Ultrahigh-resolution fiber-optic image guides derived from microstructured polymer optical fiber preforms

Ultrahigh-resolution fiber-optic image guides-fused image fiber, faceplate, and taper-were fabricated by using microstructured polymer optical fiber (MPOF) preforms composed of two polymers: polymethylmethacrylate and polystyrene. The pixel diameter in the resultant MPOF-based image guides was as small as 3 mu m. The imaging capabilities of these types of fiber-optic elements were demonstrated. (C) 2009 Optical Society of America

EFFECT OF IMAGE FORCES ON ELECTRONS CONFINED IN LOW-DIMENSIONAL STRUCTURES UNDER A MAGNETIC-FIELD

We consider the effect of image forces, arising due to a difference in dielectric permeabilities of the well layer and barrier layers, on the energy spectrum of an electron confined in a rectangular potential well under a magnetic field. Depending on the value and the sign of the dielectric mismatch, image forces can localize electrons near the interfaces of the well or in well centre and change the direct intersubband gaps into indirect ones. These effects can be controlled by variation of the magnetic field, offering possibilities for exact tuning of electronic devices.

一种基于SVR几何校正的数字水印检测算法

以回归型支持向量机(SVR)理论基础,提出了一种可有效抵抗几何攻击的图像水印检测新算法.该算法首先选取网像的组合矩作为特征向量,并通过SVR对旋转、缩放、平移等几何变换参数进行训练学习,以获得SVR训练模型;然后利用SVR训练模型对待检测图像进行数据预测,并结合预测输出结果对其进行几何校正;最后从已校正数字图像内提取出水印信息.仿真实验结果表明,本文算法对常规信号处理(滤波、叠加噪声、JPEG压缩等)和几何攻击(旋转、缩放、平移、剪切等)均具有较好的鲁棒性