WO2005051181A1 - Procede pupillometrique - Google Patents

Procede pupillometrique Download PDF

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Publication number
WO2005051181A1
WO2005051181A1 PCT/EP2004/013548 EP2004013548W WO2005051181A1 WO 2005051181 A1 WO2005051181 A1 WO 2005051181A1 EP 2004013548 W EP2004013548 W EP 2004013548W WO 2005051181 A1 WO2005051181 A1 WO 2005051181A1
Authority
WO
WIPO (PCT)
Prior art keywords
signal
brightness
pupil diameter
pupil
determined
Prior art date
Application number
PCT/EP2004/013548
Other languages
German (de)
English (en)
Inventor
Florian Kerkau
Original Assignee
Freie Universität Berlin
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Freie Universität Berlin filed Critical Freie Universität Berlin
Priority to DE112004002270T priority Critical patent/DE112004002270D2/de
Publication of WO2005051181A1 publication Critical patent/WO2005051181A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
    • A61B3/11—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring interpupillary distance or diameter of pupils
    • A61B3/112—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring interpupillary distance or diameter of pupils for measuring diameter of pupils
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
    • A61B3/14—Arrangements specially adapted for eye photography
    • A61B3/145—Arrangements specially adapted for eye photography by video means

Definitions

  • the invention relates to a pupillometric method according to the preamble of claim 1 and a device according to the preamble of claim 7.
  • the invention further relates to certain applications and uses of the method and the device.
  • the invention relates to determining the physiological activation potential of a person.
  • the physiological activation potential ("arousel”) of a person is interpreted as a correlate of the mental or emotional stress (mental workload) of the person and thus provides valuable information about the mental state of stress
  • the mental stress level of a person is a quantity that is of great importance in terms of the person's performance. This information can be used for various purposes, e.g. in diagnostics or in process control using biofeedback signals.
  • Activation potential increased.
  • the diameter of the pupil is measured, an actual value of the pupil diameter being determined.
  • Preferred such measuring devices contain a camera or video camera that works either in the visible or in the infrared spectral range. As an example here is the infrared video
  • the pupil since the pupil not only reacts to changes in the autonomic nervous system caused by emotional and mental stress, but also to other factors, a correction must be made in pupillometric methods to determine the physiological activation potential.
  • the strongest factor influencing the pupil size is the prevailing luminance.
  • the maximum change in pupil diameter caused by the change in luminance is approximately 8 mm, while the change in mental stress causes a change in pupil diameter of only approximately 2 mm.
  • the development of pupillometry as a method of measuring mental stress in. documented work science contexts. It is described that it is necessary to free the measured pupil diameters from the influence of brightness in such a way that the pupil diameter values determined are comparable with one another in order to obtain the measurement values for mental stress that can be used from the pupillometry.
  • the measured pupil diameter is in one corrected pupil diameter converted, which is the theoretical value that the diameter would have with a luminance of 0 cd / m 2 . It is assumed that the pupil diameter decreases linearly with increasing luminance, so that the following applies:
  • LD is the current luminance
  • A is a correction factor
  • the correction factor A is the slope of the straight line that results when the pupil diameter is plotted against the brightness.
  • the correction factor A differs individually and must be determined again for each test person. To this end, the test subjects are presented with two luminance levels (calibration point luminances) LD d un and LD he i and the pupil diameters (PDdun and PDh e i) that occur are measured. The correction factor is then determined from the change in pupil diameter between the two calibration point luminances:
  • a device for determining the vigilance state of a person is known from DE 198 03 158 CI.
  • the device contains an image recording system with a CCD video camera and infrared lighting for recording images of the area of at least one eye of the person and an image evaluation system which evaluates the images recorded by the image recording system.
  • the image evaluation system has means for determining the pupil diameter.
  • the vigilance state is inter alia determined by an evaluation device. depending on the pupil diameter state information obtained by the pupil diameter determining means.
  • the image evaluation system contains an image processing unit, to which the images recorded by the video camera are transmitted.
  • the image processing unit works with two operating states, between which it is constantly switched back and forth. In a first operating state, when the infrared lighting is switched off, the ambient light, i.e.
  • the average brightness produced are measured and this information is output as a brightness signal.
  • the infrared lighting is switched on and the image processing unit evaluates the image obtained from the monitored eye.
  • the pupil diameter of the observed eye is determined by the pupil diameter determination means.
  • the image evaluation unit outputs the information about the current pupil diameter in the form of a pupil diameter signal.
  • a correlation unit correlates the time profile of the continuously measured
  • Pupil diameter with the information about the ambient brightness obtained via the ambient brightness signal.
  • This correlation is intended to eliminate the normal pupil response to fluctuations in the ambient brightness as a disturbing influence.
  • the correlation unit emits a corresponding correlation signal, which contains information about the extent to which changes in the pupil diameter are caused by a changing ambient brightness or not. However, it is not specified how this brightness signal is determined.
  • Many conventional interfaces for human-machine interaction are designed in such a way that a request for action by the machine is answered by a human action. Input devices such as a mouse and keyboard play a major role in this form of interaction. Entries are therefore subject to cognitive control by the user and are accordingly imprecise in certain areas.
  • US 5,896,164 discloses a bio-feedback control of an image output device.
  • the image of the image output device is changed by a signal changing unit.
  • the signal change unit is acted upon by a control signal which is obtained from the psychophysiological parameters (e.g. electrodermal activity) of a user.
  • the invention has for its object to provide a method and an apparatus of the type mentioned by which a reliable determination of a value of the pupil diameter of a person corrected in terms of brightness is made possible, in particular in the case of people viewing a screen.
  • the invention is also based on the object of creating a method or a device of the type mentioned at the outset, by means of which the determined state of a person provides a reliable measure of the person's physiological activation potential.
  • the invention is also based on the object of a new method or a new one
  • the pupillometric measurement of the body activation establishes a direct connection to the autonomous nervous system of the user.
  • Physical activation as an indicator of mental processes is not subject to arbitrary control of the cognitive apparatus and is therefore very reliable.
  • pupillometric methods provide usable values for the pupil diameter corrected for the brightness or the physiological activation potential if one exponentially relates the pupil diameter caused by the brightness (PD h eii) and the current ambient luminance ( LD) assumes.
  • parameters a, b and k are determined from experimentally determined values.
  • the values used to determine parameters a, b and k can be determined experimentally at a specific location (for example at a workstation in front of a screen) and / or at a single person. This person is then preferably the person whose value of the corrected for the brightness
  • Pupil diameter or its physiological activation potential to be determined later in certain activities can, however, also be determined experimentally on several persons, in which case mean values of the parameters a, b and k can be formed.
  • the present invention can be used not only for determining the brightness of the pupil diameter corrected for the brightness or the physiological activation potential, but also for process control of a device in the sense of a human-machine interface ("bio-feedback"), in particular for controlling multimedia learning systems ,
  • a control signal is generated from the determined corrected pupil diameter value PD corr and applied to the device, with process control of the device taking place as a function of this control signal.
  • Embodiments of the invention are the subject of the dependent claims.
  • Fig. 1 is a schematic representation and shows a user at a workplace with a Hämo ⁇ itor, as well as parts of a pupillometric device.
  • FIG. 2 is a schematic block diagram and illustrates a sample embodiment of a pupillometric device.
  • Activation potential of a person 10 (“user”) is used in a work station with a work computer (“subject PC”) (not shown in the figures) with work monitor 12.
  • subject PC work computer
  • the keyboard 14 of the work computer is also indicated in FIG. 1.
  • the work monitor 12 generates a strongly fluctuating ambient luminance which has to be taken into account by the pupillometric method.
  • control PC is a commercially available infrared camera 18 (REM ⁇ from SensoMotoric Instruments GmbH, Teltow) for measuring the
  • the eye 20 of the user 10 is filmed by the infrared camera 18 and the video data obtained in this way are fed to the first computer 16, in the first computer 16 these video data are evaluated by means of a video card • and the current actual pupil diameter (PD measurement ) of the eye 20 is determined , From this we get a corresponding one
  • Pupil diameter signal PD meSs signal generated.
  • a commercially available luxmeter 24 (Testo 545 from Testo AG, Lenzkirch) is connected to the second computer 22 (“stearing PC”).
  • the luxmeter 24 is used for light measurement in the vicinity of the pupil to be measured and supplies data about the ambient brightness in the form of brightness values LD to the second computer 22. In this computer, these brightness values are converted into brightness pupil diameter values
  • the second computer 22 is also supplied with the pupil diameter data determined in the first computer 16 in the form of pupil diameter signals PD measurement signal. In the second computer 22 these pupil diameter signals PD meSS -
  • the corresponding brightness pupil diameter values (PDheii) and corresponding brightness pupil diameter signals PD he ii signal are determined using a function described in more detail later. From the pupil diameter signals PD raeSs -
  • This corrected pupil diameter value (PD corr ) can then be used as a correlate of the physiological
  • Activation potential of the user From this can be mental and emotional
  • the two data records (PD mess and LD) are read in as tables.
  • PDheii the brightness pupil diameter values
  • LD luminance
  • the parameter k describes how quickly the pupil diameter changes with increasing luminance
  • the parameters a, b and k in equation (5) are determined experimentally by suitable measurements of the luminance (LD) at the workplace shown in FIG. 1 and the associated brightness pupil diameter values (PD he ii) of users.
  • the calibration for determining a and b is carried out using a black (dark) monitor and a white (light) monitor.
  • the measurements can be carried out on several users and the parameters a, b and k can be determined from these measurements as mean values. It is also possible to carry out the measurements directly only on the user whose physiological activation potential is to be determined later.
  • the parameters a, b and k are calculated with a nonlinear least-square fit with data from several users.
  • the analysis program (“mental workload analyzer") takes over the measured values of the pupil diameter and cleans them up for any measurement errors (such as those caused by blinking) by eliminating these extreme values. For this purpose, an average and the associated standard deviation are determined. All values that are more than two standard deviations away from the mean are ignored for the further calculations. The remaining values are then around the measurement errors.
  • the values of the pupil diameters PD meS s, PDheii and PDkorr as well as the values of the parameters a and b are given in suitable units of length, which, however, depend on the Depending on the measurement method, in the exemplary embodiment shown, these values are given in number of pixels of the sensor (camera) used.
  • the evaluation of the data can either in
  • This database can be used to control adaptive computer systems. For example, a learning environment can be continuously adapted to the performance of the user to ensure the best possible learning process. The learning process can experience a significant increase in efficiency through the targeted coordination of user ability and system requirements.
  • the control of adaptive computer systems may be mentioned as a first example of an area of application of the method and the device according to the invention. Since the pupil size serves as a physical correlate of a mental stress situation, the current level of the mental stress of the user is possible in real time by measuring the pupil. Using the data from the pupillometric method, the work computer can control the difficulty of the application in such a way that the load level of the user is as favorable as possible.
  • Media analysis may be mentioned as a second example of an area of application of the method and the device according to the invention.
  • important analysis data can be provided for media research, for example at Commercials, thrillers or computer applications.
  • a bio-feedback device based on the method according to the invention can advantageously replace the previously used method of measuring the skin conductance, since the pupil is the faster and more accurate indicator of the activity of the autonomic nervous system. Furthermore, no annoying wiring by the user is necessary.

Abstract

L'invention concerne un procédé pupillométrique permettant d'obtenir la valeur, corrigée en termes de luminosité, du diamètre pupillaire (PDkorr) d'une personne. Selon l'invention, le diamètre d'au moins une des pupilles d'une personne est mesuré, et un premier signal de diamètre pupillaire (PDmess-Signal) représentant un diamètre pupillaire réel (PDmess) est généré. La luminosité environnante est mesurée à proximité de la pupille à mesurer, et un signal de luminosité (LD) représentant cette luminosité environnante est généré. Une valeur de diamètre pupillaire à la luminosité (PDhell) qui est liée à la luminosité est déterminée en fonction de la valeur de luminosité (LD) déterminée, et un signal de diamètre pupillaire à la luminosité (PDhell-Signal) correspondant est généré. Le premier signal de diamètre pupillaire (PDmess-Signal) et le signal de diamètre pupillaire à la luminosité (PDhell-Signal) sont entrés dans un dispositif de traitement de signaux (22) pour générer un deuxième signal de diamètre pupillaire (PDkorr-Signal) qui correspond à la valeur, corrigée en termes de luminosité, du diamètre pupillaire (PDkorr), à partir de la relation PDkorr = PDmess - PDhell, dans laquelle PDhell = a + b?exp(-k?LD), où a, b, k ε R, b ? 0 et k > 0. Les paramètres a, b et k sont déterminés à partir de valeurs estimées ou de valeurs établies expérimentalement.
PCT/EP2004/013548 2003-11-25 2004-11-25 Procede pupillometrique WO2005051181A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112004002270T DE112004002270D2 (de) 2003-11-25 2004-11-25 Pupillometrisches Verfahren

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2003155880 DE10355880A1 (de) 2003-11-25 2003-11-25 Pupillometrisches Verfahren zum Ermitteln des physiologischen Aktivierungspotentials
DE10355880.2 2003-11-25

Publications (1)

Publication Number Publication Date
WO2005051181A1 true WO2005051181A1 (fr) 2005-06-09

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DE (2) DE10355880A1 (fr)
WO (1) WO2005051181A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022207025A1 (de) 2022-07-11 2024-01-11 Robert Bosch Gesellschaft mit beschränkter Haftung Verfahren zu einem Betrieb einer eine virtuelle Netzhautanzeige umfassenden Datenbrille, Recheneinheit und Datenbrille

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005024974B4 (de) * 2005-05-25 2010-04-01 Freie Universität Berlin Pupillometrisches Verfahren

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689135A (en) * 1971-01-26 1972-09-05 Laurence R Young Method for monitoring movement of a subject{40 s eyes
DE19649542A1 (de) * 1996-10-11 1998-04-23 Univ Eberhard Karls Verfahren zum Vermessen einer Pupille
DE19803158C1 (de) * 1998-01-28 1999-05-06 Daimler Chrysler Ag Vorrichtung zur Vigilanzzustandsbestimmung

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9315034D0 (en) * 1993-07-20 1993-09-01 Software Solutions Limited Display apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689135A (en) * 1971-01-26 1972-09-05 Laurence R Young Method for monitoring movement of a subject{40 s eyes
DE19649542A1 (de) * 1996-10-11 1998-04-23 Univ Eberhard Karls Verfahren zum Vermessen einer Pupille
DE19803158C1 (de) * 1998-01-28 1999-05-06 Daimler Chrysler Ag Vorrichtung zur Vigilanzzustandsbestimmung

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102022207025A1 (de) 2022-07-11 2024-01-11 Robert Bosch Gesellschaft mit beschränkter Haftung Verfahren zu einem Betrieb einer eine virtuelle Netzhautanzeige umfassenden Datenbrille, Recheneinheit und Datenbrille

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Publication number Publication date
DE112004002270D2 (de) 2006-10-19
DE10355880A1 (de) 2005-08-25

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