A device for determining a vital sign of a subject comprises an interface for receiving a data stream derived from detected electromagnetic radiation reflected from a region of interest including a skin area of the subject, said data stream comprising a data signal per skin pixel area of one or more skin pixels for a plurality of skin pixel areas of said region of interest, a data signal representing the detected electromagnetic radiation reflected from the respective skin pixel area over time. An analyzer is provided for analyzing spatial and/or optical properties of one or more data signals in one or more wavelength ranges. A processor is provided for determining a vital sign information signal of the subject based on the data signals of skin pixel areas within the skin area, and a post-processor is provided for determining the desired vital sign from said vital sign information signal. The determined spatial and/or optical properties are used by the processor for determining the vital sign information signal and/or by the post-processor for determining the desired vital sign.