Orbifolds are a modern mathematical concept that arises in the research of hyperbolic geometry with applications in computer graphics and visualization. In this paper, we make use of rooms with mirrors as the visual metaphor for orbifolds. Given any arbitrary two-dimensional kaleidoscopic orbifold, we provide an algorithm to construct a Euclidean, spherical, or hyperbolic polygon to match the orbifold. This polygon is then used to create a room for which the polygon serves as the floor and the ceiling. With our system that implements Möbius transformations, the user can interactively edit the scene and see the reflections of the edited objects. To correctly visualize non-Euclidean orbifolds, we adapt the rendering algorithms to account for the geodesics in these spaces, which light rays follow. Our interactive orbifold design system allows the user to create arbitrary two-dimensional kaleidoscopic orbifolds. In addition, our mirror-based orbifold visualization approach has the potential of helping our users gain insight on the orbifold, including its orbifold notation as well as its universal cover, which can also be the spherical space and the hyperbolic space.

Audio recordings contain rich information about sound sources and their properties such as the location, loudness, and frequency of events. One prevalent component in sound recordings is the sound texture, which contains a massive number of events. In such a texture, there can be some distinct and repeated sounds that we term as a foreground sound. Birds chirping in the wind is one such decorative sound texture with the chirping as a foreground sound and the wind as a background texture. To render these decorative sound textures in real-time and with high quality, we create two-layer Markov Models to enable smooth transitions from sound grain to sound grain and propose a hierarchical scheme to generate Head-Related Transfer Function filters for localization cues of sounds represented as area/volume sources. Moreover, during the synthesis stage, we provide control over the frequency and intensity of sounds for customization. Lastly, foreground sounds are often blended into background textures such as the sound of rain splats on car surfaces becoming submerged in the background rain. We develop an extraction component that outperforms existing learning-based methods to facilitate our synthesis with perceptible foreground sounds and well-defined textures.

Three-dimensional (3D) ultrasound is extensively used in obstetrics and gynecology, and realistic rendering results can both enhance the accuracy of diagnosis and facilitate communication between obstetricians and pregnant women. This paper proposes an interactive and realistic rendering method using global illumination effects for 3D ultrasound images with low signal-to-noise-ratio (SNR) values. The method is capable of generating both single and multiple scattering effects, and separately rendering these two illuminations using ray-casting. Volumetric photon mapping is used to simulate indirect illumination. In order to avoid complex storage structures and accelerate the computational speed, a new screen-space destiny estimation is proposed to calculate the radiance of each photon. In addition, to solve the issue of the foetal skin exceeding the dynamic range capability of the display device, high-dynamic range (HDR) methods are further incorporated in our method. Experiments demonstrate that our method can produce realistic rendering results with enhanced depth information compared to traditional approaches.