Eye-tracker communication system

• US 4,648,052 A
• Filed: 11/14/1983
• Issued: 03/03/1987
• Est. Priority Date: 11/14/1983
• Status: Expired due to Fees

• Current Assignee: Sentient Systems Technology, Inc. (Tobii Dynavox AB)
• Original Assignee: Sentient Systems Technology, Inc. (Tobii Dynavox AB)
• Inventors: Dzmura, Mark R., Friedman, Mark B., Kiliany, Gary J.
• Primary Examiner(s): Krass, Errol A.
• Assistant Examiner(s): Dixon, Joseph L.
• Application Number:
  US06/551,309
• Time in Patent Office: 1,205 Days
• Field of Search: 364/550, 364/415, 364/518, 351/205, 351/209, 351/210, 351/211, 358/93, 358/107, 340/825.19, 340/365 P, 250/221
• US Class Current: 348/78
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61F 4/00 Methods or devices enabling patients or disabled persons to operate an apparatus or a device not forming part of the body operating or control means for prostheses A61F2/48, A61F2/68
• CPC Class Codes: G06T 7/00 Image analysis
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: G09B 21/00 Teaching, or communicating with, the blind, deaf or mute audible presentation of material to be studied G09B5/04; devices or methods for replacing direct visual or auditory perception by another kind of perception A61F9/08, A61F11/04; audible indication of meter readings or of colour G01D7/12; watches for blind persons G04B25/02; speech analysis, speech recognition G10L; sound-recording or reproducing, per se G11B

Abstract

A system for computer vision comprises a source of digitized video signals and a frame encoder circuit connected to the source of digitized video signals. The frame encoder encodes threshold crossing events at at least two threshold levels and stores encoded data for a two-dimensional area within the frame in a cache memory. The threshold levels are programmable. A computer is in communication with the encoder circuit at least via its data bus and address bus for programming the threshold levels and controlling the encoder and accessing the data in said cache memory. The computer has an associated main memory with a stored task for reading the cache memory and interactively controlling the frame encoder circuit and interpreting the data gathered thereby. Data is encoded by event type and pixel address wherein the event type is indicative of threshold crossed and direction of crossing. The task stored in main memory has an algorithm for continuously changing the threshold levels and analyzing the data in successive frames until the desired threshold levels are achieved.

Claims

1. An eye-tracker system comprising:

(a) a light source;

(b) a television camera producing video signals;

(c) a frame encoder circuit connected to the video signal output from the camera for encoding the signals at at least two threshold levels and storing said encoded data for a two dimensional area within said frame in a cache memory, said threshold levels being programmable; and

(d) a computer in communication with said encoder circuit at least via its data bus and address bus for programming said threshold levels, controlling the encoder and accessing data in said cache memory;

(e) said computer having an associated main memory with a stored task for reading the cache memory and interactively controlling the frame encoder including a subtask for finding the corneal reflection of an eye upon which the camera is focussed by lowering the upper threshold until the brightest spot on the frame is detected and having a subtask for finding the pupil of the eye by raising the lower threshold at least until the border between the pupil and the iris of the eye upon which the camera is focussed is defined and having a third subtask for finding the center of the corneal reflection and the center of the pupil and establishing the vector from the center of the corneal reflection to the center of the pupil.

2. An eye-tracker communication system comprising:

(a) a display bearing indicia which may be selected by a user with one of the user'"'"'s eyes;

(b) a light source;

(c) a television camera producing video signals, said television camera and light source arranged to be focussed upon the eye of a user facing the display;

(d) a frame encoder circuit connected to the video signal output from the camera for encoding the signals at at least two threshold levels and storing said encoded data for a two dimensional area within said frame in a cache memory, said threshold levels being programmable; and

(e) a computer in communication with said encoder circuit at least via its data bus and address bus for programming said threshold levels, controlling the encoder and accessing data in said cache memory;

(f) said computer having an associated main memory with

(i) a stored task for reading the cache memory and interactively controlling the frame encoder including a subtask for finding the corneal reflection of an eye upon which the camera may be focussed by lowering the upper threshold until the brightest spot on the frame is detected and having a subtask for finding the pupil by raising the lower threshold at least until the border between the pupil and the iris of the eye upon which the camera may be focussed is defined and having a third subtask for finding the center of the corneal reflection and the center of the pupil and establishing the vector from the center of the corneal reflection to the center of the pupil; and

(ii) a task for correlating the vector with the indicia upon the display and outputting a signal indicative of the indicia selected by a user.