一种新的快速相关精跟踪算法

文中针对瞄准吊舱中前视红外成像跟踪的工作状态，提出了一种新的相关跟踪算法。该算法采用一维直方图快速搜索和二维多级亚采样精定位方案，使算法的实时实现成为可能。该算法还科像系列的相关性。采用隔帧修正累积误差的方法，有效地提高了系统的跟踪精度。最后，给出实验结果，结果与理论相符。     

Odor discrimination by G protein-coupled olfactory receptors

The vertebrate olfactory system possesses a remarkable capacity to recognize and discriminate a variety of odorants by sending the coding information from peripheral olfactory sensory neurons in the olfactory epithelium to the olfactory bulb of the brain. The recognition of odorants appear to be mediated by a G protein-coupled receptor superfamily that consists of approximately 1% of total genes in vertebrates. Since the first discovery of the olfactory receptor gene superfamily in the rat, similar chemosensory receptors have been found in various species across different phyla. The functions of these receptors, however, had been uncharacterized until the recently successful functional expression and ligand screening of some olfactory receptors in various cell expression systems. The functional cloning of odorant receptors from single olfactory neurons allowed for the identification of multiple receptors that recognized a particular odorant of interest. Reconstitution of the odorant responses demonstrated that odorant receptors recognized various structurally-related odorant molecules with a specific molecular receptive range, and that odor discrimination is established based on a combinatorial receptor code model in which the identities of different odorants are encoded by a combination of odorant receptors. The receptor code for an odorant changes at different odorant concentrations, consistent with our experience that perceived quality of an odorant changes at different concentrations. The molecular bases of odor discrimination at the level of olfactory receptors appear to correlate well with the receptive field in the olfactory bulb where the input signal is further processed to create the specific odor maps.     

Co-volume method for Riemannian mean curvature flow in subjective surfaces multiscale segmentation

We introduce semi-implicit complementary volume numerical scheme for solving the level setformulation of Riemannian mean curvature flow problem arising in image segmentation, edge detection, missing boundary completion and subjective contour extraction. The scheme is robust and efficient since it is linear, and it is stable in L_∞ and weighted W ^1,1 sense without any restriction on a time step. The computational results related to medical image segmentation with partly missing boundaries and subjective contours extraction are presented.     

The role of the corpus callosum in dichotic listening: A combined morphological and diffusion tensor imaging study.

The objective of the present study was to examine the role of the corpus callosum (CC) in dichotic listening. For this purpose, 40 right-handed healthy male participants were assessed with morphological and diffusion tensor imaging, which yielded macrostructural (midsagittal area) and microstructural (mean diffusion, fractional anisotropy) measures of the total CC and predefined subregions. Applying the standard consonant-vowel Bergen Dichotic Listening Test (including 3 different attentional instructions), the authors found dichotic listening performance to be substantially related to the integrity of the CC at both macro- and microstructural levels. Results indicate a dual role of the CC; it is relevant not only for the stimulus-driven (bottom-up) transfer of left-ear input to the left hemisphere but also for its attentional (top-down) modulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

乏氧显像和乏氧干预在32P间质内放疗中作用的实验研究

核素内放疗已越来越多应用于临床,预测、增敏其疗效具有实际应用价值.本研究对荷S180瘤小鼠在32p肿瘤间质内注射治疗前行99mTc-HL91乏氧显像,并用Carbogen吸入进行乏氧干预,结果显示99mTc-HL91肿瘤滞留量在Carbogen吸入后明显减少,同时32p肿瘤间质内注射治疗后Carbogen吸入组小鼠肿瘤大小明显小于空气吸入组;但是,99mTc-HL91肿瘤滞留量多少与32p肿瘤间质内注射治疗后肿瘤大小间无明显相关性.说明99mTc-HL91乏氧显像可以反映乏氧干预效果,但不能预测32p肿瘤间质内注射治疗疗效,而Carbogen吸入可以提高32P肿瘤间质内注射治疗疗效.     

相移法光栅投影3维物体表面重建中一种消除交叠的算法

光栅投影成像是3维物体重建和测量的重要技术。它将广泛应用于科学研究、生产、文化艺术、医学等各个领域。目前,这项技术的自动化程度较低,速度较慢。因此,对其研究具有重要的理论意义和实用价值。首先介绍了光栅投影成像和3维物体重建的基本原理,然后提出了利用光栅投影条纹编码、解码、相移技术和莫尔法相位解缠确定3维物体深度信息的方法。光栅投影条纹采用逐步二分的二进制7位码编码,相移采用间隔π48步相移的正弦相移技术。此外,还提出了一种算法以消除因光栅条纹图像发生交叠而造成条纹解码产生的错码。这种算法利用各幅条纹编码图像中条纹位置的相关性,通过对条纹边界线灰度值的迭代,实现交叠条纹的区分。该算法加快了条纹解码和相位解缠速度,减少了存储量,提高了自动化程度和测量精度。     

MR图像运动伪影的遗传算法校正

磁共振成像过程中,由于患者的生理运动或自主性运动会使扫描数据发生相位偏移,致使重建图像含有运动伪影,从而降低成像的质量,而且严重的伪影则会影响医生对病灶的精确定位。为了能有效地抑制运动伪影,利用遗传算法高度并行、随机和自适应全局寻优的特点,提出了基于遗传算法的运动伪影修正方法,即采用逐次修正扫描信号在K空间中已偏移的相位的方法来抑制伪影。基于遗传算法的修正方法,由于能有效校正扫描数据的相位偏移,因而可达到抑制运动伪影的目的。实验表明,该方法对由较小运动引起的伪影有很好的抑制作用,对含噪声及较大运动引起的伪影的抑制作用,与经典的迭代算法相比,也有很大地改善。     

机载SAR 实时成像处理系统设计

介绍了机载SAR 实时信号处理器的体系结构和实时信号处理的算法流程, 通过对载机平台实测数据进行成像处理, 给出了高分辨率的SAR 图像, 验证了该系统的可靠性。
     

概率模型下的K-means 算法在SAR 图像分类中的应用

遥感图像分类是将图像所有的像元按其性质分为若干个类的技术过程。常用的分类方法有监督分类和非监督分类。监督分类需要有足够的先验知识; 非监督算法是按照某种相似性准则对样本进行合并或分类, 所以并不需要有先验知识。但是传统的非监督分类算法存在着分类精度较低, 分类结果比较粗糙等缺点。例如K-means 算法、isodata 算法等。提出一种基于高斯分布和瑞利分布两种概率模型的K-means 算法, 从结果可以看出, 分类效果要明显优于传统的K-means 算法。     

精细表面下细小缺陷的磁光涡流成像实时探测

磁光涡流成像检测装置可实现精细表面下细小缺陷探测。在该装置中，通过物体表面上方的交流激励线圈实现传统的涡流感应，涡流所感应的磁场由法拉第效应来检测。为了实现表面下缺陷的检测目标，激光穿过安放在激励线圈中的特殊的磁光晶体，激光偏振方向在晶体中的旋转大小取决于检测区域磁场的大小，缺陷将使检测区域磁场分量发生变化并使偏振光的旋转角发生相应变化，通过一光学装置转化成“明”或“暗”图像，该光学装置由传统的显微镜、照明系统、偏振器和CCD图像传感器组成。给出了初步的实验探测结果。