52 research outputs found
Most Likely Separation of Intensity and Warping Effects in Image Registration
This paper introduces a class of mixed-effects models for joint modeling of
spatially correlated intensity variation and warping variation in 2D images.
Spatially correlated intensity variation and warp variation are modeled as
random effects, resulting in a nonlinear mixed-effects model that enables
simultaneous estimation of template and model parameters by optimization of the
likelihood function. We propose an algorithm for fitting the model which
alternates estimation of variance parameters and image registration. This
approach avoids the potential estimation bias in the template estimate that
arises when treating registration as a preprocessing step. We apply the model
to datasets of facial images and 2D brain magnetic resonance images to
illustrate the simultaneous estimation and prediction of intensity and warp
effects
Cross-Scale Cost Aggregation for Stereo Matching
Human beings process stereoscopic correspondence across multiple scales.
However, this bio-inspiration is ignored by state-of-the-art cost aggregation
methods for dense stereo correspondence. In this paper, a generic cross-scale
cost aggregation framework is proposed to allow multi-scale interaction in cost
aggregation. We firstly reformulate cost aggregation from a unified
optimization perspective and show that different cost aggregation methods
essentially differ in the choices of similarity kernels. Then, an inter-scale
regularizer is introduced into optimization and solving this new optimization
problem leads to the proposed framework. Since the regularization term is
independent of the similarity kernel, various cost aggregation methods can be
integrated into the proposed general framework. We show that the cross-scale
framework is important as it effectively and efficiently expands
state-of-the-art cost aggregation methods and leads to significant
improvements, when evaluated on Middlebury, KITTI and New Tsukuba datasets.Comment: To Appear in 2013 IEEE Conference on Computer Vision and Pattern
Recognition (CVPR). 2014 (poster, 29.88%
DDFlow: Learning Optical Flow with Unlabeled Data Distillation
We present DDFlow, a data distillation approach to learning optical flow
estimation from unlabeled data. The approach distills reliable predictions from
a teacher network, and uses these predictions as annotations to guide a student
network to learn optical flow. Unlike existing work relying on hand-crafted
energy terms to handle occlusion, our approach is data-driven, and learns
optical flow for occluded pixels. This enables us to train our model with a
much simpler loss function, and achieve a much higher accuracy. We conduct a
rigorous evaluation on the challenging Flying Chairs, MPI Sintel, KITTI 2012
and 2015 benchmarks, and show that our approach significantly outperforms all
existing unsupervised learning methods, while running at real time.Comment: 8 pages, AAAI 1
Occlusion Aware Unsupervised Learning of Optical Flow
It has been recently shown that a convolutional neural network can learn
optical flow estimation with unsupervised learning. However, the performance of
the unsupervised methods still has a relatively large gap compared to its
supervised counterpart. Occlusion and large motion are some of the major
factors that limit the current unsupervised learning of optical flow methods.
In this work we introduce a new method which models occlusion explicitly and a
new warping way that facilitates the learning of large motion. Our method shows
promising results on Flying Chairs, MPI-Sintel and KITTI benchmark datasets.
Especially on KITTI dataset where abundant unlabeled samples exist, our
unsupervised method outperforms its counterpart trained with supervised
learning.Comment: CVPR 2018 Camera-read
Disparity and Optical Flow Partitioning Using Extended Potts Priors
This paper addresses the problems of disparity and optical flow partitioning
based on the brightness invariance assumption. We investigate new variational
approaches to these problems with Potts priors and possibly box constraints.
For the optical flow partitioning, our model includes vector-valued data and an
adapted Potts regularizer. Using the notation of asymptotically level stable
functions we prove the existence of global minimizers of our functionals. We
propose a modified alternating direction method of minimizers. This iterative
algorithm requires the computation of global minimizers of classical univariate
Potts problems which can be done efficiently by dynamic programming. We prove
that the algorithm converges both for the constrained and unconstrained
problems. Numerical examples demonstrate the very good performance of our
partitioning method
Real-time tracker with fast recovery from target loss
In this paper, we introduce a variation of a state-of-the-art real-time
tracker (CFNet), which adds to the original algorithm robustness to target loss
without a significant computational overhead. The new method is based on the
assumption that the feature map can be used to estimate the tracking confidence
more accurately. When the confidence is low, we avoid updating the object's
position through the feature map; instead, the tracker passes to a single-frame
failure mode, during which the patch's low-level visual content is used to
swiftly update the object's position, before recovering from the target loss in
the next frame. The experimental evidence provided by evaluating the method on
several tracking datasets validates both the theoretical assumption that the
feature map is associated to tracking confidence, and that the proposed
implementation can achieve target recovery in multiple scenarios, without
compromising the real-time performance.Comment: arXiv admin note: substantial text overlap with arXiv:1806.0784
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