Eye activity monitor

• US 6,346,887 B1
• Filed: 09/14/1999
• Issued: 02/12/2002
• Est. Priority Date: 09/14/1999
• Status: Expired due to Fees

• Current Assignee: United States Department Of Health And Human Services (Government of the United States of America)
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Jung, Tzyy-Ping, Makeig, Scott, Van Orden, Karl F.
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US09/408,653
• Time in Patent Office: 882 Days
• Field of Search: 340/575, 340/576, 180/272
• US Class Current: 340/575
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 5/163 by tracking eye movement, gaze, or pupil change
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

An eye activity monitor of the present invention integrates multiple eye activity parameters and applies them to alertness models to determine the onset of operator fatigue or drowsiness in real time.

Claims

1. An eye activity monitor for alerting a task operator, the monitor comprising:

a signal processing module comprising

input means for receiving eye activity data representing the eye activity of the task operator,

an eye tracking module coupled to the input means for measuring the eye activity of the task operator and for producing a signal representing the eye activity data including pupil diameter and pupil position,

update means for updating the eye activity data at least 60 times per second,

memory means for storing a sample history representing at least ninety seconds of the eye activity data,

processing means for calculating eye activity parameters representing a moving average of pupil diameter, a history of blink frequency and duration, and a history of visual fixation frequency and duration, and

output means for producing a signal representing the calculated eye activity parameters for use in generating an alertness estimate; and

a fatigue countermeasures module for generating alarms to alert the task operator responsive to the alertness estimate.

2. An eye activity monitor for alerting a task operator, the monitor comprising:

a signal processing module comprising

input means for receiving eye activity data representing the eye activity of the task operator,

memory means for storing a sample history representing at least ninety seconds of the eye activity data,

processing means for calculating eye activity parameters representing a moving average of pupil diameter, a history of blink frequency and duration, and a history of visual fixation frequency and duration,

update means for updating the calculated eye activity parameters at least once every ten seconds, and

output means for producing a signal representing the calculated eye activity parameters for use in generating an alertness estimate; and

a fatigue countermeasures module for generating alarms to alert the task operator responsive to the alertness estimate.

3. An eye activity monitor for alerting a task operator, the monitor comprising:

a signal processing module comprising

input means for receiving eye activity data representing the eye activity of the task operator,

memory means for storing a sample history representing at least ninety seconds of the eye activity data,

processing means for calculating eye activity parameters representing a moving average of pupil diameter, a history of blink frequency and duration, and a history of visual fixation frequency and duration, and

output means for producing a signal representing the calculated eye activity parameters for use in generating an alertness estimate;

an alertness estimation module coupled to the output means for accepting the calculated eye activity parameters and for producing an alertness estimate corresponding to an alertness function comprising a linear regression model; and

a fatigue countermeasures module for generating alarms to alert the task operator responsive to the alertness estimate.

4. The eye activity monitor of claim 3 wherein the alertness estimation module further comprises:

estimation function means for generating a signal representing the alertness estimate corresponding to an alertness function A*Vfd+B*Vff, where A and B are preselected coefficients, Vfd is a calculated eye activity parameter representing visual fixation duration, and Vff is a calculated eye activity parameter representing visual fixation frequency.