Device for determining a fixation point

• US 6,553,281 B1
• Filed: 02/28/2000
• Issued: 04/22/2003
• Est. Priority Date: 08/26/1997
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Heinrich-Hertz-Institut Fuer Nachrichtentechnik Berlin GmbH
• Inventors: Liu, Jin
• Primary Examiner(s): Patel, Ramesh
• Assistant Examiner(s): Gain, Edward F.
• Application Number:
  US09/486,584
• Time in Patent Office: 1,149 Days
• Field of Search: 700/302, 700/275, 700/56, 700/57, 700/59, 700/60, 700/61, 700/62, 700/66, 351/209, 351/210, 351/205, 351/246
• US Class Current: 700/302
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

The invention relates to a device for determining a fixation point (3) on screen (1), comprising an eye reference point detector (6) an a direction of view detector (9) which is mounted on a pivoting/inclining element (11) in such a way that it can be pivoted and inclined. By means of three transformation steps, namely rotation, scaling and translation, a direction of view function can be transformed by a system of direction of view coordinates assigned to the direction of view detector (9) in an object coordinate system which is assigned to the screen (1). In this way it is possible, to trigger certain functions by fixation of areas of the screen (1) rendered sensitive, whereby the eye plays the role of a mouse.

Claims

1. Apparatus for estimating a fixation point of an anthropomorphically constructed eye (5) when viewing an object (1) with an eye reference point detection device for defining spatial eye reference point coordinates of an eye reference point (49), with a gaze direction detection device for defining a viewing direction of the eye as a viewing direction function, and with a computer for defining the fixation point (3) of the eye (5) from the gaze direction function and the eye reference point coordinate values, characterized by the fact that the eye reference point detection device comprises an eye reference point detector (6) structured as a surface detector by which an image of the eye (5) may be formed within a predetermined spatial range, that the gaze direction detection device comprises a gaze direction detector (9) arranged on a pivot and tilt element (11) which is pivotable and tiltable in two overlapping directions, whereby images may be formed by the gaze direction detector (9) of at least the pupil (13) and the immediate vicinity (14, 15) of the pupil and the pivot and tilt element (11) is adjustable by a tracking unit (21) fed with control signals from the eye reference point detection device such that during spatial movements of the eye reference point (49) the gaze direction detector (9) remains fixed on the eye reference point (49), and that the computer comprises a compensation unit (24) for compensating for the movement of the eye reference point (49) to which may be fed object coordinate values associated with the object, gaze direction coordinate values associated with the gaze direction detector (9), alignment values associated with the alignment of the gaze direction detector (9) and eye reference point coordinate values for defining the fixation point (3).

2. Apparatus according to claim 1, characterized by the fact that the compensation unit (24) comprises a rotation compensation member (27), a scaling member (28) and translation compensation member (29), whereby the gaze direction function may be corrected by the alignment values by means of the rotation compensation member (27), the size of the rotationally corrected gaze direction function may be calculated by the scaling member (28) during viewing of the object (1) and the displacement of the eye reference point (49) relative to the origin of an object coordinate system (30) may be corrected by the translation compensation member (29).

3. Apparatus according to claim 2, characterized by the fact that storages (19, 20, 22, 23, 25) are connected to the eye reference point detection unit and the compensation unit (24) for storing internal instrumentation related parameters and coordinate values of the eye reference point detection device and the gaze direction detection device as functions of the object coordinate system (30).

4. Apparatus according to claim 3, characterized by the fact that the gaze direction detection device is arranged for determining the gaze direction function by the so-called “

cornea-reflex”

method.

5. Apparatus according to claim 4, characterized by the fact that the eye reference point detection device comprises a surface eye reference point defining unit (8) for defining from the image of the eye reference point detector (9) the eye reference point (49) in surface coordinates of an eye reference point coordinate system (35) and that there is provided a spatial eye reference point determining unit (18) connected to the surface eye reference point determination unit (8) which in addition to surface coordinates from the surface eye reference point defining unit (8) may be fed with surface coordinates in a gaze direction coordinate system (39) of the eye reference point detector (6) and of the gaze direction detector (9) as well as the alignment values.

6. Apparatus according to claim 4, characterized by the fact that the eye reference point detection device and the gaze direction detection device comprise a common surface detector (52) mounted on the pivot and tilt element (11) for monitoring the eye (5) within a predetermined spatial range.