Method and device for processing a set of electrical signals representing a digital image

A set of electrical signals representing a digital image obtained from the conversion of an optical image by an image sensor are processed, each signal corresponding to a pixel of the digital image. The set of signals comprises a first subset of signals corresponding to a first group of pixels and a second subset of signals corresponding to a second group of pixels, the light Lal received by the optical image to form the second group of pixels being attenuated with respect to the light Ll received by the optical image to form the first group of pixels, e.g. by an electromagnetic radiating elements (140 fig. 1). The values of at least one of the first and second subsets of signals are offset (e.g. boosted) by an offset parameter A which takes into account the attenuation of the light Lal received by the optical image to form the second group of pixels. Generation of errors due to differences in light received by an imager are mitigated.