Research on Medical Virtual Reality Technology
As a new discipline, medical virtual reality technology is gradually taking shape, and it is a new interdisciplinary research field integrating medicine, biomechanics, mechanics, materials science, computer graphics, computer vision, mathematical analysis, mechanical robotics and other disciplines. Medical virtual reality technology is a brand-new technical strategy that quietly enters the field of medical education, and it will certainly provide a broader prospect for the future development of medical technology.
Keyword data filtering; Data conversion; Virtual visual environment display; stereopicture
Abstract: As a new discipline, Medical Virtual Reality Technology is developing gradually. It is a new interdisciplinary research field, involving medicine, biomechanics, mechanics, material science, computer graphics, computer vision, robotics and mathematical analysis. Medical virtual reality technology is gradually becoming an indispensable part of the medical field. This is an important field, which will lead to the discovery of new medical technology.
Keywords: data filtering; Data conversion; VIVED stereoscopic image
1. Virtual visual environment display-animation.
By the Johnson Space Center (JSC) of NASA and other departments, the use of virtual reality technology provides people with a clever medical education strategy. It integrates all virtual reality technologies including human skull and heart, and provides people with the ability to interact with other multimedia (audio, video, etc.). ) [ 1].
2. Virtual surgery (virtual surgery)
As a developing research direction in the field of medical virtual reality technology, its purpose is to establish a simulation environment in a computer by using various medical image data, and doctors can use the information in the virtual environment to make surgical plans, conduct surgical drills, conduct surgical teaching, conduct surgical skills training, guide surgery during surgery, and recover after surgery. Virtual surgery fully embodies the role of virtual reality as computer graphics in the medical process.
3. Hardware
A reality engine computer produced by Silicon Graphics Company is used to open slices of computer axial tomography (CAT/CT) and magnetic resonance imaging, and put them into three-dimensional volume images and movies, which can produce the observation effect of body "flying". Watch the final 3D image on a Macintosh IICX computer with 16M memory. The reason why Mac is chosen first is because its cost performance and audio-visual performance are better than similar PCs. In addition, it is widely used in the school system in North America. Can be said to be the leader of desktop multimedia, all kinds of software and hardware support. VR movies can be stored on hard disk, or transferred to CD and watched through red and blue glasses. You can also use virtual reality helmet display (HMD) or binocular omni-directional display (boom system) to watch. The final image can be stored on a CD-ROM or a laser disc.
4. Software
4. 1 file conversion and data preparation
Three-dimensional images were created by using 65438±0.5mm thick human skull CAT/CT slices and cardiac MRI slices provided by Galveston Company. In the process of CT scanning of skull, it passes through a foam belt, so it will produce some useless data. The result of skull scanning is to generate a data set, in which more than 120 pieces pass through the skull and 60 pieces pass through the mandible (chin), while MRI scanning of the heart can export 200 pieces of data set. Send the data files created by the medical division to IGOAL company (integrated graphics card, operation and analysis laboratory). Scan and filter there, eliminate irrelevant data, and try not to lose any important information. IGOAL developed a program called. Ctimager？ Threshold calculation tool, so as to remove unnecessary noise and irrelevant data in the slice.
4.2 Data Filtering and Converting Volume Data into Polygon Data
In what IGOAL said? dispfly？ The development tool of, can convert a large amount of data into direct display by computer in the future. This tool is used in a variety of filtering algorithms to prepare a form of transforming CT and magnetic resonance imaging data into polygons. Generating anatomical model based on moving cube algorithm. Filtering usually includes thresholding the data to eliminate most of the noise. A low-pass filter is used to minimize irregular surface roughness when high-frequency noise is input into the algorithm. This process produces a relatively smooth surface, approximately scans the sample and reduces the number of noisy polygons. A unique filter only smoothes the creation of cardiac data between scans, without other filtering [2]. Because there are a lot of slices in the heart and skull, several models are established, each model represents a small number of slices. A grid algorithm? Meht? Later, it was developed to improve the display performance. The algorithm is transformed into the original efficient banded triangle set. On average, more than 100 triangles make up each triangle band. .
4.3 Generate stereoscopic images
After the model is established, the stereo sequence is rendered. IGOAL has developed a tool called OOM (Object Oriented Manipulator) to store each rendered frame on disk. These images are stereoscopic images represented by red and blue colors separately. Once these sequences are recorded on the disc, the data format is converted into Macintosh.pict format, and the full-color image sequence is transmitted to the Mac according to stereoscopic viewing.
4.4 Stereo images and multimedia
Edit Mac images to produce desired effects, such as digital corpse overlay or inserting text to describe what you are watching. Using apple's QuickTime extension, the image is converted into QuickTime movie animation on Mac.
5. Conclusion
The medical image of skull is scanned by CT, and the information of helmet display or arm system is processed by Macintosh computer, and finally high-quality VR image is generated. At present, scientists are trying to generate a VR model of the heart using the imaging data of magnetic vibration.
The preliminary results show that this kind of imaging data can be used to develop high-resolution models. However, in order to maintain high-quality VR imaging targets, a large number of data are described by frame sequences, which will cause some problems. To alleviate this problem, scientists are exploring alternative hardware and software solutions.
Another problem is that this technology is aimed at HMD display system. In order to maintain high-quality virtual reality experience, LCD has no requirement for resolution. CRT monitors can meet the resolution requirements of various educational platforms, but the cost is too high. Surgical simulation may become a routine, especially when making complicated and rare surgical plans.
6. Application and research status of 6.VIVED
The current research emphasizes the importance of creating a high-resolution human virtual reality simulator for educational purposes. The application of this technology must fully understand its complex three-dimensional relationship, such as in the following fields: anatomical education, various mechanical equipment, biochemical and pathological research, surgeons, simulated plastic surgery and training surgeons with endoscopes.
7. Other applications
With the development of medical virtual reality technology, new educational solutions and strategies have sprung up. For example, the University of North Carolina at Chapel Hill uses ultrasound, magnetic resonance imaging and X-ray to create dynamic image radiotherapy? Forecast? Model. Dartmouth Medical College has established mathematical models of human face and lower limbs to study the effect evaluation of surgical operation. Green leaf medical system developed in Palo Alto? EVAL？ And then what? Gloves are talkative? System, as an implementation? Evaluation and demonstration? System. Data gloves and data suits lined with sensors have been widely used, and the injury degree of sports injuries and disabled patients can be effectively measured. ? Gloves are talkative? It is a sign language device of data gloves to help patients recover. People don't need to make sounds (stroke or cerebral palsy patients), just use gestures that computers can understand. The use of helmet display enables patients who need rehabilitation to learn again, such as opening and closing doors, walking, pointing or turning around [3].
8. Conclusion
High-quality VR images can be generated by using helmet-mounted display or boom system on Macintosh computer. At present, scientists are developing a heart VR model based on magnetic resonance imaging data. The preliminary research results show that the high resolution model can be realized by using the imaging data technology of this method. In order to maintain high-quality virtual reality target imaging, it must be adjusted appropriately. Fly over? The amount of data in a frame sequence. Hardware and software solutions developed by other civilizations are just to explore and alleviate this problem. Then the display system technology of HMD. Because in all kinds of medical education platforms, LCD screen does not involve the problem of maintaining high-quality virtual reality, and the cost of realizing high-resolution CRT display is too high.
refer to
[1] "Commercial Application of NASA Technology Transfer Space Technology", NASA, Technology Application.
[2] Porter, Stephen, Virtual Reality, Computer Graphics World, (March, 1992), 42-54.
[3]Sprague, Laurie A., Bell, Brad, Sullivan, Tim and Voss, Mark, "Virtual Reality in Medical Education and Evaluation", Technology 20031February, 1993.
Correspondent: Lou Yan.
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