Topic
Centroid
About: Centroid is a research topic. Over the lifetime, 4110 publications have been published within this topic receiving 53637 citations. The topic is also known as: barycenter (geometry) & geometric center of a plane figure.
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01 Jan 2014TL;DR: A novel algorithm for extracting sharp features automatically from scanned 3D data of man-made CAD-like objects by applying Otsu's method to the histogram of the projected distances to select the optimal threshold value, which is used to detect potential sharp features at a single scale.
Abstract: A novel algorithm is proposed for extracting sharp features automatically from scanned 3D data of man-made CAD-like objects. The input of our method consists of a mesh or an unstructured point cloud that is captured on the object surface. First, the vector between a given point and the centroid of its neighborhood at a given scale is projected on the normal vector and called the ‘projected distance’ at this point. This projected distance is calculated for every data point. In a second stage, Otsu's method is applied to the histogram of the projected distances in order to select the optimal threshold value, which is used to detect potential sharp features at a single scale. These two stages are applied iteratively with the other incremental scales. Finally, points recorded as potential features at every scale are marked as valid sharp features. The method has many advantages over existing methods such as intrinsic simplicity, automatic selection of threshold value, accurate and robust detection of sharp features on various objects. To demonstrate the robustness of the method, it is applied on both synthetic and real 3D data of point clouds and meshes with different noise levels.
11 citations
TL;DR: In this paper, a real-time VLSI optical centroid processor has been developed as part of a larger Shack-Hartmann wavefront sensor system for applications in adaptive optics.
Abstract: A real-time VLSI optical centroid processor has been developed as part of a larger Shack-Hartmann wavefront sensor system for applications in adaptive optics. The implementation of the optical centroid detection system was demonstrated successfully using a hardware emulation system. Subsequently, the design has been implemented as a CMOS single-chip solution. This has advantages in terms of speed, power consumption, system size, and cost. The design of the different components of the system will be discussed along with test results of the fabricated device.
11 citations
TL;DR: A robust non-rigid feature matching approach for image registration with geometry constraints is proposed and demonstrates that the proposed approach has better performance than current state-of-the-art methods.
Abstract: In this paper, a robust non-rigid feature matching approach for image registration with geometry constraints is proposed. The non-rigid feature matching approach is formulated as a maximum likelihood (ML) estimation problem. The feature points of one image are represented by Gaussian mixture model (GMM) centroids, and are fitted to the feature points of the other image by moving coherently to encode the global structure. To preserve the local geometry of these feature points, two local structure descriptors of the connectivity matrix and Laplacian coordinate are constructed. The expectation maximization (EM) algorithm is applied to solve this ML problem. Experimental results demonstrate that the proposed approach has better performance than current state-of-the-art methods.
11 citations
TL;DR: In this article, feature extraction techniques are developed for two-dimensional binary images of ice particles and raindrops for statistical classification of these patterns into one of seven basic hydrometeor shapes.
Abstract: New feature extraction techniques are developed for two-dimensional binary images of ice particles and raindrops. These features are employed in the statistical classification of these patterns into one of seven basic hydrometeor shapes. These images have been recorded by an airborne two-dimensional probe in order to provide information leading to an understanding of important physical processes in clouds. Minimum average probability of classification error is employed as the performance criterion with informal minimization of computing time. A synthetic image set was generated to develop feature extraction techniques. Moment normalization and rotation normalization are employed to convert all images to a common size and orientation. Ten time domain features are explored including a new development (circular deficiency) and a new application (cross correlation). Three frequency domain features are investigated including a new Fourier descriptor (centroid distance). An original method of reducing ...
11 citations
04 Sep 2002
TL;DR: The relationship between the focal spot location and the center of mass is discussed in detail and a mathematical analysis and a few practical ideas are concluded to improve the accuracy of the Center of mass technique.
Abstract: In general the center of mass technique is a fast and robust way to approximate the location of a focal spot. This paper discusses in detail the relationship between the focal spot location and the center of mass. We start with a mathematical analysis and conclude with a few practical ideas to improve the accuracy of the center of mass technique.
11 citations