References of "Goncalves Almeida Antunes, Michel 50001878"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailUnsupervised Vanishing Point Detection and Camera Calibration from a Single Manhattan Image with Radial Distortion
Goncalves Almeida Antunes, Michel UL; Barreto, Joao P.; Aouada, Djamila UL et al

in IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2017 (2017)

The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene ... [more ▼]

The article concerns the automatic calibration of a camera with radial distortion from a single image. It is known that, under the mild assumption of square pixels and zero skew, lines in the scene project into circles in the image, and three lines suffice to calibrate the camera up to an ambiguity between focal length and radial distortion. The calibration results highly depend on accurate circle estimation, which is hard to accomplish, because lines tend to project into short circular arcs. To overcome this problem, we show that, given a short circular arc edge, it is possible to robustly determine a line that goes through the center of the corresponding circle. These lines, henceforth called Lines of Circle Centres (LCCs), are used in a new method that detects sets of parallel lines and estimates the calibration parameters, including the center and amount of distortion, focal length, and camera orientation with respect to the Manhattan frame. Extensive experiments in both semi-synthetic and real images show that our algorithm outperforms state- of-the-art approaches in unsupervised calibration from a single image, while providing more information. [less ▲]

Detailed reference viewed: 523 (26 UL)
Full Text
Peer Reviewed
See detailVideo-Based Feedback for Assisting Physical Activity
Baptista, Renato UL; Goncalves Almeida Antunes, Michel UL; Aouada, Djamila UL et al

in 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISAPP) (2017)

In this paper, we explore the concept of providing feedback to a user moving in front of a depth camera so that he is able to replicate a specific template action. This can be used as a home based ... [more ▼]

In this paper, we explore the concept of providing feedback to a user moving in front of a depth camera so that he is able to replicate a specific template action. This can be used as a home based rehabilitation system for stroke survivors, where the objective is for patients to practice and improve their daily life activities. Patients are guided in how to correctly perform an action by following feedback proposals. These proposals are presented in a human interpretable way. In order to align an action that was performed with the template action, we explore two different approaches, namely, Subsequence Dynamic Time Warping and Temporal Commonality Discovery. The first method aims to find the temporal alignment and the second one discovers the interval of the subsequence that shares similar content, after which standard Dynamic Time Warping can be used for the temporal alignment. Then, feedback proposals can be provided in order to correct the user with respect to the template action. Experimental results show that both methods have similar accuracy rate and the computational time is a decisive factor, where Subsequence Dynamic Time Warping achieves faster results. [less ▲]

Detailed reference viewed: 370 (66 UL)
Full Text
Peer Reviewed
See detailEnhanced Trajectory-based Action Recognition using Human Pose
Papadopoulos, Konstantinos UL; Goncalves Almeida Antunes, Michel UL; Aouada, Djamila UL et al

in IEEE International Conference on Image Processing, Beijing 17-20 Spetember 2017 (2017)

Action recognition using dense trajectories is a popular concept. However, many spatio-temporal characteristics of the trajectories are lost in the final video representation when using a single Bag-of ... [more ▼]

Action recognition using dense trajectories is a popular concept. However, many spatio-temporal characteristics of the trajectories are lost in the final video representation when using a single Bag-of-Words model. Also, there is a significant amount of extracted trajectory features that are actually irrelevant to the activity being analyzed, which can considerably degrade the recognition performance. In this paper, we propose a human-tailored trajectory extraction scheme, in which trajectories are clustered using information from the human pose. Two configurations are considered; first, when exact skeleton joint positions are provided, and second, when only an estimate thereof is available. In both cases, the proposed method is further strengthened by using the concept of local Bag-of-Words, where a specific codebook is generated for each skeleton joint group. This has the advantage of adding spatial human pose awareness in the video representation, effectively increasing its discriminative power. We experimentally compare the proposed method with the standard dense trajectories approach on two challenging datasets. [less ▲]

Detailed reference viewed: 258 (60 UL)
Full Text
Peer Reviewed
See detailPiecewise-Planar Reconstruction using Two Views
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro; Nunes, Urbano

in Image and Vision Computing (2016)

Detailed reference viewed: 183 (22 UL)
Full Text
Peer Reviewed
See detailA Revisit to Human Action Recognition from Depth Sequences: Guided SVM-Sampling for Joint Selection
Goncalves Almeida Antunes, Michel UL; Aouada, Djamila UL; Ottersten, Björn UL

in IEEE Winter Conference on Applications of Computer Vision (WACV), 2016 (2016)

Detailed reference viewed: 195 (38 UL)
Full Text
Peer Reviewed
See detailVisual and human-interpretable feedback for assisting physical activity
Goncalves Almeida Antunes, Michel UL; Baptista, Renato UL; Demisse, Girum UL et al

in European Conference on Computer Vision (ECCV) Workshop on Assistive Computer Vision and Robotics Amsterdam, (2016)

Physical activity is essential for stroke survivors for recovering some autonomy in daily life activities. Post-stroke patients are initially subject to physical therapy under the supervision of a health ... [more ▼]

Physical activity is essential for stroke survivors for recovering some autonomy in daily life activities. Post-stroke patients are initially subject to physical therapy under the supervision of a health professional, but due to economical aspects, home based rehabilitation is eventually suggested. In order to support the physical activity of stroke patients at home, this paper presents a system for guiding the user in how to properly perform certain actions and movements. This is achieved by presenting feedback in form of visual information and human-interpretable messages. The core of the proposed approach is the analysis of the motion required for aligning body-parts with respect to a template skeleton pose, and how this information can be presented to the user in form of simple recommendations. Experimental results in three datasets show the potential of the proposed framework. [less ▲]

Detailed reference viewed: 272 (45 UL)
Full Text
Peer Reviewed
See detailParallel refinement of slanted 3D reconstruction using dense stereo induced from symmetry
Ralha, Ricardo; Falcão, Gabriel; Amaro, João et al

in Journal of Real-Time Image Processing (2016)

Detailed reference viewed: 70 (4 UL)
Full Text
Peer Reviewed
See detailRGB-D and Thermal Sensor Fusion
Rocco, Ignacio; Goncalves Almeida Antunes, Michel UL; Aouada, Djamila UL et al

in 11th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISAPP) (2016)

Detailed reference viewed: 228 (16 UL)
Full Text
Peer Reviewed
See detailLine-Sweep: Cross-Ratio for Wide-Baseline Matching and 3D Reconstruction
Ramalingam, Srikumar; Goncalves Almeida Antunes, Michel UL; Snow, Daniel et al

in IEEE Conference on Computer Vision and Pattern Recognition (CVPR) (2015)

Detailed reference viewed: 301 (13 UL)
Full Text
Peer Reviewed
See detailDistributed Dense Stereo Matching for 3D Reconstruction using Parallel-based Processing Advantages
Ralha, Ricardo; Falcao, Gabriel; Andrade, Joao et al

in Proc. of the 40th International Conference on Acoustics, Speech and Signal Processing (ICASSP) (2015)

Detailed reference viewed: 119 (6 UL)
Full Text
Peer Reviewed
See detailPiecewise-Planar StereoScan: Structure and Motion from Plane Primitives
Raposo, Carolina; Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro

in European Conference on Computer Vision (ECCV) (2014, September)

Detailed reference viewed: 147 (30 UL)
Full Text
Peer Reviewed
See detailSymStereo: Stereo Matching using Induced Symmetry
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro

in International Journal of Computer Vision (2014)

Detailed reference viewed: 114 (21 UL)
Full Text
Peer Reviewed
See detailUsing the GPU for fast symmetry-based dense stereo matching in high resolution images
Mota, Vasco; Falcao, Gabriel; Goncalves Almeida Antunes, Michel UL et al

in IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP) (2014)

Detailed reference viewed: 68 (8 UL)
Full Text
Peer Reviewed
See detailUnsupervised intrinsic calibration from a single frame using a "plumb-line" approach
Melo, Rui; Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro et al

in International Conference on Computer Vision (ICCV) (2013, December)

Detailed reference viewed: 106 (8 UL)
Full Text
Peer Reviewed
See detailEfficient Stereo Matching using Histogram Aggregation with Multiple Slant Hypothesis
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro

in 6th Iberian Conference on Pattern Recognition and Image Analysis (IbPria) (2013, June)

Detailed reference viewed: 41 (4 UL)
Full Text
Peer Reviewed
See detailA Global Approach for the Detection of Vanishing Points and Mutually Orthogonal Vanishing Directions
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro

in Conference on Computer Vision and Pattern Recognition (CVPR) (2013, June)

Detailed reference viewed: 91 (12 UL)
Full Text
Peer Reviewed
See detailPlane-based Odometry using an RGB-D Camera
Raposo, Carolina; Lourenco, Miguel; Goncalves Almeida Antunes, Michel UL et al

in British Machine Vision Conference (BMVC) (2013)

Detailed reference viewed: 366 (7 UL)
Full Text
Peer Reviewed
See detailCan Stereo Vision replace a Laser Rangefinder?
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro; Premebida, Cristiano et al

in IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (2012, October)

Detailed reference viewed: 69 (5 UL)
Full Text
Peer Reviewed
See detailSemi-dense piecewise planar stereo reconstruction using SymStereo and PEARL
Goncalves Almeida Antunes, Michel UL; Barreto, João Pedro

in 3DimPVT (2012, October)

Detailed reference viewed: 50 (2 UL)