A method for determining vital parameters of a human body using a device with at least one optical recording unit and a computing unit includes the following steps: recording a sequence of individual image data of a single limited area of the skin of the human body using the optical recording unit evaluating the image data, including determining a pulse wave transit time and determining vital parameters of the human body from the image data using the computing unit. Further, a device determines vital parameters. In addition, a method authenticates a person and a method identifies a reaction of a person.
