Time filter

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Gu X.,Yanshan University | Gu X.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 2 more authors.
ICIC Express Letters | Year: 2014

In order to effectively eliminate outliers and noise points in 3D scattered point cloud, a denoising smoothing algorithm which is the combination of removing outliers algorithm and trilateral filter is proposed. This is accomplished by rejecting outliers, correcting the normal direction and moving noise points along the modified normal direction within local adaptive neighborhoods. First, the outliers are removed by the method of mathematical statistics, on this basis, estimating normal direction and curvature of point cloud by covariance analysis method. Then, correct the normal direction by combining trilateral filter weighting factor with adaptive optimal neighborhood function. Finally, calculate position offset of data points in the direction of normal amendment by trilateral filter weighting factor in order to smooth the point cloud. Experimental results show that the proposed method is simple and effective, successfully removing noise from point cloud while preserving inherent geometric features. © 2014 ISSN 1881-803X.


Kong D.,Yanshan University | Kong D.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 4 more authors.
Journal of Computational Information Systems | Year: 2015

In three-dimension space, with the minimum bounding rectangular (MBR) of any type of object's projections in xoy and xoz planes, there are four possible types of projection: minimum bounding rectangular, horizontal line, vertical line and point, then a boundary sensitive directional relationship matrix model (BSDRM) is proposed, the model can unified representation direction relations between objects of the four different types of projection, further, the three dimensional direction relation is inferred by combining the two direction matrixes in plane xoy and plane xoz. Based on this model, single direction relation reasoning table and multi direction relation reasoning method are proposed. Finally, direction relation reasoning arithmetic is given and proved to be true. © 2015, by Binary Information Press


Cao F.,Yanshan University | Cao F.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 2 more authors.
Journal of Information and Computational Science | Year: 2014

Since the method of isotropic filtering will result in blurring sharp features, a new approach of anisotropic filtering algorithm is proposed, direction and scale of such filter vary according to changes of sharp features' direction and scale. According to the local neighborhood of the point to be processed, the direction and scale of the filter were adaptively computed by covariance analysis. And because the results of covariance analysis are determined by the selection of neighborhood points, order to adaptively select neighborhood points, a method about the selection of optimal neighborhood radius was also proposed which is based on projection direction. This method adopts projection direction to restrict the selection of neighboring points, thus adaptively get best neighborhood radius related with surface features. Experimental results show that: the algorithm combined with bilateral filtering not only can make point cloud smooth while retaining sharp features but also can adaptively select parameters. Copyright © 2014 Binary Information Press.


Gu X.,Yanshan University | Gu X.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 2 more authors.
Journal of Information and Computational Science | Year: 2015

In order to remove the noise of three-dimensional scattered point cloud, and to smooth point cloud model effectively, an algorithm which uses different filtering strategies on different feature regions of a point cloud model is proposed. The algorithm firstly estimates the normal vectors of a point cloud model by using covariance analysis method, then estimates Gaussian curvatures of the point cloud model by using parabolic fitting method, and uses the average Gaussian curvature in the k-neighborhood as the threshold, to divide the point cloud model into flat neighborhood type regions and mutant neighborhood type regions, and, we use improved median filtering algorithm and bilateral filtering algorithm on different feature regions, so as to achieve the purpose of smoothing scattered point cloud. Experimental results show that it has a very good smoothing effect and maintains the detail features of the point cloud model, which has proved the algorithm is simple and effective. Copyright © 2015 Binary Information Press.


Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | Gu X.,Yanshan University | Gu X.,Data Industry Research Laboratory
ICIC Express Letters | Year: 2015

To solve the time-consuming problem of Iterative Closest Point (ICP) in the process of registration for 3D point cloud, a registration algorithm based on neighborhood features is proposed. First, an improved down-sampling method is adopted to select the feature points. Next, the computation approach of the closest point is improved to improve the accuracy of registration. Then the neighborhood features which are robustly computed by the weighted covariance matrix method are applied to reducing the possibility of mismatching. Experimental results show that the algorithm overcomes the problem of huge calculation, improves the precision and speed of registration and obtains the good effect of registration. © 2015 ICIC International.


Liu Y.-S.,Yanshan University | Liu Y.-S.,Data Industry Research Laboratory | Wang P.,Yanshan University | Wang P.,Data Industry Research Laboratory
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2012

An intelligent progressive transmission strategy was proposed, which made the download accuracy more pertinently according to different requirements of different users. The limited bandwidth can be used reasonable and effectively. And network delay can be reduced. The strategy bases on the DOP-SLOD model coding method. 3D models can be rendered smoothly through the network when browsed by users. Transmission accuracy is determined by the needs of users that could avoid the downloading of useless model data. As the experiment shows, the strategy can realize the streaming transmission of model on network and reduce the network delay of data transmission.


Gu X.,Yanshan University | Gu X.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory
Journal of Computational Information Systems | Year: 2014

Since the SIFT feature point extraction algorithm with scale changes, rotation transformation invariance, is widely used in image registration. In this paper, the SIFT algorithm is applied to three-dimensional point cloud coarse registration, the proposed 3DSIFT extraction algorithm is suitable for three-dimensional point cloud data, then point coordinates, curvature, the nearest neighbor distance mean and other information compose fourteen-dimensional vector to conduct correspondence match, use the interior point rate of Ransac to obtain optimal transformation, and finally transform the coordinates for source point clouds using the optimal transform, complete the point cloud data coarse registration. Experimental results show that our coarse registration algorithm can effectively extract feature points, and it is robust for the point cloud with noisy point, it can provide accurate and effective initial value for the precise registration such as ICP. Copyright © 2014 Binary Information Press.


Hao F.,Yanshan University | Hao F.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | Chen W.,Yanshan University
Journal of Computational Information Systems | Year: 2014

In order to solve the overload problem of root ONS in the EPC network, a load balancing algorithm based on multi-root ONS is proposed. Based on the proposed load balancing ONS (LB ONS) architecture, the ONS Root is defined to have two states, idle or busy. According to CPU utilization and memory utilization of the ONS Root and in combination with threshold controlling to periodically update the ONS Root states, which makes the requests coming from client applications be transferred to an ONS Root which is idle. Experiment results show that the algorithm can reduce query hops and query delays effectively and offer lookup service efficiently. © 2014 Binary Information Press.


Jia Q.,Yanshan University | Jia Q.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 2 more authors.
Journal of Computational Information Systems | Year: 2014

The existing model simplification algorithm in simplified speed and quality can't reach a better compromise, so we present an improved quadric error metrics edge collapse mesh simplification algorithm. This algorithm makes the local region unevenness of vertex, the local region average area of vertex and edge length as constraint factors add to the edge collapse cost, by changing the order of the edge collapse to retain the important detail features of the original model. New vertex position is calculated on the different types of edge, keeping the boundary characteristics of the mesh model. Experimental results show that the improved algorithm not only runs faster, but also maintains a higher degree on the model feature region. © 2014 Binary Information Press.


Kong D.,Yanshan University | Kong D.,Data Industry Research Laboratory | Liu Y.,Yanshan University | Liu Y.,Data Industry Research Laboratory | And 2 more authors.
Journal of Information and Computational Science | Year: 2014

The formal model of spatial directional relations is one of the most important parts in spatial relation research. The most of models are based on Minimum Bounding Rectangle (MBR), and they are not compliant with the regular pattern of human cognition. In order to get a closer conclusion to human cognition on directional relationship, Angle Histogram model based on Double-projection and Rounded-subdivision (AHDPRS) is proposed in this paper. The model uses the maximum inscribed circles to find out the maximum parts of the object, and calculates the directional relationship between the centers of the circles. This model ignores the inessential details to ensure the result which will be closer to human cognition. The experiments show that this model is feasible. Copyright © 2014 Binary Information Press.

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