Biomedical subjects

H H Ip

Publications and source records attributed to H H Ip.

5 recordsLinked to original sources

PubMed2001

Three-dimensional virtual-reality surgical planning and soft-tissue prediction for orthognathic surgery.

Complex maxillofacial malformations continue to present challenges in analysis and correction beyond modern technology. The purpose of this paper is to present a virtual-reality workbench for surgeons to perform virtual orthognathic surgical planning and soft-tissue prediction in three dimensions. A resulting surgical planning system, i.e., three-dimensional virtual-reality surgical-planning and soft-tissue prediction for orthognathic surgery, consists of four major stages: computed tomography (CT) data post-processing and reconstruction, three-dimensional (3-D) color facial soft-tissue model generation, virtual surgical planning and simulation, soft-tissue-change preoperative prediction. The surgical planning and simulation are based on a 3-D CT reconstructed bone model, whereas the soft-tissue prediction is based on color texture-mapped and individualized facial soft-tissue model. Our approach is able to provide a quantitative osteotomy-simulated bone model and prediction of postoperative appearance with photorealistic quality. The prediction appearance can be visualized from any arbitrary viewing point using a low-cost personal-computer-based system. This cost-effective solution can be easily adopted in any hospital for daily use.

Humans↗

PubMed2000

Computer-assisted three-dimensional surgical planning and simulation: 3D virtual osteotomy.

A computer-assisted three-dimensional virtual osteotomy system for orthognathic surgery (CAVOS) is presented. The virtual reality workbench is used for surgical planning. The surgeon immerses in a virtual reality environment with stereo eyewear, holds a virtual "scalpel" (3D Mouse) and operates on a "real" patient (3D visualization) to obtain pre-surgical prediction (3D bony segment movements). Virtual surgery on a computer-generated 3D head model is simulated and can be visualized from any arbitrary viewing point in a personal computer system.

Algorithms↗

PubMed2000

Computer-assisted three-dimensional surgical planing and simulation. 3D soft tissue planning and prediction.

The purpose of this paper is to report a new technique for three-dimensional facial soft-tissue-change prediction after simulated orthognathic surgical planning. A scheme for soft tissue deformation, "Computer-assisted three-dimensional virtual reality soft tissue planning and prediction for orthognathic surgery (CASP)", is presented. The surgical planning was based on three-dimensional reconstructed CT visualization. Soft tissue changes were predicted by two newly devised algorithms: Surface Normal-based Model Deformation Algorithm and Ray Projection-based Model Deformation Algorithm. A three-dimensional color facial texture-mapping technique was also used for generating the color photo-realistic facial model. As a final result, a predicted and simulated patient's color facial model can be visualized from arbitrary viewing points.

Algorithms↗

PubMed2000

Three-dimensional virtual reality surgical planning and simulation workbench for orthognathic surgery.

A new integrated computer system, the 3-dimensional (3D) virtual reality surgical planning and simulation workbench for orthognathic surgery (VRSP), is presented. Five major functions are implemented in this system: post-processing and reconstruction of computed tomographic (CT) data, transformation of 3D unique coordinate system geometry, generation of 3D color facial soft tissue models, virtual surgical planning and simulation, and presurgical prediction of soft tissue changes. The basic mensuration functions, such as linear and spatial measurements, are also included. The surgical planning and simulation are based on 3D CT reconstructions, whereas soft tissue prediction is based on an individualized, texture-mapped, color facial soft tissue model. The surgeon "enters" the virtual operatory with virtual reality equipment, "holds" a virtual scalpel, and "operates" on a virtual patient to accomplish actual surgical planning, simulation of the surgical procedure, and prediction of soft tissue changes before surgery. As a final result, a quantitative osteotomy-simulated bone model and predicted color facial model with photorealistic quality can be visualized from any arbitrary viewing point in a personal computer system. This system can be installed in any hospital for daily use.

Cephalometry↗

PubMed1984

A preliminary study of computer recognition and identification of skeletal landmarks as a new method of cephalometric analysis.

The usefulness of results obtained with cephalometrics is limited by measurement error. Much of this is due to the subjective nature of landmark identification on X-rays. Such subjectivity is not eliminated by electronic plotting equipment - despite its high resolution. Automatic (non-subjective) landmark identification of sella and menton was carried out in this study using the CLIP4 image processing system. The results obtained on 23 radiographs were compared with those of conventional techniques.

Cephalometry↗