... Consistent uncertainties of background and sources are provided. The source probability is evaluated for single pixels as well as for pixel domains to enhance source detection of weak and extended sources. ... Method Given the observed data set D = {dij } N0 , where dij expresses photon counts in a pixel cell ij , two complementary hypotheses arise: Bij dij = bij + ij B ij dij = bij + sij + ij Hypothesis Bij specifies that dij consists only of background bij spoiled with noise ij . ...