The present disclosure relates in general to an eye model. The present disclosure relates in particular to an eye model which is recordable by means of an infrared camera, a method for producing the eye model, and a device for using the eye model in conjunction with an infrared camera.
In a number of measurement methods for measuring the eye, electromagnetic radiation (hereinafter “light” for short) is radiated onto and/or into the eye to be examined, and the radiation reflected from the eye is detected and evaluated. Thus, for example, in the field of refractive laser treatment of the human eye, eye tracking systems (so-called eye trackers) having at least one infrared camera are used for recording infrared light reflected from the eye and determining a position and an orientation of the eye based on the recorded infrared images. By use of suitable processing software, a movement of the eye in the course of treatment may thus be detected and quantified.
The determination of the position and the orientation of the eye by means of the eye tracker is based on the detection of eye structures, such as the eye pupil, the iris structure, the limbus, and blood vessels within the sclera, within the recorded infrared images or VIS images. Test objects for use in test measurements (during calibration, for example) of the eye tracker therefore also have such eye structures. The test objects are customarily present as sheet- or plate-shaped objects having an imprinted replica of one or more of the eye structures (for example, only the eye pupil).
For example, a lateral translation of an eye may be simulated and tracked by means of the eye tracker by effecting a two-dimensional relative movement between the eye tracker and the test object. However, it should be noted that the eye (for example, during the refractive laser treatment) may also undergo translations along the optical axis of the eye, and rotations about the optical axis and also about spatial axes extending perpendicularly thereto. Eye trackers nowadays are configured for detecting the described movements. However, within the scope of test measurements it is not possible to adequately simulate all degrees of freedom of the eye movement by means of the sheet- or plate-shaped test objects.
An object of the present invention is to provide an eye model for use as a test object within the scope of a test measurement of an eye tracking system.
One aspect of the present invention is an eye model comprising a sclera simulation which is made of a bright plastic material, the plastic material containing polyvinyl chloride at least as the main component, and comprising a pattern which contrasts in color with the sclera simulation, the pattern simulating an eye pupil and/or an iris structure.
As the result of using polyvinyl chloride at least as the main component of the plastic material, no significant diffuse reflection occurs in the sclera simulation during an infrared illumination of the eye model. In one preferable embodiment, the plastic material consists of a polyvinyl chloride.
The sclera simulation made of the plastic material appears bright under infrared illumination. Thus, the pattern contrasts in color with the sclera simulation, even under diffused or direct infrared illumination. The plastic material is preferably white in the area of the sclera simulation.
In one embodiment, the eye model is formed from an eye body whose surface in the area of the sclera simulation forms an annular surface in accordance with the shape of a spherical or ellipsoidal surface. Due to the three-dimensional design of the eye body, in particular due to the convex curvature of the annular surface (which, for example, models a scleral surface of a human eye), by rotating the eye model it is possible to simulate a rotational movement about the optical axis of the eye (z-axis) and about spatial axes extending perpendicularly thereto (so-called eye roll about the x-axis and the y-axis).
The eye body of the eye model may have a flattened area on which at least a portion of the pattern, preferably the complete pattern, is situated. It may be provided that the pattern is situated on only a partial region of the flattened area. At least in this case, the pattern may simulate only the eye pupil, for example, which is preferably centrally situated on the flattened area. In addition, it may be provided that the pattern is situated essentially on the entire region of the flattened area.
The transition from the annular surface to the flattened area may be formed by a ring-shaped edge. The pattern preferably adjoins the ring-shaped edge. The pattern may simulate at least the iris structure, and its outer edge may adjoin the ring-shaped edge. In any case, the pattern may be formed by imprinting or painting of the eye body, or by adhering to the eye body an adhesive element which bears the pattern.
In one embodiment of the eye model, the eye body has a threaded hole on the annular surface or on the side of the annular surface opposite from the pattern. A cross section of the threaded hole may be oriented substantially parallel or substantially rectangular to the flattended area in which at least a portion of the pattern is situated. Preferably, the eye body has a flattened area on the side of the annular surface opposite from the pattern, and is provided with the threaded hole in the region of this flattened area. The threaded hole may be provided for purposes of fastening the eye model.
A further aspect of the present invention is an eye model, in particular the eye model described herein. The eye model includes an eye body having a flattened area, and a bright, in particular white, sclera simulation which surrounds the flattened area in a ring-like manner, wherein a pattern is formed on the flattened area, the pattern contrasting in color with the sclera simulation and simulating an eye pupil and/or an iris structure. The surface of the eye body in the area of the sclera simulation forms a convexly curved annular surface.
A further aspect of the present invention is a method for producing an eye model, in particular for producing one of the eye models described herein. The method comprises provisioning of a plate-shaped or rectangular blank, the blank being made of a bright, in particular white, plastic material which contains polyvinyl chloride at least as the main component, wherein the blank has two oppositely situated blank flat sides. The method also includes cutting or chipping machining of the blank in order to separate at least one eye body from the blank, the separated eye body having a first flattened area which is formed from a first of the blank flat sides, and having a convexly curved peripheral surface which surrounds the first flattened area in a ring-like manner, and forming of a pattern, which contrasts in color with the plastic material and which simulates an eye pupil and/or an iris structure, in an area of the first blank flat side which corresponds to the first flattened area.
It may be provided to separate a single eye body or a plurality of eye bodies from the blank. Separating the plurality of eye bodies may take place, for example, essentially simultaneously, or essentially simultaneously within a portion of the plurality of eye bodies, or chronologically in succession.
Forming the pattern on the first blank flat side may take place after the eye body has been separated from the blank. However, the pattern is preferably formed on the first blank flat side prior to the step of separating the eye body from the blank. In particular the production of a plurality of eye models based on a single blank may be simplified and speeded up in this way.
According to a further development of the method, a threaded hole is introduced into the blank on the second of the blank flat sides, in association with each eye body to be separated from the blank, before the respective eye body is separated from the blank. The separated eye body may have a second flattened area which may be formed by the second blank flat side, and in which the threaded hole may be situated.
A further aspect of the present invention relates to the use of an eye model, in particular the use of one of the eye models described herein, for recording images of the eye model by means of a camera. An infrared camera is used as the camera, and for the eye model, an eye body is used which has a sclera simulation which is made of a bright plastic material containing polyvinyl chloride at least as the main component, and which has a pattern, the pattern contrasting in color with the sclera simulation and simulateing an eye pupil and/or an iris structure. It may be provided that the images of the eye model contain at least the pattern and a portion of the sclera simulation.
The infrared camera may be part of an eye tracking system, wherein the eye model is moved relative to the infrared camera while the images are recorded, and the eye tracking system detects eye movements on the basis of the recorded images. For this purpose, it may be provided that the eye tracking system also has a processing unit which is configured for determining a position and/or an orientation of the pattern included by the eye model within the recorded infrared image.
It may also be provided that for use, the eye model is situated on a patient table in the area of a head support of the patient table while the images are recorded. For example, a positioning device for the eye model to which the eye model is fastened (screwed, for example) may be integratable into the head support.
Supplemental features, advantages, and components of the present invention are apparent from the following description of the appended drawings, which show the following:
In the exemplary embodiment shown in
The eye body 12 also has a second flattened area 20 opposite from the cover surface 14. The second flattened area 20 forms a disk-shaped (for example, ellipsoidal and in particular circular) base area of the eye model 10. It may be provided that the base area 20 (via a ring-shaped edge) adjoins the annular surface 18. In the exemplary embodiment shown in
The eye model 10 shown in
In another exemplary embodiment, it may be provided that instead of being made of white polyvinyl chloride, the eye body 12 is made of a bright, in particular white, plastic material containing (for example, white) polyvinyl chloride at least as the main component. The plastic material may include further components, such as plasticizers or additional plastics. In any case, the plastic material should be designed in such a way that it appears bright, in particular white, even under infrared illumination.
For the eye model 10 shown in
As is apparent in
It may also be provided that a portion of the pattern 28 (for example, the simulation of the iris structure 32) extends in a convexly curved surface area of the eye body 12 or is applied entirely in a convexly curved surface area of the eye body 12 (for example, conforming to the shape of the annular surface 18). In the latter case, it may be provided that only the simulation replica of the eye pupil 30 is situated on the cover surface 14 of the eye model 10.
As is apparent in
At least in the exemplary embodiment shown in
In addition, the flattened area which forms the base area 20 of the eye model 10 is present as a circular disk. A diameter φG of the base area 20 is about 24 mm, at least in the exemplary embodiment shown in
In another exemplary embodiment, at least one of the values of the diameter φG and of the heights hU, hM of the eye body 12 may differ from the stated values. Thus, in the case of the simulation of a smaller or larger portion of the human sclera, it may be provided that the diameter φG and the height hU vary as a function of one another.
As is clear in
In the exemplary embodiment shown in
The plate-shaped blank 40 of the plastic material (in this case, white polyvinyl chloride) has two planar, oppositely situated blank flat sides 42, 44. A plurality of patterns 28 (see
For producing the eye model 10 shown in the preceding figures, an eye body 12 or a plurality of eye bodies 12 is separated from the blank 40 (as marked by dashed lines in
The plurality of the eye bodies 12 separated from the blank 40, i.e., the plurality of produced eye models 10, preferably corresponds to the plurality of the patterns 28 applied to (i.e., formed on) the blank 40. According to the exemplary embodiment of the blank 40 shown in
Applying the patterns 28 prior to the separation step simplifies and speeds up the production of the eye models 10 compared to individually applying a pattern 28 to a respective eye body 12 which has already been separated. In another exemplary embodiment, it may still be provided to apply an individual pattern 28 or a plurality of patterns 28 (on a planar and/or a convexly curved area of the surface) after the eye body 12 or the plurality of eye bodies 12 has been separated. The plurality of patterns 28 may substantially resemble each other. At least in this case, the applying of the plurality of patterns 28 to the eye bodies 12 or to the blank 40 may be carried out on an automated basis.
The pattern 28 is preferably imprinted on the blank 40 or the eye body 12 which has already been separated from the blank 40. Alternatively, the pattern 28 may be formed in some other way on the blank 40 or the eye body 12 which has already been separated from the blank 40. Thus, for example, it may be provided to paint on the pattern 28, or to apply an adhesive element which bears the pattern 28. It may be further provided to apply another pattern, such as a simulation of blood vessels, to the portion of the eye body 12 having the sclera simulation (as described with regard to
In another exemplary embodiment, it may also be provided that only a single eye body 12 is separated from the blank 40 in order to produce a single eye model 10. At least in this case, the blank 40 may also be rectangular shaped, for example.
It is provided to mill out the eye bodies 12 from the blank 40 shown in
The production of the eye model 10 may include further steps. Thus, it is provided to introduce the threaded hole 30 shown in
In an alternative embodiment, at least some of the steps of producing the eye model 10 may be replaced by 3D printing. For example, the eye body 12 may be 3D printed with the plastic material (such as white polyvinyl chloride). In this case, the 3D printing may further include the step of applying the pattern 28 to the eye body 12 by printing colored plastic material (such as colored polyvinyl chloride).
The device 50 includes an eye tracking system 52 and a laser device 53 for refractive laser treatment of a human eye. The eye tracking system 52 may be an eye tracker which is designed for detecting and quantifying a translational and a rotational eye movement in multiple dimensions, in particular in more than two dimensions. The eye tracker 52 may, for example, be part of the laser device 53, illustrated in a highly schematic manner.
The eye tracker 52 may be implemented in various ways known to those skilled in the art. In the exemplary embodiment shown in
The infrared camera unit 54 is configured for recording a plurality of infrared images of the eye model 10 (and the stripe projector), for example by means of one or a plurality of infrared cameras positioned around the eye model 10. It is provided that such an infrared image of the eye model 10 contains the pattern 28 and at least one portion of the sclera simulation which adjoins the pattern 28 (i.e., an area of the annular surface 18 of the eye body 12). On account of the plastic material described with reference to
The processing unit 56 is configured for determining a position of the center of the simulation of the eye pupil 30 and an orientation of the simulation of the iris structure 32 (see
In the exemplary embodiment shown in
In the exemplary embodiment shown in
The positioning device 62 is also designed to mechanically adjust the position and orientation of the eye model 10. A relative movement between the eye model 10 and the eye tracker 52 is thus effected. Alternatively or additionally, in another exemplary embodiment the relative movement between the eye tracker 52 and the eye model 10 may take place by changing the position and orientation of the eye tracker 52.
As the result of such a relative movement between the eye model 10 and the eye tracker 52, the three-dimensional sclera simulation (as described with reference to
When the eye model 10 is used in conjunction with the device shown in
Number | Date | Country | Kind |
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102015014324.7 | Nov 2015 | DE | national |