Micah Taylor

AD-Frustum: Adaptive Frustum Tracing for Interactive Sound Propagation

We present an interactive algorithm to compute sound propagation paths for transmission, specular reflection and edge diffraction in complex scenes. Our formulation uses an adaptive frustum representation that is automatically sub-divided to accurately compute intersections with the scene primitives. We describe a simple and fast algorithm to approximate the visible surface for each frustum and generate new frusta based on specular reflection and edge diffraction. Our approach is applicable to all triangulated models and we demonstrate its performance on architectural and outdoor models with tens or hundreds of thousands of triangles and moving objects. In practice, our algorithm can perform geometric sound propagation in complex scenes at 4-20 frames per second on a multi-core PC.

RESound: interactive sound rendering for dynamic virtual environments

We present an interactive algorithm and system (RESound) for sound propagation and rendering in virtual environments and media applications. RESound uses geometric propagation techniques for fast computation of propagation paths from a source to a listener and takes into account specular reflections, diffuse reflections, and edge diffraction. In order to perform fast path computation, we use a unified ray-based representation to efficiently trace discrete rays as well as volumetric ray-frusta. RESound further improves sound quality by using statistical reverberation estimation techniques. We also present an interactive audio rendering algorithm to generate spatialized audio signals. The overall approach can render sound in dynamic scenes allowing source, listener, and obstacle motion. Moreover, our algorithm is relatively easy to parallelize on multi-core systems. We demonstrate its performance on complex game-like and architectural environments.

FastV: from-point visibility culling on complex models

We present an efficient technique to compute the potentially visible set (PVS) of triangles in a complex 3D scene from a viewpoint. The algorithm computes a conservative PVS at object space accuracy. Our approach traces a high number of small, volumetric frusta and computes blockers for each frustum using simple intersection tests. In practice, the algorithm can compute the PVS of CAD and scanned models composed of millions of triangles at interactive rates on a multi‐core PC. We also use the visibility algorithm to accurately compute the reflection paths from a point sound source. The resulting sound propagation algorithm is 10–20X faster than prior accurate geometric acoustic methods.

Guided Multiview Ray Tracing for Fast Auralization

We present a novel method for tuning geometric acoustic simulations based on ray tracing. Our formulation computes sound propagation paths from source to receiver and exploits the independence of visibility tests and validation tests to dynamically guide the simulation to high accuracy and performance. Our method makes no assumptions of scene layout and can account for moving sources, receivers, and geometry. We combine our guidance algorithm with a fast GPU sound propagation system for interactive simulation. Our implementation efficiently computes early specular paths and first order diffraction with a multiview tracing algorithm. We couple our propagation simulation with an audio output system supporting a high order interpolation scheme that accounts for attenuation, cross fading, and delay. The resulting system can render acoustic spaces composed of thousands of triangles interactively.

Direct-to-Indirect Acoustic Radiance Transfer

We present an efficient algorithm for simulating diffuse reflections of sound in a static scene. Our approach is built on recent advances in precomputed light transport techniques for visual rendering and uses them to develop an improved acoustic radiance transfer technique. We precompute a direct-to-indirect acoustic transfer operator for a scene, and use it to map direct sound incident on the surfaces of the scene to multibounce diffuse indirect sound, which is gathered at the listener to compute the final impulse response. Our algorithm decouples the transfer operator from the source position so we can efficiently update the acoustic response at the listener when the source moves. We highlight its performance on various benchmarks and observe significant speedups over prior methods based on acoustic radiance transfer.

Fast and Accurate Geometric Sound Propagation Using Visibility Computations

Geometric Acoustics (GA) techniques based on the image-source method, ray tracing, beam tracing, and ray-frustum tracing, are widely used to compute sound propagation paths. In this paper, we highlight the connection between these propagation techniques with the research on visibility computation in computer graphics and computational geometry. We give a brief overview of visibility algorithms and apply some of these methods to accelerate GA, specifically early specular reflections and finite-edge diffraction. Moreover, we survey our recent work on fast and accurate GA methods that use accurate and conservative visibility techniques. This includes: a) an algorithm for fast computation of early specular reflections using conservative from-point visibility computation; and b) a fast method for finite-edge diffraction using conservative from-region visibility computation. Our approach for computing specular reflections is based on the image-source method and we reduce the number of image sources by using conservative visibility computations. The edge diffraction computation is based on the well known Biot-Tolstoy-Medwin (BTM) diffraction model and we combine it with efficient algorithms for region-based visibility to significantly reduce the number of edge pairs that need to be processed for higher-order diffraction computation. We highlight the performance of these methods on many complex models. Our initial results indicate that we obtain considerable speedups over prior methods for accurate geometric sound propagation.

Interactive gpu-based sound auralization in dynamic scenes

We present an auralization algorithm for interactive virtual environments with dynamic objects, sources, and listener. Our approach uses a modified image source method that computes propagation paths combining direct transmission, specular reflections, and edge diffractions up to a specified order. We use a novel multi-view raycasting algorithm for parallel computation of image sources on GPUs. Rays that intersect near diffracting edges are detected using barycentric coordinates and further propagated. In order to reduce the artifacts in audio rendering of dynamic scenes, we use a high order interpolation scheme that takes into account attenuation, crossfading, and delay. The resulting system can perform auralization at interactive rates on a high-end PC with NVIDIA GTX 280 GPU with 2–3 orders of reflections and 1 order of diffraction. Overall, our approach can generate plausible sound rendering for game-like scenes with tens of thousands of triangles. We observe more than an order of magnitude improvemen...

Interactive gpu-based acoustic walkthrough in dynamic scenes

We present an auralization algorithm for interactive virtual environments with dynamic objects, sources, and listener. Our approach uses a modified image source method that computes propagation paths combining direct transmission, specular reflections, and edge diffractions up to a specified order. We use a novel multi-view raycasting algorithm for parallel computation of image sources on GPUs. Rays that intersect near diffracting edges are detected using barycentric coordinates and further propagated. In order to reduce the artifacts in audio rendering of dynamic scenes, we use a high order interpolation scheme that takes into account attenuation, crossfading, and delay. The resulting system can perform auralization at interactive rates on a high-end PC with NVIDIA GTX 280 GPU with 2-3 orders of reflections and 1 order of diffraction. Overall, our approach can generate plausible sound rendering for game-like scenes with tens of thousands of triangles. We observe more than an order of magnitude improvemen...