| 1. |
- Yun, Yixiao, 1987, et al.
(författare)
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Maximum-Likelihood Object Tracking from Multi-View Video by Combining Homography and Epipolar Constraints
- 2012
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Ingår i: 6th ACM/IEEE Int'l Conf on Distributed Smart Cameras (ICDSC 12), Oct 30 - Nov.2, 2012, Hong Kong. - 9781450317726 ; , s. 6 pages-
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Konferensbidrag (refereegranskat)abstract
- This paper addresses problem of object tracking in occlusion scenarios, where multiple uncalibrated cameras with overlapping fields of view are used. We propose a novel method where tracking is first done independently for each view and then tracking results are mapped between each pair of views to improve the tracking in individual views, under the assumptions that objects are not occluded in all views and move uprightly on a planar ground which may induce a homography relation between each pair of views. The tracking results are mapped by jointly exploiting the geometric constraints of homography, epipolar and vertical vanishing point. Main contributions of this paper include: (a) formulate a reference model of multi-view object appearance using region covariance for each view; (b) define a likelihood measure based on geodesics on a Riemannian manifold that is consistent with the destination view by mapping both the estimated positions and appearances of tracked object from other views; (c) locate object in each individual view based on maximum likelihood criterion from multi-view estimations of object position. Experiments have been conducted on videos from multiple uncalibrated cameras, where targets experience long-term partial or full occlusions. Comparison with two existing methods and performance evaluations are also made. Test results have shown effectiveness of the proposed method in terms of robustness against tracking drifts caused by occlusions.
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| 2. |
- Dobnik, Simon, 1977
(författare)
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Coordinating spatial perspective in discourse
- 2012
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Ingår i: Proceedings of the Workshop on Vision and Language 2012 (VL'12): The 2nd Annual Meeting of the EPSRC Network on Vision and Language.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present results of an on-line data collection experiment where we investigate the assignment and coordination of spatial perspective between a pair of dialogue participants situated in a constrained virtual environment.
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| 3. |
- Gu, Irene Yu-Hua, 1953, et al.
(författare)
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Grassmann Manifold Online Learning and Partial Occlusion Handling for Visual Object Tracking under Bayesian Formulation
- 2012
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Ingår i: Proceedings - International Conference on Pattern Recognition. - 1051-4651. - 9784990644109 ; , s. 1463-1466
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Konferensbidrag (refereegranskat)abstract
- This paper addresses issues of online learning and occlusion handling in video object tracking. Although manifold tracking is promising, large pose changes and long term partial occlusions of video objects remain challenging.We propose a novel manifold tracking scheme that tackles such problems, with the following main novelties: (a) Online estimation of object appearances on Grassmann manifolds; (b) Optimal criterion-based occlusion handling during online learning; (c) Nonlinear dynamic model for appearance basis matrix and its velocity; (b) Bayesian formulations separately for the tracking and the online learning process. Two particle filters are employed: one is on the manifold for generating appearance particles and another on the linear space for generating affine box particles. Tracking and online updating are performed in alternative fashion to mitigate the tracking drift. Experiments on videos have shown robust tracking performance especially when objects contain significantpose changes accompanied with long-term partial occlusions. Evaluations and comparisons with two existing methods provide further support to the proposed method.
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| 4. |
- ur Réhman, Shafiq, 1978-
(författare)
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Expressing emotions through vibration for perception and control
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses a challenging problem: “how to let the visually impaired ‘see’ others emotions”. We, human beings, are heavily dependent on facial expressions to express ourselves. A smile shows that the person you are talking to is pleased, amused, relieved etc. People use emotional information from facial expressions to switch between conversation topics and to determine attitudes of individuals. Missing emotional information from facial expressions and head gestures makes the visually impaired extremely difficult to interact with others in social events. To enhance the visually impaired’s social interactive ability, in this thesis we have been working on the scientific topic of ‘expressing human emotions through vibrotactile patterns’. It is quite challenging to deliver human emotions through touch since our touch channel is very limited. We first investigated how to render emotions through a vibrator. We developed a real time “lipless” tracking system to extract dynamic emotions from the mouth and employed mobile phones as a platform for the visually impaired to perceive primary emotion types. Later on, we extended the system to render more general dynamic media signals: for example, render live football games through vibration in the mobile for improving mobile user communication and entertainment experience. To display more natural emotions (i.e. emotion type plus emotion intensity), we developed the technology to enable the visually impaired to directly interpret human emotions. This was achieved by use of machine vision techniques and vibrotactile display. The display is comprised of a ‘vibration actuators matrix’ mounted on the back of a chair and the actuators are sequentially activated to provide dynamic emotional information. The research focus has been on finding a global, analytical, and semantic representation for facial expressions to replace state of the art facial action coding systems (FACS) approach. We proposed to use the manifold of facial expressions to characterize dynamic emotions. The basic emotional expressions with increasing intensity become curves on the manifold extended from the center. The blends of emotions lie between those curves, which could be defined analytically by the positions of the main curves. The manifold is the “Braille Code” of emotions. The developed methodology and technology has been extended for building assistive wheelchair systems to aid a specific group of disabled people, cerebral palsy or stroke patients (i.e. lacking fine motor control skills), who don’t have ability to access and control the wheelchair with conventional means, such as joystick or chin stick. The solution is to extract the manifold of the head or the tongue gestures for controlling the wheelchair. The manifold is rendered by a 2D vibration array to provide user of the wheelchair with action information from gestures and system status information, which is very important in enhancing usability of such an assistive system. Current research work not only provides a foundation stone for vibrotactile rendering system based on object localization but also a concrete step to a new dimension of human-machine interaction.
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| 5. |
- Liu, Yang, et al.
(författare)
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Movement Status Based Vision Filter for RoboCup Small-Size League
- 2012
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Ingår i: Advances in Automation and Robotics, Vol. 2. - Berlin, Heidelberg : Springer. - 9783642256455 - 9783642256462 ; , s. 79-86
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Small-size soccer league is a division of the RoboCup (Robot world cup) competitions. Each team uses its own designed hardware and software to compete with othersunder defined rules. There are two kinds of data which the strategy system will receive from the dedicated server, one of them is the referee commands, and the other one is vision data. However, due to the network delay and the vision noise, we have to process the data before we can actually use it. Therefore, a certain mechanism is needed in this case.Instead of using some prevalent and complex algorithms, this paper proposes to solve this problem from simple kinematics and mathematics point of view, which can be implemented effectively by hobbyists and undergraduate students. We divide this problem by the speed status and deal it in three different situations. Testing results show good performance with this algorithm and great potential in filtering vision data thus forecasting actual coordinates of tracking objects.
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| 6. |
- Rødseth, Ørnulf Jan, et al.
(författare)
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Communication Architecture for an Unmanned Merchant Ship
- 2013
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Ingår i: OCEANS - Bergen, 2013 MTS/IEEE. - 9781479900008 ; :2013, s. 1-9
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Konferensbidrag (refereegranskat)abstract
- Unmanned ships is an interesting proposal toimplement slow steaming and saving fuel while avoiding that the crew has to stay on board for very long deep-sea passages. To maintain efficiency and safety, autonomy has to be implemented to enable the ship to operate without requiring the SCC to continuously control the ship. Communication between ship and a shore control center (SCC) is therefore critical for the unmanned ship and proper safety and security precautions are required, including sufficient redundancy and backup solutions.Communication systems should be able to supply at least 4Megabits/second for full remote control from SCC, but reduced operation can be maintained at down to 125 kilobits/second. In autonomous mode, the required communication bandwidth will be very low. For an autonomous ship the higher bandwidth requirements are from ship to shore which is the opposite of the situation for normal ships. Cost and availability of communication is an issue. The use of technical and functionalindexes will enable the SCC to monitor the status of the ship at minimum load on operators and on the communication systems. The security and integrity of information transfers is crucial and appropriate means must be taken to ensure failure tolerance and fail to safe properties of the system.
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| 7. |
- Lu, Zhihan, et al.
(författare)
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Anaglyph 3D stereoscopic visualization of 2D video based on fundamental matrix
- 2013
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Ingår i: 2013 International Conferenceon Virtual Reality and Visualization. - : IEEE. - 9780769551500 - 9781479923229 ; , s. 305-308
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a simple Anaglyph 3Dstereo generation algorithm from 2D video sequence with monocularcamera. In our novel approach we employ camera poseestimation method to directly generate stereoscopic 3D from 2Dvideo without building depth map explicitly. Our cost effectivemethod is suitable for arbitrary real-world video sequence andproduces smooth results. We use image stitching based on planecorrespondence using fundamental matrix. To this end we alsodemonstrate that correspondence plane image stitching based onHomography matrix only cannot generate better result. Furthermore,we utilize the structure from motion (with fundamentalmatrix) based reconstructed camera pose model to accomplishvisual anaglyph 3D illusion. The proposed approach demonstratesa very good performance for most of the video sequences.
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| 8. |
- Kavathatzopoulos, Iordanis, 1956-, et al.
(författare)
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What are ethical agents and how can we make them work properly?
- 2011
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Ingår i: The computational turn. - Münster : MV-Wissenschaft. - 9783869913551 ; , s. 151-153
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Konferensbidrag (refereegranskat)abstract
- To support ethical decision making in autonomous agents, we suggest to implement decision tools based on classical philosophy and psychological research. As one possible avenue, we present EthXpert, which supports the process of structuring and assembling information about situations with possible moral implications.
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| 9. |
- Höglund, Lars, 1946, et al.
(författare)
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Maskininlärningsbaserad indexering av digitaliserade museiartefakter - projektrapport
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Projektet har genomfört försök med maskinbaserad analys och maskininlärning för automatisk indexering och analys av bilder som stöd för registrering av föremål i museibestånd. Resultaten visar att detta är möjligt för avgränsade delmängder i kombination med maskininlärning som stöd för, men inte som ersättning för, manuell analys. Projektet har också funnit behov av utveckling av ett användargränssnitt för både text och bildsökning och utvecklat en prototyplösning för detta, vilket finns dokumenterat i denna rapport och i ett separat appendix till rapporten. Materialet utgör grundunderlag för implementeringar som innebär utökade sökmöjligheter, effektivare registrering samt ett användarvänligt gränssnitt. Arbetet ligger i framkant av forskningsområdets resultat och etablerade metoder och kombinerar statististiska, lingvistiska och datavetenskapliga metoder. Se länk till rapport och även länk till appendix längre ned.
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| 10. |
- Yun, Yixiao, 1987, et al.
(författare)
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Image Classification by Multi-Class Boosting of Visual and Infrared Fusion with Applications to Object Pose Recognition
- 2013
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Ingår i: Swedish Symposium on Image Analysis (SSBA 2013), March 14-15, Göteborg, Sweden. ; , s. 4-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper proposes a novel method for multiview object pose classification through sequential learning and sensor fusion. The basic idea is to use images observed in visual and infrared (IR) bands, with the same sampling weight under a multi-class boosting framework. The main contribution of this paper is a multi-class AdaBoost classification framework where visual and infrared information interactively complement each other. This is achieved by learning hypothesis for visual and infrared bands independently and then fusing the optimized hypothesis subensembles. Experiments are conducted on several image datasets including a set of visual and thermal IR images containing 4844 face images in 5 different poses. Results have shown significant increase in classification rate as compared with an existing multi-class AdaBoost algorithm SAMME trained on visual or infrared images alone, as well as a simple baseline classification-fusion algorithm.
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