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
  • A61B3/113—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for determining or recording eye movement
• • 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
  • A61B3/02—Subjective types, i.e. testing apparatus requiring the active assistance of the patient
  • A61B3/028—Subjective types, i.e. testing apparatus requiring the active assistance of the patient for testing visual acuity; for determination of refraction, e.g. phoropters
  • A61B3/032—Devices for presenting test symbols or characters, e.g. test chart projectors
• • 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
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C13/00—Assembling; Repairing; Cleaning
  • G02C13/003—Measuring during assembly or fitting of spectacles
  • G02C13/005—Measuring geometric parameters required to locate ophtalmic lenses in spectacles frames

Definitions

• the present invention relates generally to the analysis of the visual behavior of a subject, for purposes of optimizing the optical characteristics of corrective lenses, or ophthalmic lenses, which he must wear.
• a subject may follow a line of writing by turning his or her eyes more with respect to the head, or on the contrary more the head with respect to the eyes.
• This behavior of the subject advantageously determines the design of the glasses, and in particular the width of the zones in view from afar and in close view on the latter.
• a commercially available apparatus for providing a first indication of the optical behavior appears to include an accessory ported by the subject above the eyes, and provided with sharp markers, and a housing provided with wireless transmission and reception means capable of from signals sent to said markers and returned by them, to determine the position of the head of the subject when it looks fixed points laterally shifted to left and right.
• the system makes it possible to deduce summarily whether the subject tends to move his eyes or tends to move his head during a lateral displacement vision.
• the present invention aims to propose a system that makes it possible to determine the behavior of the subject when his vision is moving, while retaining the advantages of video technology, in particular in order to optimize the position of the lenses in a frame, or to allow the subject to to observe each other with different types of virtual frames superimposed on the real image of his face in computer graphics or other technology, etc.
• a system for assisting in determining the correction of the sight characterized in that it comprises in combination:
• a camera capable of taking animated images of the subject's face along a determined axis of view
• a display device for representing the images taken by the camera
• an accessory capable of being fixedly worn by the subject's head and carrying a plurality of visual cues
• visual target means capable of covering at least two predetermined regions with respect to the camera
• image analysis means capable of analyzing the position of the visual cues in the images taken by the camera and of deducing from it the position and the orientation in the space of the accessory, and therefore of the subject 's head , when his gaze is on a visual target, to deduce a visual behavior information of the subject during a vision that has moved.
• the visual target means (s) comprise two localized visual targets located to the left and to the right of a vertical plane passing through the axis of the camera, respectively.
• the visual target means (s) comprise at least one generally horizontal line.
• the visual target means (s) comprise: two targets spaced vertically from one another.
• the system comprises means for moving at least one target.
• the system comprises means for moving the camera vertically and orienting its line of sight in low-angle.
• the system comprises means for moving at least one target vertically with the camera.
• the image analysis means are able to determine the rotation of the head during the displacement of gaze on the targets, and the system comprises calculation means for deriving information of rotation of the head and the position of said targets. in relation to the camera, information of movement of the eyes, so as to obtain a distribution between the movement of the head and the movement of the eyes of the subject during this movement: the gaze.
• the image analysis means and the calculation means are able to produce said information statically, when the subject is looking at a target.
• the image analysis means and the calculation means are capable of producing said information dynamically, during the movement of the gaze of the subject.
• the image analysis means and the calculation means are capable of producing said information dynamically, during the arrival of the subject's gaze on a target.
• the system comprises means for calculating an average between several positions of the accessory, found in the same situation.
• the image analysis means are also able to determine a reference position of the head of the subject, where the accessory occupies a generally symmetrical position relative to a vertical plane parallel to the line of sight of the camera.
• the visual cues of the accessory are localized areas of a specific color, and in that the image analysis means comprise a colorimetric filtering means.
• FIG. 1 is a schematic perspective view of a system according to the invention
• FIG. 2 is a block diagram of the various essential components of the system of the invention.
• FIG. 3 is a perspective view of an accessory used in the system of the invention.
• a system for assisting in the determination of vision correction for the purpose of designing spectacle lenses or ophthalmic lenses.
• This system comprises a frame 10 in the upper region of which are housed a color camera 12 and a color display screen 14 for example cathode ray or liquid crystal.
• FIG. 2 shows that the camera 12 is connected to a central unit 11 via a video acquisition card 13, in a manner known per se.
• the central unit 11 drives the screen 14 via a video output circuit, not shown, in a manner also known.
• a keyboard 16 as well as any other input device such as mouse, etc., not shown, allows to control the system, as will be discussed in detail below.
• the system also comprises two visual targets 21, 22, located laterally on either side of the frame, intended to be viewed by a subject: at the instruction of an operator, as will be seen in detail below. These targets may be visually well identifiable areas, occupying well-defined or determinable positions with respect to the line of sight of the camera 12.
• the system further comprises an accessory intended to be secured to the head of the subject S, and illustrated in detail in FIG.
• This accessory 30 made for example of transparent plastic material, comprises a main body
• the main body 32 lies horizontally with two lateral branches 33, 34 also horizontal, extending substantially at right angles to the rear relative to the main body.
• the main body 32 comprises along its lower edge two small tongs 35, 36 intended to hang along the upper edges of two glasses glasses (or on a frame) carried by the subject S, the branches 33, 34 may also include, in a manner not shown, arrangements for wedging on the branches of the frame.
• the accessory 30 comprises a certain number of markers or visual cues, here eight square zones 41 to 46 of a well-identified color, for example a bright green of a well-defined wavelength, two visual cues
• the main body 32 of the accessory has an upwardly projecting portion 37, in the upper region of which there is a mark 45, and a projecting portion 38 at the front, free end of which is a marker 46.
• the last two marks 47 and 48 are on the left and right, in the vicinity of the departure of the branches 33 and 34.
• any other arrangement of markers if necessary more numerous, can be used, depending in particular on the types of movements whose analysis is preferred, the desired accuracy and any ambiguities to be solved when the markers are too many. few and / or too evenly spaced.
• the central unit 11 has, preferably by appropriate programming, means for analyzing the images taken by the camera 12 and intended to:
• these calculations are performed in relation to a reference position (position "in the axis") initially determined, for example in accordance with document FR-2860887A in the name of the applicant, the appropriate height of the line of sight of the camera 12 having been previously set manually or automatically. This is preferably done by looking for the position of the head where the accessory occupies a generally symmetrical position with respect to a vertical plane parallel to the line of sight of the camera.
• the positions of the visual references of the accessory in this reference position are stored.
• the subject is then asked to look at the visual target on the left and then the visual target on the right.
• an instruction is given to the system, for example by means of a key on the keyboard 16, so that the image analysis means calculate the current position of the head of the subject from the running position. visual cues in the image.
• the system proceeds in real time or deferred the sequence of images taken by the camera during these movements. It can for example calculate an average position of the head (which will serve as a reference position) during these movements, an average position of the head when the left target 2] is viewed, and finally an average position of the head when the Right target 22 is watched.
• the image processing means note in the image taken at the time of the aforementioned instruction the coordinates of the visual cues actually visible, and mainly of the four visual cues 45-48 that are likely to make the most face the camera, and it is easy to understand that thanks to the specific arrangement of visual cues, and thanks to algorithms based mainly on trigonometric geometry, the central unit is able to determine the changes of position and ⁇ 'inclination ⁇ e the head by relative to the reference position according to the six degrees of freedom.
• the variations of angle of view between the observation of the left target and the observation of the right target are known thanks to the fact that the system knows on the one hand the position of said targets and on the other hand, thanks to to the accessory 30, the position of the subject's head.
• the system is thus able to determine information on the relative importance of the movement of the head when shifting vision from one target to another, and to deduce the relative importance of eye movement.
• This information is delivered at an output 18 (display, printing, glass making equipment, etc.).
• the system can be designed to measure the inclination movement of the head downwards, especially when the subject goes from 'a vision from a distance (a glance raised horizontally or substantially) to a vision of reading closely (looking down, and this once or several times alternately as in the case above.
• the system advantageously comprises a first visual target placed substantially at the height of the camera (for example fixed to said camera, and a second target placed at a certain distance below the camera, for example a few tens of
• This second target could be either an open book or a sheet of paper with characters that will be asked about to read, in which case it is advantageous to associate or integrate to this target a light source, for example a small reflector fed by batter, this source being directed towards the subject's face so as to obtain an image of satisfactory quality, in particular for detecting by image analysis the position of the pupils of the eyes of the subject with the corneal reflection, and if necessary to facilitate the position of the accessory 30, and therefore of the subject's head.
• manual or motorized means are provided for moving the camera and the targets, independently of each other or in concert, so that the camera and the first target are substantially at eye level and that the second target is located at the desired distance below the camera.
• the second target typically characters to be read
• the second target typically characters to be read
• the second target is simply a book or a document placed in the hands of the subject as indicated above, the subject then adopting a natural reading position.
• the exact position of the second target is then not known precisely by the system (no position determined with respect to the camera), but any means can be provided (visual references on the book and / or on the frame) allowing to have the most determined position possible so that the analysis of the visual behavior is reliable.
• system may be designed to analyze the subject's behavior when reading a fixed size document.
• the system analyzes in this case a series of images taken during the reading phase, to make the aforementioned determination dynamically, in real time or in deferred time depending in particular on the computing power of the system.
• the target here constituted by the written document can belong to the system, being then preferably behind a window inside the frame and being able to move in height with respect to the camera, or simply be held in the hands of the subject.
• the camera is in a low-angle position to obtain an image allowing the image analysis process to proceed in the most reliable manner.
• the physical arrangement of the various components of the system can vary widely from what is described. For example, it is possible to ensure, by semi-transparent mirror return optical systems, that the line of sight of the camera 12 and the axis of the screen (the normal to the screen at its center) 14 are neighbors or merged so take the subject in front when facing the screen.
• the camera 12 can if necessary be motorized, in vertical displacement but also in lateral displacement, inclination, magnification, etc.
• the Mvencion system it is possible thanks to the Mvencion system to perform a dynamic analysis of the visual behavior.
• this process can be implemented in both near vision and far vision.
• the invention may be combined with any image processing that makes it possible, in particular, to superimpose on the subject's face synthetic images representing different models of frames, to retreat the area occupied by the accessory 30 so that it is invisible on the screen.
• Delivered image including reprocessing of visual cues whose strongly marked color may be undesirable to the screen, etc.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Ophthalmology & Optometry (AREA)
• Medical Informatics (AREA)
• Surgery (AREA)
• Veterinary Medicine (AREA)
• Public Health (AREA)
• Biophysics (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• General Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Animal Behavior & Ethology (AREA)
• Optics & Photonics (AREA)
• Geometry (AREA)
• General Physics & Mathematics (AREA)
• Multimedia (AREA)
• Human Computer Interaction (AREA)
• Eyeglasses (AREA)
• Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
• Image Analysis (AREA)
• Eye Examination Apparatus (AREA)

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• 2005
  • 2005-10-21 FR FR0510778A patent/FR2892529B1/fr active Active
• 2006
  • 2006-10-23 JP JP2008536063A patent/JP5289962B2/ja active Active
  • 2006-10-23 US US12/084,011 patent/US8315439B2/en active Active
  • 2006-10-23 EP EP06807475A patent/EP1937133A2/fr not_active Ceased
  • 2006-10-23 KR KR1020087012198A patent/KR101208062B1/ko active IP Right Grant
  • 2006-10-23 WO PCT/EP2006/067667 patent/WO2007045694A2/fr active Application Filing

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