1,934 research outputs found
Hardware acceleration of photon mapping
PhD ThesisThe quest for realism in computer-generated graphics has yielded a range of algorithmic
techniques, the most advanced of which are capable of rendering images at close to photorealistic
quality. Due to the realism available, it is now commonplace that computer graphics are used in
the creation of movie sequences, architectural renderings, medical imagery and product
visualisations.
This work concentrates on the photon mapping algorithm [1, 2], a physically based global
illumination rendering algorithm. Photon mapping excels in producing highly realistic, physically
accurate images.
A drawback to photon mapping however is its rendering times, which can be significantly longer
than other, albeit less realistic, algorithms. Not surprisingly, this increase in execution time is
associated with a high computational cost. This computation is usually performed using the
general purpose central processing unit (CPU) of a personal computer (PC), with the algorithm
implemented as a software routine. Other options available for processing these algorithms
include desktop PC graphics processing units (GPUs) and custom designed acceleration hardware
devices.
GPUs tend to be efficient when dealing with less realistic rendering solutions such as rasterisation,
however with their recent drive towards increased programmability they can also be used to
process more realistic algorithms. A drawback to the use of GPUs is that these algorithms often
have to be reworked to make optimal use of the limited resources available.
There are very few custom hardware devices available for acceleration of the photon mapping
algorithm. Ray-tracing is the predecessor to photon mapping, and although not capable of
producing the same physical accuracy and therefore realism, there are similarities between the
algorithms. There have been several hardware prototypes, and at least one commercial offering,
created with the goal of accelerating ray-trace rendering [3]. However, properties making many of
these proposals suitable for the acceleration of ray-tracing are not shared by photon mapping.
There are even fewer proposals for acceleration of the additional functions found only in photon
mapping.
All of these approaches to algorithm acceleration offer limited scalability. GPUs are inherently
difficult to scale, while many of the custom hardware devices available thus far make use of large
processing elements and complex acceleration data structures.
In this work we make use of three novel approaches in the design of highly scalable specialised
hardware structures for the acceleration of the photon mapping algorithm. Increased scalability is
gained through:
• The use of a brute-force approach in place of the commonly used smart approach, thus
eliminating much data pre-processing, complex data structures and large processing units
often required.
• The use of Logarithmic Number System (LNS) arithmetic computation, which facilitates a
reduction in processing area requirement.
• A novel redesign of the photon inclusion test, used within the photon search method of
the photon mapping algorithm. This allows an intelligent memory structure to be used for
the search.
The design uses two hardware structures, both of which accelerate one core rendering function.
Renderings produced using field programmable gate array (FPGA) based prototypes are presented,
along with details of 90nm synthesised versions of the designs which show that close to an orderof-
magnitude speedup over a software implementation is possible. Due to the scalable nature of
the design, it is likely that any advantage can be maintained in the face of improving processor
speeds.
Significantly, due to the brute-force approach adopted, it is possible to eliminate an often-used
software acceleration method. This means that the device can interface almost directly to a frontend
modelling package, minimising much of the pre-processing required by most other proposals
Hardware acceleration of photon mapping
The quest for realism in computer-generated graphics has yielded a range of algorithmic techniques, the most advanced of which are capable of rendering images at close to photorealistic quality. Due to the realism available, it is now commonplace that computer graphics are used in the creation of movie sequences, architectural renderings, medical imagery and product visualisations. This work concentrates on the photon mapping algorithm [1, 2], a physically based global illumination rendering algorithm. Photon mapping excels in producing highly realistic, physically accurate images. A drawback to photon mapping however is its rendering times, which can be significantly longer than other, albeit less realistic, algorithms. Not surprisingly, this increase in execution time is associated with a high computational cost. This computation is usually performed using the general purpose central processing unit (CPU) of a personal computer (PC), with the algorithm implemented as a software routine. Other options available for processing these algorithms include desktop PC graphics processing units (GPUs) and custom designed acceleration hardware devices. GPUs tend to be efficient when dealing with less realistic rendering solutions such as rasterisation, however with their recent drive towards increased programmability they can also be used to process more realistic algorithms. A drawback to the use of GPUs is that these algorithms often have to be reworked to make optimal use of the limited resources available. There are very few custom hardware devices available for acceleration of the photon mapping algorithm. Ray-tracing is the predecessor to photon mapping, and although not capable of producing the same physical accuracy and therefore realism, there are similarities between the algorithms. There have been several hardware prototypes, and at least one commercial offering, created with the goal of accelerating ray-trace rendering [3]. However, properties making many of these proposals suitable for the acceleration of ray-tracing are not shared by photon mapping. There are even fewer proposals for acceleration of the additional functions found only in photon mapping. All of these approaches to algorithm acceleration offer limited scalability. GPUs are inherently difficult to scale, while many of the custom hardware devices available thus far make use of large processing elements and complex acceleration data structures. In this work we make use of three novel approaches in the design of highly scalable specialised hardware structures for the acceleration of the photon mapping algorithm. Increased scalability is gained through: • The use of a brute-force approach in place of the commonly used smart approach, thus eliminating much data pre-processing, complex data structures and large processing units often required. • The use of Logarithmic Number System (LNS) arithmetic computation, which facilitates a reduction in processing area requirement. • A novel redesign of the photon inclusion test, used within the photon search method of the photon mapping algorithm. This allows an intelligent memory structure to be used for the search. The design uses two hardware structures, both of which accelerate one core rendering function. Renderings produced using field programmable gate array (FPGA) based prototypes are presented, along with details of 90nm synthesised versions of the designs which show that close to an orderof- magnitude speedup over a software implementation is possible. Due to the scalable nature of the design, it is likely that any advantage can be maintained in the face of improving processor speeds. Significantly, due to the brute-force approach adopted, it is possible to eliminate an often-used software acceleration method. This means that the device can interface almost directly to a frontend modelling package, minimising much of the pre-processing required by most other proposals.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Serious Games in Cultural Heritage
Although the widespread use of gaming for leisure purposes has been well documented, the use of games to support cultural heritage purposes, such as historical teaching and learning, or for enhancing museum visits, has been less well considered. The state-of-the-art in serious game technology is identical to that of the state-of-the-art in entertainment games technology. As a result the field of serious heritage games concerns itself with recent advances in computer games, real-time computer graphics, virtual and augmented reality and artificial intelligence. On the other hand, the main strengths of serious gaming applications may be generalised as being in the areas of communication, visual expression of information, collaboration mechanisms, interactivity and entertainment. In this report, we will focus on the state-of-the-art with respect to the theories, methods and technologies used in serious heritage games. We provide an overview of existing literature of relevance to the domain, discuss the strengths and weaknesses of the described methods and point out unsolved problems and challenges. In addition, several case studies illustrating the application of methods and technologies used in cultural heritage are presented
Developing serious games for cultural heritage: a state-of-the-art review
Although the widespread use of gaming for leisure purposes has been well documented, the use of games to support cultural heritage purposes, such as historical teaching and learning, or for enhancing museum visits, has been less well considered. The state-of-the-art in serious game technology is identical to that of the state-of-the-art in entertainment games technology. As a result, the field of serious heritage games concerns itself with recent advances in computer games, real-time computer graphics, virtual and augmented reality and artificial intelligence. On the other hand, the main strengths of serious gaming applications may be generalised as being in the areas of communication, visual expression of information, collaboration mechanisms, interactivity and entertainment. In this report, we will focus on the state-of-the-art with respect to the theories, methods and technologies used in serious heritage games. We provide an overview of existing literature of relevance to the domain, discuss the strengths and weaknesses of the described methods and point out unsolved problems and challenges. In addition, several case studies illustrating the application of methods and technologies used in cultural heritage are presented
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