基于图切割的图像拼接技术研究

虽然图像拼接技术已进行多年研究,但是鬼影和曝光差异仍然难以消除。为解决这两个问题,提出了一种基于图切割的图像拼接方法。该方法结合图切割和泊松融合技术,首先利用每个像素邻域统计得到的梯度方向直方图来计算重叠区的带权有向图的权值,并通过实现稳定的图切割缝合线搜索,以消除鬼影;然后利用重叠过渡的泊松融合过程解决了缝合线拼接后的曝光差异问题,从而最终实现平滑的图像拼接。实验表明,该算法能够效地消除鬼影和曝光差异。     

一种适于移动设备的全景图快速拼接方法

针对传统移动端全景图生成方法存在拼接速度慢、消耗内存以及存在接缝和“鬼影”等问题,提出了一种适用于移动设备的全景图生成算法。算法首先对源序列图像进行色彩校正,从而保证色彩及亮度均匀,以缩短后期图像融合时间;然后在全景图拼接过程中检测“鬼影”,同时运用梯度域目标移除和区域填充方法移除“鬼影”,利用泊松融合进行拼接后的平滑处理;同时在图像拼接过程中优化了内存分配机制,以减少在图像拼接过程中的内存消耗。通过编程实现了该算法,在配置为332MHz处理器和128MB内存的手机上对不同光照下拍摄的分辨率为1280×720的照片进行测试,并与传统的全局全景图拼接算法进行对比,若利用全局全景图拼接算法对2至9张源序列图像进行拼接,内存消耗为12.3~23.6MB,而提出的算法占用更少内存,分别为9.9~14.5MB。实验结果表明该方法消除图像接缝及“鬼影”较彻底,拼接速度快且节省内存,生成的最终全景图质量较好,可用于移动设备上的全景图拼接。     

基于图切割的图像拼接技术

图像拼接作为基于图像绘制的一部分近年来成为研究的热点之一.本文对图像拼接技术进行研究,详细的分析了新的基于图切割的拼接方法.该方法在相位校正的基础上将图切割和泊松融合相结合实现拼接,图切割用于搜索全局最优的缝合线以去除鬼影,泊松融合用于曝光差异的处理.本文给出新的基于梯度方向直方图统计的权值计算方法,实现稳定的图切割.另外,本文还设计出重叠过渡的泊松融合方法,较好地完成图像合成.     

基于最佳缝合线的序列遥感图像拼接融合方法

在图像融合过程中常采用重叠区域像素加权融合方法,这会存在鬼影现象。为解决这一问题,提出了一种改进的最佳缝合线生成算法和沿最佳缝合线的融合方法,并将其应用于序列遥感图像的拼接融合。首先在重叠图像中,对重叠区域的边赋予权值,然后进行最大流最小割,最终获取最佳缝合线。在计算边权值时引入了图像梯度信息,使缝合线更准确。在图像融合时,沿最佳缝合线生成一个条带形融合区域,采用渐入渐出法对缝合线两侧的条带形融合区域图像进行过渡处理,使拼接后的图像更为真实。在序列遥感图像拼接上,采用捆绑调整算法调整拼接图像的参数来实现全局误差最小化。实验表明,该方法能够有效消除鬼影并且能获得准确的拼接图像与融合,对于序列遥感图像的拼接融合能够获得很好的效果。     

面向电子助视系统的文档图像拼接算法研究

电子助视系统是一种运用实时图像处理技术来提高低视力患者阅读能力的仪器。由于传统电子助视系统使用单摄像头采集图像,视角较小,要多次移动助视设备或目标书籍才能完成阅读,因此用户体验不佳。针对此问题,设计了一种基于多路摄像头采集的文档图像拼接算法。在图像配准步骤,提出了一种针对文档图像的区域特征描述方法,提取单个文字区域作为特征区域,其质心作为特征点,通过描述特征区域的纹理信息完成特征点的描述,提高了特征匹配效率。在图像融合步骤,提出了一种利用文档图像字符间隙的最优拼接缝搜索算法,消除了拼接鬼影;构建多尺度的图像金字塔,使用多分辨率融合算法,抑制了融合图像的曝光差异。从实验结果来看,算法获得了很好的配准和融合效果,提升了配准速度,消除了配准鬼影和曝光差异,能够获得较广的阅读视角,可以较好的用于电子助视系统。     

基于不变矩相似度的快速图像拼接

针对图像拼接中普遍存在的效率低和误匹配等问题,提出了一种基于不变矩相似度的快速拼接方法。首先利用不变矩相似度准则,预估输入图像的重叠区域,然后采用SIFT算法进行特征点检测和匹配,减少了不必要的特征提取和误匹配。利用稳健的RANSAC算法实现特征点提纯并计算单应性矩阵。最后,针对带运动目标的动态场景融合后易出现鬼影的现象,提出一种改进的分段线性加权融合算法以消除拼接鬼影。     

一种消除图像拼接缝和鬼影的快速拼接算法

由于提取SIFT特征进行图像拼接的算法复杂度较高且不能很好地处理拼接缝和鬼影等问题,提出了一种消除拼接缝和鬼影的快速图像拼接算法.该算法首先划定提取SIFT特征的范围,计算出匹配特征点后使用RANSAC算法求取两幅图像间的坐标变换关系矩阵H,然后结合最佳缝合线算法和改进的加权平均融合算法实现无缝拼接.实验结果表明,提出的算法不仅有效地消除了拼接缝和鬼影,也提高了图像拼接的效率.     

基于拉普拉斯金字塔融合的岩心图像拼接算法

针对岩心图像拼接效率低以及易出现鬼影现象的问题,提出了一种基于最佳缝合线的拉普拉斯金字塔融合的岩心图像拼接方法.首先将待拼接的两幅岩心图像进行灰度变换,根据ORB算法计算并描述特征点;其次使用改进的random sample consensus (RANSAC)算法对特征点进行提纯,完成特征点匹配;根据匹配的特征点计算图像间的配准关系,最后根据最佳缝合线实现岩心图像的拉普拉斯金字塔融合,完成拼接.实验结果表明,改进的RANSAC算法能在保证正确率的同时提升速度,而且本文提出的图像融合方法避免了鬼影的产生,在融合区域的PSNR、SSIM和DoEM客观评价指标上与另外两种图像融合算法相比都有所提升.     

基于灰度级映射函数建模的多曝光高动态图像重建

为解决传统多曝光图像融合的实时性和动态场景鬼影消除问题,提出了基于灰度级映射函数建模的多曝光高动态图像重建算法。对任意大小的低动态范围（Low dynamic range,LDR）图像序列,仅需拟合与灰阶数目相同个数而不是与相机分辨率个数相同的视觉适应的S形曲线,利用最佳成像值判别方法直接融合,提高了算法的融合效率,能够达到实时性图像融合要求。对动态场景的融合,设计灰度级映射关系恢复理想状态的多曝光图像,利用差分法检测运动目标区域,作鬼影消除处理,融合得到一幅能够反映真实场景信息且不受鬼影影响的高动态范围图像。     

一种快速去除大尺寸工件鬼影图像的精密拼接算法

为了提高大尺寸工件测量的精度和效率,针对现有拼接方法复杂度高且不能很好处理图像鬼影的问题,提出了一种快速去除大尺寸工件鬼影图像的精密拼接算法。该算法先通过SURF算法检测出相邻图像对应特征点,然后结合最近邻匹配法匹配特征点,零均值归一化互相关算法（ZNCC）判断、检测出图像是否存在鬼影;若存在鬼影,则用小波变换融合算法去除鬼影,并求出相邻两幅图像之间的单应性矩阵H,最后实现大尺寸工件精密拼接。结果表明,该算法不仅能有效地去除大尺寸工件图像鬼影,同时提高图像拼接精度和效率。     

基于通用比较模型的t-可诊断系统的特征化及并行诊断算法

文中介绍了一种系统级故障诊断模型－－通用比较模型,该模型处理器作为自身的比较器,综合经典的ＰＭＣ模型和Ｍａｅｎｇ／Ｍａｌｅｋ模型的优点,基于该报多处理器系统的ｔ＿可诊断性问题,给出了ｔ＿可诊断系统的特征化,证明了一个系统成为ｔ－可诊断系统的新的充分必要条件,其次,证明在通用比较模型中,确定故障顺集的问题等价于求解一个超图的最小横切集（Ｍｉｎｉｍｕｍ ｔｒａｖｅｒｓａｌ）,该超图是根据多处理器的通信     

混合关系中的函数依赖及其相关规则

在实际应用中有这样一类关系数据库,其中数据项在某个属性上的取值本身又是一个关系。讨论这种混合关系中的函数依赖及其相应的相关规则具有一定的理论意义和实际应用价值。给出这种混合关系的形式定义、混合关系中4种类型的函数依赖关系以及相应的4种类型的相关规则;并给出混合关系到一般关系的转换,通过这个转换说明了混合关系与普通关系的联系及其差别。给出一个实际应用中的例子,来说明混合关系中的函数依赖和相关规则的形式多样性。     

K(Knowledge)-net: building up and its dynamics

The essence of intelligence is to use certain abilities to obtain knowledge, to use that knowledge, and to operate with that knowledge. New knowledge learned by a human is often related to old existing knowledge, and sometimes we could have more conceptual knowledge based on old knowledge. So, the knowledge in the brain exists in a related structural form, and this structure is dynamic, and therefore is evolvable. Based on the understanding of the real process of learning by a human being, we discuss how to make a model to describe the dynamic structure of knowledge. This model is also a principle of artificial brain design. Most of the knowledge a child learns is from natural language and perception information, and we define this as semantic knowledge. The model to describe the process and structure of knowledge growing in a network form is called a K-net. It is a dynamic network with two main dynamics: one is new knowledge added, and the other is aggregating knowledge existing in the network with some probability. Under these very natural conditions, we found that the network is originally a simple random net, and then some characteristics of a complex network gradually appear when more new knowledge is added and aggregated. A more interesting phenomenon is the appearance of a random hierarchical structure. Does this mean emergence?     

An Order-Based Theory of Updates for Closed Database Views

The fundamental problem in the design of update strategies for views of database schemata is that of selecting how the view update is to be reflected back to the base schema. This work presents a solution to this problem, based upon the dual philosophies of closed update strategies and order-based database mappings. A closed update strategy is one in which the entire set of updates exhibit natural closure properties, including transitivity and reversibility. The order-based paradigm is a natural one; most database formalisms endow the database states with a natural order structure, under which update by insertion is an increasing operation, and update by deletion is decreasing. Upon augmenting the original constant-complement strategy of Bancilhon and Spyratos – which is an early version of a closed update strategy – with compatible order-based notions, the reflection to the base schema of any update to the view schema which is an insertion, a deletion, or a modification which is realizable as a sequence of insertions and deletions is shown to be unique and independent of the choice of complement. In addition to this uniqueness characterization, the paper also develops a theory which identifies conditions under which a natural, maximal, update strategy exists for a view. This theory is then applied to a ubiquitous example – single-relational schemata constrained by equality-generating dependencies. Within this framework it is shown that for a view defined as a projection of the main relation, the only possibility is that the complement defining the update process is also a projection, and that the reconstruction is based upon functional dependencies.     

Detection of microdroplet size and speed using capacitive sensors

Detection of the presence, size and speed of microdroplets in microfluidic devices is presented using commercially available capacitive sensors which make the droplet based microfluidic systems scalable and inexpensive. Cross-contamination between the droplets is eliminated by introducing a passivation layer between the sensing electrodes and droplets. A simple T-junction generator is used to generate droplets in microchannels. Coplanar electrodes are used to form a capacitance through the microfluidic channel. The change in capacitance due to the presence of a droplet in the sensing area is detected and used to determine the size and speed of the droplet. The design of a single pair of electrodes is used to detect the presence of a droplet and the interdigital finger design is used to detect the size and speed of the droplet. An analytical model is developed to predict the detection signal and guide the experimental optimization of the sensor geometry. The measured droplet information is displayed through a Labview interface in real-time. The use of capacitance sensors to monitor droplet sorting at a T-junction is also presented. The discussions in this paper can be generalized to any droplet detection application and can serve as a guideline in sensor selection.     

基于Struts和JDO的信息管理系统

Struts是广泛应用的Web框架，但它没有提供如何访问数据的方法。JDO是数据访问框架，利用O-R映射来访问数据库，而一般要用JDBC和SQL来访问数据库，较之JDO更加方便和快捷。一个成熟的应用需要两者结合起来才能形成一个完整的方案。这里提出用Struts作为前台和逻辑控制，用JDO作为后台数据访问层来开发B/S架构的信息管理系统的一种方案。     

Using genetic algorithm for lot sizing and scheduling problem with arbitrary job volumes and distinct job due date considerations

This paper considers an integrated lot sizing and scheduling problem for a production–distribution environment with arbitrary job volumes and distinct due dates considerations. In the problem, jobs are firstly batch processed on a batching machine at production stage and then delivered to a pre-specified customer at the subsequent delivery stage by a capacitated vehicle. Each job is associated with a distinct due date and a distinct volume, and has to be delivered to the customer before its due date, i.e. delay is not allowed. The processing time of a batch is a constant independent of the jobs it contains. In production, a constant set-up time as well as a constant set-up cost is required before the first job of this batch is processed. In delivery, a constant delivery time as well as a constant delivery cost is needed for each round-trip delivery between the factory and the customer. Moreover, it is supposed that a job that arrives at the customer before its due date will incur a customer inventory cost. The objective is to find a coordinated lot sizing and scheduling scheme such that the total cost is minimised while guaranteeing a certain customer service level. A mixed integer formulation is proposed for this problem, and then a genetic algorithm is developed to solve it. To evaluate the performance of the proposed genetic algorithm, a lower bound on the objective value is established. Computational experiments show that the proposed genetic algorithm performs well on randomly generated problem instances.     

基于支持向量机与遗传算法的网络入侵检测的应用

入侵检测实质上是一个分类的问题,对于提高分类精度是十分重要的.支持向量机(SVM)是一个功能强人的用于解决分类问题的工具.基于支持向量机的入侵检测精度较高,但如何获得更高的精度是一个新的问题.本文利用基于支持向量机和遗传算法(GA)的入侵检测来解决这些问题.我们首先利用遗传算法进行特征选择及优化,然后使用支持向量机模型...     

抗主动攻击的保密比较协议

互联网、物联网和大数据的迅速发展,为数据共享带来了无限的机遇,也给私有数据的隐私保护带来了严峻的挑战.安全多方计算是数据共享中隐私保护的关键技术,是密码学的一个重要研究方向,也是国际密码学界研究的热点.保密比较两个数的大小是安全多方计算的一个基本问题,是构建其他隐私保护协议的一个基本模块.当比较的数较小时,还没有可靠的能够抵抗主动攻击的保密比较问题解决方案.很多应用场景中的参与者可能会发动主动攻击,因为尚没有抗主动攻击的保密比较协议,这些场景中的保密比较问题还无法解决.因而研究抗主动攻击的保密比较问题解决方案有重要理论与实际意义.提出了一种加密-选择安全多方计算模式和编码+保密洗牌证明的抵抗主动攻击方法.在此基础上,设计了半诚实模型下安全的保密比较协议,用模拟范例证明了协议的安全性;分析了恶意参与者可能实施的主动攻击,结合ElGamal密码系统的乘法同态性、离散对数与保密洗牌的零知识证明设计阻止恶意行为的措施,将半诚实模型下安全的保密比较协议改造成抗主动攻击的保密比较协议,并用理想-实际范例证明了协议的安全性.最后分析了协议的效率,并通过实验验证协议是可行的.     

A virtual target approach for resolving the limit cycle problem in navigation of a fuzzy behaviour-based mobile robot

A virtual target approach is proposed for resolving the limit cycle problem in navigation of a behaviour-based mobile robot. Starting from the onset point of a possible limit cycle path, the real target is switched to a virtual location and the robot is navigated according to the virtual target set up temporarily and the real environment information sensed, until a switching-back condition is reached. The cause of the limit cycle is analysed and the abrupt change in target orientations at two consecutive reaction instants is then identified to be the condition for shifting the target from the real location to the virtual one. The condition for switching back to the real target is established using a specific change in the obstacle information sensed. The algorithm is described together with some particular considerations in implementation. Efficiency and effectiveness of the proposed approach are verified through simulation and experiments conducted with a Nomad 200 robot incorporating a fuzzy behaviour-based controller.