Robust Separation of Reflection from Multiple Images Xiaojie Guo 1 - - PowerPoint PPT Presentation

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Robust Separation of Reflection from Multiple Images Xiaojie Guo 1 - - PowerPoint PPT Presentation

Robust Separation of Reflection from Multiple Images Xiaojie Guo 1 Xiaochun Cao 1 Yi Ma 2 1. SKLOIS, Institute of Information Engineering, Chinese Academy of Sciences 2. School of Information Science and Technology, ShanghaiTech University


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SLIDE 1

Robust Separation of Reflection from Multiple Images

Xiaojie Guo1 Xiaochun Cao1 Yi Ma2

  • 1. SKLOIS, Institute of Information Engineering, Chinese Academy of Sciences
  • 2. School of Information Science and Technology, ShanghaiTech University

08:30-10:00 (THURSDAY, 26th June) Orals 6A – Physics-based Vision and Shape-from-X

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SLIDE 2

Motivation

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Captured Frame f = Transmitted Layer t + Reflected Layer r The separation problem is highly ill-posed !!! = +

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SLIDE 3

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

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SLIDE 4

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Align Align

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SLIDE 5

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

= = + + …

Align Align

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SLIDE 6

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

= = + + …

Align Align High Correlation

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SLIDE 7

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

= = + + …

Align Align Reflection Sparsity High Correlation

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SLIDE 8

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Gradient Sparsity

= = + + …

Align Align Reflection Sparsity High Correlation

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SLIDE 9

Observations & Pri riors

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Gradient Sparsity Gradient Independence

= = + + …

Align Align Element-wise product Reflection Sparsity High Correlation

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SLIDE 10

Problem Form rmulation

  • The problem can be naturally formulated as:

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

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Problem Form rmulation

  • The problem can be naturally formulated as:

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Correlation Reflection Sparsity Noise By assuming the targeting region lies on a (nearly) planar surface, 2D homographs can be found to transform the misaligned regions to well aligned. The values of both the transmitted and reflected layers are non-negative. Gradient Field Sparsity

Where * is convolution, d1 and d2 are horizontal and vertical derivative filters, respectively.

Gradient Field Independence is element wise product.

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SLIDE 12

Convex Relaxation, Lin inearization and Optimization

Two main difficulties remain the problem intractable:

  • The non-convexity of the Rank operator and the L0 norm.

Replace the rank function and the L0 norm with the nuclear norm and L1 norm.

  • The non-linearity of the constraint .

Linearize the constraint by . Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

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Convex Relaxation, Lin inearization and Optimization

Two main difficulties remain the problem intractable:

  • The non-convexity of the Rank operator and the L0 norm.

Replace the rank function and the L0 norm with the nuclear norm and L1 norm.

  • The non-linearity of the constraint .

Linearize the constraint by . Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Final formulation of the separation problem is:

(1)

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SLIDE 14

Alg lgorithm-Superimposed Im Image Decomposition

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

We empirically set The initial transformation is obtained by feature matching with RANSAC Outer loop is terminated when the change between two neighboring iterations is small enough, or the maximal number

  • f iteration is reached

Inner loop iteratively solves the problem (1) with an updated

  • transformation. The inner loop is stopped when

with , or the maximal number of iteration is reached.

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SLIDE 15

Sim imulation-Convergence Speed of f In Inner Loop

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

First: Transmitted Layer. Rest: Reflections. 3 of 15 synthesized superposed images. The result at the 40th iteration is very close to that at the 100th.

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Experiment-Benefit of f Ali lignment

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

The results after 1st

  • iter. of outer loop

The results after 10st

  • iter. of outer loop
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SLIDE 17

Experiment-Comparison on Real Data wit ith SPBS-M[1]

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

[1] Blind separation of superimposed moving images using image statistics, Gai et al., TPAMI, 2012.

Comparison with SPBS-M. The top row is from our method, while the bottom from SPBS-M [1].

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SLIDE 18

Experiment-Comparison on Real Data wit ith RASL[2]

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

[2] RASL: Robust Alignment by Sparse and Low-Rank Decomposition for linearly correlated Images, Peng et al., TPAMI, 2012

Comparison with RASL. The top row is from our method, while the bottom from RASL [2].

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SLIDE 19

Experiment-Comparison on Real Data wit ith SIU IUA[3]

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

[3] User Asissted Separation of Reflections from a Single Image Using a Sparsity Prior, Levin and Weiss, TPAMI, 2007

Comparison with SIUA. The top row is from our method, while the bottom from SIUA [3].

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SLIDE 20

Experiment-Failure Case

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

Original frame is blurred Recovered reflection Recovered transmitted layer

  • Recovered reflection: largely correct + some ghosting effect.
  • Recovered transmitted layer: blur reduced + good quality (correlation).
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Conclusion

Robust Separation of Reflection from Multiple Images, IEEE CVPR 2014, Guo, Cao and Ma

  • Several priors, including correlation, reflection-sparsity, gradient-sparsity and gradient-

independence, have been exploited to make the problem well-defined.

  • An efficient ALM-ADM based algorithm has been designed to seek the optimal solution.
  • Both the two layers recovered by our method are with high qualities.

Thank you for your attention! Any Questions?

The code is available at: cs.tju.edu.cn/orgs/vision/~xguo/homepage.htm If any problem, please do not hesitate to contact Xiaojie Guo Email: xj.max.guo@gmail.com