Shandong Province Key Laboratory of Digital Media Technology

Jinan, China

Shandong Province Key Laboratory of Digital Media Technology

Jinan, China
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Li P.,Shandong University of Science and Technology | Zhang C.,Shandong University of Science and Technology | Zhang C.,Shandong Province Key Laboratory of Digital Media Technology | Zhang C.,Shandong University of Finance and Economics | And 2 more authors.
Journal of Advanced Mechanical Design, Systems and Manufacturing | Year: 2012

In the fields of computer aided geometric design, computer graphics and so on, curvature variation minimization has been widely used for constructing curve and surface. This paper investigates the minimal curvature variation in constructing the cubic Hermite curve that interpolates the given positions and unit tangent vectors at two points, while the magnitudes of the tangent vectors are unknown. The computation of this problem is very hard to handle and a very time-consuming task. To reduce the computing cost, simpler models are used to approximate it, but the existing simpler models can't give a good approximation, and hence make the curves constructed have unsatisfactory shapes. So a new model is presented in this paper. In the new model, the magnitude of each tangent vector is expressed as polynomial function of the tangent vector angles, which is easy to compute, and the shapes of constructed curves are visually similar to the ones constructed by minimizing the accurate curvature variation. Copyright © 2012 by JSME.


Jia S.,Shandong University of Science and Technology | Jia S.,Ludong University | Zhang C.,Shandong University of Science and Technology | Zhang C.,Shandong Province Key Laboratory of Digital Media Technology | And 2 more authors.
Graphical Models | Year: 2014

Mesh saliency is a perception-inspired metric for regional importance which is helpful to many aspects of mesh processing. However, existing mesh saliency cannot be used in mesh resizing directly because of the neglect of resizing direction. In this paper, we propose a region descriptor based on its vulnerability to a resizing direction, and use this descriptor to compute the region's saliency based on its contrast to neighboring regions. In order to avoid being misled by repeated small-scale features on the mesh, we put forward a hierarchical method for saliency computing. We build a hierarchical coarse-to-fine segmentations of the input mesh, and evaluate the saliency value on different levels of segmentations. Finally these saliency values are integrated into one saliency map after applying non-linear suppression. Equipped with the saliency map, a framework for non-homogeneous mesh resizing is presented. We regard every edge as a spring, and scale the mesh by stretching the edge. Based on the salience value, we build a global energy function on the mesh. Experiments show that our resizing method based on hierarchical saliency analysis can produce visually appealing results. © 2014 Elsevier Inc. All rights reserved.


Jia S.,Shandong University of Science and Technology | Li X.,Shandong University of Science and Technology | Guo H.,Shandong University of Science and Technology | Zhang C.,Shandong University of Science and Technology | Zhang C.,Shandong Province Key Laboratory of Digital Media Technology
Journal of Information and Computational Science | Year: 2014

Model resizing is very useful when creating new models based on existing ones or applying models in different scenes. In order to determine the features to be preserved, recent resizing techniques have focused on mesh analysis to get low-level characteristics like edge and face vulnerability to scale, or high-level characteristics like mesh symmetry and parallelism. We observe that the extraction of such mesh information is time-consuming and very limited, so we let the user choose the features to be maintained, and provide the user with a flexible selection mode based on a simple mesh segmentation. Our method can precisely preserve the user-specified features and maintain its boundary continuity, meeting the requirements of engineering applications. The method resizes the model by a spacedeformation technique, so it can handle complex models with multiple connected components and intertwined features. A number of experimental results have shown that our approach has obtained pleasing results and outperformed the previous approaches. Copyright © 2014 Binary Information Press.


Zhang X.,Shandong University of Science and Technology | Zhang X.,Ludong University | Zhang C.,Shandong University of Science and Technology | Zhang C.,Shandong University of Finance and Economics | And 4 more authors.
Science China Information Sciences | Year: 2012

Image segmentation is one of the most important problems in medical image processing, and the existence of partial volume effect and other phenomena makes the problem much more complex. Fuzzy C-means, as an effective tool to deal with PVE, however, is faced with great challenges in efficiency. Aiming at this, this paper proposes one improved FCM algorithm based on the histogram of the given image, which will be denoted as HisFCM and divided into two phases. The first phase will retrieve several intervals on which to compute cluster centroids, and the second one will perform image segmentation based on improved FCM algorithm. Compared with FCM and other improved algorithms, HisFCM is of much higher efficiency with satisfying results. Experiments on medical images show that HisFCM can achieve good segmentation results in less than 0.1 second, and can satisfy real-time requirements of medical image processing. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.

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