Blind image deconvolution using sparse and redundant representation

This work devotes to the image deconvolution problem that restores clear image from its blurred and noisy measurements with little prior about the blur. A deconvolution method based on sparse and redundant representation theory is developed in this paper. It firstly represents the blur and image over different redundant dictionaries and imposes sparsity constraint to their representation coefficients respectively, then alternately estimates them using an iterative algorithm employing optimization technique. Experimental results on astronomical images show that the proposed method can achieve as good performance as the method requiring a known blur, which demonstrates its effectiveness.     

An infrared image super-resolution reconstruction method based on compressive sensing

Limited by the properties of infrared detector and camera lens, infrared images are often detail missing and indistinct in vision. The spatial resolution needs to be improved to satisfy the requirements of practical application. Based on compressive sensing (CS) theory, this thesis presents a single image super-resolution reconstruction (SRR) method. With synthetically adopting image degradation model, difference operation-based sparse transformation method and orthogonal matching pursuit (OMP) algorithm, the image SRR problem is transformed into a sparse signal reconstruction issue in CS theory. In our work, the sparse transformation matrix is obtained through difference operation to image, and, the measurement matrix is achieved analytically from the imaging principle of infrared camera. Therefore, the time consumption can be decreased compared with the redundant dictionary obtained by sample training such as K-SVD. The experimental results show that our method can achieve favorable performance and good stability with low algorithm complexity.     

基于IBP的实用的SRR重构算法研究

由于红外探测器像元尺寸的限制,红外图像的分辨率相对于可见光要低得多,SRR(Super-resolution reconstruction)是提高红外图像空间分辨率是最有前景的方法,它是通过多幅有子像素位移的有欠采样的图像重构出超过系统Nyquist频率极限的图像,在"一种改进的IBP重构方法"中通过改进反投影修正因子,使改进的算法收敛速度加快,相对于传统的POCS(Projection on Convex Set)与IBP(Iterative Backward Projection)对低SNR(Signal Noise Ratio)的LR(Low-resolution image)重构有更好效果,在此基础上,对前文中提出的算法,在实现上,采用矩阵投影运算,相对之前采用的逐像素循环计算,大大节省了运算时间,同时反投影修正因子,考虑了各LR间的位移差,进一步提高了重构图像质量.     

一种新颖的双陷波超宽带天线设计

针对超宽带系统易受窄带信号干扰的问题,设计了一种新颖的基于金属开口谐振环结构的双陷波平面超宽带天线。通过在天线的辐射贴片上加载U形槽和在接地板上引入寄生条带的方法实现了双陷波特性。利用仿真软件研究了U形槽和寄生条带的物理尺寸对陷波特性的影响,并对所设计的超宽带天线进行了制作和测量。仿真和测试结果表明,天线在超宽带系统3.1～10.6GHz工作频段内的电压驻波比小于2,在WiMAX和WLAN频率范围具有良好的陷波特性,有效地抑制了超宽带通信系统与窄带通信系统之间潜在的干扰。     

Compact frequency and bandwidth tunable stopband filters using split ring resonators and varactors coupled transmission line

Two highly compact tunable stopband filters using microstrip transmission lines coupled with split ring resonators (SRRs) and varactor diodes are presented. Frequency or bandwidth tuning capability of each device is demonstrated. The frequency tunable filter, realized by a single stage, shows a wide tuning range of 19.8% with a maximum bandwidth of 5% and an insertion loss of approximately 20 dB at 4 GHz. The bandwidth tunable filter, realized by double stages, shows a 10-dB bandwidth of 19–34% with a biasing voltage of 0–10 V. The implemented frequency tuning and bandwidth tuning devices show a significant area reduction of 60.1% and 53.5%, respectively, in comparison with a similar frequency or bandwidth tunable structure presented by others. Equivalent circuit models are presented. The measured S-parameters are in good agreement with simulated ones.     

图像复原与超分辨率重构基本适用条件及提高空间分辨率上限的研究

从离散—离散的成像系统出发,在理论上分析了图像复原与超分辨率重构的基本适用条件及提高图像分辨率的上限,从图像处理的角度给出了基本适用条件的量化指标,最后对理论分析结论进行了实验验证,并对实际应用中不可避免的噪声影响进了研究,实验结果与理论研究结论一致.     

一种基于金属开口谐振环和杆阵列的左手材料宽带吸收器

用数值仿真在微波X波段研究了金属开口谐振环和杆阵列这一最基本的谐振结构.通过合理的参数调节,这种结构在10.91GHz附近可以表现出高达98%的吸收率,并且半高峰宽达到3.5GHz.用散射参量提取法计算其有效电磁参数,发现在谐振频率附近其介电常数、磁导率和折射率的实部均为负值.相比于传统的左手材料,这种结构的电磁参数在谐振区域均具有较大的虚部,是形成高吸收率的根本原因.本文的左手材料吸收器在电磁加热、电磁隐身等领域具有许多潜在的应用.     

关于科研成果质量管理的探讨

本在建立科研成果的质量管理系统模式的基础上，从科研项目立项评估、科研项目的系统过程控制，科研成果鉴定和完善信息反馈系统四个方面进行了科研成果质量管理的探讨。     

Broadband planar left-handed metamaterials using split-ring resonator pairs

In this paper, we showed that split-ring resonator (SRR) pairs can be used as broadband planar left-handed metamaterials (LHMs). Simulations were carried out for one layer of infinite LHM slab using SRR pairs. The results showed that by carefully adjusting dimensions of the SRR pairs, magnetic and electric resonances can be coexistent at some frequency ranges and in the frequency range where there are both negative magnetic and electric responses, there is a broad LH band. Equivalent circuits for the magnetic and electric resonance were offered to give a qualitative and quantitative explanation of the LH behaviors of LHMs using SRR pairs.