The present invention relates to a device for obtaining a vital sign of a subject, comprising an interface (20) for receiving a set of image frames of a subject, a motion analysis unit (30) for analyzing at least one measurement area within the image frames of the set of image frames and for characterizing motion of the subject within the set of image frames, a signal extraction unit (40) for extracting photoplethysmographic, PPG, signals from the set of image frames using the characterization of motion of the subject within the set of image frames, and a vital signs determination unit (50) for determining vital sign information from the extracted PPG signals. The motion analysis unit comprises a motion estimation unit (32), a spatial characteristic extraction unit (34), and a motion characterization unit (36).
