A direct approach for parametric estimation of 2D affine deformations between compound shapes is proposed. It provides the result as a least-square solution of a linear system of equations. The basic idea is to fit Ga...
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ISBN:
(纸本)9781424456536;9781424456543
A direct approach for parametric estimation of 2D affine deformations between compound shapes is proposed. It provides the result as a least-square solution of a linear system of equations. The basic idea is to fit Gaussian densities over the objects yielding covariant functions, which preserves the effect of the unknown transformation. Based on these functions, linear equations are constructed by integrating nonlinear functions over appropriate domains. The main advantages are: linear complexity, easy implementation, works without any time consuming optimization or established correspondences. Comparative tests show that it outperforms state-of-the-art methods both in terms of precision, robustness and complexity.
Skeletons are widely used shape descriptors which summarize the general form of binary objects. A technique to obtain skeletons is the thinning, that is an iterative layer-by-layer erosion in a topology-preserving way...
Skeletons are widely used shape descriptors which summarize the general form of binary objects. A technique to obtain skeletons is the thinning, that is an iterative layer-by-layer erosion in a topology-preserving way. Conventional thinning algorithms preserve line endpoints to provide important geometric information relative to the object to be represented. Bertrand and Couprie proposed an alternative strategy by accumulating isthmus points that are line interior points. In this paper we present six new 2D parallel thinning algorithms that are derived from some sufficient conditions for topology preserving reductions and based on isthmus-preservation.
There are three possible partitionings of the continuous plane into regular polygons that leads to triangular, square, and hexagonal grids. The topology of the square grid is fairly well-understood, but it cannot be s...
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There are three possible partitionings of the continuous plane into regular polygons that leads to triangular, square, and hexagonal grids. The topology of the square grid is fairly well-understood, but it cannot be said of the remaining two regular sampling schemes. This paper presents a general characterization of simple pixels and some simplified sufficient conditions for topology-preserving operators in all the three types of regular grids.
The problem of simultaneously estimating affine deformations between multiple objects occur in many applications. Herein, a direct method is proposed which provides the result as a solution of a linear system of equat...
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The problem of simultaneously estimating affine deformations between multiple objects occur in many applications. Herein, a direct method is proposed which provides the result as a solution of a linear system of equations without establishing correspondences between the objects. The key idea is to construct enough linearly independent equations using covariant functions, and then finding the solution simultaneously for all affine transformations. Quantitative evaluation confirms the performance of the method.
With the development of the advanced printer and scanner, it is easy to transform images between the digital format and the printed. So, the digital watermarking algorithm resilient to the print and scan operation is ...
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With the development of the advanced printer and scanner, it is easy to transform images between the digital format and the printed. So, the digital watermarking algorithm resilient to the print and scan operation is necessary. In this paper, we analyze a watermark software product which could resist print-scan attack. Using original images and watermarked images , the principle of the watermark software can be estimated, that is : first add yellow borders to the original images , then separately process R,G,B components of color images: segment the images into blocks with 16*16 size, and take discrete cosine transform (DCT) to every sub-block. Finally, embed watermarking to images through modifying the intermediate frequency coefficients of sub-block. After learning the algorithm theory, it is easy to copy a watermarking to another image. Experimental results show that the algorithm is effective.
In this paper, we present the modeling schemes of a class of Bézier surface with negative Gaussian curvature over the rectangular domain and the triangular domain. We have proved that the surface over the rectang...
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In this paper, we present the modeling schemes of a class of Bézier surface with negative Gaussian curvature over the rectangular domain and the triangular domain. We have proved that the surface over the rectangular domain is fully determined by the control points of the two opposed boundary curves, and the surface over the triangular domain is fully determined by the control points on the first and second layers. In particular, we can control the shape of the surface by the shape parameter, which increases the degree of freedom of surface modeling.
The reconstruction of binary images from their projections is an important problem in discrete tomography. The main challenge in this task is that in certain cases the projections do not uniquely determine the binary ...
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ISBN:
(纸本)9789531841160;9531841160
The reconstruction of binary images from their projections is an important problem in discrete tomography. The main challenge in this task is that in certain cases the projections do not uniquely determine the binary image. This can yield an extremely large number of (sometimes very different) solutions. Moreover, under certain circumstances the reconstruction becomes NP-hard. A commonly used technique to reduce ambiguity and to avoid intractability is to suppose that the image to be reconstructed arises from a certain class of images having some geometrical properties. This paper studies the reconstruction problem in the class of hv-convex images having their components in so-called decomposable configurations. First, we give a negative result showing that there can be exponentially many images of the above class having the same three projections. Then, we present a heuristic that uses four projections to reconstruct an hv-convex image with decomposable configuration. We also analyze the performance of our heuristic from the viewpoints of accuracy and running time.
Barcode detection is required in a wide range of real-life applications. Imaging conditions and techniques vary considerably and each application has its own requirements for detection speed and accuracy. In our earli...
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Barcode detection is required in a wide range of real-life applications. Imaging conditions and techniques vary considerably and each application has its own requirements for detection speed and accuracy. In our earlier works we built barcode detectors using morphological operations and uniform partitioning with several approaches and showed their behaviour on a set of test images. In this work, we examine ensemble efficiency of those simple detectors using various aggregation methods. Using a combination of several simple features localization performance improves significantly.
Traditional paper maps display information following the well-known rules based on experiences gathered during centuries. Nowadays, more and more geospatial information is represented in digital form and we have to fa...
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Traditional paper maps display information following the well-known rules based on experiences gathered during centuries. Nowadays, more and more geospatial information is represented in digital form and we have to face new challenges when trying to find the best solution for the geovisualization. The Hungarian Digital Toponym Registry is developed due to a cross-discipliner collaboration to store, manage, analyze and visualize toponyms. This paper presents some issues concerning the geovisualization with some comments about their cognitive aspects.
A big part of data around us is in image format and people use these images in many of their decisions. The popularity of an item, in many cases, depends highly on its visual quality. For instance, the shape of a car ...
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A big part of data around us is in image format and people use these images in many of their decisions. The popularity of an item, in many cases, depends highly on its visual quality. For instance, the shape of a car has a significant influence on the attitude of potential customers toward it. Recommender systems try to provide people with recommendations resulted from an automatic process which is aimed at giving the users a better experience working with system, and perhaps improve the system owner's sales. As images are quite important in users' decisions, in this paper we have proposed a method to take images into account when trying to give the user a recommendation, which despite its apparent advantages has not found a fair amount of attention so far.
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