a strongly correlated with NAO and ENSO in the southern CS. Weak correlations of 2–2.5-year cycle wavelet amplitudes of Chl-a with NAO and ENSO suggested that variations do not always directly translate to a biological response. A negative anomaly in the Chl-a autumn peaks observed during 2011–2016 in the middle and southern CS, when NAO phases were persistently positive. The interannual variations of summer peaks in the northern CS, and autumn peaks in the middle and southern CS were broadly related to the precipitation. SST and wind stress. Moreover, it was shown that the Volga discharge has a significant influence on Chl-a variability in the northern CS. 相似文献
106.
Linear low‐density polyethylene (LLDPE), based on butene‐1 or hexene‐1, was irradiated with γ‐rays under vacuum or in the presence of air. The study focused on the influence of the dose rate and the γ‐dose on the thermal properties of LLDPE. Differential scanning calorimetry, thermogravimetric analysis (TGA), and TGA/FTIR techniques were used to address the thermal behavior as a result of γ‐irradiation. During this irradiation, competition between crosslinking and scission reactions, subsequent to oxidation reactions, occurred in the polymeric material, which strongly depends on the experimental conditions. A decrease of the crystallinity for γ‐irradiated samples was observed in particular for samples irradiated under vacuum. This observation may be explained by increased hindrance of segment mobility due to crosslinking reactions that prevent crystal growth. TGA investigations revealed an enhancement of the thermal stability for samples irradiated under vacuum but not for those irradiated in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2790–2795, 2006 相似文献
107.
Shoei-Chin Wu 《Polymer》2004,45(3):733-738
The crystallization characterization of bulk syndiothactic polystyrene (s-PS) sample is thoroughly studied using the Fourier transform infrared spectroscopy (FTIR). The WAXD is further used to identify the s-PS crystal formation to confirm the specific absorbance in FTIR spectra. Both melt and cold-crystallization behavior are quantitatively determined using FTIR spectra ranging from 870 to 820 cm−1 at 264 °C. Fitting curves to IR spectra provides direct evidence of bulk s-PS crystallization behavior in quantification. The melt-crystallization process yields the β-form only; while the cold-crystallization process yields both the α and the β-form crystal in bulk s-PS sample. The β-form crystal is generated from the phase-transformation of the α-form crystal by cold-crystallization process, the α-form crystal is the initial phase. The activity energy of the α-form formation is lower that that of the β-form, suggesting that the α-form crystal is kinetically favorable while the β-form crystal is thermodynamically favorable. 相似文献
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110.
提出了一种基于距离变换、形态重构和分水岭算法的图像分割算法。将一幅图像通过距离变换得到距离灰度图,与形态重构算法结合,得到颗粒图像的标识点图,用标识点图对距离灰度图进行分割,再用分水岭变换对分割后的距离灰度图进行变换。试验表明,该算法能有效合理地解决粘连或者重叠颗粒等物体的分割。 相似文献