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affine transformation of virtual 3D object using 2D localization of fingertips

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Virtual Reality & Intelligent Hardware 2020年第6期2卷 534-555页

作者： Mohammad Mahmudul ALAM S.M.Mahbubur RAHMAN Department of Electrical and Electronic Engineering Bangladesh University of Engineering and TechnologyDhaka 1000Bangladesh

Background Interactions with virtual 3D objects in the virtual reality(VR)environment using the gesture of fingers captured in a wearable 2D camera have emerging applications in *** This paper presents an approach of a two-stage convolutional neural network,one for the detection of hand and another for the *** purpose of VR environments is to transform a virtual 3D object with affine parameters by using the gesture of thumb and index *** To evaluate the performance of the proposed system,one existing,and another developed egocentric fingertip databases are employed so that learning involves large variations that are common in *** results show that the proposed fingertip detection system outperforms the existing systems in terms of the precision of *** The interaction performance of the proposed system in the VR environment is higher than that of the existing systems in terms of estimation error and correlation between the ground truth and estimated affine parameters.

关键词： affine transformation Detection of fingertips Detection of hand Human-computer interaction Virtual reality

Realization of Fractal affine transformation

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Journal of Shanghai University(English Edition) 2001年第1期5卷 31-34页

作者： XU Jing, LIN Yi xia School of Electromechanical Engineering and Automation, Shanghai University, Shanghai 200072, China School of Electromechanical Engineering and Automation Shanghai University Shanghai China

This paper gives the definition of fractal affine transformation and presents a specific method for its realization and its corresponding mathematical equations which are essential in fractal image construction.

关键词： fractal IFS (iterated function system) affine transformation

The Research of Blind Watermarking Based on Zigzag and affine transformation

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The Research of Blind Watermarking Based on Zigzag and Affin...

Real-Time Tool for affine transformations of Two Dimensional IFS Fractal

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作者： Hui Wang Yukun Hu Lijun Yu Weijie Sun Harbin Engineering University

Image scrambling in the watermarking image encryption has been widely *** when the image watermarking is under attack or interception,the attacker can easily crack through the image texture or using conventional *** this paper,we propose a new method to preprocess the image watermarking by combining a kind of zigzag transformation scanning from the upper right corner and affine *** scrambling method can achieve better effect of scrambling and encryption and it is difficult to be cracked when *** the DWT will be used to embed the scrambling *** this method was verified by a series of simulation *** result proves that using DWT transformation to embed watermark,you don’t need the original image to get a good watermark recovery.

关键词： zigzag affine transformation DWT(Discrete Wavelet Transform) blind watermarking

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Journal of Electrical Engineering 2016年第3期4卷 150-155页

作者： Elena Hadzieva Marija Shuminoska University of lnformation Science and Technology "St. Paul the Apostle " Ohrid 6000 Macedonia

This work introduces a novel tool for interactive, real-time affine transformations of two dimensional IFS fractals. The tool uses some of the nice properties of the barycentric coordinates that are assigned to the points that constitute the image ofa fractal, and thus enables any affine transformation of the affine basis, done by click-and-drag, to be immediately followed by the same affine transformation of the fractal. The barycentric coordinates can be relative to an arbitrary affine basis of ~2, but in order to have a better control over the fractal, a kind of minimal simplex that contains the fractal attractor is used.

关键词： IFS fractal affine transformation barycentric coordinates real-time tool.

A Method of Non-textured Regions Matching

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Chinese Journal of Electronics 2019年第3期28卷 598-603页

作者： JIA Di ZHAO Mingyuan CAO Jun SONG Weidong School of Electronic and Information Engineering Liaoning Technical University School of Computing Informatics Decision System Engineering Arizona State University School of Geomatics Liaoning Technical University

It is difficult for existing dense or quasidense matching algorithms to obtain accurate matching results due to the lack of effective feature information in non-textured regions. This may affect the quality of subsequent 3 D reconstruction and super-resolution reconstruction. We propose a method of non-textured regions matching. To reduce the impact of noise and illumination, vector sampling normalized cross correlation is proposed to directly measure coherence between two colour images by the effective information of multi-channel features. Three mathematical properties are used in affine transformation: 1) Centroid location is not affected by affine transformation; 2) affine transformation transforms a straight line into another straight line; 3) affine transformation maintains the linear relation invariant. In non-textured regions, we can construct texture regions which have affine invariant properties to improve the accuracy of template matching. This could provide more information for the diffusion of dense or quasi-dense matching. In experiments, we demonstrate that the method has high accuracy in cases where there is no big distortion between the two viewing angles from two aspects of simulated images and photographic images.

关键词： Stereo matching Dense matching Nontextured region affine transformation

Variational Bayesian Approximation for affine Point Set Matching

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Chinese Journal of Electronics 2015年第2期24卷 349-354页

作者： XIANG Lin QU Hanbing TAO Haijun WANG Jiaqiang College of Information Engineering China Jiliang University Key Laboratory of Pattern Recognition Beijing Academy of Science and Technology School of Electronic and Information Engineering Hebei University of Technology

In this paper, we propose a variational approach for the affine point set matching problems under the Bayesian probabilistic framework. A directed acyclic graph is provided for the representation of the joint probability over affine transformation, random variables and the point sets. Based on the directed graph, a variational iterative algorithm is derived to approximate the posteriors of the random variables and the anisotropic Gaussian mixtures are used for the estimation of the spurious outliers instead of the frequently-used uniform distribution. Experimental results demonstrate that our method achieves good performance in terms of both robustness and accuracy and is comparable to other state-of-the-art point registration algorithms especially in the case of complicated outliers.

关键词： Point set matching Variational inference affine transformation Gaussian mixture model

Extraction of affine invariant features for shape recognition based on ant colony optimization

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Journal of Systems Engineering and Electronics 2011年第6期22卷 1003-1009页

作者： Yuxing Mao Ching Y. Suen Wei He State Key Laboratory of Power Transmission Equipment ＆ System Security and New Technology Chongqing University Chongqing 400044 E R. China Centre for Pattern Recognition and Machine Intelligence Concordia University Montreal QC H3G 1M8 Canada

A new approach to extraction of affine invariant features of contour image and matching strategy is proposed for shape ***,the centroid distance and azimuth angle of each boundary point are ***,with a prior-defined angle interval,all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating *** that,the centroid distance ratios（CDRs） of any two opposite contour points to the barycenter are achieved as the representation of the shape,which will be invariant to affine *** the angles of contour points will change non-linearly among affine related images,the CDRs should be resampled and combined sequentially to build one-by-one matching pairs of the corresponding *** core issue is how to determine the angle positions for sampling,which can be regarded as an optimization problem of path *** ant colony optimization（ACO）-based path planning model with some constraints is presented to address this ***,the Euclidean distance is adopted to evaluate the similarity of shape features in different *** experimental results demonstrate the efficiency of the proposed method in shape recognition with translation,scaling,rotation and distortion.

关键词： shape recognition affine transformation centroid distance ratio(CDR) ant colony optimization(ACO) path planning.

A non-uniform grid for triangular differential quadrature

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Science China(Physics,Mechanics & Astronomy) 2016年第12期59卷 52-59页

作者： HongZhi Zhong Jia Xu Department of Civil Engineering Tsinghua University

The triangular differential quadrature method based on a non-uniform grid is proposed in the paper. Explicit expressions of the non-uniform grid point coordinates are given and the weighting coefficients of the triangular differential quadrature method are determined with the aid of area coordinates. Two typical examples are presented to testify the effectiveness of the non-uniform grid. It is shown that rapid convergence is achieved under the non-uniform grid in comparison with those from the uniform grid with the same order of approximation.

关键词： differential quadrature triangular differential quadrature non-uniform grid weighting coefficient affine transformation

Color image encryption scheme based on chaotic systems

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The Journal of China Universities of Posts and Telecommunications 2018年第2期25卷 39-48页

作者： Min Xiangshen Fan Jiulun Zhang Xuefeng Ren Fang Department of Communications and Information Engineering Xi'an University of Posts and Telecommunications

To improve the security of the color image encryption scheme,a color image encryption scheme based on chaotic systems is proposed. Firstly, the proposed scheme sets the color image as a three-dimensional matrix which is scrambled by affine transformation. Second, the Logistic chaotic sequence applied to generate the control parameter and auxiliary key is used to encrypt the three-dimensionaL matrix. Here, we mainly focus on two methods for encryption processes. One is to generate a chaotic sequence by Logistic map and Henon map, which is used to perform XOR operation with the scrambled components R＇, G＇, B＇ respectively. The other one is to adopt a binary Logistic sequence to select the pixel position for the scrambled components R＇, G＇, B＇ image, and then applying the Henon map and Logistic map with the auxiliary key to perform the replacement encryption. Based on this, an encrypted image is synthesized. Simulation results show that the proposed image encryption scheme can implement better encryption and achieve higher security performance.

关键词： color image cncryption chaotic systems affine transformation Logistic map Henon map security performance