Realistic simulations of the ocean surface based on statistical wave models typically rely on very large Fourier grids. Real-time requirements severely limit the size of the grids that can be used, even if the FFT is implemented on the GPU. Moreover, none of the grids used so far are sufficient for capturing the entire dynamic range of ocean waves, which can easily span four to five orders of magnitude. Our approach removes the FFT as the computational bottleneck of sea surface simulations. By splitting the wave number range into a small number of non-overlapping, relatively narrow bands within which the samples are equidistantly spaced allows making use of the FFT while having some of the flexibility of the adaptive approaches that concentrate wave number samples in high-energy regions of the spectrum.

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In this work we present a new method for the realistic real-time simulation of rivers. Our solution includes a 2D fluid solver that simulates the flow of a river's surface, an efficient method for adaptively computing 3D flow information and an animated 3D procedural wave texture that is advected through the fluid via advection particles in order to mimic the highly detailed fluid surfaces that are characteristic of rivers. Our technique that couples animated texture advection with a pseudo-3D fluid simulation produces stable results that are representative of large scale real-world rivers and suitable for use in real-time applications. Our system surpasses prior work on real-time river rendering both with regards to efficiency and visual quality, which we establish through the rendering of rivers tens of kilometers long.

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With the advent of ever-cheaper genome sequencing technologies, a wide range of organisms can now be examined at the genetic level, and biodiversity can be expressed in quantitative terms of genetic similarity and shared function. These techniques are now being applied to samples collected directly from the environment to give a cross-section of the diversity that exists at different locations in different habitats. We are developing an open source, 3D geospatial information system to examine and test relationships between biodiversity, geography, and the environment. The goal is to acquire cartographic and environmental data from many sources, and overlay user-provided genomic sample sites and genetic sequences.

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NetFlow data is being accumulated from the borders between private networks and the public internet. The data aggregate grows at the rate of gigabytes per day, stored in SiLK repositories. While tools exist to look for known malicious activities such as scanning, the volume of the data, its volatility, and the difficulty of establishing its “ground truth” preclude the use of conventional anomaly detection approaches for detecting malicious activity. To aid analysts in understanding this data, we are developing a comprehensive and extensible set of visualization tools, integrated with the SiLK tool suite via a relational database that stores data such as sets and multisets (“bags”), derived from NetFlow and similar sources.

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We physically relate to our environment in three dimensions. However, familiar modes of interaction reside in 2D, which mimic our interactions with traditional paper-based media. In this work, our aim is to combine the situational understanding that can be gained from 3D GIS, with familiar paper-based interaction. Our system situates 3D terrains within a metaphor of a 2D interactive scrapbook or journal. This allows the geospatial professional to maintain 3D records of their analysis over time and perform calculations directly over extracted terrain regions. In addition, the system would be useful as a teaching aid imparting an understanding of the third dimension.

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This work presents a technique to transform digital images into renderings that approximate the appearance of mixed media artwork, which incorporates two or more traditional visual media. This is achieved this by first separating an input image into distinct regions based on the detail present in the image. Each region is then processed independently with a user-selected NPR filter. This allows the user to treat highly detailed regions differently from regions of low frequency content. The separately processed regions are then blended in the gradient domain. In addition, the work is extended to the rendering of mixed media portraits. Portraits pose unique challenges that we address with our method of segmentation, which is based on a composite of face detection and image detail. Our approach offers the user a great deal of flexibility over the end result, while at the same time requiring very little input.

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A stained glass window possesses a distinctive style partly due to the unique color ranges produced through the interaction of color enamels, glass and light. The imposition of lead calmes further separates the appearance of stained glass from other mediums. This project presents a method of re-styling an image so that it approximates the appearance of a work of stained glass. To this end, a novel approach has been developed which involves image warping, segmentation, querying, and colorization along with texture synthesis. In the method, a given input image is first segmented. Each segment is subsequently transformed to match real segments of stained glass queried from a database of image exemplars. By using real sources of stained glass, the method produces high quality results in this nascent area of non-photorealistic rendering. The generation of the stained glass requires only modest amounts of user interaction. This interaction is facilitated with a unique region-merging tool.

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In many interactive computer graphics applications, maps in three dimensions are central to enabling the exploration, presentation and manipulation of geographical data. Advanced graphical libraries such as OpenGL enable efficient modelling and rendering of the third geographical dimension. In this project we are developing a unique Geographical Information System (GIS) that seamlessly integrates 2D and 3D views of the same spatial and aspatial data. Multiple layers of information are continuously transformed between the 2D and 3D modes under the control of the user, directly over a base-terrain. Although many existing commercial 3D GIS systems have 2D views they are typically isolated from the 3D view in that they are presented in a separate window. In this project we introduce a 2D/3D hybrid GIS that allows the user to view the 2D data in direct relation to the 3D view within the same view.

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Image editing software is often characterized by a seemingly endless array of toolbars, filters, transformations and layers. But recently, a counter trend has emerged in the field of image editing which aims to reduce the user’s workload through semi-automation. This alternate style of interaction has been made possible through advances in directed texture synthesis and computer vision. It is in this context that we have developed our texture editing system that allows complex operations to be performed on images with minimal user interaction. This is achieved by utilizing the inherent self-similarity of image textures to replicate intended manipulations globally. Our image editing approach includes operations for replicated painting, cloning and warping.

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The automatic generation of audio has been explored both as artifact in itself and for the accompaniment of existing animations. The most recent work automatically generates soundtracks for input animation based on existing animation soundtrack. This technique can greatly simplify the production of soundtracks in computer animation and video by re-targeting existing soundtracks. A segment of source audio is used to train a statistical model which is then used to generate variants of the original audio to fit particular constraints. These constraints can either be specified explicitly by the user in the form of large-scale properties of the sound texture, or determined automatically and semi-automatically by matching similar motion events in a source animation to those in the target animation. Earlier work explored connections between music and mathematics. MWSCCS is a concurrent stochastic process algebra for musical modeling and generative composition. This allows the creation music directly from mathematical processes.

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Two research projects have been undertaken in the area of motion editing. The first is a framework for synchronising motion curves to music in computer animation. Motions are locally modified using perceptual cues extracted from the music. The key to this approach is the use of standard music analysis techniques on complementary MIDI and audio representations of the same soundtrack. The second project allows the replicated editing of human movement contained in a motion capture sequence or database of sequences. To this end, we rapidly retrieve perceptually similar occurrences of a particular motion in a long motion capture sequence or unstructured motion capture database. The user is then able to replicate editing operations with minimal input: one or more editing operations on a given motion are made to affect all similar matching motions. New video added!

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I am always keen on talking with new students. If you are interested in doing a thesis (PhD, Master's or Honor's) or a directed studies in the areas of computer graphics, animation or visualization then feel free to drop by or send me an email to discuss it. I have a number of projects on the go and would be interested in supervising students with some level of experience with animation, graphics, image processing or visualization (i.e. having taken a course in any of these topics would be fine).

In addition to my own research grants for funding students there are a number of scholarships, awards and funding sources are available to students & Postdocs in Canada and at Dalhousie. These are some of the major ones for PostDocs: NSERC Postdoctoral Fellowships Killam Postdoctoral Fellowships These are some of the major ones for graduate students: NSERC Canada Graduate Scholarships NSERC Industrial Postgraduate Scholarship Killam Scholarships MITACS Internship Program Funding for Women ... and lots more for graduate students here These are some of the major ones for undergraduate students: NSERC Undergraduate Student Research Awards Nova Scotia Co-operative Employment Program (as a research assistant) Ada Byron Award for Women Citizenship Award Leadership Award ... and lots more for undergraduate students here If you are interested in applying for one of these, feel free to email me about it.

Herbenio Junior, CALDO Undergraduate Internship. Topic: Visual Querying. Julia Weber, CALDO Undergraduate Internship. Topic: Virtual Presence. Mohammad Salimian, PhD Thesis. Topic: Virtual Presence. Kevin Gao, PhD Thesis. Topic: Computer Graphics. Raheleh Makki, PhD Thesis. Topic: Visual Text Analytics. Zezi Ai, MCS Thesis. Topic: Mobile Graphics. Matthew MacDonald, MCS Thesis. Topic: Mobile Graphics. Devin Horsman, MCS Thesis. Topic: Procedural Modeling.

Ryan MacLeod, NSERC USRA. Topic: Visual Querying. Jake Seigel, part-time reseacher. Topic: Automated Analysis of User Study Video. Mohammad Salimian, MCS Thesis. Topic: Geographic Visualization. Jake Seigel, MCS Thesis. Topic: Video Data Exploration for Film Production and User Study Analysis. Matthew MacDonald, full-time reseacher. Topic: Visualization of Network Data. Maswood Mostafi, MCS Thesis. Topic: Visualizing Geospatial Uncertainty in Marine Animal Tracks. Chris Smith, full-time reseacher. Topic: Visualization Text Data. Teryl Taylor, full-time reseacher. Topic: Visualization of Network Data. Christopher Smith, MCS Thesis. Topic: Databurst: Interactive Analysis of Hierarchical Data Using Radial Space-Filling Diagrams. Rafael Falcon-Lins, Part-time MCS Thesis. Topic: Feature-Based Mesh Simplification with Quadric Error Metric Using A Line Simplification Algorithm. Sandy Chapman, Honors Thesis. Topic: Simulating Wetland Ecosystems Through Grammar Based Plant Creation, Tool Assisted Terrain Design And Dynamic Distribution of Plant Species. Jessie Xin Zhang, PhD Thesis. Topic: Audio Segmentation, Classification and Visualization. Stephen Chisholm, MCS Thesis. Topic: Tone Mapping By Interactive Evolution. Teryl Taylor, MCS Thesis. Topic: FloVis: A Network Security Visualization Framework. Andrew Shouldice, Honors Thesis. Topic: Real-time Ocean Surface Simulation. Tim Burrell, MCS Thesis. Topic: Advected River Textures. Andrew Shouldice, NSERC USRA, Summer 2008. Topic: Physical Simulation of Ocean Water. Graham LeBlanc, NSERC USRA, Summer 2008. Topic: Physical Simulation of Ocean Water. Devin Horsman, NSERC USRA, Summer 2008. Topic: Mesh Simplification. Jacqueline L. Whalley, visiting researcher on sabbatical for 6 months, 2008. From Auckland University of Technology. Topic: Geospatial Information Systems. Suwen Wang, full-time research assistant, 2007-2008. Dalhousie University. Topic: Geospatial Information Systems. Harman Clair, full-time research assistant, 2007-2008. Dalhousie University. Topic: Geospatial Information Systems. Mark Dennis, Honors Thesis, 2008. Topic: Tabletop Display Magnets. Marcelo Ruetalo, MACS Thesis, 2007. Topic: Physical Simulation of Ocean Water. Michael Welsman-Dinelle, Honors Thesis, 2007. Topic: Interactive Gradient Domain Texture Blending. Suwen Wang, Honors Thesis, 2007. Topic: Collapsable 3D GIS Visualization. Steven Avery, Directed Studies, 2006. Topic: A Viewer and Podcaster for Digital Artwork. Andrew Pahuru, Joint Final Year Project, 2005. Topic: 3D Teamlink Groupware. David Shorter, Joint Final Year Project, 2005. Topic: 3D Teamlink Groupware. George Harker, Honors Thesis, 2003. Topic: Efficient and Believable Tree Motion. Jason Thomson, Honors Thesis, 2003. Topic: 3D Accelerated User Interfaces. Karen Inglis, Honors Thesis, 2002. Topic: Computer Generated Cartograms. David Stimpson, Honors Thesis, 2002. Topic: Graphically Simulated Generation of Plant Life.