Method for evaluating binocular performance of spectacle lenses, method for displaying binocular performance, and apparatus therefore

• US 20030076479A1
• Filed: 09/06/2002
• Published: 04/24/2003
• Est. Priority Date: 09/06/2001
• Status: Active Grant

• Current Assignee: Dana Automotive Systems Group, LLC (Dana, Inc.)
• Original Assignee: Hoya Corporation
• Inventors: Qi, Hua
• Granted Patent: US 6,979,084 B2
• Time in Patent Office: Days
• US Class Current: 351/233
• CPC Class Codes: G01M 11/0235 by measuring multiple properties of lenses, automatic lens meters
• CPC Class Codes: G01M 11/0257 by analyzing the image formed by the object to be tested
• CPC Class Codes: G02C 7/027 considering wearer's parameters

Abstract

To enable evaluation of the binocular performance of spectacle lenses and display of the result of the evaluation, a method and an apparatus for evaluating and indicating the binocular performance of spectacle lenses. Binocular performance indexes indicating the binocular performance of the spectacle lenses to an object point within a visual field when it is observed through specific positions on both lenses are defined. For all object points in the visual field, the binocular performance indexes are derived. An image of the visual field, in which each pixel is assigned a monochromatic luminosity or a set of primary RGB color luminosity according to the value of the binocular performance index for viewing the corresponding object point, is created and displayed.

Claims

1. A method for indicating binocular performance of spectacle lenses when a visual field is seen by an observer through right and left spectacle lenses comprising the steps of:

defining a binocular performance index expressing a binocular performance of the spectacle lenses for viewing an object point in the visual field to obtain a binocular performance index definition;

deriving a binocular performance index for each of a plurality of object points distributed over the visual field using the binocular performance index definition; and

displaying a scale of the derived binocular performance indexes in a visually understandable mode.

2. A method for indicating binocular performance of spectacle lenses when a visual field is seen by an observer through right and left spectacle lenses comprising the steps of:

defining a binocular performance index expressing a binocular performance of the spectacle lenses for viewing an object point in a visual field to obtain a binocular performance index definition;

deriving a binocular performance index for all object points in the visual field using the binocular performance index definition, each object point having a binocular performance index and corresponding to a pixel of an image which covers the visual field; and

creating a binocular performance index image covering the visual field, wherein a monochromatic or RGB color luminosity of each pixel is assigned to indicate a value of the binocular performance index for viewing the corresponding object point.

3. A method for indicating binocular performance of spectacle lenses according to claim 2, wherein said step of creating a binocular performance index image further comprises the steps of:

creating an original image comprising placing a midpoint of binocular rotation at a specific position, the midpoint of binocular rotation being a midpoint between centers of monocular rotation of right and left eyes, and creating, as the original image, an image within the visual field defined as a specific pyramidal field having an apex at the midpoint of binocular rotation;

creating a distorted original image by a ray tracing method, wherein the distorted original image is an image having distortion determined by observing a plurality of object points in the visual field through the spectacle lenses;

deriving positions of spectacle frames by creating images of spectacle frame marks that indicate positions of right and left spectacle frames on the original image or on the distorted original image by using data of principal ray-passing positions obtained in the step of creating a distorted original image;

deriving binocular performance indexes with respect to the plurality of object points, each object point corresponding to a pixel of the original image or the distorted original image created respectively in the step of creating the original image or creating the distorted original image, in an optical system comprising the spectacle lenses and an ocular model; and

creating a binocular performance index image by assigning, to each pixel of the original image or the distorted original image, a monocular luminance or luminances of three primary colors of RGB determined in accordance with a value of the binocular performance index derived in the step of deriving a binocular performance index, and overlaying the binocular performance index image with a frame mark image of spectacle frames created in the step of deriving positions of spectacle frames.

4. A method for indicating binocular performance of spectacle lenses according to claim 2, wherein the step of creating a binocular performance index image further comprises the steps of:

(a) creating an original image, further comprising the steps of;

(i) creating virtual objects by using computer graphics and placing the virtual objects in a virtual three-dimensional space;

(ii) placing a midpoint of binocular rotation at a specific position in the virtual three-dimensional space;

(iii) creating an original image of the virtual objects within a visual field, the visual field defined as a pyramid having an apex located at the midpoint of binocular rotation and a central axis oriented along a direction of a specific central visual line; and

(iv) deriving, with respect to a plurality of object points, wherein each object point corresponds to a pixel of the original image, an object distance, wherein object distance is defined as a distance between the object point and the midpoint of binocular rotation;

(b) creating a distorted original image, further comprising steps of;

(i) defining, for viewing an object point, a direction of synkinetic binocular rotation that is uniquely determined by both directions of monocular rotation of right and left eyeballs directed toward the object point;

(ii) deriving a central direction of synkinetic binocular rotation with a ray tracing method so that each of right and left monocular central principal rays pass through a specific position on each spectacle lens, respectively, wherein the central direction of synkinetic binocular rotation is the direction of synkinetic binocular rotation for viewing the object point located at a center of the visual field and the right and the left monocular central principal rays are principal rays directed from right and left eyeballs, respectively, toward the central object point;

(iii) deriving, with respect to each object point, a direction of synkinetic binocular rotation for viewing the object point as the position of the object point in an after-lens visual field with a ray tracing method, wherein the after-lens visual field is a visual field with a central axis oriented along the central direction of synkinetic binocular rotation;

(iv) creating the distorted original image, the distorted original image being defined as an image obtained in the after-lens visual field and having distortion caused by the spectacle lenses; and

(v) deriving, with respect to each object point, both right and left principal ray-passing positions, wherein a principal ray-passing position is a position on the spectacle lens through which a principal ray directed toward the object point passes;

(c) deriving positions of spectacle frames by creating images of spectacle frame marks that indicate positions of right and left spectacle frames on the original image or on the distorted original image by using data of the principal ray-passing positions obtained in the step of creating a distorted original image;

(d) deriving the binocular performance index, further comprising the steps of;

(i) providing an accommodation-dependent ocular optical system for each of the right and left eyes as a model of the ocular optical system;

(ii) calculating, with respect to each object point corresponding to a pixel of the original image or the distorted original image, distances from the object point to the right and left centers of monocular rotation using the object distance obtained in the step of creating an original image;

(iii) setting, with respect to each object point corresponding to a pixel of the original image or the distorted original image, powers of accommodation of right and left eyes to a same value or different values in accordance with each distance from the object point to each center of monocular rotation, and each refractive power of spectacle lens at each principal ray-passing position determined in the step of creating a distorted original image; and

(iv) deriving, with respect to each object point corresponding to a pixel of the original image or the distorted original image, the binocular performance index of spectacle lenses in a combined optical system comprising the spectacle lens and the accommodation-dependent ocular optical system which is rotated in accordance with a direction of monocular rotation; and

(e) creating the binocular performance index image, further comprising the steps of;

(i) creating a binocular performance index image by assigning, to each pixel of the original image or the distorted original image, a monocular luminance or a set of luminances of three primary colors of RGB determined in accordance with the value of the binocular performance index of spectacle lenses, and

(ii) overlaying the binocular performance index image with the frame mark images of spectacle frames created in the step of deriving positions of spectacle frames.

5. A method for indicating binocular performance of spectacle lenses when an observer sees through right and left spectacle lenses comprising the steps of:

creating virtual objects by using computer graphics and placing the virtual objects in a virtual three-dimensional space;

creating a story of changes with time by using positions of the observer'"'"'s eyes, a direction of a central visual line, ray-passing positions in the right and the left lenses and an amount of deformation and displacement of the virtual objects;

creating a binocular performance index image of spectacle lenses at each point of time, wherein the method according to claim 2 is used to create each binocular performance index image for each point of time; and

editing binocular performance index images at all points of time to create a video movie.

6. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein said binocular performance index is defined as a binocular residual corrective error for viewing said object point.

7. A method for indicating binocular performance of spectacle lenses according to claim 6, wherein said binocular residual corrective error is defined as a residual power or a residual astigmatism derived from a right or a left residual wavefront.

8. A method for indicating binocular performance of spectacle lenses according to claim 6, wherein said binocular residual corrective error is defined as a residual power or a residual astigmatism derived from an wavefront defined as an average of, or the difference between, a right and a left residual wavefront.

9. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein the binocular performance index is defined as a binocular vertical deviation, which is a vertical deviation between right and left visual lines, that is derived from directions of right and left monocular rotations for viewing said object point.

10. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein the binocular performance index is defined as a degree of disagreement between a convergence and an accommodation for viewing said object point.

11. A method for indicating binocular performance of spectacle lenses according to claim 10, wherein the degree of disagreement is defined as the difference between a power of convergence and a power of accommodation.

12. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein the binocular performance index is defined as a binocular point deformation index expressing a degree of deformation for viewing said object point.

13. A method for indicating binocular performance of spectacle lenses according to claim 12, wherein the binocular point deformation index is derived by determining deforming changes in the shape of a small circle centered at said object point when binocularly viewed through the spectacle lenses, wherein the deformed shape of the small circle is approximated to be an ellipse.

14. A method for indicating binocular performance of spectacle lenses according to claim 13, wherein the binocular point deformation index is defined as a ratio of major axis to minor axis of said ellipse.

15. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein the binocular performance index is defined as an aniseikonic index expressing a degree of optical aniseikonia for viewing said object point.

16. A method for indicating binocular performance of spectacle lenses according to claim 15, wherein the aniseikonic index is derived by determining deforming changes in the shape of a small circle centered at said object point changes when viewed through the right spectacle lens and the left spectacle lens, each deformed shape of the small circle corresponding to viewing through the right spectacle lens and the left spectacle lens, respectively, is approximated to be an ellipse.

17. A method for indicating binocular performance of spectacle lenses according to claim 16, wherein the aniseikonic index is defined as the square root of a ratio of the area of a right point deformed ellipse to the area of a left point deformed ellipse.

18. A method for indicating binocular performance of spectacle lenses according to any one of claims 1-5, wherein the binocular performance index is defined as a binocular clearness index which expresses a degree of clearness for viewing said object point binocularly.

19. A method for indicating binocular performance of spectacle lenses according to claim 17, wherein the binocular clearness index is derived by determining monocular point spread functions (PSF) for each of the right eye and the left eye for viewing said object point, approximating a spreading range of the right and the left monocular point spread functions to an ellipse, combining both right and left spreading ellipses into a binocular spreading ellipse, and defining the binocular clearness index as half of a diagonal length of a rectangle that circumscribes the binocular spreading ellipse.

20. An apparatus for indicating binocular performance of spectacle lenses when an observer sees through right and left spectacle lenses, the apparatus comprising:

(a) means for creating an original image, further comprising;

(i) means for creating virtual objects by using computer graphics and placing the virtual objects in a virtual three-dimensional space;

(ii) means for placing a midpoint of binocular rotation at a specific position in the virtual three-dimensional space;

(iii) means for creating an original image of the virtual objects within a visual field, the visual field defined as a pyramid having an apex located at the midpoint of binocular rotation and a central axis oriented along a direction of a specific central visual line; and

(iv) means for deriving, with respect to a plurality of object points, each object point corresponding to a pixel of the original image, an object distance, wherein the object distance is defined as a distance between the object point and the midpoint of binocular rotation;

(b) means for creating a distorted original image, further comprising;

(i) means for defining a direction of synkinetic binocular rotation for viewing an object point, wherein the synkinetic binocular rotation is uniquely determined by both directions of monocular rotation for right and left eyeballs directed toward the object point;

(ii) means for deriving a central direction of synkinetic binocular rotation with a ray tracing method so that each of right and left monocular central principal rays pass through a specific position on each spectacle lens, respectively, wherein the central direction of synkinetic binocular rotation is the direction of synkinetic binocular rotation for viewing the object point located at a center of the visual field and the right and left monocular central principal rays are principal rays directed from the right and left eyeballs, respectively, toward the central object point;

(iii) means for deriving, with respect to each object point, a direction of synkinetic binocular rotation for viewing the object point as a position of the object point in an after-lens visual field with a ray tracing method, wherein the after-lens visual field is a visual field that has a central axis oriented along the central direction of synkinetic binocular rotation;

(iv) means for creating a distorted original image, the distorted original image being defined as an image obtained in the after-lens visual field and having distortion caused by the spectacle lenses; and

(v) means for deriving, with respect to each object point, both right and left principal ray-passing positions, wherein each principal ray-passing position is a position on the respective spectacle lens through which a principal ray directed toward the object point passes;

(c) means for deriving positions of spectacle frames by creating images of spectacle frame marks that indicate positions of right and left spectacle frames on the original image, or on the distorted original image, by using data of the principal ray-passing positions determined when creating a distorted original image;

(d) means for deriving a binocular performance index, further comprising;

(i) means for providing an accommodation-dependent ocular optical system for each of the right and left eyes as a model of the ocular optical system;

(ii) means for calculating, with respect to each object point corresponding to a pixel of the original image or the distorted original image, distances from the object point to the right and left centers of monocular rotation using the object distance obtained when creating an original image;

(iii) means for setting, with respect to each object point corresponding to a pixel of the original image or the distorted original image, powers of accommodation of right and left eyes to a same value or to different values in accordance with each distance from the object point to each center of monocular rotation, and each refractive power of spectacle lens at each principal ray-passing position determined when creating a distorted original image; and

(iv) means for deriving, with respect to each object point corresponding to a pixel of the original image or the distorted original image, a binocular performance index of spectacle lenses in a combined optical system comprising the spectacle lens and the accommodation-dependent ocular optical system which is rotated in accordance with a direction of monocular rotation; and

(e) means for creating a binocular performance index image, further comprising;

(i) means for creating the binocular performance index image by assigning, to each pixel of the original image or the distorted original image, a monocular luminance or luminances of three primary colors of RGB determined in accordance with a value of the binocular performance index of spectacle lenses, and

(ii) means for overlaying the binocular performance index image with the frame mark images of spectacle frames created when deriving positions of spectacle frames.

21. An apparatus for indicating binocular performance of spectacle lenses when an observer sees through right and left spectacle lenses, comprising:

means for creating virtual objects by using computer graphics and placing the virtual objects in a virtual three-dimensional space;

means for creating a story of changes with time using positions of the observer'"'"'s eyes, a direction of a central visual line, ray-passing positions for the right and left lenses, respectively, and an amount of deformation and displacement of the virtual objects;

means for creating a binocular performance index image of spectacle lenses at each point of time that performs the method according to claim 18;

and

means for editing binocular performance index images at all points of time to create a video movie.