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
• • 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 invention relates to a device for adapting a position of at least one spectacle lens of a pair of glasses relative to the position of a pupil of an eye of a person assigned to the spectacle lens, with a lighting device for an eye area of the person wearing a still unglazed spectacle frame, with at least one camera for generating an image of the Around the eyes and with means for marking the position of the pupil in the image.
• the invention further relates to a method for adapting a position of at least one spectacle lens of a pair of glasses relative to the position of a pupil of a person's eye associated with the spectacle lens, in which an eye area of the person wearing a still unglazed spectacle frame illuminates an image of the eye area using a first light source , and the position of the pupil is marked in the image.
• a device and a method of the aforementioned type are known, for example from the "Video Infral System II" of the applicant.
• an optician To adapt a pair of glasses, in particular glasses with varifocal lenses, an optician must determine the position of the customer's pupil centers with the usual head and body posture relative to the lens frame used. It must be ensured that the position of the pupil centers is determined at a point in time when the customer looks straight ahead and does not look to the side, for example because the optician is working near his eyes.
• this measurement is carried out from a greater distance of, for example, five meters.
• the customer is put on the still unglazed frame and the eye area of the customer is measured from the distance mentioned.
• a video camera is used in known systems.
• the image of the customer's eye area is recorded and displayed on a computer screen.
• the Opticians then mark the pupil centers in the picture, as well as certain reference lines for the position of the lens frame.
• a disadvantage of the known systems is that incorrect measurements with regard to the exact position of the pupil centers can occur if the image taken in the area of the pupils is too low in contrast, with the result that the optician cannot find and mark the pupil centers exactly in the video image. This is especially true for customers with a dark iris, from whom the pupils hardly stand out. If the general lighting in the measuring room is set to be very bright, the customer also has a natural constriction of the pupils.
• a light source of a type not described in detail is used to illuminate the person or the spectacle frame, which is designed in a ring shape.
• a light source of a type which is also not described in more detail is used, which is shown as a conventional light bulb.
• FR 2 663 528 A3 describes yet another device of this type, which uses a spot lamp of the type which is likewise not described in detail for lighting.
• a normal light that is, a white ambient light.
• the invention is therefore based on the object of developing a device and a method of the type mentioned at the outset such that the exact position of a person's pupils relative to a spectacle lens frame can also be determined in those cases in which there is only normal lighting in the measuring room result in low-contrast images of the pupils of the person.
• the measurement should be able to be carried out to such an extent that the position of the pupil centers can be detected and marked by the system itself, so that manual marking of the positions by the optician with all the sources of error associated therewith is avoided.
• the lighting device contains at least one light source which operates in a wavelength range, the light of which is reflected by the retina of the eye with a high degree of reflection, and in that the sensitivity of the camera to the Wavelength of the light emitted by the light source is optimized.
• the object is achieved according to the invention in that the eye area is illuminated with at least one light from a wavelength range which is reflected by the retina of the eye with a high degree of reflection, and in that the image of the eye area with a sensitivity optimized to the wavelength of light is generated.
• the retina of the eye is caused to reflect this light, so that it contrasts with the surrounding iris in the image.
• the use of the camera optimized for the wavelength has the advantage that particularly clear and high-contrast images can be obtained even with low light intensity.
• a method for measuring a pupil is already known from DE 196 49 542 C2, in which the pupil is illuminated with infrared light, the use of the infrared In this case, however, (invisible) light only makes sense to exclude the nuisance of the measured patient.
• a reflex from the retina that would illuminate the entire pupil is not taken into account in this known arrangement. Because of the angle between the direction of illumination and the direction of observation, such a reflection does not occur either.
• a system for measuring the function of pupils is known from US Pat. No. 5,150,137, in which, in one exemplary embodiment (FIG. 34), an arrangement is provided in which an infrared light-emitting diode emits a measuring light in the same optical axis along which the observation device also strikes the eye is directed.
• FIG. 34 In this known system, however, only a single eye is examined at a short distance, so that the problems explained at the outset do not arise here.
• the light source emits light in the red to infrared range, the light source preferably being a light emitting diode or a gate of light emitting diodes.
• the lighting device expediently contains a lens in order to bundle the light emitted by the light source in the desired manner.
• the camera has a plurality of color channels and image signals of the color channel which spectrally comes closest to the light emitted by the light source, in particular the red color channel, can be processed separately to form images.
• This measure has the advantage that commercially available video cameras can be used which have a red channel, so that the associated image signals can be processed separately into images in which the red light remitted by the retina presents itself particularly well.
• This measure also has the advantage that both images with normal light and images with the specified special light can be generated, which will be discussed further below.
• the camera and the light source are oriented essentially along the same optical axis to the eye.
• the camera and the light source can be inclined to one another by less than 2 °, preferably less than 1 °.
• This measure has the advantage that the light remitted by the retina is received particularly well in the camera can, because at least in the case of non-ametropia, the light irradiated into the eye is reflected or remitted by the retina as a narrow beam of light with little divergence.
• a beam splitter for coupling the light from the light source is arranged in the beam path between the camera and the eye, the light being reflected by the beam splitter in the direction of the optical axis of the camera away from the latter.
• This measure has the advantage that the above-mentioned coaxial alignment of the camera on the one hand and light source light on the other hand is achieved with simple structural measures.
• the beam splitter has a reflectance of less than 50%, preferably between 8% and 40%, for the light remitted by the eye.
• a light trap is arranged on the side of the beam splitter facing away from the light source.
• This measure has the advantage that the light emitted by the light source, insofar as it is not deflected away from the camera by the beam splitter, is absorbed in a reliable manner.
• additional light sources directed towards the eye area are provided outside the optical axis.
• This measure has the advantage that the invention can also be used in patients with severe ametropia in whom the light of the light source radiated in the optical axis is not narrow, i.e. little divergent light bundle is reflected along the radiation axis.
• a strong ametropia in particular myopia
• a signal remitted by the retina is received in the camera, which signal remains unchanged along the optical axis mentioned.
• the additional light sources are arranged uniformly, ie in a ring-like manner, around the optical axis and are inclined to it.
• the beam path between the camera and the lighting device on the one hand and the eye on the other hand has a length of several meters, preferably between two and eight meters.
• the spatial conditions in the measuring room do not permit such dimensions, it is also preferred in a manner known per se if the beam path is folded.
• general lighting for the eye area is provided in addition to the lighting device, and means for controlling the camera such that the camera alternatively takes a first picture only with the general lighting when the light source is switched off and a second picture with the light source switched on.
• This measure has the advantage that, in separate work steps, a first, normal image of the person's eye area and, on the other hand, a second image can be recorded on which the pupils light up compared to the first image.
• the position of the pupils can easily be found by means of image processing in a difference image of the two images and then exactly determined in the second image with the pupils lighting up.
• the camera takes the second image when the general lighting is switched off. This measure has the advantage that interference with the taking of the second image by the general lighting is avoided.
• the camera records the first and the second image in chronological succession, in particular if the camera is a so-called "interlaced" camera and the camera records the first and the second image as fields of a full image ,
• the measures have the advantage that procedures known per se, namely so-called “interlaced” procedures, can be used.
• Figure 1 shows a first embodiment of a device according to the invention, in a side view and extremely schematic.
• FIG. 2 shows a modification of the exemplary embodiment according to FIG. I
• FIG. 3 shows an image of a person's eye area, as can be recorded with the devices according to FIGS. 1 or 2;
• FIG. 4 shows a detailed illustration to explain the mode of operation of the device according to FIG. 2;
• FIG. 5 shows a further detailed illustration to explain the mode of operation of the device according to FIG. 2 in connection with FIG. 4;
• FIG. 6 is a block diagram showing an electronic control for the device according to FIGS. 1 or 2;
• FIG. 7 shows a pulse diagram to explain the block diagram according to FIG. 6.
• FIG. 1 10 overall designates a device for adapting a position of at least one spectacle lens, in particular a progressive lens, of a pair of glasses relative to the position of a pupil of a person's eye associated with the spectacle lens.
• the person is indicated overall at 12, only one eye 14 and glasses 16 or spectacle lens frame 18 is shown.
• a distance D which can be several meters, preferably two to eight meters, there is a recording system designated as a whole by 20.
• the recording system 20 contains a camera 22, the optical axis of which is designated 23.
• An illumination device 24 is provided at a right angle to the axis 23.
• the lighting device 24 contains a light source 26, in particular a light-emitting diode (LED), which operates in the red or infrared range.
• a lens 28 is assigned to the light source 26.
• the light source 26 is directed to a beam splitter 30, on the opposite side of which there is a light trap 32.
• the recording system 20 also includes general lighting 34 with normal white light.
• 40a, 40b indicate marginal rays of the light 42 which is emitted by the light source 26.
• the light 42 or the marginal rays 40a, 40b are reflected on the beam splitter 30 and directed onto the eye 14 of the person 12.
• the light 42 enters the eye 14 through an eye lens 44 and falls on the retina 46, where an image 48 is generated.
• a normal-sighted person 12 is a sharp image 48, while a defective person 12 creates a correspondingly blurred image, as will be explained below.
• the light remitted by the retina 46 is designated by 49. This in turn strikes the beam splitter 30 and partly reaches the camera 22.
• the beam splitter 30 is preferably designed as a partially transparent mirror. It consists of a transparent, plane-parallel plate, e.g. made of glass, in which one side (the lower side in FIG. 1) is untreated or partially mirrored and the other side is non-reflective.
• the mirror can have a degree of reflection of 50%, for example. With this choice of reflectance, most of the remitted light 49 would be directed into the camera 22.
• the light 42 emitted by the light source 26 is namely reflected at the mirror with the same degree of reflection, directed towards the eye 14 and remitted there by the retina 46.
• a mirroring is preferably selected which expediently has an even lower reflectance at the wavelengths at which the light 42 has no or only a low intensity.
• Lower reflectivities than those mentioned
• the light source 26 is preferably a light-emitting diode that operates in the red or in the infrared range.
• a bundle of such diodes can alternatively be used, a corresponding honeycomb arrangement then having to be selected as the lens 28, as is known per se.
• the light trap 32 only indicated in FIG. 1 has the task of absorbing the light 42 which passes through the beam splitter 30 without being reflected.
• a black cardboard, a sooty sheet or a surface covered with black velvet can be used as the light trap 32, for example.
• Such a light trap can also be designed, for example, as a so-called "black bag”.
• FIG. 3 shows an image 60 recorded by the camera 22.
• An eye area 61 of the person 12 can be seen.
• the right and left pupils of the person 12 are identified by 62r, 621, the associated iris by 64r, 641.
• the center of each Iris 64r, 641 is drawn in FIG. 3 as a cross between two dash-dotted lines.
• the retina 46 behind the pupils 62r and 621 shines brightly, so that the pupils 62r, 621 stand out clearly from the respective iris 64r and 641, respectively. This also and especially applies when the iris 64r, 641 is relatively dark by default.
• Fig. 4 shows the situation in a person 12 who is at a short distance, e.g. to position 70 is accommodated, in particular because the person 12 is short-sighted. At point 70 there is a real image of retina 46 in eye 14.
• the exemplary embodiment according to FIG. 2 is used, in which additional light sources 50a, 50b are arranged around the axis 23, in particular in the form of a ring.
• the marginal rays 52a, 52b shown in FIG. 2 identify the light emitted by the additional light sources 50a, 50b. This light runs towards the middle of the person's pupils. Because of the ametropia, blurred images of the additional light sources 50a, 50b form on the retina 46 of the eye 14.
• the intensity distributions around the geometric projection points along the marginal rays 52a, 52b are shown schematically on the partial images 72a to 72c on the right in FIG. 4. In Fig. 4 are the angles between the edge rays 52a, 52b and Axis 23 is obviously exaggerated and much larger than in reality.
• an extensive, unsharp image 48 thus shines on the retina 46, and in fact significantly brighter than only the unsharp partial image of the central intensity distribution 72a.
• the eye lens 44 designs the real aerial image of the retina 46, on which the blurred image 48 illuminates.
• FIG. 6 shows a schematic block diagram for controlling the device according to the invention in a preferred embodiment.
• a computer 80 is connected to a control 82 for the light sources 26 and 50.
• the computer 80 is also connected to an image acquisition device 29 to which the camera 22 is connected.
• FIG. 7 shows the situation with a conventional camera in the so-called "interlaced" method. Two fields are created in succession, which can be combined to form a full image. However, cameras that can only be operated in full-screen mode can of course also be used in the context of the present invention.
• lines a) and b) for the two fields are shown as pulses 90 and 92, the lines in which the camera is sensitive to the fields (integration time).
• lines c) and d) represent lighting pulses 94 and control pulses 96.
• the measurement is started with a control pulse 96, whereupon a first field 90 and a second field 92 are generated. 7 clearly shows that the two fields have a certain overlap area x, that is to say a time range in which both fields are sensitive to light.
• a first cycle I the two fields are only recorded with the general lighting 34 switched on.
• the light sources 26 and 50 are briefly switched on, as indicated by the lighting pulse 94, for example at the point in time at which both fields are sensitive to light.
• the computer 80 now has two fields from cycle I only with general lighting 34 and from cycle II two fields with light sources 26 and 50 switched on. General lighting 34 can also be switched off in cycle II.
• the desired positions can now be determined manually or automatically from the images recorded in this way (cf. FIG. 3) in the manner already mentioned.

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• General Physics & Mathematics (AREA)
• Biophysics (AREA)
• Engineering & Computer Science (AREA)
• Biomedical Technology (AREA)
• Geometry (AREA)
• Optics & Photonics (AREA)
• Molecular Biology (AREA)
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• Animal Behavior & Ethology (AREA)
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• Public Health (AREA)
• Veterinary Medicine (AREA)
• Eye Examination Apparatus (AREA)
• Eyeglasses (AREA)

Applications Claiming Priority (3)

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• 2003
  • 2003-01-28 DE DE10304185A patent/DE10304185B4/de not_active Expired - Fee Related
• 2004
  • 2004-01-24 BR BR0407040-2A patent/BRPI0407040A/pt not_active IP Right Cessation
  • 2004-01-24 CN CN200480002919.9A patent/CN1742224A/zh active Pending
  • 2004-01-24 EP EP04705005A patent/EP1588209A1/de not_active Withdrawn
  • 2004-01-24 JP JP2006501596A patent/JP2006516752A/ja not_active Withdrawn
  • 2004-01-24 AU AU2004208208A patent/AU2004208208A1/en not_active Abandoned
  • 2004-01-24 WO PCT/EP2004/000600 patent/WO2004068216A1/de active Application Filing
• 2005
  • 2005-07-22 US US11/188,234 patent/US20060044509A1/en not_active Abandoned

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