Video flow measurement method and device adapting to water level change, equipment and medium

The invention provides a video flow measurement method, device and equipment adapting to water level changes and a medium, and belongs to the technical field of water flow speed measurement. The method comprises the following steps: S1, selecting mark points according to the position of a camera and a real-time horizontal plane, and determining mark point images, constructing a homography matrix reflecting a perspective transformation relation based on the mark points and the images thereof; s2, monitoring the change of the water level, and when the change of the water level exceeds a set threshold value, introducing a virtual mark point to update the homography matrix; and S3, frame selection is carried out from the video stream according to a preset frame taking interval, feature points are extracted from selected adjacent frames, feature point tracking is carried out, object space coordinates are obtained after the traceable feature points are transformed by using a homography matrix, and the velocity fiel