共查询到20条相似文献,搜索用时 78 毫秒
1.
Ching-Liang Su 《Expert systems with applications》2011,38(6):7195-7200
This study did not extract the characters in the car plate separately. Instead, a whole 2-D car plate was processed as an entity; subsequently, it was recognized. In this study a ring-to-line mapping technique is used to map a car plate image to several straight-line signals. Moreover, the vector magnitude invariant transform technique is used to transfer a car plate signal to an invariant vector magnitude for comparison, a procedure that can solve the image-rotation problem. Various vertical magnitude strips are generated to manage the image-shifting problem. The algorithm developed in this study can precisely identify car plate images. 相似文献
2.
A fast algorithm for computing moments of gray images based on NAM and extended shading approach 总被引:1,自引:0,他引:1
Computing moments on images is very important in the fields of image processing and pattern recognition. The non-symmetry
and anti-packing model (NAM) is a general pattern representation model that has been developed to help design some efficient
image representation methods. In this paper, inspired by the idea of computing moments based on the S-Tree coding (STC) representation
and by using the NAM and extended shading (NAMES) approach, we propose a fast algorithm for computing lower order moments
based on the NAMES representation, which takes O(N) time where N is the number of NAM blocks. By taking three idiomatic standard
gray images ‘Lena’, ‘F16’, and ‘Peppers’ in the field of image processing as typical test objects, and by comparing our proposed
algorithm with the conventional algorithm and the popular STC representation algorithm for computing the lower order moments,
the theoretical and experimental results presented in this paper show that the average execution time improvement ratios of
the proposed NAMES approach over the STC approach, and also the conventional approach are 26.63%, and 82.57% respectively
while maintaining the image quality. 相似文献
3.
4.
We show that vector space semantics and functional semantics in two-sorted first order logic are equivalent for pregroup grammars.
We present an algorithm that translates functional expressions to vector expressions and vice-versa. The semantics is compositional,
variable free and invariant under change of order or multiplicity. It includes the semantic vector models of Information Retrieval
Systems and has an interior logic admitting a comprehension schema. A sentence is true in the interior logic if and only if
the ‘usual’ first order formula translating the sentence holds. The examples include negation, universal quantifiers and relative
pronouns. 相似文献
5.
Anand Ramani 《Structural and Multidisciplinary Optimization》2010,41(6):913-934
An algorithm has been developed which uses material as a discrete variable in multi-material topology optimization and thus
provides an alternative to traditional methods using material interpolation and level-set approaches. The algorithm computes
‘pseudo-sensitivities’ of the objective and constraint functions to discrete material changes. These are used to rank elements,
based on which a fraction of elements are selected for material ID modification during the optimization iteration. The algorithm
is of general applicability and avoids frequent matrix factorizations so that it is applicable to large structural problems.
In addition to the conventionally used evolutionary and morphogenesis approaches for iteration, a new iteration scheme of
‘resubstitution’ which combines the two approaches is presented. The application and functioning of the algorithm is demonstrated
through case studies and comparisons with a few benchmark problems, showing its capability in providing mass-optimal topologies
under stiffness constraints for various structural problems where multiple materials are considered. 相似文献
6.
The 1-median problem on a network asks for a vertex minimizing the sum of the weighted shortest path distances from itself
to all other vertices, each associated with a certain positive weight. We allow fornegative weights as well and devise an exact algorithm for the resulting ‘pos/neg-weighted’ problem defined on a cactus. The algorithm
visits every vertex just once and runs thus in linear time.
This research has been supported by the Spezialforschungsbereich F 003 ‘Optimierung und Kontrolle’, Projektbereich Diskrete
Optimierung. 相似文献
7.
We present a novel approach to the robust classification of arbitrary object classes in complex, natural scenes. Starting
from a re-appraisal of Marr's ‘primal sketch’, we develop an algorithm that (1) employs local orientations as the fundamental
picture primitives, rather than the more usual edge locations, (2) retains and exploits the local spatial arrangement of features
of different complexity in an image and (3) is hierarchically arranged so that the level of feature abstraction increases
at each processing stage. The resulting, simple technique is based on the accumulation of evidence in binary channels, followed
by a weighted, non-linear sum of the evidence accumulators. The steps involved in designing a template for recognizing a simple
object are explained. The practical application of the algorithm is illustrated, with examples taken from a broad range of
object classification problems. We discuss the performance of the algorithm and describe a hardware implementation. First
successful attempts to train the algorithm, automatically, are presented. Finally, we compare our algorithm with other object
classification algorithms described in the literature. 相似文献
8.
Gloria Haro Marcelo Bertalmío Vicent Caselles 《International Journal of Computer Vision》2006,69(1):109-117
In film production, it is sometimes not convenient or directly impossible to shoot some night scenes at night. The film budget,
schedule or location may not allow it. In these cases, the scenes are shot at daytime, and the ‘night look’ is achieved by
placing a blue filter in front of the lens and under-exposing the film. This technique, that the American film industry has
used for many decades, is called ‘Day for Night’ (or ‘American Night’ in Europe.) But the images thus obtained don’t usually
look realistic: they tend to be too bluish, and the objects’ brightness seems unnatural for night-light. In this article we
introduce a digital Day for Night algorithm that achieves very realistic results. We use a set of very simple equations, based
on real physical data and visual perception experimental data. To simulate the loss of visual acuity we introduce a novel
diffusion Partial Differential Equation (PDE) which takes luminance into account and respects contrast, produces no ringing,
is stable, very easy to implement and fast. The user only provides the original day image and the desired level of darkness
of the result. The whole process from original day image to final night image is implemented in a few seconds, computations
being mostly local. 相似文献
9.
Todd Zickler Satya P. Mallick David J. Kriegman Peter N. Belhumeur 《International Journal of Computer Vision》2008,79(1):13-30
Complex reflectance phenomena such as specular reflections confound many vision problems since they produce image ‘features’
that do not correspond directly to intrinsic surface properties such as shape and spectral reflectance. A common approach
to mitigate these effects is to explore functions of an image that are invariant to these photometric events. In this paper
we describe a class of such invariants that result from exploiting color information in images of dichromatic surfaces. These
invariants are derived from illuminant-dependent ‘subspaces’ of RGB color space, and they enable the application of Lambertian-based
vision techniques to a broad class of specular, non-Lambertian scenes. Using implementations of recent algorithms taken from
the literature, we demonstrate the practical utility of these invariants for a wide variety of applications, including stereo,
shape from shading, photometric stereo, material-based segmentation, and motion estimation. 相似文献
10.
J. G. Keller S. K. Rogers M. Kabrisky M. E. Oxley 《Pattern Analysis & Applications》1999,2(3):251-263
The automated recognition of targets in complex backgrounds is a difficult problem, yet humans perform such tasks with ease.
We therefore propose a recognition model based on behavioural and physiological aspects of the human visual system. Emulating
saccadic behaviour, an object is first memorised as a sequence of fixations. At each fixation an artificial visual field is
constructed using a multi-resolution/ orientation Gabor filterbank, edge features are extracted, and a new saccadic location
is automatically selected. When a new image is scanned and a ‘familiar’ field of view encountered, the memorised saccadic
sequence is executed over the new image. If the expected visual field is found around each fixation point, the memorised object
is recognised. Results are presented from trials in which individual objects were first memorised and then searched for in
collages of similar objects acting as distractors. In the different collages, entries of the memorised objects were subjected
to various combinations of rotation, translation and noise corruption. The model successfully detected the memorised object
in over 93% of the ‘object present’ trials, and correctly rejected collages in over 98% of the trials in which the object
was not present in the collage. These results are compared with those obtained using a correlation-based recogniser, and the
behavioural model is found to provide superior performance.
Received: 15 July 1998?Received in revised form: 24 December 1998?Accepted: 9 February 1999 相似文献
11.
By using the concept of generating function associated with a Toeplitz matrix, we analyze existence conditions for the probability
invariant vector π of certain stochastic semi-infinite Toeplitz-like matrices. An application to the shortest queue problem
is shown. By exploiting the functional formulation given in terms of generating functions, we devise a weakly numerically
stable algorithm for computing the probability invariant vector π. The algorithm is divided into three stages. At the first
stage the zeros of a complex function are numerically computed by means of an extension of the Aberth method. At the second
stage the first k components of π are computed by solving an interpolation problem, where k is a suitable constant associated
with the matrix. Finally, at the third stage a triangular Toeplitz system is solved and its solution is refined by applying
the power method or any other refinement method based on regular splittings. In the solution of the triangular Toeplitz system
and at each step of the refinement method, special FFT-based techniques are applied in order to keep the arithmetic cost within
the O(n log n) bound, where n is an upper bound to the number of the computed components. Numerical comparisons with the available
algorithms show the effectiveness of our algorithm in a wide set of cases. 相似文献
12.
Stefan Klink Thomas Kieninger 《International Journal on Document Analysis and Recognition》2001,4(1):18-26
Document image processing is a crucial process in office automation and begins at the ‘OCR’ phase with difficulties in document
‘analysis’ and ‘understanding’. This paper presents a hybrid and comprehensive approach to document structure analysis. Hybrid
in the sense that it makes use of layout (geometrical) as well as textual features of a given document. These features are
the base for potential conditions which in turn are used to express fuzzy matched rules of an underlying rule base. Rules
can be formulated based on features which might be observed within one specific layout object. However, rules can also express
dependencies between different layout objects. In addition to its rule driven analysis, which allows an easy adaptation to
specific domains with their specific logical objects, the system contains domain-independent markup algorithms for common
objects (e.g., lists).
Received June 19, 2000 / Revised November 8, 2000 相似文献
13.
杨杰 《计算机科学技术学报》2002,17(2):0-0
The fast computation of Zernike moments from normalized gometric moments has been developed in this paper,The computation is multiplication free and only additions are needed to generate Zernike moments .Geometric moments are generated using Hataming‘s filter up to high orders by a very simple and straightforward computaion scheme.Other kings of monents(e.g.,Legendre,pseudo Zernike)can be computed using the same algorithm after giving the proper transformaitons that state their relations to geometric moments.Proper normaliztions of geometric moments are necessary so that the method can be used in the efficient computation of Zernike moments.To ensure fair comparisons,recursive algorithms are used to generate Zernike polynoials and other coefficients.The computaional complexity model and test programs show that the speed-up factor of the proposed algorithm is superior with respect ot other fast and /or direct computations It perhaps is the first time that Zernike moments can be computed in real time rates,which encourages the use of Zernike moment features in different image retrieval systems that support huge databases such as the XM experimental model stated for the MPEG-7 experimental core.It is concluded that choosing direct copmutation would be impractical. 相似文献
14.
Miklós Erdélyi-Szabó László Kálmán Agi Kurucz 《Journal of Logic, Language and Information》2008,17(1):1-17
The paper sets out to offer an alternative to the function/argument approach to the most essential aspects of natural language
meanings. That is, we question the assumption that semantic completeness (of, e.g., propositions) or incompleteness (of, e.g.,
predicates) exactly replicate the corresponding grammatical concepts (of, e.g., sentences and verbs, respectively). We argue
that even if one gives up this assumption, it is still possible to keep the compositionality of the semantic interpretation
of simple predicate/argument structures. In our opinion, compositionality presupposes that we are able to compare arbitrary
meanings in term of information content. This is why our proposal relies on an ‘intrinsically’ type free algebraic semantic
theory. The basic entities in our models are neither individuals, nor eventualities, nor their properties, but ‘pieces of
evidence’ for believing in the ‘truth’ or ‘existence’ or ‘identity’ of any kind of phenomenon. Our formal language contains
a single binary non-associative constructor used for creating structured complex terms representing arbitrary phenomena. We
give a finite Hilbert-style axiomatisation and a decision algorithm for the entailment problem of the suggested system. 相似文献
15.
Kernel Nearest-Neighbor Algorithm 总被引:2,自引:0,他引:2
The ‘kernel approach’ has attracted great attention with the development of support vector machine (SVM) and has been studied
in a general way. It offers an alternative solution to increase the computational power of linear learning machines by mapping
data into a high dimensional feature space. This ‘approach’ is extended to the well-known nearest-neighbor algorithm in this
paper. It can be realized by substitution of a kernel distance metric for the original one in Hilbert space, and the corresponding
algorithm is called kernel nearest-neighbor algorithm. Three data sets, an artificial data set, BUPA liver disorders database
and USPS database, were used for testing. Kernel nearest-neighbor algorithm was compared with conventional nearest-neighbor
algorithm and SVM Experiments show that kernel nearest-neighbor algorithm is more powerful than conventional nearest-neighbor
algorithm, and it can compete with SVM.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
16.
An algorithm for solving optimal active vibration control problems by the finite element method (FEM) is presented. The optimality
equations for the problem are derived from Pontryagin’s principle in the form of a set of the fourth order ordinary differential
equations that, together with the initial and final boundary conditions, constitute the boundary value problem in the time
domain, which in control is referred to as a two-point-boundary-value problem. These equations decouple in the modal space
and can be solved by the FEM technique. An analogy between the optimality equations and the governing equations for a set
of certain static beams permits obtaining numerical solutions to the optimal control problem with the help of standard ‘structural’
FEM software. The optimal action of actuators is automatically calculated by applying the independent modal space control
concept. The structure’s response to actuation forces is also determined and can independently be verified for spillover effects.
As an illustration, the algorithm is used for the analysis of optimal action of actuators to attenuate vibrations of an elastic
fin. 相似文献
17.
Ho-Quoc-Phuong Nguyen Hee-Jun Kang Young-Soo Suh 《International Journal of Control, Automation and Systems》2011,9(2):317-327
This paper introduces a robot visual-inertial tracking algorithm for a robot manipulator intended to track an object using
inertial sensors incorporated into the object. To create this algorithm, the inertial Jacobian is first newly defined in order
to show the relationship between an angle set velocity vector of the object and the angular velocity vector of the robot tip.
Then, the inertial Jacobian is combined with the conventional image Jacobian. Therefore, the proposed algorithm requires only
two landmarks with the help of an inertial measurement unit to track a moving object with six degrees of freedom, while at
least three landmarks are required in the conventional stereo visual servoing algorithm. Further, the possession of a multi-rate
controller allows the integration system to out-perform conventional systems in the tracking of an object’s attitude change.
A suggested application of the proposed method is tracking and selection of a container from a shipping vessel that is being
affected by large waves. Simulations and experiments were conducted to verify the feasibility of the proposed methodology. 相似文献
18.
Stefan Raiser Edwin Lughofer Christian Eitzinger James Edward Smith 《Machine Vision and Applications》2010,21(5):627-641
In surface inspection applications, the main goal is to detect all areas which might contain defects or unacceptable imperfections,
and to classify either every single ‘suspicious’ region or the investigated part as a whole. After an image is acquired by
the machine vision hardware, all pixels that deviate from a pre-defined ‘ideal’ master image are set to a non-zero value,
depending on the magnitude of deviation. This procedure leads to so-called “contrast images”, in which accumulations of bright
pixels may appear, representing potentially defective areas. In this paper, various methods are presented for grouping these
bright pixels together into meaningful objects, ranging from classical image processing techniques to machine-learning-based
clustering approaches. One important issue here is to find reasonable groupings even for non-connected and widespread objects.
In general, these objects correspond either to real faults or to pseudo-errors that do not affect the surface quality at all.
The impact of different extraction methods on the accuracy of image classifiers will be studied. The classifiers are trained
with feature vectors calculated for the extracted objects found in images labeled by the user and showing surfaces of production
items. In our investigation artificially created contrast images will be considered as well as real ones recorded on-line
at a CD imprint production and at an egg inspection system. 相似文献
19.
Summary The informational divergence between stochastic matrices is not a metric. In this paper we show that, however, consistent
definitions can be given of ‘spheres’, ‘segments’ and ‘straight lines’ using the divergence as a sort of ‘distance’ between
stochastic matrices. The geometric nature of many ‘reliability functions’ of Information Theory and Mathematical Statistics
is thus clarified.
This work has been done within the GNIM-CNR research activity. 相似文献
20.
小波变换的多分辨率特征使其在计算机视觉中得到广泛的应用,在形状匹配中,小波变换对起始点的依赖制约了小波变换的应用。为了克服小波变换对起始点的依赖,引入Zernike矩,提出一种起始点无关的小波系数形状匹配算法。对输入图像进行预处理后提取目标轮廓,生成具有平移、尺度不变的形状链状表达,并通过小波变换进行多尺度分析。最后计算各个尺度下的各阶Zernike矩,来解决小波变换的起始点问题,实现形状表达的旋转不变性。实验结果表明该算法适用于轮廓较明显的目标,同时具有速度快、精度高、鲁棒性强的优点。 相似文献