Image blurring of thick specimens due to MeV transmission electron scattering: a Monte Carlo study

Image blurring of MeV transmission electrons for gold nanoparticles on the top surface of micrometer-thick specimens has been investigated using the Monte Carlo simulation. Both the simulated line density profile and therefore image blurring were in good agreement with the experimental ones in the ultrahigh voltage electron microscope. Quantitative effects of specimen thickness and electron energy on image blurring were presented, in which the specimen thickness had a greater influence. Image blurring was demonstrated to be caused mainly by multiple elastic scattering, but it could be reduced to several nanometers for a 5?μm thick epoxy-resin specimen at the electron energy of 2?MeV.     

Impact of point spread function on infrared radiances from geostationary Satellites

The blurring from diffraction for the infrared (IR) radiances on a geostationary satellite (GEO) e.g., the next generation of Geostationary Operational Environmental Satellite (GOES-R) was simulated by using Moderate Resolution Imaging Spectroradiometer Airborne Simulator data and the point spread function (PSF) model for an unobscured telescope. The portion of the total radiance contributed from each nearby geometrical field of view (GFOV) was calculated. For 90% ensquared energy (EE) (equivalent to 10% of the energy coming from outside the footprint), the closest GFOVs contribute 7%; the contribution from the closest GFOVs increases to 22% for 70% EE. The increased portion from the nearby GFOVs causes larger blurring and degrades the pixel-based retrieval product accuracy. Radiance contamination from the nearby field for the GEO IR radiances with 90%, 80%, and 70% EE causes 0.2-, 0.3-, and 0.4-K blurring errors, respectively, in the 12-/spl mu/m IR longwave window band in clear 300-K scenes. The blurring error is doubled in cloudy 230-K scenes. For the 13.8-/spl mu/m absorption band, the blurring error will be smaller than that of the 12-/spl mu/m band because the atmospheric layer where the temperature sensitivity peaks for the 13.8 /spl mu/m is more uniform than the surface where the 12 /spl mu/m is most sensitive. This indicates that the PSF has a greater impact on a heterogeneous surface. Similar blurring errors occur at both 4- and 10-km spatial resolution IR sensors. The blurring error is not random, and it varies spectrally. These conclusions are very relevant to the design of a cost-effective GEO IR sounder that meets the science requirements.     

线性调频求取多目标距离的算法研究

脉冲多普勒雷达是先进战斗机上广泛采用的火控攻击雷达，对这种雷达，有些理论问题仍需进一步研究。其根本的特征是通过测量目标的速度来发现目标，为了避免出现速度模糊实现准确测速，一般都采用了高发射脉冲重复频率，但随之而来的又出现了距离模糊。本文论述了某多普勒雷达通过线性调频解决距离模糊问题并测得多个目标的距离的方法。     

频域迭代盲解卷积图像恢复方法及其算法实现

详细讨论了一种新的模糊图像复原法 ,使用这种方法 ,不需知道图像模糊过程的模糊因子 ,就可以实现图像的恢复。该算法易于编程 ,且具有较强的通用性。分析了计算机算法 ,并给出了处理的结果。     

Attenuation of eye movements evoked by a vestibular implant at the frequency of the baseline pulse rate

We are developing a vestibular implant to electrically stimulate vestibular neurons in the semicircular canals in order to alleviate vertigo, which is a commonly occurring problem. However, since electrical stimulation causes synchronous (phase-locked) neural responses, such electrical stimulation might also cause inappropriate vestibuloocular eye movements, which might, in turn, cause visual blurring. We investigated the eye movements evoked in the guinea pig using electric stimulation with a constant rate of 250 pulses per second (pps), and measured 0.010(°) peak-to-peak eye movements on an average at 250 Hz, with an average peak velocity amplitude of 8.1(°)/s, which might cause visual blurring. However, after half an hour of stimulation, that component reduced to 1.6(°)/s (0.0020(°) peak-to-peak). The average time constant for this reduction was 5.0 min. After one week of constant stimulation, the 250-Hz response component was only slightly smaller, at 1.2(°)/s (0.0015(°) peak-to-peak). We conclude that although an electrical prosthesis with a resting rate of 250 pps may cause some visual blurring when first turned on, such blurring is very likely to attenuate and be imperceptible within several minutes.     

Spatial Filtering to Improve Transverse Tomography

A new transverse tomographic apparatus is described that enables the tomogram to be related to the ideal image by a linear blurring operation. It is shown that digital and optical linear spatial filtering techniques may be employed to remove the blurring that is present in the tomographic image obtained with the new device. Experimental verification of both restoration methods is presented.     

全视差彩虹全息色模糊分析

对用光栅制作的全视差彩虹全息再现像的色模糊进行了定量分析,得出在固定点观察时进入眼瞳波长范围引起的像点纵向和横向位移,指出当像点位于全息图平面时,色模糊为 0。     

Influence of Aerosol Scattering on Atmospheric Blurring of Surface Features

We investigate the influence of the shape of atmospheric scattering phase functions on blurring of surface detail in images acquired from space. The effects are characterized by computing atmospheric transfer functions and by solving the multidimensional equation of radiative transfer using a Fourier transform method. We predict that increased forward scattering enhances the detectability of atmospheric blurring near reflectance boundaries. Results for off-nadir viewing are also presented.     

Implementation of a pearl visual simulator based on blurring andinterference

Visual simulation using computer graphics has attracted wide attention in many fields. We propose a method of modeling and visualizing pearls to implement a pearl visual simulator. Pearls manifest a very specific optical phenomenon. To investigate this feature, we propose an optical model of blurring and pearl interference. The experimental results show that the physics-based modeling of internal blurring in the multilayer of a pearl and the partial coherent interference model are effective for high-quality pearl visualization     

用Hopfield网络实现边缘模糊图象的二值化处理

本文基于Hopfield网络提出了一个实现边缘模糊图象二值化处理的新方法.首先将图象二值化处理问题转化成优化问题,然后构造相应的Hopfield网络参数并用Hopfield网络实现这个优化问题的解.实验说明,该方法具有较高的精度,同时对较小图象,甚至一维信号亦具有好的效果.     

基于运动模糊效应的图像测速方法

通过分析影像与成像平面以及地面景物之间相对运动关系,建立了航拍图像运动模糊模型,分析了模糊带宽度和相机运动及曝光时间之间的关系,设计了基于模糊带边缘增强和自相关分析的模糊带宽度测量算法,在此基础上提出了基于运动模糊效应的图像测速方法.给出了实用的测速算法,并分析了像素尺寸、模糊带宽度、相机姿态等对测速精度的影响.与传统的基于多普勒、地形匹配等测速算法相比,此方法无需增加额外设备和保障数据,实现更为简单.算例分析表明,此算法对于速度无剧烈变化的准匀速运动具有较好的测速效果,为飞行器实时飞行速度的测量提供了一种新的解决手段.     

TFT-LCD保持模式显示运动图像的局限和解决方法

分析了TFT-LCD因其工作在保持模式,显示运动图像时会产生模糊的原因。有代表性地介绍了运动图像模糊的测量和定量评价方法。讨论了提高液晶像素的响应速度、提高帧频、背光源闪烁、背光源扫描、插入黑场和采用图像处理技术等多种解决方法,并对各种方法进行了分析和评论。     

分布式小卫星系统沿航迹干涉SAR测速去模糊方法

本文结合分布式小卫星系统的多基线结构阐述了沿航迹干涉SAR(Along-Track Interferometric SAR)测速的解模糊问题,提出利用多个卫星的干涉相位信息去除沿航迹干涉SAR的测速模糊。以往单颗卫星作SAR-GMTI时,用固定长度基线的双天线作动目标检测总会遇到速度模糊问题,而此问题在分布式系统中多基线组合情况下则迎刃而解。本文还分析了小卫星编队立体队形及地球自转等因素下的动目标测速去模糊。     

A novel collaborative approach for location prediction in mobile networks

Human location prediction has been a matter of concern for several years due to its many applications. It has become more important nowadays because of prevalence of mobile devices which have adequate tools for inferring location. Different approaches for making this prediction could be divided into three categories, based on the movement history they use. These include history of mobile user himself, history of all mobile users in a place, and history of only related mobile users. Besides the problem of limiting shared data to only required data, preserving privacy is the matter of concern for persuading mobile users to share their data. In this paper we have proposed a new method in which the amount of the shared data is decreased to a minimum, and only the data which will improve the partner’s prediction will be shared. Our method preserves privacy by blurring the shared data up to different degrees. The experimental results show that regardless of amount of blurring, as long as the user movement is not lost because of blurring, the accuracy of prediction will be improved about 7 %.     

Combining self-learning based super-resolution with denoising for noisy images

In this paper, we propose a new learning based joint Super-Resolution (SR) and denoising algorithm for noisy images. The individual processing of denoising and SR when super-resolving a noisy image has drawbacks such as noise amplification, blurring and SR performance reduction. In the proposed joint method, principal component analysis (PCA) based denoising is closely combined with a self-learning SR framework in order to minimize the SR visual quality degradation caused by noise. Experimental results show that the joint method achieves an SR image quality improvement in terms of noise and blurring, when compared with the state-of-the-art joint method and sequential combinations of individual denoising and SR.     

A micro-image fusion algorithm based on region growing

Due to the limitation of Depth Of Field (DOF) of microscope, the regions which are not within the DOF will be blurring after imaging. Thus for micro-image fusion, the most important step is to identify the blurring regions within each micro-image, so as to remove their undesirable impacts on the fused image. In this paper, a fusion algorithm based on a novel region growing method is proposed for micro-image fusion. The local sharpness of micro-image is judged block by block, then blocks whose sharpness is lower than an adaptive threshold are used as seeds, and the sharpness of neighbors of each seed are evaluated again during the region growing until the blurring regions are identified completely. With the decreasing in block size, the obtained region segmentation becomes more and more accurate. Finally, the micro-images are fused with pixel-wise fusion rules. The experimental results show that the proposed algorithm benefits from the novel region segmentation and it is able to obtain fused micro-image with higher sharpness compared with some popular image fusion method.     

运动模糊图像点扩展函数的自动识别方法

在获取图像的过程中,传感器和场景的相对运动所造成的图像模糊是一类常见的图像退化模式。为对模糊图像进行恢复,首先要给出精确的点扩展函数估计。针对匀速运动降晰的情况,提出了一种新的误差-参数曲线法,并依据这种曲线提出了一种点扩展函数的自动估计算法。通过引入奇异因子、光滑因子以及平坦因子来实现点扩展函数的估计。实验结果表明,该方法可以取得较为精确的估计效果。     

基于区域纹理合成的图像修补算法

针对传统修补技术在图像恢复中出现的纹理模糊现象,该文根据纹理合成技术,提出了一种区域纹理合成的修补算法。算法根据破损点邻域特征选择模板,去除模板内的破损点后进行匹配,在搜索范围内寻找最佳匹配点。该文采用由边缘向中心逐步推进的修补次序,提高破损区域内纹理结构延伸方向的正确性以及连续性,避免出现纹理模糊现象。算法能够适用于多种性质的纹理,在处理真实图像时使人在视觉上获得满意的效果。     

基于模糊度和噪声水平的图像质量评价方法

针对图像质量评价的重要性,提出了一种新的无参考图像质量客观评价方式。算法考虑了模糊度与噪声水平两方面,用平均边缘宽度衡量图像的模糊度,通过比较去噪前后的图像预测图像受噪声污染的程度,最后通过两者的综合作为无参考图像质量评价指标。实验结果表明:将模糊度和噪声评价相结合,具有很强的抗噪性和广泛的适用范围;与峰值信噪比(PSNR)和结构类似性(SSIM)等算法比较,本文算法可以很好地区分各种失真类型图像的质量好坏,其结果接近人眼的主观感受。     

Blind and Semi-Blind Deblurring of Natural Images

A method for blind image deblurring is presented. The method only makes weak assumptions about the blurring filter and is able to undo a wide variety of blurring degradations. To overcome the ill-posedness of the blind image deblurring problem, the method includes a learning technique which initially focuses on the main edges of the image and gradually takes details into account. A new image prior, which includes a new edge detector, is used. The method is able to handle unconstrained blurs, but also allows the use of constraints or of prior information on the blurring filter, as well as the use of filters defined in a parametric manner. Furthermore, it works in both single-frame and multiframe scenarios. The use of constrained blur models appropriate to the problem at hand, and/or of multiframe scenarios, generally improves the deblurring results. Tests performed on monochrome and color images, with various synthetic and real-life degradations, without and with noise, in single-frame and multiframe scenarios, showed good results, both in subjective terms and in terms of the increase of signal to noise ratio (ISNR) measure. In comparisons with other state of the art methods, our method yields better results, and shows to be applicable to a much wider range of blurs.