Dynamic Real-World Lighting for Complex Scenes with Applications to Design of the Built Environment

基于物理的渲染是使用物理上精确的材料和光源创建精确的计算机生成图像并计算照明模拟的过程。任何需要在计算机生成的环境中准确表示照明的学科都需要基于物理的渲染，它可以准确地预测新建筑将如何影响周围的环境，它允许设计师在任何可能的照明环境下测试他们的产品，只需点击一个按钮，它使考古学家能够深入研究过去的重建。它可以让表演者创造出前所未有的逼真环境。这个为期12个月的项目将提高物理精确的计算机生成图像的真实感，并为复杂的照明场景计算它们所需的时间。这些新方法将通过奥雅纳的咨询和评估应用于建筑环境，奥雅纳是一家在建筑环境的所有领域提供工程设计、规划和项目管理服务的全球性公司。计算机生成图像的真实感已经通过一种称为基于图像的照明（IBL）的过程得到改善，该过程依赖于高动态范围（HDR）图像的捕获。与普通图像不同，HDR图像可以代表大多数真实世界的亮度，并且可以在环境中的单个点捕获整个照明。这种捕获的HDR图像，称为环境地图，用于用捕获的真实世界的亮度精确地重新照亮虚拟环境。对于由环境地图直接照明的场景，这个过程相对简单，但是对于需要间接计算照明的场景，例如在建筑环境中常见的应用程序，例如当计算从办公大楼内部完全从外部照明的视图的照明时，这个过程可能非常缓慢。该项目的第一个目标是创建一种新颖的渲染算法，该算法使用巧妙的采样方法，将这种复杂场景的计算减少到简单情况的计算。到目前为止，由于硬件捕获的限制，IBL的环境映射捕获仅限于静态场景。WMG拥有世界上第一台HDR摄像机，该摄像机可以以每秒30帧的速度以1920x1080像素的高清分辨率捕获多达20个f档，从而可以捕获动态环境地图。goHDR一家拥有HDR专业知识的公司将提供他们的压缩方法，使动态环境地图能够存储为HDR视频。在不压缩的情况下，HDR视频的单个高清分辨率帧将消耗24MB。这种压缩将允许HDR视频以最小的开销存储在标准视频上，并使动态环境地图的处理可行。这将实现本研究的第二个主要目标，即创建可以使用动态环境地图计算物理精确渲染动画的算法，用于动态改变复杂场景的照明。

Physically-based rendering is the process of creating accurate computer generated images using physically accurate materials and light sources and computing a simulation of the lighting. Physically-based rendering is needed by any discipline that requires an accurate representation of the lighting in an computer generated environment, it makes it possible to accurately predicate how a new building will affect the environment around it, it allows designers to test their products under any possible lighting environment at the click of a button, it enables archaeologists to delve into reconstructions of the past, and it allows entertainers to create realistic environments that may have never existed before. This 12 month project will improve the realism of physically-accurate computer generated images, and the time it takes to compute them for complex lighting scenarios. The novel methods will be used for applications in the built environment through consultancy and evaluation from Arup, a global firm providing engineering design, planning and project management services in all areas of the built environment. The realism of computer generated images has been improved by a process known as image-based lighting (IBL) which relies on the capture of High Dynamic Range (HDR) images. Unlike normal images, HDR images can represent most of the real world luminance and has made it possible to capture the entire lighting at a single point in an environment. This captured HDR image, termed an environment map is used to accurately relight a virtual environment with the captured real world luminance. This process is relatively straightforward for scenes which are directly lit by the environment map, but can be very slow to compute for scenes where the lighting needs to be computed indirectly, such as is common in applications in the built environment, for example when computing the lighting of a view from inside an office building which is entirely lit from the outside. The first goal of this project is to create a novel rendering algorithm that uses clever sampling methods which will reduce the computation of such complex scenarios to that of the straightforward case. The capture of environment maps for IBL has, until now, due to limitations in hardware capture, been limited to static scenarios. WMG is in possession of the world's first HDR video camera which can capture up to 20 f-stops at an HD resolution of 1920x1080 pixels at 30 frames per second, making it possible to capture dynamic environment maps. goHDR a company with HDR expertise will provide their compression method that will enable the dynamic environment maps to be stored as HDR videos. When not compressed, HDR videos would consume 24MB for a single HD resolution frame. This compression will allow HDR videos to be stored with a minimal overhead over a standard video, and make processing of dynamic environment maps feasible. This will enable the second major goal of this research which is to create algorithms that can compute physically-accurate rendered animations using dynamic environment maps for dynamically change lighting for complex scenarios.