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Optimization & Learning for Registration of Moving Dynamic Textures. Junzhou Huang 1 , Xiaolei Huang 2 , Dimitris Metaxas 1 Rutgers University 1 , Lehigh University 2. Outline. Background Goals & Problems Related Works Proposed Method Experiment Results Discussion & Conclusion.

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optimization learning for registration of moving dynamic textures

Optimization & Learning for Registration of Moving Dynamic Textures

Junzhou Huang1, Xiaolei Huang2, Dimitris Metaxas1

Rutgers University1, Lehigh University2

outline
Outline
  • Background
  • Goals & Problems
  • Related Works
  • Proposed Method
  • Experiment Results
  • Discussion & Conclusion
background
Background
  • Dynamic textures (DT)
    • static camera, exhibits a certain stationary
  • Moving Dynamic textures (MDT)
    • dynamic textures captured by a moving camera

DT, [Kwatra et al. SIGGRAPH’03]

MDT, [Fitzgibbon ICCV’01]

background1
Background
  • Video registration
    • Required by many video analysis applications
  • Traditional assumption
    • Static, rigid, brightness constancy
    • Bergen et al. ECCV’92, Black et al. ICCV’93
  • Relaxing rigid assumption
    • Dynamic textures
    • Doretto et al. IJCV’03, Yuan at al. ECCV’04, Chan et al. NIPS’05, Lin et al. PAMI’07, Rav-Acha at al. Workshop at ICCV’05
our goals
Our Goals
  • Registration of MDT
    • Recover the camera motion and register the image sequences including moving dynamic textures

Left Translation

Right Translation

complex optimization problems
Complex Optimization Problems
  • Complex optimization
    • Camera motion, dynamic texture model
    • Chicken-and-Egg Problems
  • Challenges
    • About the mean images
    • About LDS model
    • About the camera motion?
related works
Related Works
  • Fitzgibbon, ICCV’01
    • Pioneering attempt
    • Stochastic rigidity
    • Non-linear optimization
  • Vidal et al. CVPR’05
    • Time varying LDS model
    • Static assumption in small time window
    • Simple and general framework but under estimation
formulation
Formulation
  • Registration of MDT
    • I(t), the video frame
    • camera motion parameters
    • y0 , the desired average image of the video
    • y(t), related with appearance of DT
    • x(t), related with dynamics of DT
generative model
Generative Model

Generative image model for a MDT

first observation
First Observation
  • Good registration
    • a good registration according to the accurate camera motion should simplify the dynamic texture model while preserving all useful information
    • Used by Fitzgibbon, ICCV’01, Minimizing the entropy function of an auto regressive process
    • Used by Vidal, CVPR’05, optimizing time varying LDS model by optimizing piecewise LDS model
second observation
Second Observation
  • Good registration
    • A good registration according to the accurate camera motion should lead to a sharp average image whose statistics of derivative filters are similar to those of the input image frames.
  • Image statistics
    • Student-t distribution / heavy tailed image priors
    • Huang et al. CVPR’99, Roth et al. CVPR’05
prior models
Prior Models
  • The Average image priors
  • The motion priors
  • The dynamic priors
average image priors
Average Image Priors
  • Student-t distribution
    • Model parameters / contrastive divergence method

(a) Before registration, (b) in the middle of registration (c) after registration

motion dynamic priors
Motion / Dynamic Priors
  • Gaussian Perturbation (Motion)
    • Uncertainty in the motion modeled by a Gaussian perturbation about the mean estimation M0 / the covariance matrix S ( a diagonal matrix.)
    • Motivated by the work [Pickup et al. NIPS’06]
  • GPDM / MAR model (Dynamic)
    • Marginalizing over all possible mappings between appearance and dynamics
    • Motivated by the work [Wang et al. NIPS’05] [Moon et al. CVPR’06]
joint optimization
Joint Optimization
  • Generative image model
  • Optimization
    • Final marginal likelihood
    • Scaled conjugate gradients algorithm (SCG)
procedures
Procedures
  • Obtaining image derivative prior model
  • Dividing the long sequence into many short image sequences
  • Initialization for video registration
  • Performing model optimization with the proposed prior models until model convergence.
  • With estimated y0, Y and X, the camera motion is then obtained
obtaining data
Obtaining Data
  • Three DT video sequences
    • DT data, [Kwatra et al. SIGGRAPH’03]
  • Synthesized MDT video sequence
    • 60 frames each, no motion from 1st to 20th frame and from 41st to 60th
    • Camera motions with speed [1, 0] from 21st to 40th
grass mdt video
Grass MDT Video
  • The average image

(a) One frame, (b) the average image after registration, (c) before registration

grass mdt video1
Grass MDT Video
  • The statistics of derivative filter responses
evaluation comparison
Evaluation / Comparison
  • False Estimation Fraction
  • Comparison with two classical methods
    • Hybrid method, [Bergen et al. ECCV’92] [Black et al. ICCV’93]
    • Vidal’method, [Vidal et al. CVPR’05]
waterfall mdt video
Waterfall MDT Video
  • Motion estimation

(a) Ground truth, (b) by hybrid method, (c) by Vidal’s, (d) proposed

waterfall mdt video1
Waterfall MDT Video
  • The average Image and its statistics

The average image and related distribution after registration by

(a) proposed method, (b) Vidal’s method, (c) hybrid method

fef comparisons
FEF Comparisons
  • On three synthesized MDT video
real mdt video
Real MDT Video
  • Moving flower bed video
  • Ours
    • 554 frames totally
    • Ground truth 110 pixels
    • Estimation 104.52 pixels ( FEF 4.98%)
  • Vidal’s
    • 250 frames
    • Ground truth 85 pixels
    • Estimation 60 pixels

( FEF 29.41%)

conclusions
Conclusions
  • What proposing:
    • Powerful priors for MDT registration
  • What getting out:
    • Camera motions
    • Average image
    • Dynamic texture model
  • What learning?
    • Registration simplify DT model while preserving useful information
    • Better registration lead to sharper average image
future works
Future Works
  • More complex camera motions
  • Different Metric functions for evaluation
  • Multiple dynamic texture segmentation
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