1. A method for determining vital parameters of a human body via a device, in particular a smart device, said device comprising an optical recording unit and a computing unit, said method comprising the following steps: recording a sequence of individual image data of limited area of the skin of the human body via the optical recording; unit; evaluating the image data, including determining a pulse wave transit time by: subdividing into tiles the area of the skin reflected in the individual image data; determining a color, brightness and/or volume in each of the tiles of the individual image data; comparing the color, brightness and/or volume of the tiles in the consecutive image data of the sequence; determining a modification profile of the color, brightness and/or volume of a plurality of tiles located at different positions in the image and in accordance with the sequence of image data, wherein the modification profile reflects a pulse wave propagating through the area of the skin; temporally measuring a pulse wave velocity; and computing the pulse wave transit time from the modification profile and from the pulse wave velocity; and determining one or more vital parameter(s) of the human body from the image data via the computing unit.