Method for determining a behavioural, postural or geometric-morphological characteristic of a person wearing spectacles

1. A device for determining at least one characteristic for optimizing the wear position of a pair of spectacles on the face of a wearer, said optimizing characteristic being a geometrico-morphological, postural or behavioral characteristic, the device comprising:

at least one infrared light source configured to illuminate at least part of the head of said individual;

an infrared image sensor configured to acquire an image of at least part of the head of said individual illuminated by the infrared light source; and

a processing unit programmed to execute the following steps: locate, on said image, largest reflections of the infrared light source reflected by two lenses of the pair of spectacles and at least one corneal reflection of the infrared light source reflected by one of the two eyes of the wearer, and deduce said geometrico-morphological, postural or behavioral characteristic depending on:

the distances separating an observable axis from the centers of the two largest reflections, and

the position of said corneal reflection in said image.

2. The determining device as claimed in claim 1 , wherein the processing unit is a central processing unit of a computer, and the infrared light source and the infrared image sensor are separate from the central processing unit and include a communication system configured to communicate with the central processing unit of the computer.

3. The determining device as claimed in claim 1 , further comprising a single light source movably mounted relative to said image sensor or for at least two light sources that are distant from each other in order to generate two separate reflections on said image.

4. The determining device as claimed in claim 1 , wherein the at least one infrared light source is composed of at least one light-emitting diode.

5. The determining device as claimed in claim 1 , wherein the infrared image sensor is configured to acquire images in the visible domain.

6. The determining device as claimed in claim 5 , further comprising one or more of a display system configured to display the images acquired in the visible domain, and a printing system configured to print the images acquired in the visible domain.

7. The determining device as claimed in claim 1 , further comprising a visible image sensor that is separate from the infrared image sensor and that is configured to acquire an image of the wearer in the visible domain.

8. The determining device as claimed in claim 7 , further comprising one or more of a display system configured to display the images acquired in the visible domain, and a printing system configured to print the images acquired in the visible domain.

9. The determining device as claimed in claim 1 , further comprising an acquisition system configured to acquire at least one dimension of the pair of spectacles.

10. The determining device as claimed in claim 1 , further comprising a supporting structure to which the infrared light source, the infrared image sensor, and the processing unit are securely fastened.

11. The determining device as claimed in claim 10 , wherein the supporting structure includes a mounting and a slide that is movably mounted on the mounting and that supports the infrared light source or the infrared image sensor.

12. The determining device as claimed in claim 11 , wherein the mobility of the slide is motorized, and said processing unit is configured to automatically control a position of the slide such that the face of said individual is visible to the infrared image sensor.

13. A method for determining at least one characteristic for optimizing the wear position of a pair of spectacles on the face of a wearer, said optimizing characteristic being a geometrico-morphological, postural or behavioral characteristic, the pair of spectacles including a frame and two lenses, the method including steps of:

a) illuminating at least part of the head of the wearer using an infrared light source;

b) acquiring, via an infrared image sensor, an image of the head of the wearer illuminated by the infrared light source, in which image the pair of spectacles and the eyes of the wearer appear;

c) locating, in the image acquired in step b), largest reflections of the infrared light source reflected by the two lenses of the pair of spectacles and at least one corneal reflection of the infrared light source reflected by one of the two eyes of the wearer; and

d) deducing by a processing unit said geometrico-morphological, postural or behavioral characteristic depending on:

the distances separating an observable axis from the centers of the two largest reflections, and

the position of said corneal reflection in said image.

14. The determining method as claimed in claim 13 , wherein

in step b), the infrared image sensor acquires at least two images of the head of the wearer,

in step c), said reflections are located in each image acquired in step b), and

in step d), the behavioral characteristic is deduced from the positions of said reflections and includes a coefficient quantifying the propensity of the wearer to turn the gaze of the wearer by moving either the head of the wearer or the eyes of the wearer.

15. The determining method as claimed in claim 13 , wherein, in step d)

said postural characteristic is deduced depending on the positions of the reflections in said image, and

said geometrico-morphological characteristic is deduced depending on the positions of said corneal reflection in said image and on said postural characteristic.

16. The determining method as claimed in claim 13 , wherein in step c), in the image acquired in step b), the corneal reflections of the infrared light source reflected by both eyes of the wearer are located.

17. The determining method as claimed in claim 13 , wherein in step b), said image is acquired in the domain of the near infrared, with a wavelength included between 780 and 1400 nm.

18. The determining method as claimed in claim 13 , wherein said postural characteristic includes a yaw angle, which separates the sagittal plane of the head of the wearer and the optical axis of the infrared image sensor.

19. The determining method as claimed in claim 13 , wherein said geometrico-morphological characteristic includes the half pupillary distances of the wearer.

20. The determining method as claimed in claim 13 , wherein said geometrico-morphological characteristic includes the pupillary heights of the wearer.

21. The determining method as claimed in claim 13 , wherein said geometrico-morphological characteristic includes the positions of the centers of rotation of the eyes of the wearer.