731 research outputs found
Pedestrian Detection and Tracking in Video Surveillance System: Issues, Comprehensive Review, and Challenges
Pedestrian detection and monitoring in a surveillance system are critical for numerous utility areas which encompass unusual event detection, human gait, congestion or crowded vicinity evaluation, gender classification, fall detection in elderly humans, etc. Researchers’ primary focus is to develop surveillance system that can work in a dynamic environment, but there are major issues and challenges involved in designing such systems. These challenges occur at three different levels of pedestrian detection, viz. video acquisition, human detection, and its tracking. The challenges in acquiring video are, viz. illumination variation, abrupt motion, complex background, shadows, object deformation, etc. Human detection and tracking challenges are varied poses, occlusion, crowd density area tracking, etc. These results in lower recognition rate. A brief summary of surveillance system along with comparisons of pedestrian detection and tracking technique in video surveillance is presented in this chapter. The publicly available pedestrian benchmark databases as well as the future research directions on pedestrian detection have also been discussed
Geometry-Aware Network for Non-Rigid Shape Prediction from a Single View
We propose a method for predicting the 3D shape of a deformable surface from
a single view. By contrast with previous approaches, we do not need a
pre-registered template of the surface, and our method is robust to the lack of
texture and partial occlusions. At the core of our approach is a {\it
geometry-aware} deep architecture that tackles the problem as usually done in
analytic solutions: first perform 2D detection of the mesh and then estimate a
3D shape that is geometrically consistent with the image. We train this
architecture in an end-to-end manner using a large dataset of synthetic
renderings of shapes under different levels of deformation, material
properties, textures and lighting conditions. We evaluate our approach on a
test split of this dataset and available real benchmarks, consistently
improving state-of-the-art solutions with a significantly lower computational
time.Comment: Accepted at CVPR 201
Editing faces in videos
Editing faces in movies is of interest in the special effects industry. We aim at
producing effects such as the addition of accessories interacting correctly with
the face or replacing the face of a stuntman with the face of the main actor.
The system introduced in this thesis is based on a 3D generative face model.
Using a 3D model makes it possible to edit the face in the semantic space of pose,
expression, and identity instead of pixel space, and due to its 3D nature allows
a modelling of the light interaction. In our system we first reconstruct the 3D
face, which is deforming because of expressions and speech, the lighting, and
the camera in all frames of a monocular input video. The face is then edited by
substituting expressions or identities with those of another video sequence or by
adding virtual objects into the scene. The manipulated 3D scene is rendered back
into the original video, correctly simulating the interaction of the light with the
deformed face and virtual objects.
We describe all steps necessary to build and apply the system. This includes
registration of training faces to learn a generative face model, semi-automatic
annotation of the input video, fitting of the face model to the input video, editing
of the fit, and rendering of the resulting scene.
While describing the application we introduce a host of new methods, each
of which is of interest on its own. We start with a new method to register 3D
face scans to use as training data for the face model. For video preprocessing a
new interest point tracking and 2D Active Appearance Model fitting technique
is proposed. For robust fitting we introduce background modelling, model-based
stereo techniques, and a more accurate light model
Unsupervised Learning of Complex Articulated Kinematic Structures combining Motion and Skeleton Information
In this paper we present a novel framework for unsupervised kinematic structure learning of complex articulated objects from a single-view image sequence. In contrast to prior motion information based methods, which estimate relatively simple articulations, our method can generate arbitrarily complex kinematic structures with skeletal topology by a successive iterative merge process. The iterative merge process is guided by a skeleton distance function which is generated from a novel object boundary generation method from sparse points. Our main contributions can be summarised as follows: (i) Unsupervised complex articulated kinematic structure learning by combining motion and skeleton information. (ii) Iterative fine-to-coarse merging strategy for adaptive motion segmentation and structure smoothing. (iii) Skeleton estimation from sparse feature points. (iv) A new highly articulated object dataset containing multi-stage complexity with ground truth. Our experiments show that the proposed method out-performs state-of-the-art methods both quantitatively and qualitatively
Adaptive Shape Kernel-Based Mean Shift Tracker in Robot Vision System
This paper proposes an adaptive shape kernel-based mean shift tracker using a single static camera for the robot vision system. The question that we address in this paper is how to construct such a kernel shape that is adaptive to the object shape. We perform nonlinear manifold learning technique to obtain the low-dimensional shape space which is trained by training data with the same view as the tracking video. The proposed kernel searches the shape in the low-dimensional shape space obtained by nonlinear manifold learning technique and constructs the adaptive kernel shape in the high-dimensional shape space. It can improve mean shift tracker performance to track object position and object contour and avoid the background clutter. In the experimental part, we take the walking human as example to validate that our method is accurate and robust to track human position and describe human contour
Analysis of cardiac motion using MRI and nonrigid image registration
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