Supervised fuzzy pattern recognition

This paper is devoted to the problem of supervised fuzzy pattern recognition. The cases with non-fuzzy and fuzzy labels are considered. Based on the properties of linearly separable fuzzy classes, some algorithms are proposed for building matching functions of these classes. All algorithms are computer oriented and can be implemented for the automatic recognition of fuzzy patterns.     

Minimum detection time (MDT) for elemental EDXRF images

When obtaining a chemical element image through energy dispersive X‐ray fluorescence (EDXRF) scanning of a specific sample, it is important to determine the minimum detection time (MDT) required per dot (pixel) and per element in order to identify the minority and the trace elements present in the sample. Starting from the statistical criteria of limit of detection, quantitative estimations can be made regarding the concentration of elements present in the samples, determining the MDT which fits to the limit of detection previously established. Given that with this technique it is possible to implement in vivo applications, in this work, a process was developed for the MDT that is capable of generating the minimum radiation exposure in imaging EDXRF. For this proposal, the MDT is determined for metals, such as Fe, Cu, and Pb, given their great biomedical interest, in a series of equivalent bone and soft tissue phantom samples. Consequently, a criteria for global scanning time per dot was established, hence providing an elemental XRF image according to the As Low As Reasonably Achievable principles, i.e. as low an exposure as reasonably possible for each sample type studied by this sort of devices, in order to obtain appropriate information for each field of application. Copyright © 2015 John Wiley & Sons, Ltd.     

A simulation-based analysis of the effect of a reflecting surface on aeroacoustic time-reversal source characterization and comparison with beamforming

This paper presents a simulation-based analysis of the effect of a reflecting surface on aeroacoustic Time-Reversal (TR) source localization/characterization and compares the results of TR with those obtained using cross-spectral Conventional Beamforming (CB). The TR technique is shown to require the use of at least two line arrays of microphones to accurately characterize the nature of aeroacoustic sources. This work, however, shows that in the presence of a rigid surface, only one line array of microphones is sufficient to accurately localize and characterize idealized aeroacoustic sources. Forward simulations were carried out using the 2-D Linearized Euler Equations on a rectangular domain with a rigid bottom boundary (modeling a 2-D semi-infinite space) for the test-cases of stationary idealized tonal aeroacoustic (monopole, dipole and lateral quadrupole) sources located in a fully-developed mean shear flow field wherein the acoustic pressure time–history was stored at the computational boundaries. A set of TR simulations are implemented that show for each test-case that only the top line array is required to accurately characterize the idealized aeroacoustic sources in the presence of a reflecting bottom boundary, thereby suggesting the redundancy of acoustic pressure measurement at the rigid surface. The test-case of convecting (moving) idealized aeroacoustic source was also considered and the TR simulation using only the top line array in the presence of reflecting bottom boundary was able to accurately retrieve the source trajectory and simultaneously characterize its nature. This numerical experiment demonstrates in principle that when a rigid surface is mounted on the floor of an Anechoic Wind Tunnel, the use of only one (top) line array of microphones should be sufficient to characterize the nature and location of experimental flow-induced noise source. Acoustic source maps were also obtained using the CB method based on the Method of Images (to model the reflecting surface) and incorporation of the Ray-Tracing algorithm necessary to account for the effect of mean flow. The CB results were found to be highly comparable to those obtained using TR for the test-cases of non-convecting sources; thereby demonstrating the conceptual equivalence of the Method of Images and directly implementing the rigid-wall condition during TR for source localization/characterization.     

系列新IFS分形图象的获取与分析

首次发现了类似墨竹叶之ＩＦＳ分形图及其系列衍生图象的生成     

Variational infrared image enhancement based on adaptive dual-threshold gradient field equalization

Infrared images are characterized by low signal to noise ratio (SNR) and fuzzy texture edges. This article introduces the variational infrared image enhancement algorithm based on gradient field equalization with adaptive dual thresholds. Firstly, we transform the image into gradient domain and get the gradient histogram. Then, we do the gradient histogram equalization. By setting adaptive dual thresholds to qualify the gradients, the image is prevented from over enhancement. The total variation (TV) model is adopted in the reconstruction of the enhanced image to suppress noise. It is shown from experimental results that the image edge details are significantly enhanced, and therefore the algorithm is qualified for enhancement of infrared images in different applications.     

基于多尺度总体最小二乘的图像去噪

提出了一种基于多尺度总体最小二乘的图像去噪算法.采用平稳小波变换对噪音图像进行分解,分别对各个分解层的高频子带,通过总体最小二乘算法估计信号小波系数|并且考虑到不同尺度小波系数之间的相关性,将尺度相关性约束到总体最小二乘算法中,进而准确估计各高频子带信号小波系数,再由估计的信号小波系数通过小波逆变换得到去噪图像.实验结果表明,考虑尺度间相关性的总体最小二乘平稳小波变换图像去噪算法能有效去除图像噪音,在信噪比和视觉质量上有了较大改善.     

FABEMD和改进局部能量窗口的红外中波和长波图像融合

针对探测波段为3.7～4.8 μm的中波红外图像和探测波段为8～14 μm长波红外图像融合过程中存在场景对比度低,显著性目标不够凸出,伪影引入严重的问题,采用快速自适应二维经验模态分解（FABEMD)对红外中波和长波图像进行多尺度分解以得到二维内蕴模函数(BIMFs)和残余分量(Residual)。对于每一层内蕴模函数选用改进的局部能量窗口融合规则,首先配置好加权算子以增加区域窗口中心像素的能量占比;选用不同的加权算子,经实验验证能有效突出红外中波和长波图像的能量特征信息;其次充分利用内蕴模函数的相位信息,当相位相反时,采用能量加权平均的方式,以解决融合系数的正负符号极性难以确定的问题;当相位相同时,判断二者的能量差距并依据差距大小选择设定的融合规则,融合规则基于红外中波和长波图像的灰度差异特性设定。对于残余分量则利用红外中波图像和改进区域能量窗口的最大对称环绕显著性权重图指导基础层系数的融合,自适应的局部环绕窗口充分利用了低频显著性信息,对无用背景的抑制效果也相当出色,能够在复杂背景图像中突出显著性对象,最终得到细节信息丰富,对比度明显的指导图像。最后通过FABEMD的逆变化重构过程得到融合图像,对4组不同背景、不同大小的红外中长波图像进行主观和客观性能评价,4组图像均来自多波段红外采集系统且都经过严格配准并和7种相关算法进行对比实验,在主观性能上显著性对象突出、清晰度度高;客观性能上在平均梯度和空间频率这两个评价指标上性能优异,验证了该算法的有效性。     

Fabrication of Patterned Images in Photochromic Organic Microfibers

Photochromic spiropyran molecules were embedded in electrospun polymer microfibers. Electrospinning of a clear viscous chloroform solution containing a spiropyran and a matrix polymer, such as polystyrene and polyethylene oxide, affords polymer microfibers that are photoswitchable. Photomasked, 365 nm UV irradiation of the microfibers results in the generation of patterned color images owing to the selective transformation of the spiropyran molecules from their ring‐closed SP to ring‐opened MC form. The UV‐irradiated areas display brilliant red fluorescence, which changes to green fluorescence upon prolonged irradiation.

     

Experimental observation of the straining field responsible for vortex ring instabilityObservation expérimentale du champ responsable de l'instabilité du tourbillon torique

The aim of this work is to show experimentally the straining field responsible for the vortex ring instability. To do so, the velocity field in the neighbourhood of the core is measured with Particle Image Velocimetry. This field is compared with the one coming from theoretical work on a thin vortex ring in an ideal fluid. Theoretical and experimental data fit well. This indicates that the linear phase of the instability is weakly influenced by viscosity. To cite this article: A. Dazin et al., C. R. Mecanique 332 (2004).