Comparison of different de-noising strategies. Top: a simulated compact galaxy affected by Poisson noise, followed by different de-noised versions. Bottom: the noise image that has been removed by each de-noising scheme. The bottom left panel shows the original Poisson noise added to the simulated image. Clearly, the noise image recovered using a method designed for Poisson noise, i.e., in this case the LET thresholding (see text), is the closest to the original noise.