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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.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigated the position centroid rendezvous/formation problems of multiple unicycle agents for the first time, and proposed a new output to convert the unicycle model to canonical normal form via feedback linearization approach.
Abstract: This work investigates the position centroid rendezvous/formation problems of multiple unicycle agents for the first time. By constructing a new output, the unicycle model is converted to canonical normal form via feedback linearisation approach. Then, we propose the centroid rendezvous and the centroid formation control laws, respectively, guaranteeing that all the agents globally meet at the common initial centroid location and the desired geometric pattern centred at the initial centroid. The proposed control laws are distributed, smooth and time-varying, ensuring the internal orientation states and the velocity inputs convergent to some fixed values and zero, respectively. All the results are proved under the communication scenarios of fixed directed balanced graph with a spanning tree. Simulation results verify the effectiveness and the robustness of the proposed control schemes.

22 citations

Journal ArticleDOI
18 Oct 2018-Sensors
TL;DR: The experimental results prove that the proposed method can significantly improve the measurement accuracy of free-form curved surfaces using LT and that the improved laser spot center extraction algorithm is more suitable for free- form curved surfaces with smaller curvature and more uniform curvature changes.
Abstract: Laser triangulation (LT) is widely used in many fields due to its good stability, high resolution and fast speed. However, the accuracy in these applications suffers from severe constraints on the data acquisition accuracy of LT. To solve this problem, the optical triangulation principle, the object equation of the optical path relationship and the deviation of the laser spot centroid are applied to deduce a mathematical model. Therefore, the image sensor inclination errors can be quantitatively calculated, and the collected data are compensated in real time. Further, a threshold sub-pixel gray-gravity (GG) extraction algorithm is proposed; the gradient function and Gaussian fit algorithm are used to set thresholds to remove the impact of the spot edge noise area on the center location; and polynomial interpolation is employed to enhance the data density of the traditional GG method, thus improving the data acquisition accuracy of LT. Finally, the above methods are applied to on-machine measurement of the American Petroleum Institute (API) thread and the screw rotor, respectively. The experimental results prove that the proposed method can significantly improve the measurement accuracy of free-form curved surfaces using LT and that the improved laser spot center extraction algorithm is more suitable for free-form curved surfaces with smaller curvature and more uniform curvature changes.

22 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that for a weighted tree, both deterministic and probabilistic, the k-eccentricity is a convex function and that the absolute k-centrum is a connected set and is contained in an elementary path.

22 citations

Patent
21 Dec 2001
TL;DR: In this article, a method and corresponding apparatus for calculating the centroid of a fragment to be rendered is disclosed, which consists of receiving a coverage mask containing at least one sample point of the pixel fragment under consideration, determining which of the sample points are within the fragment, determining a value representative of the number of sample points that are within a given fragment, and determining offset values of the fragment centroid based on the estimated number of sampled points within a fragment.
Abstract: A method and corresponding apparatus for calculating the centroid of a fragment to be rendered is disclosed. The method calls for moving the sampling point of a pixel from its initial center point to the center of the fragment containing a portion of an image to be rendered. The method comprises the steps of receiving a coverage mask containing at least one sample point of the pixel fragment under consideration; determining which of the sample points are within the fragment; determining a value representative of the number of sample points that are within the fragment; determining offset values of the fragment centroid based on the number of sample points within the fragment; and determining the barycentric coordinates of the centroid of the fragment. The centroid of the fragment is where sampling of the primitive will occur. By sampling at the centroid of the fragment, rendered image quality is improved due to the reduced anti-aliasing effects at the edges of the primitive.

22 citations

Proceedings Article
01 Dec 1998
TL;DR: A circuit for fast, compact and low-power focal-plane motion centroid localization is presented and the obstacle avoiding line-following algorithm is discussed.
Abstract: A circuit for fast, compact and low-power focal-plane motion centroid localization is presented. This chip, which uses mixed signal CMOS components to implement photodetection, edge detection, ON-set detection and centroid localization, models the retina and superior colliculus. The centroid localization circuit uses time-windowed asynchronously triggered row and column address events and two linear resistive grids to provide the analog coordinates of the motion centroid. This VLSI chip is used to realize fast lightweight autonavigating vehicles. The obstacle avoiding line-following algorithm is discussed.

22 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023492
20221,001
2021184
2020202
2019269
2018271