The present invention relates to a processor and a system (1, 1′) for screening of the state of oxygenation of a subject (100), in particular for screening of newborn babies for congenital heart disease. The system comprises an imaging unit (2) for obtaining a plurality of image frames of the subject (100) over time, and a processor (3) for processing the image frames. The imaging unit, for instance a conventional video camera as used in the vital signs monitoring using the above mentioned principle of remote PPG, is used as a contact less pulse oximeter, by use of which a body map (for at least some body parts of interest) of at least the blood oxygen saturation is created. Picking certain body areas, e.g. right upper extremity versus left upper and/or lower extremity, and combining or comparing them can serve the purpose of detecting anomalies of heart and/or circuitry functions.
