Optimal inversion of the Anscombe variance-stabilizing transformation



Abstract
The removal of Poisson noise is often performed through the following three-step procedure. First, the noise variance is stabilized by applying the Anscombe root transformation (also called Anscombe transform) to the data, producing a signal in which the noise can be treated as additive Gaussian noise with unitary variance. Second, the noise is removed using a conventional denoising algorithm for additive white Gaussian noise. Third, an inverse transformation is applied to the denoised signal, obtaining the estimate of the signal of interest.
The choice of the proper inverse transformation is crucial in order to minimize the bias error which arises when the nonlinear forward transformation is applied. We present an experimental analysis using a few state-of-the-art denoising algorithms and show that the estimation can be consistently improved by applying the exact unbiased inverse, particularly at the low-count regime.



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Software
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Denoising software for Poisson and Poisson-Gaussian data
for Matlab (ver. 6.5 or later)

download zip package

3-Mbyte zip-file
includes functions implementing the exact unbiased inverse of the generalized Anscombe variance-stabilizing transformation

v2.01, released October 2, 2011




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  Markku Mäkitalo
  Alessandro Foi



Links Links

  Block-matching and 3D filtering (BM3D) algorithm (with Matlab software)



References References

PDFMäkitalo, M., and A. Foi, “Optimal inversion of the generalized Anscombe transformation for Poisson-Gaussian noise”, submitted, September 2011.

PDFMäkitalo, M., 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. DOIdoi:10.1109/TIP.2010.2056693

PDFMäkitalo, M., 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 doi:10.1109/TIP.2011.2121085

PDFMäkitalo, M., 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. DOIdoi:10.1109/LNLA.2009.5278406



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