A 3D image analyzer for the determination of a gaze direction or a line of sight (having a gaze direction vector and a location vector, which e.g. indicates the pupil midpoint and where the gaze direction vector starts) in a 3D room is configured to receive one first set of image data and a further set of image information, wherein the first image contains a pattern, which displays a three-dimensional object from a first perspective into a first image plane, and wherein the further set contains an image having a pattern, which displays the same three-dimensional object from a further perspective into a further image plane, or wherein the further set has an image information and/or a relation between at least two points in the first image and/or at least a position information. The 3D image analyzer has a position calculator and an alignment calculator and calculates therewith a gaze direction in a 3D room.
3D image analyzer for determining the gaze direction