共查询到20条相似文献,搜索用时 109 毫秒
1.
2.
3.
李玉峰 《系统工程与电子技术》1989,(12)
本文从最优化方法的观点出发,提出了一种新的图象位移估计算法。它对一定时间间隔内两次采样得到的图象进行运算,用最陡梯度下降法直接迭代出图象位移的估计值。本文还对算法的性能进行了详细的分析,得出估计方差与信噪比、图象相关函数等参数之间的定量关系式,以及由于坐标量化引起的算法对图象特性的限制条件。理论分析和实验表明,该算法具有较强的抗干扰能力和计算量少等优点,可应用于成象跟踪和图象编码等领域。 相似文献
4.
5.
图形仿真所采用的分辨单元简单几何关系模拟法,得到的视景图象往往没有景深和能见度等视觉效果,缺乏真实感。在视景图象仿真研究中,真实感是关键因素,也是研究视景真实视觉效果模拟技术的难题。本文试图从图象仿真与图形仿真的区别入手,探索解决这一难题的途径。通过对不同距离景物的成象影响因素分析,发现能见度差异是以往线性投影关系模拟法不能解决的障碍,研究大气光学传递特性及传递函数表征方法,利用计算机数字技术模拟反映能见度差异本质的空间频率域滤波变换,建立了能见度模拟模型和方法,探索实现了视景真实视觉效果图象的数字仿真。 相似文献
6.
适用大场景高分辨合成孔径雷达的快速BP算法 总被引:2,自引:1,他引:2
在进行大场景、高分辨合成孔径雷达(synthetic aperture radar,SAR)成像处理时,基于后向投影(back-projection,BP)的SAR成像算法由于运算量大其应用受到限制,而基于快速变换的算法是在信号的频率域进行,要求线性孔径,对运动补偿的要求太高其应用也受到限制。提出了一种快速后向投影(fast back-projection,FBP)算法,对大场景、高分辨的SAR成像处理时其计算效率比传统的BP算法有显著提高。仿真结果表明,其成像质量与传统的BP算法相近。 相似文献
7.
一、引言 在很多领域中,计算机处理的对象是各种各样的图形或图象。如何把这些图形或图象变换成能为计算机处理的二进制数值信息,是图形或图象输入技术所要解决的问题。 图形往往指的是各种线型图,如图表、地图、测量记录波形、或工程设计图等。而图象则主要指照片或胶片等具有连续明暗变化的面状图,通常是指可见光波段的物象。而目前在遥感或医学领域中,所处理的大都是非可见光波段的图象,因此,也有人把这方面的应用叫做影象处理。本文所说的图象 相似文献
8.
9.
10.
间歇采样转发干扰(interrupted sampling repeater jamming, ISRJ)利用合成孔径雷达的匹配滤波特性,在其图像中产生间隔分布的假目标,对目标检测等造成欺骗效果,故针对ISRJ的检测与抑制具有重大意义,而现阶段相关研究主要集中在信号域。对此,在图像域中开展ISRJ检测研究。首先将实测数据与仿真干扰相结合,基于不同实测场景与仿真参数构建ISRJ样本;其次针对假目标间隔分布的特点,选用深度学习检测领域具有代表性的“两阶段”与“单阶段”模型;再次,使用单一场景的ISRJ样本对模型进行训练,再利用训练好的模型对其他场景的样本进行测试;最终,得到ISRJ检测结果。基于MiniSAR数据的实验表明,对于不同类别、不同场景以及不同参数的ISRJ样本,所用深度学习模型能够达到95.75%的平均总体检测精度,具有很强的泛化能力。此外,对于尺寸大小为501像素×501像素的样本,上述模型的最少检测用时为0.035 s。 相似文献
11.
Fast interactive segmentation algorithm of image sequences based on relative fuzzy connectedness 总被引:1,自引:0,他引:1
Tian Chunna & Gao XinboSchool of Electronic Engineering Xidian Univ. Xi''''an P. R. China 《系统工程与电子技术(英文版)》2005,16(4)
1.INTRODUCTION Imagesegmentationistoseparatetheobjectofinter estfrombackground.Itistheimportantfoundation ofhigher levelimageanalysis,anditremainsanopen problem.Sofar,variousalgorithmshavebeenpro posed.However,mostofthealgorithmscanonly dealwithspecifickindsofimages.Theseavailableal gorithmscanbeclassifiedintothreegroupsaccording tothesegmentationstyle,automaticsegmentation,manualsegmentation,andinteractivesegmenta tion[1~5].Theautomaticsegmentationmethods,suchas algorithmsbasedonthegra… 相似文献
12.
基于遗传优化的采样模糊C均值聚类算法 总被引:14,自引:0,他引:14
在数据挖掘领域,模糊C均值聚类法(FCM)在处理小量低维的数据挖掘时是有效的,但是面向数据库的数据挖掘经常要处理大量、高维的数据.在这种情况下,FCM算法在时间性能上难以令人满意.本文基于采样技术对FCM算法进行改进,以提高算法的时间性能,并利用遗传算法对聚类结果进行优化以保证聚类的质量,给出了一种新的基于遗传优化的采样模糊C均值聚类算法SFGO(SamplingFCMwithGeneticOptimization).仿真实验证明SFGO算法在大规模数据库的聚类挖掘中,在时间性能和聚类质量上都能获得较满意的结果. 相似文献
13.
To recognize circular objects rapidly in satellite remote sensing imagery, an approach using their geometry properties is presented. The original image is segmented to be a binary one by one dimension maximum entropy threshold algorithm and the binary image is labeled with an algorithm based on recursion technique. Then, shape parameters of all labeled regions are calculated and those regions with shape parameters satisfying certain conditions are recognized as circular objects. The algorithm is described in detail, and comparison experiments with the randomized Hough transformation (RHT) are also provided. The experimental results on synthetic images and real images show that the proposed method has the merits of fast recognition rate, high recognition efficiency and the ability of anti-noise and anti-jamming. In addition, the method performs well when some circular objects are little deformed and partly misshapen. 相似文献
14.
动态八叉树在复杂场景设计中的应用 总被引:3,自引:0,他引:3
主要介绍一种适合管理复杂三维场景的面向对象动态八叉树。方法利用对象间的空间位置关系,将八叉树、AABB树与面向对象概念相结合,构成一种能根据动态场景快速更新的面向对象动态八叉树。该树叶节点是带有AABB层次树的物体对象,场景设计时通过八叉树、AABB树、三角面族这种从宏观到微观的搜索方式快速确定要编辑的对象及其部位,有效避免了对场景中所有物体的遍历,提高了场景设计效率。 相似文献
15.
1 .INTRODUCTIONThe efficient detection of moving objects in video se-quences is a challenging and an i mportant task incomputer vision. It has many applications such assurveillance , video conference , traffic monitor-ing[1 ,2]. Traditionally, the most i mportant task ofsurveillance systemis based on human visual observa-tion,whichis a hard workfor watchmen.Therefore ,the automatic detection of moving objects is requiredinthe surveillance system. Tofacilitate a surveillancesystem,efficien… 相似文献
16.
17.
CONTROL THEORY AND APPLICATION1. INTroDUCTIONOver the past several years, vision servoing, especially hand-eye coordination, has been a major research topicin intelligellt robotic area [l]. The traditional approaches solve the 3-D relationship between the robot and theenvironment based on 2-D vision measurements [2]. However, these measurements require accurate calibrationof the infernal and external parameters of camera, which could be tedious and error prone and in some situat… 相似文献
18.
针对复杂物体间碰撞检测,为提高碰撞检测效率,减少计算量,解决普通算法不直接适用于非凸体等问题,提出了一种连续碰撞检测算法。首先,该算法在初检测阶段利用基于波前法的三角网格生成,对非凸体等复杂物体表面进行网格划分,获取高质量三角形,得到三角形点、线、面参数信息;然后,用动态投影分离剔除法对三角形单元对进行高层剔除,从而剔除掉不可能发生碰撞的三角形;最后,针对可能碰撞的三角形特征对进行精确相交测试,返回发生第一次碰撞时间,完成碰撞检测。经过复杂度分析和实验论证,该算法响应速度快,在结构复杂物体的连续碰撞检测中效率较高,对于非凸体也可适用。 相似文献
19.
Although cardiac magnetic resonance imaging (MRI) can provide high spatial resolution image, the area gray level inhomogenization, weak boundary and artifact often can be found in MR images. So, the MR images segmentation using the gradient-based methods is poor in quality and efficiency. An algorithm, based on the competitive hopfield neural network (CHNN) and the curve propagation, is proposed for cardiac MR images segmentation in this paper. The algorithm is composed of two phases. In first phase, a CHNN is used to classify the image objects, and to make gray level homogenization and to recognize weak boundaries in objects. In second phase, based on the classified results, the level set velocity function is created and the object boundaries are extracted with the curve propagation algorithm of the narrow band-based level set. The test results are promising and encouraging. 相似文献
20.
Wu Chuanjie Li ShizhiDept. of Electronic Engineering Beijing Institute of Technology P.O. Box Beijing China 《系统工程与电子技术(英文版)》1991,(1)
Microwave diffraction tomography is a process to infer the internal structure of an objectfrom multiple angle views of microwave diffraction shadow. Being sensitive to variations in refractive index of the object, the procedure can be used to measure permittivity distributions within dielectric objects and to image soft tissues for biomedical applications. The optimal resolution distance obtainable is half a wavelength, but this can rarely be achieved because of practical limitations. Some procedures, however, are available to improve the practical resolution. One, which is suitable for microwave tomography, is to use multiple angle views data and to combine the resulting images. The other, which is suitable for improving the image reconstruction resolution, is to use the digital filtering technique and the filtered backpropagation algorithm. A system operating over the X-band microwave frequency is described and some experimental results for objects in air are given. 相似文献