公开(公告)号：US11611812B2

公开(公告)日：2023-03-21

申请号：US17169597

申请日：2021-02-08

Applicant: Axis AB

Inventor： Jimmie Jönsson ,  Pontus Rosenberg ,  Ola Håkansson ,  Axel Thuresson

IPC: H04N5/235 ,  H04N23/74 ,  H04N23/56

Abstract: A method for assessing an ambient light level during video acquisition with a video camera is provided. The video camera is operably connected with an IR illuminator, and having a day mode in which an IR-cut filter is arranged in front of an image sensor and a night mode in which the IR-cut filter is not arranged in front of the image sensor. The method comprises: acquiring a stream of images with the video camera in night mode, with the IR illuminator having a first illumination output level, and then reducing an output level of the IR illuminator to a predetermined illumination output level during acquisition of a sequence of a predetermined number of consecutive image frames within the image stream, and then assessing a measure representative of an ambient light level from an evaluation of the sequence of image frames.