The invention relates to devices for processing images making it possible to identify, to process and to select discrete light sources present in a video image composed of pixels. The aim is the presentation, in real time, to a user of a processed image allowing better recognition of light sources in a weakly contrasted image. In aeronautical use, this device affords a landing aid by allowing better recognition of runway lamps in conditions of degraded visibility, in particular in foggy weather. The invention relies on three major principles: 1) the main processing of images is performed only on a small number of pixels whose level is greater than a threshold; 2) a likelihood estimator evaluates the probability of existence of sources in the image; 3) the threshold is variable as a function of a certain number of parameters of the image.