The identification of mammalian species through the classification of hair patterns using image pattern recognition
- Moyo, Thamasanqa, Bangay, Shaun D, Foster, Greg
- Authors: Moyo, Thamasanqa , Bangay, Shaun D , Foster, Greg
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432938 , vital:72914 , https://doi.org/10.1145/1108590.1108619
- Description: The identification of mammals through the use of their hair is important in the fields of forensics and ecology. The application of computer pattern recognition techniques to this process provides a means of reducing the subjectivity found in the process, as manual techniques rely on the interpretation of a human expert rather than quantitative measures. The first application of image pattern recognition techniques to the classification of African mammalian species using hair patterns is presented. This application uses a 2D Gabor filter-bank and motivates the use of moments to classify hair scale patterns. Application of a 2D Gabor filter-bank to hair scale processing provides results of 52% accuracy when using a filter-bank of size four and 72% accuracy when using a filter-bank of size eight. These initial results indicate that 2D Gabor filters produce information that may be successfully used to classify hair according to images of its patterns.
- Full Text:
- Date Issued: 2006
- Authors: Moyo, Thamasanqa , Bangay, Shaun D , Foster, Greg
- Date: 2006
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432938 , vital:72914 , https://doi.org/10.1145/1108590.1108619
- Description: The identification of mammals through the use of their hair is important in the fields of forensics and ecology. The application of computer pattern recognition techniques to this process provides a means of reducing the subjectivity found in the process, as manual techniques rely on the interpretation of a human expert rather than quantitative measures. The first application of image pattern recognition techniques to the classification of African mammalian species using hair patterns is presented. This application uses a 2D Gabor filter-bank and motivates the use of moments to classify hair scale patterns. Application of a 2D Gabor filter-bank to hair scale processing provides results of 52% accuracy when using a filter-bank of size four and 72% accuracy when using a filter-bank of size eight. These initial results indicate that 2D Gabor filters produce information that may be successfully used to classify hair according to images of its patterns.
- Full Text:
- Date Issued: 2006
Evaluating parts-of-speech taggers for use in a text-to-scene conversion system
- Glass, Kevin R, Bangay, Shaun D
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
- Authors: Glass, Kevin R , Bangay, Shaun D
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432654 , vital:72890 , https://www.cs.ru.ac.za/research/groups/vrsig/currentprojects/053texttoscene/paper01.pdf
- Description: This paper presents parts-of-speech tagging as a first step towards an autonomous text-to-scene conversion system. It categorizes some freely available taggers, according to the techniques used by each in order to automatically identify word-classes. In addition, the performance of each identified tagger is verified experimentally. The SUSANNE corpus is used for testing and reveals the complexity of working with different tagsets, resulting in substantially lower accuracies in our tests than in those reported by the developers of each tagger. The taggers are then grouped to form a voting system to attempt to raise accuracies, but in no cases do the combined results improve upon the individual accuracies. Additionally a new metric, agreement, is tentatively proposed as an indication of confidence in the output of a group of taggers where such output cannot be validated.
- Full Text:
- Date Issued: 2005
Kaleidoscope configurations for reflectance measurement
- Bangay, Shaun D, Radloff, Judith D
- Authors: Bangay, Shaun D , Radloff, Judith D
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432891 , vital:72910 , https://doi.org/10.1145/1029949.1029979
- Description: Simulations of different configurations of the symmetrical tapered kaleidoscope are performed to assess their merits for measurement of BRDFs and BTFs. The relationship between optimal kaleidoscope layout, and factors such as hardware restrictions and the resolution of the required reflectance function, is derived. The effect on the measurement of the reflectance function of changing these independent variables is examined through the simulation. These experiments highlight issues affecting the measurement of BTFs using kaleidoscopes, and suggest configurations that allow sampling at regular parameter intervals. A number of other kaleidoscope architectures are explored, which offer the benefits of potentially doubling the range of directions that can be sampled, and allowing adaptive control of sample intervals.
- Full Text:
- Date Issued: 2004
- Authors: Bangay, Shaun D , Radloff, Judith D
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432891 , vital:72910 , https://doi.org/10.1145/1029949.1029979
- Description: Simulations of different configurations of the symmetrical tapered kaleidoscope are performed to assess their merits for measurement of BRDFs and BTFs. The relationship between optimal kaleidoscope layout, and factors such as hardware restrictions and the resolution of the required reflectance function, is derived. The effect on the measurement of the reflectance function of changing these independent variables is examined through the simulation. These experiments highlight issues affecting the measurement of BTFs using kaleidoscopes, and suggest configurations that allow sampling at regular parameter intervals. A number of other kaleidoscope architectures are explored, which offer the benefits of potentially doubling the range of directions that can be sampled, and allowing adaptive control of sample intervals.
- Full Text:
- Date Issued: 2004
Modelling and rendering techniques for african hairstyles
- Patrick, Deborah, Bangay, Shaun D, Lobb, Adele
- Authors: Patrick, Deborah , Bangay, Shaun D , Lobb, Adele
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432905 , vital:72911 , https://doi.org/10.1145/1029949.1029971
- Description: We develop or enhance hair modelling and rendering techniques to produce three different forms of hair commonly found in African hairstyles. The forms of hair are natural curly hair, straightened hair, and braids or twists of hair. We use an implicit model, implemented as a series of textured layers to represent curly hair. Straightened hair is represented explicitly, and mod-elled by defining and replicating a few control hairs. Braids and twists are implemented as textured generalized cylinders. A synthesis of existing hair illumination models is used as a basis for an African hair illumination model. Parameter values to match African hair characteristics are discussed. A number of complete African hairstyles are shown, demonstrating that the techniques can be used to model and render African hair successfully.
- Full Text:
- Date Issued: 2004
- Authors: Patrick, Deborah , Bangay, Shaun D , Lobb, Adele
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432905 , vital:72911 , https://doi.org/10.1145/1029949.1029971
- Description: We develop or enhance hair modelling and rendering techniques to produce three different forms of hair commonly found in African hairstyles. The forms of hair are natural curly hair, straightened hair, and braids or twists of hair. We use an implicit model, implemented as a series of textured layers to represent curly hair. Straightened hair is represented explicitly, and mod-elled by defining and replicating a few control hairs. Braids and twists are implemented as textured generalized cylinders. A synthesis of existing hair illumination models is used as a basis for an African hair illumination model. Parameter values to match African hair characteristics are discussed. A number of complete African hairstyles are shown, demonstrating that the techniques can be used to model and render African hair successfully.
- Full Text:
- Date Issued: 2004
Wearing your PIM: experiments with an audio enhanced PIM
- Tsegaye, Melekam, Bangay, Shaun D, Terzoli, Alfredo
- Authors: Tsegaye, Melekam , Bangay, Shaun D , Terzoli, Alfredo
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432854 , vital:72904 , https://www.cs.ru.ac.za/research/g98t4414/static/papers/wpimfinal.pdf
- Description: PIM systems help organise people’s lives by providing address book, schedule and task management facilities. Current PIM’s manage this information by collecting and storing it as textual data. With the advent of the wearable computer, using text only is no longer an efficient and convenient mechanism for managing personal information. A wearable computer should use data from various sensors (video, audio, location, environmental, user state) to organise personal information. In this paper we examine how audio can be used to enhance the facilities provided by text-only PIM’s and present an example implementation of an audio based wearable PIM (wPIM) that has the capability of storing and retrieving PIM information as audio recordings. The results of the user evaluation we conducted, which was carried out outside of the laboratory, suggests that users strongly accept audio as a way to manage their personal information and to augment their memory, supporting our hypothesis that audio enhances wearable personal information management.
- Full Text:
- Date Issued: 2004
- Authors: Tsegaye, Melekam , Bangay, Shaun D , Terzoli, Alfredo
- Date: 2004
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432854 , vital:72904 , https://www.cs.ru.ac.za/research/g98t4414/static/papers/wpimfinal.pdf
- Description: PIM systems help organise people’s lives by providing address book, schedule and task management facilities. Current PIM’s manage this information by collecting and storing it as textual data. With the advent of the wearable computer, using text only is no longer an efficient and convenient mechanism for managing personal information. A wearable computer should use data from various sensors (video, audio, location, environmental, user state) to organise personal information. In this paper we examine how audio can be used to enhance the facilities provided by text-only PIM’s and present an example implementation of an audio based wearable PIM (wPIM) that has the capability of storing and retrieving PIM information as audio recordings. The results of the user evaluation we conducted, which was carried out outside of the laboratory, suggests that users strongly accept audio as a way to manage their personal information and to augment their memory, supporting our hypothesis that audio enhances wearable personal information management.
- Full Text:
- Date Issued: 2004
A digital watermarking scheme for Bezier surfaces
- Chadwick, J, Bangay, Shaun D, Wentworth, Peter E
- Authors: Chadwick, J , Bangay, Shaun D , Wentworth, Peter E
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432769 , vital:72898 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/046watermarking/paper01.pdf
- Description: Owners and vendors are increasingly publishing their materials in digital form. Because such materials can be exactly copied, a mechanism is required that will protect the legitimate owners of these works, by providing proof of original ownership. Digital watermarking has now become one accepted method of establishing ownership of digital materials. The owner of a work embeds a pattern, called a digital watermark, in the content. This embedded watermark is normally undetectable, but its presence can be demonstrated by the owner of the work or his agent, thereby proving ownership. Digital watermarking has been used for many types of multimedia content, primarily audio, video and flat images. Recently, interest has been shown in applying digital watermarking schemes to 3D surfaces, in various formats. In this paper, we examine a method whereby a digital watermark can be embedded in a Bezier surface. A prototype watermarking method for such surfaces is presented, with some experimental results, and a discussion of directions for future research.
- Full Text:
- Date Issued: 2003
- Authors: Chadwick, J , Bangay, Shaun D , Wentworth, Peter E
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432769 , vital:72898 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/046watermarking/paper01.pdf
- Description: Owners and vendors are increasingly publishing their materials in digital form. Because such materials can be exactly copied, a mechanism is required that will protect the legitimate owners of these works, by providing proof of original ownership. Digital watermarking has now become one accepted method of establishing ownership of digital materials. The owner of a work embeds a pattern, called a digital watermark, in the content. This embedded watermark is normally undetectable, but its presence can be demonstrated by the owner of the work or his agent, thereby proving ownership. Digital watermarking has been used for many types of multimedia content, primarily audio, video and flat images. Recently, interest has been shown in applying digital watermarking schemes to 3D surfaces, in various formats. In this paper, we examine a method whereby a digital watermark can be embedded in a Bezier surface. A prototype watermarking method for such surfaces is presented, with some experimental results, and a discussion of directions for future research.
- Full Text:
- Date Issued: 2003
A lightwave 3d plug-in for modeling long hair on virtual humans
- Patrick, Deborah, Bangay, Shaun D
- Authors: Patrick, Deborah , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432953 , vital:72916 , https://doi.org/10.1145/602330.602360
- Description: Multimedia applications today make use of virtual humans. Generating realistic virtual humans is a challenging problem owing to a number of factors, one being the simulation of realistic hair. The difficulty in simulating hair is due to the physical properties of hair. The average human head holds thousands of hairs, with the width of each hair often smaller than the size of a pixel. There are also complex lighting effects that occur within hair. This paper presents a LightWave 3D plug-in for modeling thousands of individual hairs on virtual humans. The plug-in allows the user to specify the length, thickness and distribution of the hair, as well as the number of segments a hair is made up of. The plug-in is able to add hairs to a head model, which the user then modifies to define a hairstyle. The hairs are then multiplied by the plug-in to produce many hairs. By providing a plug-in that does most of the work and produces realistic results, the user is able to produce a hairstyle without modeling each individual strand of hair. This greatly reduces the time spent on hair modeling, and makes the possibility of adding realistic long hair to virtual humans reasonable.
- Full Text:
- Date Issued: 2003
- Authors: Patrick, Deborah , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432953 , vital:72916 , https://doi.org/10.1145/602330.602360
- Description: Multimedia applications today make use of virtual humans. Generating realistic virtual humans is a challenging problem owing to a number of factors, one being the simulation of realistic hair. The difficulty in simulating hair is due to the physical properties of hair. The average human head holds thousands of hairs, with the width of each hair often smaller than the size of a pixel. There are also complex lighting effects that occur within hair. This paper presents a LightWave 3D plug-in for modeling thousands of individual hairs on virtual humans. The plug-in allows the user to specify the length, thickness and distribution of the hair, as well as the number of segments a hair is made up of. The plug-in is able to add hairs to a head model, which the user then modifies to define a hairstyle. The hairs are then multiplied by the plug-in to produce many hairs. By providing a plug-in that does most of the work and produces realistic results, the user is able to produce a hairstyle without modeling each individual strand of hair. This greatly reduces the time spent on hair modeling, and makes the possibility of adding realistic long hair to virtual humans reasonable.
- Full Text:
- Date Issued: 2003
Realistic autonomous fish for virtual reality
- Lobb, Adele, Bangay, Shaun D
- Authors: Lobb, Adele , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433398 , vital:72967 , https://doi.org/10.1145/602330.602361
- Description: We create realistic autonomous fish for Virtual Reality systems. The fish are realistic in appearance, movement and behaviour: the swimming behaviour being non-scripted, within real time rendering.The form of the fish is procedurally created. The size and shape of the form are controlled by a number of variables which are stored in a simple ASCII file. This allows efficient creation of different fish at run time.The behaviour is obtained by implementing a flocking algorithm.
- Full Text:
- Date Issued: 2003
- Authors: Lobb, Adele , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433398 , vital:72967 , https://doi.org/10.1145/602330.602361
- Description: We create realistic autonomous fish for Virtual Reality systems. The fish are realistic in appearance, movement and behaviour: the swimming behaviour being non-scripted, within real time rendering.The form of the fish is procedurally created. The size and shape of the form are controlled by a number of variables which are stored in a simple ASCII file. This allows efficient creation of different fish at run time.The behaviour is obtained by implementing a flocking algorithm.
- Full Text:
- Date Issued: 2003
Rendering optimisations for stylised sketching
- Winnemöller, Holger, Bangay, Shaun D
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432922 , vital:72913 , https://doi.org/10.1145/602330.602353
- Description: We present work that specifically pertains to the rendering stage of stylised, non-photorealistic sketching. While a substantial body of work has been published on geometric optimisations, surface topologies, space-algorithms and natural media simulation, rendering-specific issues are rarely discussed in-depth even though they are often acknowledged. We investigate the most common stylised sketching approaches and identify possible rendering optimisations. In particular, we define uncertainty-functions, which are used to describe a human-error component, discuss how these pertain to geometric perturbation and textured silhouette sketching and explain how they can be cached to improve performance. Temporal coherence, which poses a problem for textured silhouette sketching, is addressed by means of an easily computed visibility-function. Lastly, we produce an effective yet surprisingly simple solution to seamless hatching, which commonly presents a large computational overhead, by using 3-D textures in a novel fashion. All our optimisations are cost-effective, easy to implement and work in conjunction with most existing algorithms.
- Full Text:
- Date Issued: 2003
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432922 , vital:72913 , https://doi.org/10.1145/602330.602353
- Description: We present work that specifically pertains to the rendering stage of stylised, non-photorealistic sketching. While a substantial body of work has been published on geometric optimisations, surface topologies, space-algorithms and natural media simulation, rendering-specific issues are rarely discussed in-depth even though they are often acknowledged. We investigate the most common stylised sketching approaches and identify possible rendering optimisations. In particular, we define uncertainty-functions, which are used to describe a human-error component, discuss how these pertain to geometric perturbation and textured silhouette sketching and explain how they can be cached to improve performance. Temporal coherence, which poses a problem for textured silhouette sketching, is addressed by means of an easily computed visibility-function. Lastly, we produce an effective yet surprisingly simple solution to seamless hatching, which commonly presents a large computational overhead, by using 3-D textures in a novel fashion. All our optimisations are cost-effective, easy to implement and work in conjunction with most existing algorithms.
- Full Text:
- Date Issued: 2003
Simulation and visualization of fire using extended Lindenmayer systems
- Zaniewski, Tomasz, Bangay, Shaun D
- Authors: Zaniewski, Tomasz , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433303 , vital:72960 , https://doi.org/10.1145/602330.602337
- Description: This research introduces a method of using Lindenmayer Systems to model the spreading and behavior of fire inside a factory building. The research investigates the use of L-System propagated fires for determining factors such as where the fire is most likely to spread first and how fast. It also looks at an alternative way of storing the Lindenmayer System, not in the form of a string but rather as a graph. A variation on the building and traversal process is also investigated, in which the L-System is traversed depth first instead of breadth first. Results of fire propagation are presented and we conclude that L-Systems are a suitable tool for fire propagation.
- Full Text:
- Date Issued: 2003
- Authors: Zaniewski, Tomasz , Bangay, Shaun D
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433303 , vital:72960 , https://doi.org/10.1145/602330.602337
- Description: This research introduces a method of using Lindenmayer Systems to model the spreading and behavior of fire inside a factory building. The research investigates the use of L-System propagated fires for determining factors such as where the fire is most likely to spread first and how fast. It also looks at an alternative way of storing the Lindenmayer System, not in the form of a string but rather as a graph. A variation on the building and traversal process is also investigated, in which the L-System is traversed depth first instead of breadth first. Results of fire propagation are presented and we conclude that L-Systems are a suitable tool for fire propagation.
- Full Text:
- Date Issued: 2003
Geometric approximations towards free specular comic shading
- Winnemöller, Holger, Bangay, Shaun D
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433453 , vital:72971 , https://doi.org/10.1111/1467-8659.00590
- Description: We extend the standard solution to comic rendering with a comic‐style specular component. To minimise the computational overhead associated with this extension, we introduce two optimising approximations; the perspective correction angle and the vertex face‐orientation measure. Both of these optimisations are generally applicable, but they are especially well suited for applications where a physically correct lighting simulation is not required. Using our optimisations we achieve performances comparable to the standard solution. As our approximations favour large models, we even outperform the standard approach for models consisting of 10,000 triangles or more, which we can render exceeding 40 frames per second, including the specular component.
- Full Text:
- Date Issued: 2002
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433453 , vital:72971 , https://doi.org/10.1111/1467-8659.00590
- Description: We extend the standard solution to comic rendering with a comic‐style specular component. To minimise the computational overhead associated with this extension, we introduce two optimising approximations; the perspective correction angle and the vertex face‐orientation measure. Both of these optimisations are generally applicable, but they are especially well suited for applications where a physically correct lighting simulation is not required. Using our optimisations we achieve performances comparable to the standard solution. As our approximations favour large models, we even outperform the standard approach for models consisting of 10,000 triangles or more, which we can render exceeding 40 frames per second, including the specular component.
- Full Text:
- Date Issued: 2002
Experiences in porting a virtual reality system to Java
- Authors: Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433157 , vital:72947 , https://doi.org/10.1145/513867.513875
- Description: Practical experience in porting a large virtual reality system from C/C++ to Java indicates that porting this type of real-time application is both feasible, and has several merits. The ability to transfer objects in space and time allows useful facilities such as distributed agent support and persistence to be added. Reflection and type comparisons allow flexible manipulations of objects of different types at run-time. Native calls and native code compilation reduce or remove the overhead of interpreting code.Problems encountered include difficulty in achieving cross-platform code portability, limitations of the networking libraries in Java, and clumsy coding practices forced by the language.
- Full Text:
- Date Issued: 2001
- Authors: Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433157 , vital:72947 , https://doi.org/10.1145/513867.513875
- Description: Practical experience in porting a large virtual reality system from C/C++ to Java indicates that porting this type of real-time application is both feasible, and has several merits. The ability to transfer objects in space and time allows useful facilities such as distributed agent support and persistence to be added. Reflection and type comparisons allow flexible manipulations of objects of different types at run-time. Native calls and native code compilation reduce or remove the overhead of interpreting code.Problems encountered include difficulty in achieving cross-platform code portability, limitations of the networking libraries in Java, and clumsy coding practices forced by the language.
- Full Text:
- Date Issued: 2001
Implementation and applications of the distortion operator
- Authors: Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433382 , vital:72966 , https://doi.org/10.1145/513867.513872
- Description: The distortion operator transforms 2D images in a manner similar to image warping or morphing, allowing source pixels to be mapped to any destination pixel. This operator can be implemented on current hardware, allowing at least one distortion per frame at interactive frame rates. Potential applications are numerous, but those described include re-mapping images for correct projection onto curved screens, correcting camera distortion from multiple sources simultaneously, and allowing constant time dynamic texturing and lighting of a static scene which is independent of geometric complexity.
- Full Text:
- Date Issued: 2001
- Authors: Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/433382 , vital:72966 , https://doi.org/10.1145/513867.513872
- Description: The distortion operator transforms 2D images in a manner similar to image warping or morphing, allowing source pixels to be mapped to any destination pixel. This operator can be implemented on current hardware, allowing at least one distortion per frame at interactive frame rates. Potential applications are numerous, but those described include re-mapping images for correct projection onto curved screens, correcting camera distortion from multiple sources simultaneously, and allowing constant time dynamic texturing and lighting of a static scene which is independent of geometric complexity.
- Full Text:
- Date Issued: 2001
Rendering Primitives for a Virtual Holodeck
- Morkel, Chantelle, Bangay, Shaun D
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
- Full Text:
- Date Issued: 2001
- Authors: Morkel, Chantelle , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432795 , vital:72901 , https://www.cs.ru.ac.za/research/groups/vrsig/pastprojects/039virtualholodeck/paper02.pdf
- Description: The main objective of this research is to implement a “Star Trek”-like holodeck in a computer environment. An experiment to create graphical primitives and images solely out of spheres is being conducted. We investigate several approaches of creating primitives using spheres, and then using these primitives to create images. Initial results of this experiment are presented and we conclude that using spheres to create primitives and images is a viable approach to creating realistic-looking three-dimensional (3D) images.
- Full Text:
- Date Issued: 2001
Super-realistic rendering using real-time tweening
- Winnemöller, Holger, Bangay, Shaun D
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432810 , vital:72902 , https://citeseerx.ist.psu.edu/document?repid=rep1type=pdfoi=eec3809e91a26dbf991a37a3a6a4f1291ae4ec4d
- Description: The realism of contemporary computer graphics (and especially Virtual Reality {VR}) is limited by the great computational cost of rendering objects of appropriate complexity with convincing lighting and surface effects. We introduce a framework that allows rendering of objects in true photographic quality using tweening. The simple but effective design of our system allows us not only to perform the necessary operations in real-time on standard hardware, but also achieve other effects like morphing. Furthermore, it is shown how our system can be gainfully employed in non-VR contexts like extreme low-bandwidth video-conferencing and others.
- Full Text:
- Date Issued: 2001
- Authors: Winnemöller, Holger , Bangay, Shaun D
- Date: 2001
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432810 , vital:72902 , https://citeseerx.ist.psu.edu/document?repid=rep1type=pdfoi=eec3809e91a26dbf991a37a3a6a4f1291ae4ec4d
- Description: The realism of contemporary computer graphics (and especially Virtual Reality {VR}) is limited by the great computational cost of rendering objects of appropriate complexity with convincing lighting and surface effects. We introduce a framework that allows rendering of objects in true photographic quality using tweening. The simple but effective design of our system allows us not only to perform the necessary operations in real-time on standard hardware, but also achieve other effects like morphing. Furthermore, it is shown how our system can be gainfully employed in non-VR contexts like extreme low-bandwidth video-conferencing and others.
- Full Text:
- Date Issued: 2001
From virtual to physical reality with paper folding
- Authors: Bangay, Shaun D
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432669 , vital:72891 , https://doi.org/10.1016/S0925-7721(99)00048-6
- Description: Objects in a virtual world can be converted into hardcopy by per-pendicular projection of each face onto a sheet of paper, cutting and gluing. Previously, use of this technique was restricted to a limited class of polyhedral objects. This paper extends this process to realis-tic virtual objects, with the traditional origami restriction of using only a single sheet of paper. A number of algorithms are explored to achieve this goal. The use of heuristics allows solutions to be found without exhaustive search of all possible layouts. Approaches to deal with pathological cases are described. The techniques have al-ready been successfully applied to a number of complex models, selected from a number of model archives on the Internet.
- Full Text:
- Date Issued: 2000
- Authors: Bangay, Shaun D
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432669 , vital:72891 , https://doi.org/10.1016/S0925-7721(99)00048-6
- Description: Objects in a virtual world can be converted into hardcopy by per-pendicular projection of each face onto a sheet of paper, cutting and gluing. Previously, use of this technique was restricted to a limited class of polyhedral objects. This paper extends this process to realis-tic virtual objects, with the traditional origami restriction of using only a single sheet of paper. A number of algorithms are explored to achieve this goal. The use of heuristics allows solutions to be found without exhaustive search of all possible layouts. Approaches to deal with pathological cases are described. The techniques have al-ready been successfully applied to a number of complex models, selected from a number of model archives on the Internet.
- Full Text:
- Date Issued: 2000
A generic virtual reality interaction system and its extensions using the common object request broker architecture (CORBA)
- Rorke, Michael, Bangay, Shaun D
- Authors: Rorke, Michael , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432684 , vital:72892 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/013interaction/paper03.pdf
- Description: The paper describes the design and implementation of an immersive Virtual Reality (VR) interaction system. The system aims to provide a flexible mechanism for programmers to implement interaction in their VR applications, making good use of all accepted practices in the field. The paper further describes how the system was extended to a multi-user system using the CORBA middleware layer.
- Full Text:
- Date Issued: 1999
- Authors: Rorke, Michael , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432684 , vital:72892 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/013interaction/paper03.pdf
- Description: The paper describes the design and implementation of an immersive Virtual Reality (VR) interaction system. The system aims to provide a flexible mechanism for programmers to implement interaction in their VR applications, making good use of all accepted practices in the field. The paper further describes how the system was extended to a multi-user system using the CORBA middleware layer.
- Full Text:
- Date Issued: 1999
A Prototyping Environment for Investigating Context Aware Wearable Applications.
- Tsegaye, Melekam, Bangay, Shaun D, Terzoli, Alfredo
- Authors: Tsegaye, Melekam , Bangay, Shaun D , Terzoli, Alfredo
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432783 , vital:72900 , https://www.cs.ru.ac.za/research/g98t4414/static/papers/wearprototsegaye05.pdf
- Description: In this paper we introduce the concept of a contextaware, wearable application prototyping environment, which can be used to support research into new wearable applications. We also present an initial specification for such an environment and show how different types of sensors can be modelled to produce data that describes a given context scenario using our prototyping approach.
- Full Text:
- Date Issued: 1999
- Authors: Tsegaye, Melekam , Bangay, Shaun D , Terzoli, Alfredo
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432783 , vital:72900 , https://www.cs.ru.ac.za/research/g98t4414/static/papers/wearprototsegaye05.pdf
- Description: In this paper we introduce the concept of a contextaware, wearable application prototyping environment, which can be used to support research into new wearable applications. We also present an initial specification for such an environment and show how different types of sensors can be modelled to produce data that describes a given context scenario using our prototyping approach.
- Full Text:
- Date Issued: 1999
The Development of a Generic Framework for the Implementation of Cheap, Component-Based Virtual Video-Conferencing System
- Panagou, Soteri, Bangay, Shaun D
- Authors: Panagou, Soteri , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432824 , vital:72903 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/014humanmodelling/paper03.pdf
- Description: We address the problem of virtual-videoconferencing. The proposed solution is effected in terms of a generic framework based on an in-house Virtual Reality system. The framework is composed of a number of distinct components: model acquisition, head tracking, expression analysis, network transmission and avatar reconstruction. The framework promises to provide a unique, cheap, and fast system for avatar construction, transmission and animation. This approach affords a conversion from the traditional video stream approach to the management of an avatar remotely and consequently makes minimal demands on network resources.
- Full Text:
- Date Issued: 1999
- Authors: Panagou, Soteri , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432824 , vital:72903 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/014humanmodelling/paper03.pdf
- Description: We address the problem of virtual-videoconferencing. The proposed solution is effected in terms of a generic framework based on an in-house Virtual Reality system. The framework is composed of a number of distinct components: model acquisition, head tracking, expression analysis, network transmission and avatar reconstruction. The framework promises to provide a unique, cheap, and fast system for avatar construction, transmission and animation. This approach affords a conversion from the traditional video stream approach to the management of an avatar remotely and consequently makes minimal demands on network resources.
- Full Text:
- Date Issued: 1999
The Virtual Remote Control-An Extensible, Virtual Reality, User Interface Device
- Rorke, Michael, Bangay, Shaun D
- Authors: Rorke, Michael , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432743 , vital:72896 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/013interaction/paper02.pdf
- Description: Immersive virtual reality (VR) places the user inside of the computing envi-ronment, blurring the distinction between the environment itself and the user interface to access that environment non-obvious. This lack of distinction between environment and interface makes it difficult to place menus and other interface elements where the user is both able to access them easily and where they do not obscure large parts of the users field of view. We propose a system called the 'Virtual Remote Control' (VRC). The VRC con-sists of a physical device (a small touchpad tracked using a Polhemus In-sideTrak magnetic tracker) which the user is able to hold and for which there is a representation in the virtual environment. The VRC is represented in the environment by a virtual menu. The user is able to make selections from the virtual menu by moving their finger around the touch pad part of the VRC and 'tapping' on the required action. Additionally, the user is able to select an object for the action to be applied on, by 'pointing' the representa-tion of the VRC at the object-as one would point a remote control at a Hi-fi of TV set.
- Full Text:
- Date Issued: 1999
- Authors: Rorke, Michael , Bangay, Shaun D
- Date: 1999
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/432743 , vital:72896 , https://www.cs.ru.ac.za/research/Groups/vrsig/pastprojects/013interaction/paper02.pdf
- Description: Immersive virtual reality (VR) places the user inside of the computing envi-ronment, blurring the distinction between the environment itself and the user interface to access that environment non-obvious. This lack of distinction between environment and interface makes it difficult to place menus and other interface elements where the user is both able to access them easily and where they do not obscure large parts of the users field of view. We propose a system called the 'Virtual Remote Control' (VRC). The VRC con-sists of a physical device (a small touchpad tracked using a Polhemus In-sideTrak magnetic tracker) which the user is able to hold and for which there is a representation in the virtual environment. The VRC is represented in the environment by a virtual menu. The user is able to make selections from the virtual menu by moving their finger around the touch pad part of the VRC and 'tapping' on the required action. Additionally, the user is able to select an object for the action to be applied on, by 'pointing' the representa-tion of the VRC at the object-as one would point a remote control at a Hi-fi of TV set.
- Full Text:
- Date Issued: 1999