1 合肥工业大学 仪器科学与光电工程学院, 合肥 230009
2 合肥工业大学 计算机与信息学院, 合肥 230009
设计了一种可用于超高场磁共振成像(MRI)的负磁导率超材料磁感应透镜(MIL), 可以有效提高MRI的信噪比.MIL是由6×6个加载电容的金属开口谐振环组成的二维周期结构, 并将其加工在一层0.6 mm 厚度的FR-4介质基板上.将MIL放置于射频线圈和样品之间, 能够实现等效的磁表面等离激元效应.MIL单元电磁场分布、散射参数和等效磁导率的仿真结果表明：所设计的MIL在拉莫尔进动频率297.2 MHz产生负的磁导率, 并能增强由射频线圈产生的射频场的倏逝波分量.两个不同的标准表面射频线圈的MRI扫描实验表明, 小水膜仿体在施加MIL后可以将矢状面图像信噪比提高约200%, 大水膜仿体在施加MIL后可以将冠状面图像信噪比提高约58%.仿真和MRI图像结果均表明了所设计的MIL具有聚焦表面射频线圈磁场强度的能力, 有益于提高MRI的信噪比、空间分辨率和探测深度.
超材料 磁共振成像 信噪比 磁导率 表面等离激元 射频 Magnetic resonance imaging Metamaterial Signal-to-noise ratio Permeability Magnetic surface plasmons Radio frequency
Author Affiliations
Abstract
1 Key Laboratory of Advanced Electrical Engineering and Energy Technology, Tianjin Polytechnic University, Tianjin 300387, China
2 School of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Keiraville 2500, Australia
3 Baoding Life Automotive Lighting Group Company Limited, Baoding 071000, China
In order to realize the online measurement of lamp dimension, the bulb image dimension measurement based on vision (BIDMV) is proposed. The image of lamp is obtained by camera. After image processing, such as Otsu algorithm, median filter, ellipse fitting and envelope rectangle fitting, the dimension of lamp can be calculated. Based on this method, a non-contact real-time measurement system of the lamp’s dimension is developed. The precision of the proposed method is 0.07 mm, and it can satisfy the tolerance of the National Standard GB15766.1-2008. The experiment results show that the proposed method has a faster measuring speed and a higher precision compared with other measurement methods.
光电子快报（英文版）
2015, 11(2): 145
