METHOD AND DEVICE FOR DISTINGUISHING BLINKING EVENTS AND INSTRUMENT GAZES USING AN EYE-OPENING WIDTH

• US 20180132759A1
• Filed: 04/26/2016
• Published: 05/17/2018
• Est. Priority Date: 06/22/2015
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Wulf, Felix, Vandommele, Tjark
• Granted Patent: US 10,278,619 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: A61B 3/145 by video means
• CPC Class Codes: A61B 5/1103 Detecting eye twinkling
• CPC Class Codes: A61B 5/1128 using image analysis A61B5/1127 takes precedence
• 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: A61B 5/4809 Sleep detection, i.e. determining whether a subject is asleep or not
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: G06V 20/597 Recognising the driver's state or behaviour, e.g. attention or drowsiness
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

A method for distinguishing blinking events and instrument gazes on the basis of an eye-opening width. The eye-opening width represents an instantaneously detected clearance between the eyelids of an eye. In a step of ascertaining, a blinking event is ascertained using at least one blinking limit value. The blinking event is ascertained when an opening width value, which represents the eye-opening width, is smaller than the blinking limit value. In a step of determining, an instrument gaze is determined using a maximum blinking duration. The instrument gaze is determined when the detected blinking event is detected as lasting longer than the maximum blinking duration. The steps of the method are able to be carried out anew when the opening width value is greater than an open limit value following the determination of the instrument gaze.

Claims

1-12. -12. (canceled)

13. A method for distinguishing blinking events and instrument gazes using an eye-opening width, the eye-opening width representing an instantaneously detected clearance between eyelids of an eye, the method comprising:

ascertaining a blinking event using at least one blinking limit value, the blinking event being ascertained when an opening width value representing a value of the eye-opening width is smaller than the blinking limit value; and

determining an instrument gaze using a maximum blinking duration, the instrument gaze being determined when the detected blinking event is detected as lasting longer than the maximum blinking duration;

wherein the steps of the method are carried out anew when the opening width value is greater than an open limit value following the determination of the instrument gaze.

14. The method as recited in claim 13, wherein, in the ascertaining step, a medium blinking event is ascertained when the opening width value is smaller than a medium blinking limit value, a deep blinking event is ascertained when the opening width value is smaller than a deep blinking limit value, and a deep blinking event is ascertained when an opening width value is smaller than the deep blinking limit value following the ascertaining of the medium blinking event.

15. The method as recited in claim 13, wherein at least one of:

(i) the instrument gaze is determined in the determining step when the medium blinking event is ascertained as lasting longer than the maximum blinking duration, and (ii) no instrument gaze is determined when the deep blinking event is ascertained as lasting longer than the maximum blinking duration.

16. The method as recited in claim 13, further comprising:

storing a time characteristic of the opening width value as a blinking event characteristic when the opening width value is greater than the blinking limit value following the ascertaining of the blinking event, the steps of the method being executed anew following the step of storing.

17. The method as recited in claim 16, further comprising:

interpolating the opening width values of the blinking event characteristic to connect them into a curve.

18. The method as recited in claim 17, wherein in the step of interpolating, the curve is approximated using a predefined curve shape.

19. The method as recited in claim 18, wherein in the step of interpolating, at least one deviation value of at least one of the opening width values from the curve is determined.

20. The method as recited in claim 19, further comprising:

plausibilizing, wherein in the plausibilizing, the blinking event characteristic is discarded when the at least one deviation value or a value derived therefrom is greater than a deviation limit value.

21. The method as recited in claim 13, further comprising:

modifying, in which at least one of the blinking limit value and the open limit value is adapted using a reference level for the eye-opening width, the reference level representing the eye-opening width when at least one of no blinking event and an instrument gaze is occurring.

22. A device for distinguishing blinking events and instrument gazes using an eye- opening width, the eye-opening width representing an instantaneously detected clearance between eyelids of an eye, the device designed to:

ascertain a blinking event using at least one blinking limit value, the blinking event being ascertained when an opening width value representing a value of the eye-opening width is smaller than the blinking limit value; and

determine an instrument gaze using a maximum blinking duration, the instrument gaze being determined when the detected blinking event is detected as lasting longer than the maximum blinking duration;

wherein the device is designed to carry out the ascertaining and determining when the opening width value is greater than an open limit value following the determination of the instrument gaze.

23. A non-transitory machine-readable storage medium on which is stored a computer program for distinguishing blinking events and instrument gazes using an eye-opening width, the eye-opening width representing an instantaneously detected clearance between eyelids of an eye, the computer program, when executed by a processor, causing the processor to perform:

ascertaining a blinking event using at least one blinking limit value, the blinking event being ascertained when an opening width value representing a value of the eye-opening width is smaller than the blinking limit value; and

determining an instrument gaze using a maximum blinking duration, the instrument gaze being determined when the detected blinking event is detected as lasting longer than the maximum blinking duration;

wherein the steps of the method are carried out anew when the opening width value is greater than an open limit value following the determination of the instrument gaze.