We present a method of recovering high dynamic range radiance maps from photographs taken with conventional imaging equipment. In our method, multiple photographs of the scene are taken with different amounts of exposure. Our algorithm uses these differently exposed photographs to recover the response function of the imaging process, up to factor of scale, using the assumption of reciprocity. With the known response function, the algorithm can fuse the multiple photographs into a single, high dynamic range radiance map whose pixel values are proportional to the true radiance values in the scene. We demonstrate our method on images acquired with both photochemical and digital imaging processes. We discuss how this work is applicable in many areas of computer graphics involving digitized photographs, including image-based modeling, image compositing, and image processing. Lastly, we demonstrate a few applications of having high dynamic range radiance maps, such as synthesizing realistic motion blur and simulating the response of the human visual system.

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Recovering high dynamic range radiance maps from photographs

The rapid increase in the performance of graphics hardware, coupled with recent improvements in its programmability, have made graphics hardware a compelling platform for computationally demanding tasks in a wide variety of application domains. In this report, we describe, summarize, and analyze the latest research in mapping general-purpose computation to graphics hardware. We begin with the technical motivations that underlie general-purpose computation on graphics processors (GPGPU) and describe the hardware and software developments that have led to the recent interest in this field. We then aim the main body of this report at two separate audiences. First, we describe the techniques used in mapping general-purpose computation to graphics hardware. We believe these techniques will be generally useful for researchers who plan to develop the next generation of GPGPU algorithms and techniques. Second, we survey and categorize the latest developments in general-purpose application development on graphics hardware. This survey should be of particular interest to researchers who are interested in using the latest GPGPU applications in their systems of interest.

/pdf/a-survey-of-general-purpose-computation-on-graphics-hardware-2phx1q9xxr.pdf

A Survey of General-Purpose Computation on Graphics Hardware

A Survey of General-Purpose Computation on Graphics Hardware.

We present a new technique for the display of high-dynamic-range images, which reduces the contrast while preserving detail. It is based on a two-scale decomposition of the image into a base layer,...

/pdf/fast-bilateral-filtering-for-the-display-of-high-dynamic-43a1vkjsrr.pdf

Fast bilateral filtering for the display of high-dynamic-range images

A classic photographic task is the mapping of the potentially high dynamic range of real world luminances to the low dynamic range of the photographic print. This tone reproduction problem is also faced by computer graphics practitioners who map digital images to a low dynamic range print or screen. The work presented in this paper leverages the time-tested techniques of photographic practice to develop a new tone reproduction operator. In particular, we use and extend the techniques developed by Ansel Adams to deal with digital images. The resulting algorithm is simple and produces good results for a wide variety of images.

/pdf/photographic-tone-reproduction-for-digital-images-k89wmpv97f.pdf

Photographic tone reproduction for digital images

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A new BRDF model is presented which can be viewed as an kind of intermediary model between empirism and theory. Main results of physics are observed (energy conservation, reciprocity rule, microfacet theory) and numerous phenomena involved in light reflection are accounted for, in a physically plausible way (incoherent and coherent reflection, spectrum modifications, anisotropy, self-shadowing, multiple surface and subsurface reflection, differences between homogeneous and heterogeneous materials). The model has been especially intended for computer graphics applications and therefore includes two main features: simplicity (a small number of intuitively understandable parameters controls the model) and efficiency (the formulation provides adequation to Monte-Carlo rendering techniques and/or hardware implementations).

An Inexpensive BRDF Model for Physically-based Rendering

This paper proposes several techniques that enable to display high dynamic range pictures (created by a global illumination rendering program, for instance) on a low dynamic range device. The methods described here are based on some basic knowledge about human vision and are intended to provide “realistic looking” images on the visualization device, even with critical lighting conditions in the rendered scene. The main features of the new techniques are speed (only a handful of floating point operations per pixel are needed) and simplicity (only one single parameter, which can be empirically evaluated has to be provided by the user). The goal of this paper is not to propose a psychovisual or neurological model for subjective perception, but only to described some experimental results and propose some possible research directions.

Quantization Techniques for Visualization of High Dynamic Range Pictures

Many recent publications have shown that a large variety of computation involved in computer graphics can be moved from the CPU to the GPU, by a clever use of vertex or fragment shaders. Nonetheless there is still one kind of algorithms that is hard to translate from CPU to GPU: mesh refinement techniques. The main reason for this, is that vertex shaders available on current graphics hardware do not allow the generation of additional vertices on a mesh stored in graphics hardware. In this paper, we propose a general solution to generate mesh refinement on GPU. The main idea is to define a generic refinement pattern that will be used to virtually create additional inner vertices for a given polygon. These vertices are then translated according to some procedural displacement map defining the underlying geometry (similarly, the normal vectors may be transformed according to some procedural normal map). For illustration purpose, we use a tesselated triangular pattern, but many other refinement patterns may be employed. To show its flexibility, the technique has been applied on a large variety of refinement techniques: procedural displacement mapping, as well as more complex techniques such as curved PN-triangles or ST-meshes.

/pdf/generic-mesh-refinement-on-gpu-57klu1v3yl.pdf

Generic mesh refinement on GPU

This paper deals with modeling point sets with attributes. A point set in a geometric space of an arbitrary dimension is a geometric model of a real/abstract object or process under consideration. An attribute is a mathematical model of an object property of arbitrary nature (material, photometric, physical, statistical, etc.) defined at any point of the point set. We provide a brief survey of different modeling techniques related to point sets with attributes. It spans such different areas as solid modeling, heterogeneous objects modeling, scalar fields or "implicit surface" modeling and volume graphics. Then, on the basis of this survey we formulate requirements to a general model of hypervolumes (multidimensional point sets with multiple attributes). A general hypervolume model and its components such as objects, operations, and relations are introduced and discussed. A function representation (FRep) is used as the basic model for the point set geometry and attributes represented independently using real-valued scalar functions of several variables. Each function defining the geometry or an attribute is evaluated at the given point by a procedure traversing a constructive tree structure with primitives in the leaves and operations in the nodes of the tree. This reflects the constructive nature of the symmetric approach to modeling geometry and associated attributes in multidimensional space. To demonstrate a particular application of the proposed general model, we consider in detail the problem of texturing, introduce a model of constructive hypervolume texture, and then discuss its implementation, as well as the special modeling language we used for modeling hypervolume objects.

Constructive hypervolume modeling

Since the beginning of computer graphics, three decades ago, a large number of models intended to describe the behaviour of light on a given point of a surface have been proposed. Almost every author uses his own terminology and / or notation. To understand clearly the similarities and the differences between existing models, reformulating them with a unified notation is essential. This has been done by Hall in 1986. This paper is a new survey of shading and reflectance models, including the most recent models. Moreover, after the lengthy enumeration, some original models are proposed, which attempt to include interesting features of previous disjointed work into new formulations.

Christophe Schlick

Papers

An Inexpensive BRDF Model for Physically-based Rendering

Quantization Techniques for Visualization of High Dynamic Range Pictures

Generic mesh refinement on GPU

Constructive hypervolume modeling

A survey of shading and reflectance models