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teaching:ft1920:praktikum:cs [2020/01/19 12:32]
ipa [Projects]
teaching:ft1920:praktikum:cs [2021/03/02 13:28] (current)
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 The task is to solve numerically the matrix completion problem via the Douglas-Rachford algorithm (see lecture notes) in the noiseless case and via {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}} in a Lagrangian formulation for the noisy case. For theoretical guarantees see  {{ :​teaching:​ft1920:​vl:​cs:​files:​matrixcompletion.pdf |Candes, Tao 2010}}. For a concrete problem instance see below. An subset of the [[http://​academictorrents.com/​details/​9b13183dc4d60676b773c9e2cd6de5e5542cee9a|netflix prize data set ]] can also be used. The task is to solve numerically the matrix completion problem via the Douglas-Rachford algorithm (see lecture notes) in the noiseless case and via {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}} in a Lagrangian formulation for the noisy case. For theoretical guarantees see  {{ :​teaching:​ft1920:​vl:​cs:​files:​matrixcompletion.pdf |Candes, Tao 2010}}. For a concrete problem instance see below. An subset of the [[http://​academictorrents.com/​details/​9b13183dc4d60676b773c9e2cd6de5e5542cee9a|netflix prize data set ]] can also be used.
    
-=== Faster FISTA for Wavelet Deblurring ===  +=== Faster FISTA for Wavelet Deblurring ​(Taken!) ​===  
-The task ist to implement a fast version of FISTA {{ :​teaching:​ft1920:​vl:​cs:​files:​fasterfista.pdf | Liang, Schönlieb 2019}} and to compare results with the classical version of {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}}.+The task is to implement a fast version of FISTA {{ :​teaching:​ft1920:​vl:​cs:​files:​fasterfista.pdf | Liang, Schönlieb 2019}} and to compare results with the classical version of {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}}.
 The regulizer should be chosen as the l1-norm of the {{ :​teaching:​ft1920:​vl:​cs:​files:​wavelet.m.zip | wavelet}} transformed signal. The linear operator should be given as a blurring operator, see below. Try several blurring masks! The regulizer should be chosen as the l1-norm of the {{ :​teaching:​ft1920:​vl:​cs:​files:​wavelet.m.zip | wavelet}} transformed signal. The linear operator should be given as a blurring operator, see below. Try several blurring masks!
  
-=== FISTA versus the Chambolle-Pock Algorithm for Face Recognition === +===  FISTA versus the Chambolle-Pock Algorithm for Face Recognition ​(Taken!)  ​=== 
-The task ist to compare the performance of {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}}+The task is to compare the performance of {{ :​teaching:​ft1920:​vl:​cs:​files:​fista.pdf |FISTA}}
 to the {{ :​teaching:​ft1920:​vl:​cs:​files:​chambollepock.pdf |Chambolle-Pock}} algorithm on face recognition. to the {{ :​teaching:​ft1920:​vl:​cs:​files:​chambollepock.pdf |Chambolle-Pock}} algorithm on face recognition.
 To apply FISTA you need to consider the Lagrangian formulation,​ see e.g. eq. (4.1) in {{ :​teaching:​ft1920:​vl:​cs:​files:​magma.pdf |Hovhannisyan et al, 2016}}. Summarize the convergence results of the more recent work {{ :​teaching:​ft1920:​vl:​cs:​files:​ergodicconvergencecp.pdf |Chambolle-Pock,​ 2016}}. To apply FISTA you need to consider the Lagrangian formulation,​ see e.g. eq. (4.1) in {{ :​teaching:​ft1920:​vl:​cs:​files:​magma.pdf |Hovhannisyan et al, 2016}}. Summarize the convergence results of the more recent work {{ :​teaching:​ft1920:​vl:​cs:​files:​ergodicconvergencecp.pdf |Chambolle-Pock,​ 2016}}.
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 === Wavelet Deblurring via the Chambolle-Pock Algorithm === === Wavelet Deblurring via the Chambolle-Pock Algorithm ===
-Consider ​wavelet  ​{{ :​teaching:​ft1920:​vl:​cs:​files:​wavelet.m.zip | wavelet}} ​ deblurring. The linear operator should be given as a blurring operator for several blurring masks. As a regularizer choose the l1-norm of the+Consider {{ :​teaching:​ft1920:​vl:​cs:​files:​wavelet.m.zip | wavelet}} ​ deblurring. The linear operator should be given as a blurring operator for several blurring masks. As a regularizer choose the l1-norm of the
 wavlet transformed signal. Set up a recovery model and apply the Chambolle-Pock algorithm but in such a way that you avoid projecting onto the linear constraints. wavlet transformed signal. Set up a recovery model and apply the Chambolle-Pock algorithm but in such a way that you avoid projecting onto the linear constraints.
  
 === Total Variation Inpainting and Deblurring via the Chambolle-Pock Algorithm === === Total Variation Inpainting and Deblurring via the Chambolle-Pock Algorithm ===
-Consider anisotropic total variation minimization subject to linear constraints. The linear constraints correspond ​ either to the pixel omission operation (inpainting) or  the blurring operator for several blurring masks. Implement the Chambolle-Pock algorithm to solve the inverse problem. Be careful when implementing the proximal mapping corresponding to total variation. A good option is {{ :​teaching:​ft1920:​vl:​cs:​files:​tvprox.pdf |Beck, Teboulle, 2009}}+Consider anisotropic total variation minimization subject to linear constraints. The linear constraints correspond ​ either to the pixel omission operation (inpainting) or  the blurring operator for several blurring masks. Implement the Chambolle-Pock algorithm to solve the inverse problem. Be careful when implementing the proximal mapping corresponding to total variation. A good option is presented in {{ :​teaching:​ft1920:​vl:​cs:​files:​tvprox.pdf |Beck, Teboulle, 2009}}
  
 === Phase Transitions for Tomography Recovery by Greedy Methods === === Phase Transitions for Tomography Recovery by Greedy Methods ===
-This project is appropriate for a team of two students. ​ Generate probabilistic recovery plots similar to the ones in {{ :​teaching:​ft1920:​vl:​cs:​files:​tomophasetransitions.pdf | Kuske, Petra 2019}} for all greedy methods from the lecture (orthogonal matching pursuit (OMP) - Alg. 2, matching pursuit (MP) - Alg. 3, iterative hard thresholding (IHT) - Alg. 5, compressive sampling matching pursuit (CoSaMP) - Alg. 7. basic thresholding (BT) - Alg. 4, hard thresholding pursuit (HTP) - Alg. 6, and subspace pursuit (SP)) using this  {{ :​teaching:​ft1920:​vl:​cs:​files:​tomo_parallel_beam_binary.m.zip |tomographic projection matrix}}. Compare the results with l1-minimization. Can you modify the greedy methods to deal with nonnegative constraints?​ You might get some ideas from [[[[https://​hal.archives-ouvertes.fr/​hal-02049424/​| Nguyen et al, 2019]]]].+This project is appropriate for a team of two students. ​ Generate probabilistic recovery plots similar to the ones in {{ :​teaching:​ft1920:​vl:​cs:​files:​tomophasetransitions.pdf | Kuske, Petra 2019}} for all greedy methods from the lecture (orthogonal matching pursuit (OMP) - Alg. 2, matching pursuit (MP) - Alg. 3, iterative hard thresholding (IHT) - Alg. 5, compressive sampling matching pursuit (CoSaMP) - Alg. 7. basic thresholding (BT) - Alg. 4, hard thresholding pursuit (HTP) - Alg. 6, and subspace pursuit (SP)) using this  {{ :​teaching:​ft1920:​vl:​cs:​files:​tomo_parallel_beam_binary.m.zip |tomographic projection matrix}}. Compare the results with l1-minimization. Can you modify the greedy methods to deal with nonnegative constraints?​ You might get some ideas from [[https://​hal.archives-ouvertes.fr/​hal-02049424/​| Nguyen et al, 2019]]. 
 +===== Data Sets ===== 
 +  * {{ :​teaching:​ft1920:​vl:​cs:​files:​01lowrank.zip |Low rank matrices}} 
 +  * {{ :​teaching:​ft1920:​vl:​cs:​files:​02deblurring.zip |Deblurring}} 
 +  * {{ :​teaching:​ft1920:​vl:​cs:​files:​03inpainting.zip |Inpainting}}  
 +  * {{ :​teaching:​ft1920:​vl:​cs:​files:​04radon.zip |Radon}} 
 +  * {{ :​teaching:​ft1920:​vl:​cs:​files:​05mri.zip |MRI}} 
 +  * {{ :​teaching:​ft1920:​praktikum:​06facerecognition.zip |Face Recognition}}