1. Method for detecting and tracking eye reference point positions (EP 1 ,. .. , EPn) of multiple observers in image data of video frames (VF), which are acquired by at least one image sensor, characterised in a face finder instance (FF) for detecting face positions in video frames (VF), said instance extracting a much smaller sub-region from the total video frame as target face region (GZ) for each face in order to transmit information of said target face region (GZ) to at least one subsequent eye finder instance (EF) for detecting eye positions, said instance extracting a much smaller sub-region from each target face region (GZ) as target eye region (AZ) in order to transmit information of said target eye region (AZ) to at least one subsequent eye tracker instance (ET) for tracking the eye positions, said instance defining eye reference point positions (EP 1 ,. .. , EPn) in the target eye region (AZ) in the current video frame and in the subsequent video frames and generating information for a tracking device, wherein an instance or a group of instances is executed in parallel in a dedicated computing unit.