Voronoi Diagrams

Suppose we have a finite number of distinct points in the plane. We refer to these points as sites. We wish to partition the plane into disjoint regions called cells, each of which contains exactly one site, so that all other points within a cell are closer to that cell\u27s site than to any other site

A Work Efficient Parallel Algorithm for Exact Euclidean Distance Transform

A fully-parallelized work-time optimal algorithm is presented for computing the exact Euclidean Distance Transform (EDT) of a 2D binary image with the size of n x n. Unlike existing PRAM and other algorithms, this algorithm is suitable for implementation on modern SIMD architectures such as GPUs. As a fundamental operation of 2D EDT, 1D EDT is efficiently parallelized first. Specifically, the GPU algorithm for the 1D EDT, which uses CUDA binary functions such as ballot(), ffs(), clz() and shfl(), runs in O(log_32n) time and performs O(n) work. Using the 1D EDT as a fundamental operation, the fully parallelized work-time optimal 2D EDT algorithm is designed. This algorithm consists of three steps. Step 1 of the algorithm runs in O(log_32n) time and performs O(N) (N=n^2) of total work on GPU. Step 2 performs O(N) of total work and has an expected time complexity of O(logn) on GPU. Step 3 runs in O(log_32n) time and performs O(N) of total work on GPU. As far as we know, this algorithm is the first fully-parallelized and realized work-time optimal algorithm for GPUs. Experimental results show that this algorithm outperforms prior state-of-the-art GPU algorithms

Palmprint identification using Log Transformation of Transform Domain Features

The Palmprint is an efficient physiological biometric trait to identify a person. In this paper we propose Palmprint Identification using Log Transformation of Transform Domain Features. The Region of Interest (ROI) of palmprint image is extracted using preprocessing. The KWT and DWT are applied on preprocessed image to generate features. The KWT and DWT features of test image and database images are compared using Euclidian distance to compute EER and TSR values. The EER and TSR values of KWT and DWT are fused using Log Transformation to get better performance parameters. It is observed that the values of performance parameters are better in the case of proposed algorithm compared to existing algorithms

Clustering uncertain data using voronoi diagrams and R-tree index

We study the problem of clustering uncertain objects whose locations are described by probability density functions (pdfs). We show that the UK-means algorithm, which generalizes the k-means algorithm to handle uncertain objects, is very inefficient. The inefficiency comes from the fact that UK-means computes expected distances (EDs) between objects and cluster representatives. For arbitrary pdfs, expected distances are computed by numerical integrations, which are costly operations. We propose pruning techniques that are based on Voronoi diagrams to reduce the number of expected distance calculations. These techniques are analytically proven to be more effective than the basic bounding-box-based technique previously known in the literature. We then introduce an R-tree index to organize the uncertain objects so as to reduce pruning overheads. We conduct experiments to evaluate the effectiveness of our novel techniques. We show that our techniques are additive and, when used in combination, significantly outperform previously known methods. © 2006 IEEE.published_or_final_versio

Recognition of Electrical & Electronics Components

Recognition or more specifically Pattern or Object recognition is a typical characteristic of human beings and other living organisms. The term pattern or object means something that is set as an idea to be imitated. For example, in our childhood a shape ‘A’ is shown to us and we are asked to imitate that. So the shape is the ideal one. On the other hand, if what we produce or draw obeying that instruction is close to that shape, our teacher identifies that as ’A’. this identification is called recognition and the shapes we draw (that is object we made) may be termed as patterns. Thus, the pattern recognition means identification of the real object. Recognition should, therefore, be preceded by the development of the concept of the ideal or model or prototype. This process is called Learning. In most real life problems no ideal example is available. In that case, the concept of ideal is abstracted from many near perfect examples. Under this notion learning is of two types : supervised learning if appropriate label is attached to each of these examples ; and unsupervised learning if no labeling is available

An elementary algorithm for digital arc segmentation

International audienceThis paper concerns the digital circle recognition problem, especially in the form of the circular separation problem. General fundamentals, based on classical tools, as well as algorithmic details are given (the latter by providing pseudo-code for major steps of the algorithm). After recalling the geometrical meaning of the separating circle problem, we present an incremental algorithm to segment a discrete curve into digital arcs

Optimal Separable Algorithms to Compute the Reverse Euclidean Distance Transformation and Discrete Medial Axis in Arbitrary Dimension

In binary images, the distance transformation (DT) and the geometrical skeleton extraction are classic tools for shape analysis. In this paper, we present time optimal algorithms to solve the reverse Euclidean distance transformation and the reversible medial axis extraction problems for $d$-dimensional images. We also present a $d$-dimensional medial axis filtering process that allows us to control the quality of the reconstructed shape