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Changhua, Taiwan

Huang C.-Y.,National Central University | Luo L.-J.,National Central University | Lee P.-Y.,Show Chwan Memorial Hospital | Lai J.-Y.,National Central University | And 2 more authors.
Journal of Medical and Biological Engineering | Year: 2011

Three-dimensional (3D) surface construction from computed tomography (CT) slices has received extensive attention as many biomechanical analyses and designs rely on the development of a reliable 3D model. This study proposes a method for constructing the triangular models of anatomic structures from two-dimensional slices of CT images. A region growing algorithm is developed for the segmentation of the volume data. Each voxel on the volume data represents a pixel of 3D images. A modified marching cubes algorithm, a 3D reconstruction algorithm, is then employed to establish the triangular model. Problems caused by imprecise image data are mitigated. In addition, a data reduction algorithm that combines a pair of voxels along each coordinate direction is developed, in which piecewise linear interpolation is implemented to maintain the accuracy of the reduced model. Several examples are presented to demonstrate the feasibility of the proposed method. Source

Lee P.-Y.,Show Chwan Memorial Hospital | Lai J.-Y.,National Central University | Hu Y.-S.,National Central University | Huang C.-Y.,National Central University | And 2 more authors.
Biomedical Engineering - Applications, Basis and Communications | Year: 2012

In pelvic surgery, CT images are commonly used for diagnosis and surgical planning. The images are often displayed and manipulated in a 2D environment, which is insufficient owing to the complex geometry of a pelvic structure. Moreover, a pre-bend of the reconstruction plates is necessary, but difficult to complete, because of the lack of appropriate templates. In this study, an integrated preoperative planning system is developed to provide 3D models and physical templates so that the surgeon can simulate and observe his planning and prepare better-fitted curved plates before surgery. The proposed method can be divided into the following four stages: 3D display, bone segmentation, bone reduction, and implant placement. As for the designed curved plates, they can be fabricated as templates by means of rapid prototyping technology. Several examples, including artificial bones, real CT images and real pelvic surgery, have been presented to demonstrate the feasibility of the proposed method. © 2012 National Taiwan University. Source

Yau H.-T.,National Chung Cheng University | Yang T.-J.,National Chung Cheng University | Hsu C.-Y.,Pou Yuen Technology Ltd | Tseng H.-S.,National Chung Cheng University
Computer-Aided Design and Applications | Year: 2010

This paper presents an efficient and economic virtual teeth setup system. The virtual teeth set-up procedure follows the traditional method of using aligners to assist the dentist in solving orthodontic problems. Unlike the traditional method, our virtual set- up procedure first digitizes a plaster model using a 3D scanner. Next, crown segmentation algorithm is used to separate the virtual model into the teeth and gum. The virtual teeth can be adjusted by a force feedback device. During the chewing motion, the continuous detection algorithm is used to prevent the teeth from intersecting. In addition, in order to avoid defects while the teeth are moving, the morphing algorithm is used to deform the virtual gum during teeth movement. After orthodontic planning is finished in our system, a new orthodontic treatment method, called clear aligner, will be added to our system. First, each step of set-up model can be milled using a 5-axis machine. Then the clear aligner can be manufactured by vacuum forming technology. Finally, a clinical experiment is conducted to validate our virtual teeth set-up system. The contribution of this paper is to propose an innovative procedure designed for orthodontic alignment. It is believed that our system can greatly reduce the cost of orthodontic treatment and facilitate the conduct of orthodontic study. © 2010 CAD Solutions, LLC. Source

Huang C.Y.,National Central University | Lee P.Y.,Show Chwan Memorial Hospital | Lai J.Y.,National Central University | Luo L.J.,Pou Yuen Technology Ltd | And 2 more authors.
Computer-Aided Design and Applications | Year: 2011

Conventional approaches to segmenting skeletal structures include extracting 2D contour profiles on the 2D image domain and performing 3D region growing to acquire the 3D bone region directly. However, as far as multiple pieces of bones segmentation are concerned, these methods are not accurate or efficient enough as each bone must be processed one by one. The purpose of this study is to present a method for multiple bones segmentation. A seed regions generation algorithm is proposed to automatically generate an initial region on each bone of interest. The seed regions are then expanded iteratively. In this process, simultaneous region growing is employed to control the moving speed of the fronts, which can reduce the occurrence of overflow. An investigation of the initial threshold and target threshold is also conducted and appropriate methods to optimize the values are provided. Moreover, five cases of lower limbs are employed to demonstrate the feasibility of the proposed method. © 2011 CAD Solutions, LLC. Source

Pou Yu Biotechnology Co. and Pou Yuen Technology Co. | Date: 2007-09-11

Dental laboratory instruments and apparatus, namely, computer-aided design/computer-aided manufacturing system comprising modules for scanner, designer, and cutter, to automatically design and manufacture dental prosthesis, namely single crowns to long span bridges. Artificial teeth, dental impression trays, dental caps, artificial roots to be implanted in the gingival; dental implants.

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