Surface brightness images and residuals. (Left panel) Input surface brightness model, with five logarithmic cyan contours between 1 and 100 counts per pixel. (Second panel) Poisson realisation of input model (signal to noise ratio of 30). Shown are the model contours with red contours at the same levels. (Third panel) Reconstruction of input model using adaptive smoothing. Shown are the model contours with red contours at the same levels. (Right panel) Fractional difference between reconstructed image and input model.