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Personalized cardiovascular intervention simulation system

DOI:10.3724/SP.J.2096-5796.19.00020

Available Online:2020-01-18

Abstract (76) | PDF (11) | HTML (56)
Background
This study proposes a series of geometry and physics modeling methods for personalized cardiovascular intervention procedures, which can be applied to a virtual endovascular simulator.
Methods
Based on personalized clinical computed tomography angiography (CTA) data, mesh models of the cardiovascular system were constructed semi-automatically. By coupling 4D magnetic resonance imaging (MRI) sequences corresponding to a complete cardiac cycle with related physics models, a hybrid kinetic model of the cardiovascular system was built to drive kinematics and dynamics simulation. On that basis, the surgical procedures related to intervention instruments were simulated using specially-designed physics models. These models can be solved in real-time; therefore, the complex interactions between blood vessels and instruments can be well simulated. Additionally, X-ray imaging simulation algorithms and realistic rendering algorithms for virtual intervention scenes are also proposed. In particular, instrument tracking hardware with haptic feedback was developed to serve as the interaction interface of real instruments and the virtual intervention system. Finally, a personalized cardiovascular intervention simulation system was developed by integrating the techniques mentioned above.
Results
This system supported instant modeling and simulation of personalized clinical data and significantly improved the visual and haptic immersions of vascular intervention simulation.
Conclusions
It can be used in teaching basic cardiology and effectively satisfying the demands of intervention training, personalized intervention planning, and rehearsing.
Two-phase real-time rendering method for realistic water refraction

DOI:10.3724/SP.J.2096-5796.19.00024

Available Online:2019-12-26

Abstract (136) | PDF (15) | HTML (84)
Background
Realistic rendering has been an important goal of several interactive applications, which requires an efficient virtual simulation of many special effects that are common in the real world. However, refraction is often ignored in these applications. Rendering the refraction effect is extremely complicated and time-consuming.
Methods
In this study, a simple, efficient, and fast rendering technique of water refraction effects is proposed. This technique comprises a broad and narrow phase. In the broad phase, the water surface is considered flat. The vertices of underwater meshes are transformed based on Snell’s Law. In the narrow phase, the effects of waves on the water surface are examined. Every pixel on the water surface mesh is collected by a screen-space method with an extra rendering pass. The broad phase redirects most pixels that need to be recalculated in the narrow phase to the pixels in the rendering buffer.
Results
We analyzed the performances of three different conventional methods and ours in rendering refraction effects for the same scenes. The proposed method obtains higher frame rate and physical accuracy comparing with other methods. It is used in several game scene, and realistic water refraction effects can be generated efficiently.
Conclusions
The two-phase water refraction method produces a tradeoff between efficiency and quality. It is easy to implementin modern game engines, and thus improve the quality of rendering scenes in video games or other real-time applications.