chain codes are the most size-efficient representations of rasterised binary shapes and contours. This paper considers a new lossless chain code compression method based on move-to-front transform and an adaptive run-...
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chain codes are the most size-efficient representations of rasterised binary shapes and contours. This paper considers a new lossless chain code compression method based on move-to-front transform and an adaptive run-length encoding. The former reduces the information entropy of the chain code, whilst the latter compresses the entropy-reduced chain code by coding the repetitions of chain code symbols and their combinations using a variable-length model. In comparison to other state-of-the-art compression methods, the entropy-reduction is highly efficient, and the newly proposed method yields, on average, better compression. (C) 2013 Elsevier B.V. All rights reserved.
It is undecidable whether or not two I-retreat-bounded regular languages describe exactly the same set of pictures or they describe a picture in common. (C) 2002 Elsevier Science B.V. All rights reserved.
It is undecidable whether or not two I-retreat-bounded regular languages describe exactly the same set of pictures or they describe a picture in common. (C) 2002 Elsevier Science B.V. All rights reserved.
The registration of the infrared (IR) image and the low-light-level (LLL) image remains a challenging problem due to poor dispersion of feature points, low correlation of structure and texture information. In this pap...
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The registration of the infrared (IR) image and the low-light-level (LLL) image remains a challenging problem due to poor dispersion of feature points, low correlation of structure and texture information. In this paper, we propose a method based on neighbourhood difference chain code to address the challenge. First we extracted the feature points of the images with the binary eight or sixteen-neighborhood information. And then construct the descriptor of the feature point by neighborhood difference chain code. At last we use the Euclidean distance to match the feature points. We adopt TNO and INO data sets to verify our method, and by comparing with four objective evaluation parameters obtained by other three methods. The result demonstrated that the proposed algorithm performs competitively, compared to the state-of-arts such as Harris, SIFT and SURF, in terms of accuracy of registration and speed.
This paper presents a new chain code based on the eight-direction Freeman code. Each element in the chain is coded as a relative angle difference between it and the previous element. Statistical analysis showed that t...
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This paper presents a new chain code based on the eight-direction Freeman code. Each element in the chain is coded as a relative angle difference between it and the previous element. Statistical analysis showed that the probabilities of the Freeman codes differ importantly. Therefore, the Huffman coding was applied. The proposed chain code requires 1.97 bits/code, its chain length is short, it allows the representation of non-closed patterns and it is rotationally independent. (C) 2004 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.
This work aims to obtain a sequence of 3D point clouds associated with a 3D object that reduces the volume data and preserves the shape of the original object. The sequence contains point clouds that give different si...
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This work aims to obtain a sequence of 3D point clouds associated with a 3D object that reduces the volume data and preserves the shape of the original object. The sequence contains point clouds that give different simplifications of the object, from a very fine-tuned representation to a simple and sparse one. Such a sequence is important because it satisfies different needs, from a faithful representation with a low reduction of points to a significant data reduction that only preserves the main properties of the object. We construct the sequence in the following way. We first obtain a voxelization of the original 3D object. Then, we organize the voxels by slices to get a single chain code that represents the original 3D object. The point clouds depend on the key points of the chain code. The Hausdorff distance and the average geometric error prove that the point clouds are invariant under rigid rotations and maintain the shape of the object. Our results indicate that the proposed method has an average efficiency of 60% regarding the state-of-the-art simplification methods.
An efficient contour-based method for the coding of binary shape information is described. Conventional chain coding techniques show high coding efficiency for lossless compression, but they exploit the coherence of t...
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An efficient contour-based method for the coding of binary shape information is described. Conventional chain coding techniques show high coding efficiency for lossless compression, but they exploit the coherence of the contour in only a restricted manner. Higher coding efficiency can be achieved by realising the neighbourhood relation as a Markov chain, and this is exploited in a new coding scheme, the directional grid chain coding (DGCC). The method is computationally efficient and the coding process adapts to the inherent changes in the contour. Two schemes are proposed, a lossless and a quasi-lossless method. The lossless scheme achieves 32% saving in bit rate compared with the conventional differential chain code (DCC). The second, quasi-lossless technique achieves 44% bit reduction compared with the DCC and the distortions present in the reconstructed contour are hardly noticeable to the human eye. (c) 2007 Elsevier B.V. All rights reserved.
Local descriptors are widely used technique of feature extraction to obtain information about both local and global properties of an object. Here, we discuss an application of the chain code-Based Local Descriptor to ...
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Local descriptors are widely used technique of feature extraction to obtain information about both local and global properties of an object. Here, we discuss an application of the chain code-Based Local Descriptor to face recognition by focusing on various datasets and considering different variants of this description method. We augment the generic form of the descriptor by adding a possibility of grouping pixels into blocks, i.e., effectively describing larger neighborhoods. The results of experiments show the efficiency of the approach. We demonstrate that the obtained results are comparable or even better than those delivered by other important algorithms in the class of methods based on the Bag-of-Visual-Words paradigm.
The accelerated developments in technology led to a tremendous increase in the volumes of data to be transferred and exchanged between various network channels. These advancements create a huge demand for researchers ...
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The accelerated developments in technology led to a tremendous increase in the volumes of data to be transferred and exchanged between various network channels. These advancements create a huge demand for researchers to investigate new data compression techniques. Recent evidence from the literature shows that agent-based modeling is a promising direction to reduce the size of the data and change its original representation. In this article, the objective is to build an agent-based modeling simulation for chain coding and take advantage of it in data compression. Our agent-based model is inspired by the concept of defended territories of biological beavers. To this end, we use the pixel distribution in a bi-level image to construct a virtual environment of agents, add the beavers, and build territories around them. The main idea of defended beaver territories is to allow each beaver to maintain its area and protects it from intruders. To put it another way, defended territories allow beavers to work on different parts of an image while the algorithm tracks and records their movements, as well as manages disputes between them. Our research findings represent a further step towards employing the generated codes of movements in image processing operations other than coding and compression. Additionally, the experimental results showed that the current model was prosperous, and it could outperform many existing image compression techniques, including JBIG family methods. What's more, paired-samples t-tests reveal that the mean differences between the outcomes of the current approach and each of the other standardized benchmarks we employed in comparison are statistically significant. (C) 2020 Elsevier B.V. All rights reserved.
A new algorithm is proposed to detect a corner of a thinned binary image that is represented by an eight-connected contour chain code. The algorithm is based on chain-coded image, deriving the slope between each code,...
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A new algorithm is proposed to detect a corner of a thinned binary image that is represented by an eight-connected contour chain code. The algorithm is based on chain-coded image, deriving the slope between each code, analyze the series of chain code, and finally decide the existence of corner at the Current pixel location. The work assumes that the pre-processing processes on the image, namely thinning and digitization, have been done. Two weighted parameters identified as significant factors in determining the accuracy of the corner detection algorithm are discussed. The parameters are the length of segment and threshold value. Computational phases to derive values of rows and columns given a series of chain code are also given in detail. The algorithm can be used to interpret line drawing that represents three-dimensional object.
This paper addresses parallel execution of chain code generation on a linear array architecture. The contours in the proposed algorithm are viewed as a set of edges (or contour segments) that can be traced by a top-do...
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This paper addresses parallel execution of chain code generation on a linear array architecture. The contours in the proposed algorithm are viewed as a set of edges (or contour segments) that can be traced by a top-down contour tracing method to generate the chain codes for the outer and inner object contours. A parallel algorithm that contains the chain code generating rules and operations needed is also described, and the algorithm is mapped onto a one-dimensional systolic array containing [(1)/(2)(N + 1)] processing elements (PEs) to devise this architecture. The architecture extracts the contours of objects and quickly generates the corresponding chain codes after the image data in all rows are inputted in a linear fashion. The total processing time for generating the chain codes in an N x N image is O(3N). By doing so, the real-time requirement is fulfilled and its execution time is independent of the image content. In addition, a partition method is developed to process an image when the parallel architecture has a fixed number of PEs;say two or more. The total execution time for an N x N image by employing a fixed number of PEs is N(N + 1)/M + 2(M - 1), when M is the fixed number of PEs. (C) 2002 Elsevier Science Inc. All rights reserved.
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