A method for determining passport image data representing a digital biometric passport image for a security document, comprising: - recording a sequence of portrait images for a person by means of video image recording at a frame repetition rate and a recording resolution for the portrait images by means of a video image recording device; - storing respective portrait image data with the recording resolution and portrait image data with a reduced resolution compared to the recording resolution for the portrait images from the video image recording; and - determining passport image data representing a digital biometric passport image of the person from the portrait images of the video image recording, comprising: - selecting first portrait images from the sequence of portrait images; - determining whether the portrait image data, which are respectively associated with the first portrait images, satisfy first test criteria with respect to a suitability for a digital biometric passport image of the person, wherein the test for the portrait image data is performed with the reduced resolution; - selecting one of the first portrait images for which the associated portrait image data satisfy at least a necessary subset of the first test criteria; - determining whether the portrait image data, which are associated with the one of the first portrait images, satisfy second test criteria with respect to the suitability for the digital biometric passport image of the person, wherein the second test criteria are different from the first test criteria and the test for the portrait image data is performed with the reduced resolution; and - generating the passport image data using the portrait image data associated with the one of the first portrait images with the recording resolution if the portrait image data with the reduced resolution, which are associated with the one of the first portrait images, satisfy at least a necessary subset of the second test criteria. - recording a sequence of portrait images for a person by means of video image recording at a frame repetition rate and a recording resolution for the portrait images by means of a video image recording device; - storing respective portrait image data with the recording resolution and portrait image data with a reduced resolution compared to the recording resolution for the portrait images from the video image recording; and - determining passport image data representing a digital biometric passport image of the person from the portrait images of the video image recording, comprising: - selecting first portrait images from the sequence of portrait images; - determining whether the portrait image data, which are respectively associated with the first portrait images, satisfy first test criteria with respect to a suitability for a digital biometric passport image of the person, wherein the test for the portrait image data is performed with the reduced resolution; - selecting one of the first portrait images for which the associated portrait image data satisfy at least a necessary subset of the first test criteria; - determining whether the portrait image data, which are associated with the one of the first portrait images, satisfy second test criteria with respect to the suitability for the digital biometric passport image of the person, wherein the second test criteria are different from the first test criteria and the test for the portrait image data is performed with the reduced resolution; and - generating the passport image data using the portrait image data associated with the one of the first portrait images with the recording resolution if the portrait image data with the reduced resolution, which are associated with the one of the first portrait images, satisfy at least a necessary subset of the second test criteria. - selecting first portrait images from the sequence of portrait images; - determining whether the portrait image data, which are respectively associated with the first portrait images, satisfy first test criteria with respect to a suitability for a digital biometric passport image of the person, wherein the test for the portrait image data is performed with the reduced resolution; - selecting one of the first portrait images for which the associated portrait image data satisfy at least a necessary subset of the first test criteria; - determining whether the portrait image data, which are associated with the one of the first portrait images, satisfy second test criteria with respect to the suitability for the digital biometric passport image of the person, wherein the second test criteria are different from the first test criteria and the test for the portrait image data is performed with the reduced resolution; and - generating the passport image data using the portrait image data associated with the one of the first portrait images with the recording resolution if the portrait image data with the reduced resolution, which are associated with the one of the first portrait images, satisfy at least a necessary subset of the second test criteria.