3,734 research outputs found
A Deep-structured Conditional Random Field Model for Object Silhouette Tracking
In this work, we introduce a deep-structured conditional random field
(DS-CRF) model for the purpose of state-based object silhouette tracking. The
proposed DS-CRF model consists of a series of state layers, where each state
layer spatially characterizes the object silhouette at a particular point in
time. The interactions between adjacent state layers are established by
inter-layer connectivity dynamically determined based on inter-frame optical
flow. By incorporate both spatial and temporal context in a dynamic fashion
within such a deep-structured probabilistic graphical model, the proposed
DS-CRF model allows us to develop a framework that can accurately and
efficiently track object silhouettes that can change greatly over time, as well
as under different situations such as occlusion and multiple targets within the
scene. Experiment results using video surveillance datasets containing
different scenarios such as occlusion and multiple targets showed that the
proposed DS-CRF approach provides strong object silhouette tracking performance
when compared to baseline methods such as mean-shift tracking, as well as
state-of-the-art methods such as context tracking and boosted particle
filtering.Comment: 17 page
Calipso: Physics-based Image and Video Editing through CAD Model Proxies
We present Calipso, an interactive method for editing images and videos in a
physically-coherent manner. Our main idea is to realize physics-based
manipulations by running a full physics simulation on proxy geometries given by
non-rigidly aligned CAD models. Running these simulations allows us to apply
new, unseen forces to move or deform selected objects, change physical
parameters such as mass or elasticity, or even add entire new objects that
interact with the rest of the underlying scene. In Calipso, the user makes
edits directly in 3D; these edits are processed by the simulation and then
transfered to the target 2D content using shape-to-image correspondences in a
photo-realistic rendering process. To align the CAD models, we introduce an
efficient CAD-to-image alignment procedure that jointly minimizes for rigid and
non-rigid alignment while preserving the high-level structure of the input
shape. Moreover, the user can choose to exploit image flow to estimate scene
motion, producing coherent physical behavior with ambient dynamics. We
demonstrate Calipso's physics-based editing on a wide range of examples
producing myriad physical behavior while preserving geometric and visual
consistency.Comment: 11 page
3D object reconstruction from image sequences with a one line search method
Session 4 - Poster Session 1: Motion, 3D, Recognition, Feature: no. 4-20This paper addresses the problem of estimating the 3D model of an object from a sequence of images where the object is visible from different point of views. In particular, the paper considers the case of turntable image sequences, i.e. images captured under circular motion. A new method is hence proposed for this problem, which consists of determining the image point correspondences of each 3D point through a one line search where a photo-consistency index is maximized. Results with both synthetic and real data validate and illustrate the proposed method.postprintThe IAPR Conference on Machine Vision Applications (MVA2011), Nara, Japan, 13-15 June 2011. In Proceedings of MVA2011, 2011, p. 108-11
Discontinuity Edge Overdraw
Aliasing is an important problem when rendering triangle meshes. Efficient antialiasing techniques such as mipmapping greatly improve the filtering of textures defined over a mesh. A major component of the remaining aliasing occurs along discontinuity edges such as silhouettes, creases, and material boundaries. Framebuffer supersampling is a simple remedy, but 2x2 supersampling leaves behind significant temporal artifacts, while greater supersampling demands even more fill-rate and memory. We present an alternative that focuses effort on discontinuity edges by overdrawing such edges as antialiased lines. Although the idea is simple, several subtleties arise. Visible silhouette edges must be detected efficiently. Discontinuity edges need consistent orientations. They must be blended as they approach the silhouette to avoid popping. Unfortunately, edge blending results in blurriness. Our technique balances these two competing objectives of temporal smoothness and spatial sharpness. Finally, the best results are obtained when discontinuity edges are sorted by depth. Our approach proves surprisingly effective at reducing temporal artifacts commonly referred to as "crawling jaggies," with little added cost.Engineering and Applied Science
Efficient sketch-based creation of detailed character models through data-driven mesh deformations
Creation of detailed character models is a very challenging task in animation production. Sketch-based character model creation from a 3D template provides a promising solution. However, how to quickly find correct correspondences between user's drawn sketches and the 3D template model, how to efficiently deform the 3D template model to exactly match user's drawn sketches, and realize real-time interactive modeling is still an open topic. In this paper, we propose a new approach and develop a user interface to effectively tackle this problem. Our proposed approach includes using user's drawn sketches to retrieve a most similar 3D template model from our dataset and marrying human's perception and interactions with computer's highly efficient computing to extract occluding and silhouette contours of the 3D template model and find correct correspondences quickly. We then combine skeleton-based deformation and mesh editing to deform the 3D template model to fit user's drawn sketches and create new and detailed 3D character models. The results presented in this paper demonstrate the effectiveness and advantages of our proposed approach and usefulness of our developed user interface
Image-based photo hulls for fast and photo-realistic new view synthesis
We present an efficient image-based rendering algorithm that generates views of a scene's photo hull. The photo hull is the largest 3D shape that is photo-consistent with photographs taken of the scene from multiple viewpoints. Our algorithm, image-based photo hulls (IBPH), like the image-based visual hulls (IBVH) algorithm from Matusik et al. on which it is based, takes advantage of epipolar geometry to efficiently reconstruct the geometry and visibility of a scene. Our IBPH algorithm differs from IBVH in that it utilizes the color information of the images to identify scene geometry. These additional color constraints result in more accurately reconstructed geometry, which often projects to better synthesized virtual views of the scene. We demonstrate our algorithm running in a realtime 3D telepresence application using video data acquired from multiple viewpoints
3D Dynamic Scene Reconstruction from Multi-View Image Sequences
A confirmation report outlining my PhD research plan is presented. The PhD research topic is 3D dynamic scene reconstruction from multiple view image sequences. Chapter 1 describes the motivation and research aims. An overview of the progress in the past year is included. Chapter 2 is a review of volumetric scene reconstruction techniques and Chapter 3 is an in-depth description of my proposed reconstruction method. The theory behind the proposed volumetric scene reconstruction method is also presented, including topics in projective geometry, camera calibration and energy minimization. Chapter 4 presents the research plan and outlines the future work planned for the next two years
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