invansc package   v2.03  10.8.2012    [for Matlab v.6.5 (or later)]
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The Matlab software included in this package implements the transformations and filtering procedures for Poisson and Poisson-Gaussian data presented in the papers
[1] M. Mkitalo and A. Foi, "On the inversion of the Anscombe transformation in low-count Poisson image denoising", Proc. Int. Workshop on Local and Non-Local Approx. in Image Process., LNLA 2009, Tuusula, Finland, pp. 26-32, August 2009. doi:10.1109/LNLA.2009.5278406
[2] M. Mkitalo and A. Foi, "Optimal inversion of the Anscombe transformation in low-count Poisson image denoising", IEEE Trans. Image Process., vol. 20, no. 1, pp. 99-109, January 2011. doi:10.1109/TIP.2010.2056693
[3] M. Mkitalo and A. Foi, "A closed-form approximation of the exact unbiased inverse of the Anscombe variance-stabilizing transformation", IEEE Trans. Image Process., vol. 20, no. 9, pp. 2697-2698, September 2011. doi:10.1109/TIP.2011.2121085
[4] M. Mkitalo and A. Foi, "Optimal inversion of the generalized Anscombe transformation for Poisson-Gaussian noise", IEEE Trans. Image Process., doi:10.1109/TIP.2012.2202675


Software and publications can be downloaded from http://www.cs.tut.fi/~foi/invansc/

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 Contents
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Anscombe_forward.m                                    - Anscombe variance-stabilizing transformation
GenAnscombe_forward.m                                 - generalized Anscombe variance-stabilizing transformation
Anscombe_inverse_asympt_unbiased.m                    - asymptotically unbiased inverse of the Anscombe transformation
Anscombe_inverse_exact_unbiased.m                     - exact unbiased inverse of the Anscombe transformation
GenAnscombe_inverse_exact_unbiased.m                  - exact unbiased inverse of the generalized Anscombe transformation
Anscombe_inverse_closed_form.m                        - closed-from approximation of exact unbiased inverse of the Anscombe transformation
GenAnscombe_inverse_closed_form.m                     - closed-from approximation of exact unbiased inverse of the generalized Anscombe transformation
Anscombe_inverse_MMSE.m                               - MMSE inverse of the Anscombe transformation
Anscombe_vectors.mat                                  - precomputed expectation vectors used for defining the exact unbiased inverse of the Anscombe transformation
GenAnscombe_vectors.mat                               - precomputed expectation vectors and matrix used for defining the exact unbiased inverse of the generalized Anscombe transformation
MMSEcurves.mat                                        - precomputed curves used for defining the MMSE inverse of the Anscombe transformation

demo_Poisson_experiments_table.m                      - script reproducing the results in Table 1 of the LNLA2009 paper [1].
demo_GenAnscombe_denoising.m                          - script reproducing the results in Table 1 of the paper [4]

Poisson_denoising_Anscombe_exact_unbiased_inverse.m   - function for denoising Poisson images using the Anscombe variance-stabilizing transformation, the BM3D filter, and the exact unbiased inverse of the Anscombe transformation

./images (folder)                                     - test images used for the simulation experiments
./images/images_readme.txt                            - information about the test images contained in images.mat and used for the simulation experiments

LEGAL_NOTICE.txt                                      - TUT license and disclaimers

ReadMe_Contents.txt                                   - this file


The function Poisson_denoising_Anscombe_exact_unbiased_inverse.m and the scripts demo_Poisson_experiments_table.m and demo_GenAnscombe_denoising.m require the BM3D package for image and video denoising.
BM3D can be downloaded from http://www.cs.tut.fi/~foi/GCF-BM3D/

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 Change log
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v2.03  (10 August 2012)
 + bugfix (handling of default value of alpha=1)

v2.02  (9 August 2012)
 + bugfix (sigma normalized by alpha in the codes of the inverses)

v2.01  (2 October 2011)
 + updated some comments.

v2.00  (1 October 2011)
 + added routines for the Poisson-Gaussian case based on the generalized Anscombe transformation [4].
 + added closed-form approximation of exact unbiased inverse [2].

v1.02  (5 November 2009)
 + bugfix ('negative values' in Anscombe_inverse_asympt_unbiased.m).
 
v1.01  (5 November 2009)
 + added MMSE inverse.
 
v1.00  (9 September 2009) 
 * Initial release [1].

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 Disclaimer
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Any unauthorized use of these routines for industrial or profit-oriented activities is expressively prohibited. By downloading and/or using any of these files, you implicitly agree to all the terms of the TUT limited license, as specified in the document LEGAL_NOTICE.txt (included in this package) and online at http://www.cs.tut.fi/~foi/invansc/legal_notice.html



 Alessandro Foi and Markku Mkitalo - Tampere University of Technology - 2011-2012
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