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HDR Pipeline
Published in Francesco Banterle, Alessandro Artusi, Kurt Debattista, Alan Chalmers, Advanced High Dynamic Range Imaging, 2017
Francesco Banterle, Alessandro Artusi, Kurt Debattista, Alan Chalmers
Ray tracing. Ray tracing [417] models the geometric properties of light by calculating the interactions of groups of photons, termed rays, with geometry. This technique can reproduce complex visual effects. Rays are shot from the virtual camera and traverse the scene until the closest object is hit; see Figure 2.13(a). Here the material properties of the object at that point are used to calculate the illumination, and a ray is shot toward any light sources to account for shadow visibility. The material properties at the intersection point further dictate in which direction reflected/transmitted rays need to be shot; the process is computed recursively. Due to its recursive nature, ray tracing and extensions of the basic algorithm, such as path tracing and distributed ray tracing, are naturally suited to solving the rendering equation [186], which describes the transport of light within an environment. Ray tracing methods can thus simulate effects such as shadows, reflections, refractions, indirect lighting, subsurface scattering, caustics, motion blur, indirect lighting, and others in a straightforward manner. While ray tracing is computationally expensive, recent algorithmic and hardware advances are making it possible to compute it at interactive rates for dynamic scenes [54,300].
From Graphics to Visualization
Published in Alexandru Telea, Data Visualization, 2014
Graphics-rendering generates computer images of 3D scenes, or datasets. The ingredients of this process are a 3D scene (or set of 3D objects), a set of lights, and a viewpoint. Essentially, the process can be described as the application of a rendering equation at every point of the given dataset. For a given point, the rendering equation describes the relationship between the incoming light, the outgoing light, and the material properties at that point. In general, the rendering equation has a complex form [Foley et al. 95]. Solving the rendering equation computes the outgoing light, or illumination, for every point of a 3D scene, given the scene, light set, and viewpoint.
Interactive, in-browser cinematic volume rendering of medical images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2023
Jiayi Xu, Gaspard Thevenon, Timothee Chabat, Matthew McCormick, Forrest Li, Tom Birdsong, Ken Martin, Yueh Lee, Stephen Aylward
This paper focuses on ray-casting based rendering because it is a mature foundation for a diverse set of algorithms and it is an ongoing basis of research (Jönsson et al. 2013). We used a simplified version of the volume rendering equation by omitting emission and background radiance terms and using discrete sampling to estimate the integral: