14,644 research outputs found
The Iray Light Transport Simulation and Rendering System
While ray tracing has become increasingly common and path tracing is well
understood by now, a major challenge lies in crafting an easy-to-use and
efficient system implementing these technologies. Following a purely
physically-based paradigm while still allowing for artistic workflows, the Iray
light transport simulation and rendering system allows for rendering complex
scenes by the push of a button and thus makes accurate light transport
simulation widely available. In this document we discuss the challenges and
implementation choices that follow from our primary design decisions,
demonstrating that such a rendering system can be made a practical, scalable,
and efficient real-world application that has been adopted by various companies
across many fields and is in use by many industry professionals today
Generating Light Estimation for Mixed-reality Devices through Collaborative Visual Sensing
abstract: Mixed reality mobile platforms co-locate virtual objects with physical spaces, creating immersive user experiences. To create visual harmony between virtual and physical spaces, the virtual scene must be accurately illuminated with realistic physical lighting. To this end, a system was designed that Generates Light Estimation Across Mixed-reality (GLEAM) devices to continually sense realistic lighting of a physical scene in all directions. GLEAM optionally operate across multiple mobile mixed-reality devices to leverage collaborative multi-viewpoint sensing for improved estimation. The system implements policies that prioritize resolution, coverage, or update interval of the illumination estimation depending on the situational needs of the virtual scene and physical environment.
To evaluate the runtime performance and perceptual efficacy of the system, GLEAM was implemented on the Unity 3D Game Engine. The implementation was deployed on Android and iOS devices. On these implementations, GLEAM can prioritize dynamic estimation with update intervals as low as 15 ms or prioritize high spatial quality with update intervals of 200 ms. User studies across 99 participants and 26 scene comparisons reported a preference towards GLEAM over other lighting techniques in 66.67% of the presented augmented scenes and indifference in 12.57% of the scenes. A controlled lighting user study on 18 participants revealed a general preference for policies that strike a balance between resolution and update rate.Dissertation/ThesisMasters Thesis Computer Science 201
Multi-view Inverse Rendering for Large-scale Real-world Indoor Scenes
We present a multi-view inverse rendering method for large-scale real-world
indoor scenes that reconstructs global illumination and physically-reasonable
SVBRDFs. Unlike previous representations, where the global illumination of
large scenes is simplified as multiple environment maps, we propose a compact
representation called Texture-based Lighting (TBL). It consists of 3D meshs and
HDR textures, and efficiently models direct and infinite-bounce indirect
lighting of the entire large scene. Based on TBL, we further propose a hybrid
lighting representation with precomputed irradiance, which significantly
improves the efficiency and alleviate the rendering noise in the material
optimization. To physically disentangle the ambiguity between materials, we
propose a three-stage material optimization strategy based on the priors of
semantic segmentation and room segmentation. Extensive experiments show that
the proposed method outperforms the state-of-the-arts quantitatively and
qualitatively, and enables physically-reasonable mixed-reality applications
such as material editing, editable novel view synthesis and relighting. The
project page is at https://lzleejean.github.io/TexIR.Comment: The project page is at: https://lzleejean.github.io/TexI
A Light Source Calibration Technique for Multi-camera Inspection Devices
Industrial manufacturing processes often involve a visual control system to detect possible product defects during production. Such inspection devices usually include one or more cameras and several light sources designed to highlight surface imperfections under different illumination conditions (e.g. bumps, scratches, holes). In such scenarios, a preliminary calibration procedure of each component is a mandatory step to recover the system’s geometrical configuration and thus ensure a good process accuracy. In this paper we propose a procedure to estimate the position of each light source with respect to a camera network using an inexpensive Lambertian spherical target. For each light source, the target is acquired at different positions from different cameras, and an initial guess of the corresponding light vector is recovered from the analysis of the collected intensity isocurves. Then, an energy minimization process based on the Lambertian shading model refines the result for a pr ecise 3D localization. We tested our approach in an industrial setup, performing extensive experiments on synthetic and real-world data to demonstrate the accuracy of the proposed approach
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