首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
细胞轮廓的几何形状是细胞学涂片判读的重要参考,对研究宫颈病变的计算机辅助诊断具有重要意义。针对现有基于形状模板匹配的几何形状识别方法鲁棒性较差的问题,提出了基于曲率匹配的几何形状特征提取方法,通过比较模板轮廓和待识别轮廓的曲率,计算曲率曲线之间的相似度,进而得到细胞轮廓的形状特征,并采用依次旋转轮廓选取最佳匹配的方法来解决轮廓方向不一致的问题,采用以面积等效圆的半径比作为放大比率进行轮廓缩放的方法来解决轮廓大小不一致的问题。通过相关实验证明了该方法所提取的几何形状特征具有尺度不变性和旋转不变性,并与改进Hausdorff距离进行了实验对比,结果表明提取的形状特征能更加准确地识别出细胞轮廓的几何形状。  相似文献   

2.
吕冰  王士同 《计算机应用》2006,26(11):2781-2783
提出了一种基于核技术的求多元区别分析最佳解的K1PMDA算法,并把这一算法应用于人脸识别中。对线性人脸识别中存在两个突出问题:1、在光照、表情、姿态变化较大时,人脸图像分类是复杂的、非线性的;2、小样本问题,即当训练样本数量小于样本特征空间维数时,导致类内散布矩阵奇异。对于前一个问题,可以采用核技术提取人脸图像样本的非线性特征,对于后一个问题,采用加入一个扰动参数的扰动算法。通过对ORL,Yale Group B以及UMIST三个人脸库的实验表明,该算法是可行的、高效的。  相似文献   

3.
Navigation in a GPS-denied environment is an essential requirement for increased robotics autonomy. While this is in some sense solved for a single robot, the next challenge is to design algorithms for a team of robots to be able to map and navigate efficiently.The key requirement for achieving this team autonomy is to provide the robots with a collaborative ability to accurately map an environment. This problem is referred to as cooperative simultaneous localization and mapping (SLAM). In this research, the mapping process is extended to multiple robots with a novel occupancy grid map fusion algorithm. Map fusion is achieved by transforming individual maps into the Hough space where they are represented in an abstract form. Properties of the Hough transform are used to find the common regions in the maps, which are then used to calculate the unknown transformation between the maps.Results are shown from tests performed on benchmark datasets and real-world experiments with multiple robotic platforms.  相似文献   

4.
The metarules useful in the conflict resolution are often directly related to the multiple, conflicting, and non-commensurate objectives associated with the problem domain. However, in its current form, the use of metarules for conflict resolution has some drawbacks. Above all, the metarule use in rule selection is not tailored to the current situation or the specific user; it is tailored to the domain expert, whose domain expertise and preferences were used to construct a knowledge-based system. In this paper, we presents a new method for resolving the conflicts of rules in the knowledge-based system, using decision analysis techniques that explicitly incorporate a user’s preference judgments about the rules. To this end, we consider a conflict resolution problem as a multiple attribute decision-making problem. Further, the proposed method allows for user’s preference judgments that are specified not by rigid format but by user-friendly format for the purpose of reducing burden of information specification.We have applied the proposed methodology to an organizational information-oriented service and resource planning, in which there exist multiple conflicting objectives to be considered.  相似文献   

5.
针对传统iBeacon指纹定位技术中接收信号强度值(RSSI)波动较大、指纹库聚类复杂、存在较大跳变性定位误差等问题,提出一种基于排序特征匹配和距离加权的蓝牙定位算法。在离线阶段,该算法先对RSSI进行加权滑动窗处理,然后根据RSSI向量大小生成排序特征码等值,并与位置坐标等信息组成指纹信息,形成指纹库;在在线定位阶段,根据排序特征向量指纹匹配定位算法和基于距离的最优加权K最邻近法(WKNN)实现室内行人定位。在定位仿真实验中,该算法可以自动根据特征码进行聚类,从而降低了聚类的复杂度,能实现最大误差在0.952 m内的室内行人定位精度。  相似文献   

6.
不同流形样本点之间的关联性挖掘是决定流形对齐算法效率的关键问题。提出了一种新的思路,利用测地距离初步构造不同流形样本点之间的关联性,再利用样本点之间局部几何结构的相似性进行修正,以更为准确地挖掘不同流形样本点之间的关联性。进一步提出一种新的半监督流形对齐算法,利用已知对应点信息和所挖掘样本点之间的关联性,将多个流形数据投影到共同的低维空间。与传统的半监督流形对齐算法相比,本算法在先验信息不充分的情况下,能更准确地联结不同流形数据集。最后通过在实际数据集上的实验验证了算法的有效性。  相似文献   

7.
Shot boundary detection (SBD) is the preliminary and most significant step in Content Based Video Retrieval (CBVR). As such the effectiveness of a CBVR system depends heavily on reliable detection of shot boundaries. In this work, a simple yet effective technique for amalgamating several distance features extracted from video frames has been proposed. The aim here is to develop a technique which is able to produce a better distance feature from the existing ones by hybridizing several distance metrics. In the proposed model, any number of distance features can be incorporated and fused together. The resultant feature is not only more robust but also immune to features which are inefficient. Robustness of the proposed method is tested by combining several low performing features with the more efficient ones. Several statistical amalgamation functions are also tested for determining the most efficient one in terms of F1 score. The power of vague sets has been harnessed to detect the shot boundaries effectively using the resultant distance feature. The proposed method is proved to be effective by means of the results obtained, which show that multiple feature amalgamation can lead to a hybrid distance feature which performs better than the best feature incorporated for SBD. The proposed technique is analyzed using ANOVA. A comparison with the other existing methods portray the efficacy of the proposed approach. This method can also be applied for other research problems where several features are to be fused together for producing superior results than the ones obtained by individual methods.  相似文献   

8.
中文汉字类别繁多,书写随意性大,使得中文的手写体关键词检测具有很大的挑战性。提出一种基于文字几何信息和SIFT特征相结合的手写体关键词检测方法,通过计算文本图像特征的匹配度来检测特定书写人的手写关键词。尺度不变特征转换( scale invariance feature transform,SIFT)局部特征具有良好的稳定性和独特性,既能适应同一书写人手写汉字的差异,又能区分不同书写人的书写笔迹。结合文字的几何信息,通过滑动窗口和最大团查找方法可以有效地删除误匹配点,极大地提高关键词检测的成功率。对大量手写体文本图像的实验结果表明,该方法能够有效检测同一书写人的相同关键词,具有较高的召回率和准确率。  相似文献   

9.
This paper presents a novel robust image alignment technique that performs joint geometric and photometric registration in the total least square (TLS) sense. Therefore, we employ the total least square metric instead of the ordinary least square (OLS) metric, which is commonly used in the literature. While the OLS model is sufficient to tackle geometric registration problems, it gives no mutually consistent estimates when dealing with photometric deformations. By introducing a new TLS model, we obtain mutually consistent parameters. Experimental results show that our method is indeed more consistent and accurate in presence of noise compared to existing joint registration algorithms.  相似文献   

10.
In this paper, a multivariable adaptive control approach is proposed for a class of unknown nonlinear multivariable discrete-time dynamical systems. By introducing a k-difference operator, the nonlinear terms of the system are not required to be globally bounded. The proposed adaptive control scheme is composed of a linear adaptive controller, a neural-network-based nonlinear adaptive controller and a switching mechanism. The linear controller can assure boundedness of the input and output signals, and the neural network nonlinear controller can improve performance of the system. By using the switching scheme between the linear and nonlinear controllers, it is demonstrated that improved performance and stability can be achieved simultaneously. Theory analysis and simulation results are presented to show the effectiveness of the proposed method.  相似文献   

11.
In this paper, we demonstrate that use of a recently proposed feature set, termed Maximum Auto-Correlation Values, which utilizes information from the source part of the speech signal, significantly improves the robustness of a text independent identity verification system. We also propose an adaptive fusion technique for integration of audio and visual information in a multi-modal verification system. The proposed technique explicitly measures the quality of the speech signal, adjusting the amount of contribution of the speech modality to the final verification decision. Results on the VidTIMIT database indicate that the proposed approach outperforms existing adaptive and non-adaptive fusion techniques. For a wide range of audio SNRs, the performance of the multi-modal system utilizing the proposed technique is always found to be better than the performance of the face modality.  相似文献   

12.
Two-dimensional (2D) irregular layout is widely applied in various manufacturing processes, such as sheet metal cutting, shipbuilding, and electronic component placement. An efficient layout algorithm can effectively improve the material utilization, thereby reducing manufacturing cost. But the free-form shape layout problem is very challenge as it is difficult to exactly represent a free-form shape. There is not an efficient method currently available for the 2D free-form shape layout. This paper proposes a method based on the geometric similarity feature searching and fuzzy matching for the 2D free-form shape layout. The freeman chain code is developed to describe the contour information of shapes and forward-lines to form the basis of the layout strategy. A strategy based on fuzzy matching is proposed for the layout, which includes searching geometric similarity features using the longest common subsequence and the proposed placement algorithm to complete the collision. Three computational experiments are conducted to analyze the performance of the proposed method. Experimental results show that the proposed method is feasible and effective with the good applicability to achieve a high filling rate in reduced time.  相似文献   

13.
Discriminant feature extraction plays a central role in pattern recognition and classification. In this paper, we propose the tensor linear Laplacian discrimination (TLLD) algorithm for extracting discriminant features from tensor data. TLLD is an extension of linear discriminant analysis (LDA) and linear Laplacian discrimination (LLD) in directions of both nonlinear subspace learning and tensor representation. Based on the contextual distance, the weights for the within-class scatters and the between-class scatter can be determined to capture the principal structure of data clusters. This makes TLLD free from the metric of the sample space, which may not be known. Moreover, unlike LLD, the parameter tuning of TLLD is very easy. Experimental results on face recognition, texture classification and handwritten digit recognition show that TLLD is effective in extracting discriminative features.  相似文献   

14.
基于不同加权因子的随机多模型自适应控制   总被引:1,自引:1,他引:0  
李晓理  王伟 《控制与决策》2008,23(11):1226-1230
针对一类噪声方差未知的随机系统,基于不同加权因子设计多个参数辨识器辨识模型参数,在此基础上,构成多模型自适应控制器.在每个采样时刻基于指标切换函数选择最佳辨识模型.并将基于此最佳模型设计的控制器切换为当前控制器.同时,证明了多个模型控制器之间相互切换时整个闭环系统是全局收敛的.仿真结果表明,同单一自适应模型控制器相比,这种基于多个不同加权因子的多模型自适应控制器在模型参数发生跳变时可很好地改善被控对象的控制品质.  相似文献   

15.
With widespread development of biometrics, concerns about security and privacy are rapidly increasing. Homomorphic encryption enables us to operate on encrypted data without decryption, and it can be applied to construct a privacy-preserving biometric system. In this article, we apply two homomorphic encryption schemes based on ideal-lattice and ring-LWE (Learning with Errors), which both have homomorphic correctness over the ring of integers of a cyclotomic field. We compare the two schemes in applying them to privacy-preserving biometrics. In biometrics, the Hamming distance is used as a metric to compare two biometric feature vectors for authentication. We propose an efficient method for secure Hamming distance. Our method can pack a biometric feature vector into a single ciphertext, and it enables efficient computation of secure Hamming distance over our packed ciphertexts.  相似文献   

16.
目的 针对仿射变换下形状匹配中存在的描述子对形状的描述能力不足,以及描述子计算耗时大的问题,改进基于所有图像点投影的方法,提出一种利用轮廓计算投影面积的仿射形状匹配算法。方法 该算法分为粗匹配和精匹配两个阶段。粗匹配阶段以CSS角点作为备选特征点,首先统计轮廓投影面积分布作为特征点描述子;然后利用动态规划蚁群算法匹配两幅图片公共特征点序列,并将匹配好的特征点序列记为对应的新特征点;最后采用该新特征点划分目标曲线,得到对应的轮廓曲线;这一阶段的目的是对形状的筛选以及寻找一致的轮廓特征点,同时完成轮廓曲线的划分。精匹配阶段,采用小波仿射不变描述子,对粗匹配阶段匹配代价最小的5%的目标进行对应曲线匹配,得到精匹配阶段的匹配代价,从而实现对仿射目标的识别;精匹配弥补了描述子对轮廓细节描述不足的问题。结果 算法的平均检索速度比传统基于形状投影分布描述子提高44.3%,在MPEG-7图像库上的检索效果为98.65%,在MPEG-7仿射图像库上的查准率与查全率综合评价指标比传统的基于形状投影分布描述子高3.1%,比形状上下文高25%。结论 本文算法匹配效果好,效率高,抗噪性强,解决了仿射描述子计算速度慢、描述能力不足的问题,能有效地应用于仿射形状匹配与检索领域。  相似文献   

17.
A parallel control system, consisting of a bank of concurrently running virtual control loops and a concurrency coordinator, is proposed for plants that operate in multiple, often radically different regimes. The virtual control loops acting in parallel and exchanging information among themselves, are coordinated to obtain good closed-loop performance in each operating regime, and bumpless transfer during transitions. The basic strategy, overall structure, and the individual elements of the parallel control system are discussed; the design, analysis, and performance are illustrated via simulation of a chemical reactor designed to manufacture a product in three different regimes.  相似文献   

18.
针对商业银行电子印鉴生成和识别所面临的问题,研究了融合多特征的电子印鉴加密技术。主要融合了对称密码算法、非对称密码算法、哈希函数等技术方法,分析了各种算法的优缺点,结合非对称密码算法和对称密码算法保证电子印鉴计算的安全,同时通过使用哈希函数和数字签名技术保证了所签电子印鉴的不可抵赖,实现了电子印鉴的生成和核验。并且结合实际系统进行了系统测试和压力测试,结果表明该技术具有较高的安全性和效率。  相似文献   

19.
This study develops a Web-based collaborative system framework based on a multiple perspective approach. This framework is a recent decision support system (DSS) paradigm proposed by Courtney [Decis. Support Syst. 31 (2001) 17] for knowledge management of and decision making about a special organizational problem. It consists of four main components. The first component is a group decision-making (GDM) approach in which many participants' points of views are considered in the modeling of a specific problem. In the second component, many multiple criteria decision-making (MCDM) techniques are employed. The third component is an intelligent system. The fourth component is related to advanced communications that are supported by new technologies such as mobile tools, mobile e-service, and the wireless application protocol (WAP). A new software system called InteliTeam is developed based on the framework. InteliTeam can be accessed from application service providers (ASP), so installation of the software is not required. The software provides online mapping, online queries, and online analysis functions for users anywhere at any time. An example of the software as tested on many organizational problems is presented to illustrate its effectiveness.  相似文献   

20.
An information retrieval system is proposed as an assistance tool for diagnosing the skin lesion using Content-Based Image Retrieval approach. Efficiency of the retrieval system is deliberated in terms of the most relevant retrieval of images from database. The proposed diagnostic assistive model retrieves the skin lesion images and its disease category, case history, symptoms and treatment plan. This retrieval process is made from a dermatology database by the way of visual features in the input image such as shape, texture and colour. The author’s proposed principal component analysis (PCA) feature projection technique is to discriminate the features by projecting them onto a feature subspace. While projecting the features onto a feature subspace features are normalised orthogonally. So the proposed methodology is used to improve the classification by the way of discriminate the features, in-turn it focus the retrieval of comprehensive reference sources, so that the diagnosis accuracy of the dermatologists are also improved. Receiver-operating characteristic curve is used to analyse the proposed computer-aided diagnosis (CAD) method, while analysis we attained high contribution to detect the skin lesions. Totally 1450 images are experimented and the system produced the 99.09% specificity, 96.69% sensitivity and 98.3% accuracy. When compared with other works this system of assessment shows high retrieval and diagnosis concert.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号