Deyun Chen

Parameters estimator of GARCH(1, 1) process with heavy tailed errors

This paper studies a modification of quasi-maximum likelihood estimator for GARCH (1, 1) process with the errors, whose squares have regularly varying tail probabilities with the exponent α, α >; 0. We showed that, this estimator is unbiased and asymptotically normal with standard convergence rate of n1/2 regardless of whether the errors are heavy-tailed.

3D measurement method based on combined temporal encoding structured light

Three-dimensional (3D) vision measurement technology based on encoding structured light plays an important role and has become the main development trend in the field of 3D non-contact measurement. However, how to synthetically improve measurement speed, accuracy and sampling density is still a difficult problem. Thus in the present work, a novel 3D measurement method based on temporal encoding structured light by combining trapezoidal phase-shifting pattern and cyclic code pattern is proposed. Due to trapezoidal phase-shifting has the advantages of high sampling density and high-speed, the proposed method can maintain these advantages by using cyclic code to expand the range of trapezoidal phase-shifting. In addition, the correction scheme is designed to solve the problem of cycle dislocation. Finally, simulation experimental platform is built with 3ds max and MATLAB. Experimental analyses and results show that, the maximal error is less than 3 mm in the range from 400 mm to 1100 mm, cycle dislocation correction has a good effect.

Porcelain three-dimensional shape reconstruction and its color reconstruction

In this paper, structured light three-dimensional measurement technology was used to reconstruct the porcelain shape, and further more the porcelain color was reconstructed. So the accurate reconstruction of the shape and color of porcelain was realized. Our shape measurement installation drawing is given. Because the porcelain surface is color complex and highly reflective, the binary Gray code encoding is used to reduce the influence of the porcelain surface. The color camera was employed to obtain the color of the porcelain surface. Then, the comprehensive reconstruction of the shape and color was realized in Java3D runtime environment. In the reconstruction process, the space point by point coloration method is proposed and achieved. Our coloration method ensures the pixel corresponding accuracy in both of shape and color aspects. The porcelain surface shape and color reconstruction experimental results completed by proposed method and our installation, show that: the depth range is 860 ∼ 980mm, the relative error of the shape measurement is less than 0.1%, the reconstructed color of the porcelain surface is real, refined and subtle, and has the same visual effect as the measured surface.

High-integrated structured light 3-D measurement system based on ARM

This paper proposes a high-integrated structured light 3-D measurement system based on ARM9 development platform and embedded Linux system. System scheme, system control and system measurement were investigated. First embedded operation system based on hardware platform of S3C2440 was analyzed, peripheral expansion device camera and serial controlled projector were used to constitute measurement system. Then image acquisition was realized through Video for Linux, projector was controlled through serial communication. Finally coordinates of object were obtained by structured light 3-D measurement method. This paper describes the hardware and software of measurement system; experimental results show that miniaturization and integration were realized in structured light 3-D measurement system.