54,853 research outputs found
EpicFlow: Edge-Preserving Interpolation of Correspondences for Optical Flow
We propose a novel approach for optical flow estimation , targeted at large
displacements with significant oc-clusions. It consists of two steps: i) dense
matching by edge-preserving interpolation from a sparse set of matches; ii)
variational energy minimization initialized with the dense matches. The
sparse-to-dense interpolation relies on an appropriate choice of the distance,
namely an edge-aware geodesic distance. This distance is tailored to handle
occlusions and motion boundaries -- two common and difficult issues for optical
flow computation. We also propose an approximation scheme for the geodesic
distance to allow fast computation without loss of performance. Subsequent to
the dense interpolation step, standard one-level variational energy
minimization is carried out on the dense matches to obtain the final flow
estimation. The proposed approach, called Edge-Preserving Interpolation of
Correspondences (EpicFlow) is fast and robust to large displacements. It
significantly outperforms the state of the art on MPI-Sintel and performs on
par on Kitti and Middlebury
SceneFlowFields: Dense Interpolation of Sparse Scene Flow Correspondences
While most scene flow methods use either variational optimization or a strong
rigid motion assumption, we show for the first time that scene flow can also be
estimated by dense interpolation of sparse matches. To this end, we find sparse
matches across two stereo image pairs that are detected without any prior
regularization and perform dense interpolation preserving geometric and motion
boundaries by using edge information. A few iterations of variational energy
minimization are performed to refine our results, which are thoroughly
evaluated on the KITTI benchmark and additionally compared to state-of-the-art
on MPI Sintel. For application in an automotive context, we further show that
an optional ego-motion model helps to boost performance and blends smoothly
into our approach to produce a segmentation of the scene into static and
dynamic parts.Comment: IEEE Winter Conference on Applications of Computer Vision (WACV),
201
Parameter Inference in Differential Equation Models of Biopathways using Time Warped Gradient Matching
Parameter inference in mechanistic models of biopathways based on systems
of coupled differential equations is a topical yet computationally challenging problem,
due to the fact that each parameter adaptation involves a numerical integration of the
differential equations. Techniques based on gradient matching, which aim to minimize
the discrepancy between the slope of a data interpolant and the derivatives predicted
from the differential equations, offer a computationally appealing shortcut to the inference
problem. However, gradient matching critically hinges on the smoothing scheme
for function interpolation, with spurious wiggles in the interpolant having a dramatic
effect on the subsequent inference. The present article demonstrates that a time warping
approach aiming to homogenize intrinsic functional length scales can lead to a signifi-
cant improvement in parameter estimation accuracy. We demonstrate the effectiveness
of this scheme on noisy data from a dynamical system with periodic limit cycle and a
biopathway
High-speed Video from Asynchronous Camera Array
This paper presents a method for capturing high-speed video using an
asynchronous camera array. Our method sequentially fires each sensor in a
camera array with a small time offset and assembles captured frames into a
high-speed video according to the time stamps. The resulting video, however,
suffers from parallax jittering caused by the viewpoint difference among
sensors in the camera array. To address this problem, we develop a dedicated
novel view synthesis algorithm that transforms the video frames as if they were
captured by a single reference sensor. Specifically, for any frame from a
non-reference sensor, we find the two temporally neighboring frames captured by
the reference sensor. Using these three frames, we render a new frame with the
same time stamp as the non-reference frame but from the viewpoint of the
reference sensor. Specifically, we segment these frames into super-pixels and
then apply local content-preserving warping to warp them to form the new frame.
We employ a multi-label Markov Random Field method to blend these warped
frames. Our experiments show that our method can produce high-quality and
high-speed video of a wide variety of scenes with large parallax, scene
dynamics, and camera motion and outperforms several baseline and
state-of-the-art approaches.Comment: 10 pages, 82 figures, Published at IEEE WACV 201
A novel disparity-assisted block matching-based approach for super-resolution of light field images
Currently, available plenoptic imaging technology has limited resolution. That makes it challenging to use this technology in applications, where sharpness is essential, such as film industry. Previous attempts aimed at enhancing the spatial resolution of plenoptic light field (LF) images were based on block and patch matching inherited from classical image super-resolution, where multiple views were considered as separate frames. By contrast to these approaches, a novel super-resolution technique is proposed in this paper with a focus on exploiting estimated disparity information to reduce the matching area in the super-resolution process. We estimate the disparity information from the interpolated LR view point images (VPs). We denote our method as light field block matching super-resolution. We additionally combine our novel super-resolution method with directionally adaptive image interpolation from [1] to preserve sharpness of the high-resolution images. We prove a steady gain in the PSNR and SSIM quality of the super-resolved images for the resolution enhancement factor 8x8 as compared to the recent approaches and also to our previous work [2]
Fixation of theoretical ambiguities in the improved fits to CCFR data at the next-to-next-to-leading order and beyond
Using the results for the NNLO QCD corrections to anomalous dimensions of odd
Mellin moments and NLO corrections to their coefficient functions we
improve our previous analysis of the CCFR'97 data for . The possibility
of extracting from the fits of -corrections is analysed using three
independent models,including infrared renormalon one. Theoretical quetion of
applicability of the renormalon-type inspired large- approximation for
estimating corrections to the coefficient functions of odd and even
non-singlet moments are considered. The comparison with [1/1] Pad\'e
estimates is given. The obtained NLO and NNLO values of are
supporting the results of our less definite previous analysis and are in
agreement with the world average value . We also
present first NLO extraction of . The interplay between
higher-order perturbative QCD corrections and -terms is demonstrated.
The results of our studies are compared with those obtained recently using the
NNLO model of the kernel of DGLAP equation and with the results of the NNLO
fits to CCFR'97 data, performed by the Bernstein polynomial technique.Comment: The errors in the coefficients of
(^3\Lambda_{\bar{MS}}^{(4)}$ in
Tables 6,11,12 by 3 MeV only (details are in the enclosed Erratum (in press)
- …