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(1 - 3 of 3)
- Title
- AN APPROACH FOR COMPUTING INTERVISIBILITY USING GRAPHICAL PROCESSING UNITS.
- Creator
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Tracy, Judd, Schiavone, Guy, University of Central Florida
- Abstract / Description
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In large scale entity-level military force-on-force simulations it is essential to know when one entity can visibly see another entity. This visibility determination plays an important role in the simulation and can affect the outcome of the simulation. When virtual Computer Generated Forces (CGF) are introduced into the simulation these intervisibilities must now be calculated by the virtual entities on the battlefield. But as the simulation size increases so does the complexity of...
Show moreIn large scale entity-level military force-on-force simulations it is essential to know when one entity can visibly see another entity. This visibility determination plays an important role in the simulation and can affect the outcome of the simulation. When virtual Computer Generated Forces (CGF) are introduced into the simulation these intervisibilities must now be calculated by the virtual entities on the battlefield. But as the simulation size increases so does the complexity of calculating visibility between entities. This thesis presents an algorithm for performing these visibility calculations using Graphical Processing Units (GPU) instead of the Central Processing Units (CPU) that have been traditionally used in CGF simulations. This algorithm can be distributed across multiple GPUs in a cluster and its scalability exceeds that of CGF-based algorithms. The poor correlations of the two visibility algorithms are demonstrated showing that the GPU algorithm provides a necessary condition for a "Fair Fight" when paired with visual simulations.
Show less - Date Issued
- 2004
- Identifier
- CFE0000306, ucf:46315
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000306
- Title
- OBJECT TRACKING AND ACTIVITY RECOGNITION IN VIDEO ACQUIRED USING MOBILE CAMERAS.
- Creator
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Yilmaz, Alper, Shah, Mubarak, University of Central Florida
- Abstract / Description
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Due to increasing demand on deployable surveillance systems in recent years, object tracking and activity recognition are receiving considerable attention in the research community. This thesis contributes to both the tracking and the activity recognition components of a surveillance system. In particular, for the tracking component, we propose two different approaches for tracking objects in video acquired by mobile cameras, each of which uses a different object shape representation. The...
Show moreDue to increasing demand on deployable surveillance systems in recent years, object tracking and activity recognition are receiving considerable attention in the research community. This thesis contributes to both the tracking and the activity recognition components of a surveillance system. In particular, for the tracking component, we propose two different approaches for tracking objects in video acquired by mobile cameras, each of which uses a different object shape representation. The first approach tracks the centroids of the objects in Forward Looking Infrared Imagery (FLIR) and is suitable for tracking objects that appear small in airborne video. The second approach tracks the complete contours of the objects, and is suitable for higher level vision problems, such as activity recognition, identification and classification. Using the contours tracked by the contour tracker, we propose a novel representation, called the action sketch, for recognizing human activities.Object Tracking in Airborne Imagery: Images obtained from an airborne vehicle generally appear small and can be represented by geometric shapes such as circle or rectangle. After detecting the object position in the first frame, the proposed object tracker models the intensity and the local standard deviation of the object region defined by the shape model. It then tracks the objects by computing the mean-shift vector that minimizes the distance between the kernel distribution for the hypothesized object and its prior. In cases when the ego-motion of the sensor causes the object to move more than the operational limits of the tracking module, a multi-resolution global motion compensation using the Gabor responses of consecutive frames is performed. The experiments performed on the AMCOM FLIR data set show the robustness of the proposed method, which combines automatic model update and global motion compensation into one framework.Contour Tracker: Contour tracking is performed by evolving an initial contour toward the correct object boundaries based on discriminant analysis, which is formulated as a variational calculus problem. Once the contour is initialized, the method generates an online shape model for the object along with the color and the texture priors for both the object and the background regions. A priori texture and color PDFs of the regions are then fused based on the discrimination properties of the features between the object and the background models. The models are then used to compute the posteriori contour likelihood and the evolution is obtained by the Maximum a Posteriori Estimation process, which updates the contour in the gradient ascent direction of the proposed energy functional. During occlusion, the online shape model is used to complete the missing object region. The proposed energy functional unifies commonly used boundary and region based contour approaches into a single framework through a support region defined around the hypothesized object contour. We tested the robustness of the proposed contour tracker using several real sequences and have verified qualitatively that the contours of the objects are perfectly tracked.Behavior Analysis: We propose a novel approach to represent human actions by modeling the dynamics (motion) and the structure (shape) of the objects in video. Both the motion and the shape are modeled using a compact representation, which is called the ``action sketch''. An action sketch is a view invariant representation obtained by analyzing important changes that occur during the motion of the objects. When an actor performs an action in 3D, the points on the actor generate space-time trajectories in four dimensions $(x,y,z,t)$. Projection of the world to the imaging coordinates converts the space-time trajectories into the spatio-temporal trajectories in three dimensions $(x,y,t)$. A set of spatio-temporal trajectories constitute a 3D volume, which we call an ``action volume''. This volum
Show less - Date Issued
- 2004
- Identifier
- CFE0000101, ucf:52858
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000101
- Title
- TEMPORARY BARRIERS REDUCE RUBBERNECKING AND EXTERNAL DISTRACTION ON ROADWAYS.
- Creator
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Colon, Nicholas, Mouloua, Mustapha, University of Central Florida
- Abstract / Description
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The purpose of the current study was to empirically examine the effects of accident scenes on eye movement as well as driving behavior. Fifty-four participants drove in a driving simulator wearing a head-mounted eye-tracker in three experimental drives, one of which had an accident scene. The participants were put into one of three different conditions (no barrier, partial barrier, or full barrier). The results showed significant main effects of distraction (accident vs. no accident) on dwell...
Show moreThe purpose of the current study was to empirically examine the effects of accident scenes on eye movement as well as driving behavior. Fifty-four participants drove in a driving simulator wearing a head-mounted eye-tracker in three experimental drives, one of which had an accident scene. The participants were put into one of three different conditions (no barrier, partial barrier, or full barrier). The results showed significant main effects of distraction (accident vs. no accident) on dwell frequency and duration, average speed, and root mean square error of the steering wheel angle during the drive with the accident scenes. In addition, the results also showed significant interaction effects between distraction and type of barrier (no, partial, or full) on dwell frequency and duration. The full barrier condition had the biggest effect on decreasing dwell duration and frequency. The findings support the Salience Effort Expectancy Value (SEEV) model of attention and previous research stating objects high in salience attract attention (Wickens & Horrey, 2008; Itti & Koch, 2000). These findings also support previous research by Mayer, Caird, Milloy, Percival, & Ohlhauser (2010) stating that drivers drive in the safest manner (lowest passing speed) when an emergency vehicles are present with the emergency lights on. Temporary barriers could be used to help decrease the effects of rubbernecking on highways when an accident scene is present (Masinick & Teng, 2004; Potts, Harwood, Hutton, & Kinzel, 2010)
Show less - Date Issued
- 2013
- Identifier
- CFH0004331, ucf:45059
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004331
