1. A device for obtaining a vital sign of a subject, comprising an interface for receiving a set of image frames of a subject, an image frame including a plurality of image pixels having associated pixel values; a signal extraction unit for extracting a photoplethysmographic, PPG, signal of the subject from said set of image frames; a signal evaluation unit for determining a feature of said PPG signal indicative of the quality of the information content of the extracted PPG signal with respect to a desired vital sign of the subject; a processing unit for determining a binning configuration based on the determined feature of the extracted PPG signal and based on a lookup table including a number of binning configurations for different values of the determined feature of the extracted PPG signal or a continuous or discrete function thereof, said binning configuration being provided for controlling binning of image pixels of an image frame a binning unit for binning image pixels of an image frame based on the determined binning configuration to obtain a binned image frame, wherein the signal extraction unit is configured to extract the PPG signal from said binned image frames; and a vital signs determination unit for determining vital sign information from the extracted PPG signal.