Correlated background estimated using the LAMBDAR randoms routine. Left: Local region of the image under analysis, with the 100 realisations of the random aperture shown as translucent black circles. The image has been masked using the fiducial mask, seen as the missing triangular region (a diffraction spike) at the bottom of the image. Right: Distribution of pixel values measured within the random apertures, for all apertures (black) and the individual apertures (colours). There are some apertures that are coincident with sources, resulting in large positive fluxes. These are limited in the computation of the random noise estimate through the use of median statistics. The distribution of aperture fluxes from the randoms is shown by the box-and-whisker plot, with the outlier fluxes shown as stars. This figure is a direct output of the LAMBDAR code.