Method and apparatus for refraction and vision measurement

Abstract

Consumer products such as refraction measurement devices may be used for obtaining refraction measurements allow consumers to track their vision without visiting an optometrist or ophthalmologist. Such consumer products may work in concert with smart phones or other products having a touch screen that present images to refraction measurement devices. Smart phones may have resolution rates, sometimes measured as PPI or pixels per inch that are unknown to the user and/or refraction measurement device. One aspect of the invention is to provide an optical interface for the user to manually match the view port boundary of the smartphone to comport with the view port boundary of the refraction measurement device. Another aspect of the invention is the use of pre-distortion in images presented to the user. By noting the corrective movements exerted by the user upon the refractive measurement device, the user's own refractive error can be derived.

Claims

1. A method to measure refraction error of an optical system, the method comprising the steps of: a) using a first lens for demagnification; b) using a second and third lens, with the second and third lens each defining one slit; and wherein the second lens is of a different color as compared to the third lens; c) using a view screen to project a first line through the first and second lenses and using the view screen to project a second line through the first and third lenses, wherein the first and second lines are pre-distorted so as to project relatively straight lines as perceived by a user; d) using meridian angles to rotate the first and second lines projected by the view screen; e) using a first meridian angle to initially dispose the first and second lines projected by the view screen and using the optical system being tested to adjust the first line and second line to alignment to derived a first distance of line movement for the first meridian angle; f) using a second meridian angle, the second meridian angle being a predefined angular difference from the first meridian angle; adjusting the first line and second line, as perceived by the optical system being tested, such that the first and second lines are aligned to derived a second distance of line movement for the second meridian angle; g) using the first and second distance of line movement in conjunction with the first and second meridian angles, to derive the refractor error of the optical system.

2. The method of claim 1, further including the step of projecting a view port indicia (430) upon the view screen; the user adjusting the view port screen to comport with a view port of the first and second lens lines.

3. The method of claim 2, further including the step of calculating a display resolution of the display screen by use of the size of the view port screen size, as adjusted by the user.

4. A system to measure refraction error of an optical system, the system comprising: a) a first lens used for demagnification; b) a second and third lens, with the second and third lens each defining one slit; and wherein the second lens is of a different color as compared to the third lens; c) a view screen to project a first line through the first and second lenses and using the view screen to project a second line through the first and third lenses, wherein the first and second lines are pre-distorted so as to project relatively straight lines as perceived by a user; d) using meridian angles to rotate the first and second lines projected by the view screen; e) a first meridian angle employed to initially dispose the first and second lines projected by the view screen and using the optical system being tested to adjust the first line and second line to alignment to derived a first distance of line movement for the first meridian angle; f) a second meridian angle being a predefined angular difference from the first meridian angle; adjusting the first line and second line, as perceived by the optical system being tested, such that the first and second lines are aligned to derived a second distance of line movement for the second meridian angle; g) using the first and second distance of line movement in conjunction with the first and second meridian angles, to derive the refractor error of the optical system.

5. The system of claim 4, further comprising of a view port indicia (430) disposed upon the view screen; the view port screen adjusted to comport with a view port of the first and second lens lines.

6. The system of claim 4, wherein display resolution is derived by use of the size of the view port screen size.

7. The system of claim 4, wherein the second lens is the same color as the third lens.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 Current process for getting eye glasses

(2) FIG. 2 Proposed example of process for obtaining eyeglasses

(3) FIG. 3 Example of proposed enterprise model

(4) FIG. 4A-C Example of display resolution measurement implementation

(5) FIG. 5 Example of display resolution measurement implementation

(6) FIG. 6A-C Example of image distortion correction

(7) FIG. 7 depicts a first lens used for demagnification, a first and second lens each defining one slit, with the second lens of a different color from the third lens.

REFERENCE NUMERALS IN THE DRAWINGS

(8) 100 current listing of steps to obtain eye glasses

(9) 200 proposed steps of obtaining eyeglasses

(10) 300 attachment device, such as a Personal Vision Tracker

(11) 320 straight lines spaced apart as observed through an attachment device as a result of using a pre-distorted image 490

(12) 350 straight lines disposed upon one another as a result of user adjustments of the attached device

(13) 400 display device, such as a smart phone

(14) 430 view port indicia for a user to adjust to comport with an attached device

(15) 480 image presented upon a display device, such as a smart phone

(16) 490 pre-distorted image presented by the smartphone

(17) 500 alternative attachment device, such as an Insight

(18) 540 input area of attached device

(19) 560 touch points

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(20) The following detailed description is directed to certain specific embodiments of the invention. However, the invention can be embodied in a multitude of different ways as defined and covered by the claims and their equivalents. In this description, reference is made to the drawings wherein like parts are designated with like numerals throughout.

(21) Unless otherwise noted in this specification or in the claims, all of the terms used in the specification and the claims will have the meanings normally ascribed to these terms by workers in the art.

(22) Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number, respectively. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application.

(23) In an embodiment of the invention, a resolution measurement is performed on a display, for example, of a smartphone. The user is asked to attach the device used in the refraction or vision test. The user is then presented with a shape on the display that is the same shape and aspect ratio of the attached device. The user then adjusts the size and location of the displayed shape until is matches the outline of the base of the attached device. FIG. 4 illustrates an example of an implementation of this method. FIG. 4A shows a device attached to a smartphone display where the outlined shape presented to the user is too large compared to the base of the attached device. FIG. 4C shows a device attached to a smartphone display where the outlined shape presented to the user is too small compared to the base of the attached device. FIG. 4.b. shows a device attached to a smartphone display where the outlined shape presented to the user is the right size of the base of the attached device. At that point the user may indicate the match and the size of the shape is then measured in pixels. As the size of the device is well known the display resolution (PPI—pixels per inch) can be calculated according to:

(24) $\mathrm{PPI}=\frac{d_p}{D_D}$
Where d.sub.p is the presented shape final match size in pixels taken from the drawn shape on the display, and D.sub.D is the well known shape size of the base of the device in inches.

(25) In another embodiment of the invention the resolution measurement could be performed by using sensors rather than by user input. In a suggested implementation a measurement device could be mounted on a frame that includes at least two touch points or the device itself has embedded on itself at least two touch points. These touch points are made of a material that allows interaction with a touch screen. An example would be a rubber dome attached to a slightly conductive plastic frame. The touch points are then attached to the display which includes a touch screen (e.g. as on a smartphone). The display then senses the two touch points and registers the pixel values for each of the points. The distance between the points could then be calculated according to the following formula:
d.sub.p=√{square root over ((y.sub.2−y.sub.1).sup.2−(x.sub.2−x.sub.1).sup.2)}
Where (x.sub.1,2, y.sub.1,2) are touch points 1 and 2 coordinates sensed on the screen. The PPI could then be calculated using the same formula above with D.sub.D the distance in inches between the touch points on the device. In another embodiment of the invention, three touch points or more could be implemented such that the resolution could be measured in more than one direction.

(26) FIG. 5. shows and example implementation of the proposed embodiment. In the figure, an attachment device is held in a frame which has two touch points. The distance of between which is well known. The device with the frame and the touch points are then attached to a touch capable display. The display then senses the touch points and can determine the touch pixels. The above procedure for calculating PPI can then be followed.

(27) In another embodiment of the invention a method for aberration correction is presented. In particular, distortion type aberration. The distortion is mapped spatially, and the distortion map is used to create pre-distorted images that when viewed through the distorting optics present clear images to the user. The distortion map could be obtained through simulation or empirically. Simulation of the distortion map could be achieved through ray tracing or other calculation (analytic or numerical). Empirical mapping could be done for example by observing through the optical device and presenting a lines of varying distances and assigning a curvature to each line as a function of the distance from the center in order to get a straight line when observed through the optical system. In other implementations, grids or dots may be used for the mapping instead of lines, in which case the curvature is used to straighten the grid or create an equidistant dots array, respectively. In an example implementation the curvature would be matched to a radius of a circle. In another implementation the curves will be matched to a polynomial expansion of a function. A best fit could be performed to match the curvature as a function of distance from the center. This could in turn be used to correct presented images to the user through the optical device. In an example implementation, for centrally symmetric images, the measurement of the distance could be bilateral (between two concentric lines) rather than single distance to the center. In a simplified implementation, where the presented image is intended to be of line bars, the curvature could be taken as uniform for the entire bar based for example on the curvature of the center of the bar. This could be done to simplify having to create different curvatures for the sides of the bar. This approximation works well if the bar thickness is small relative to the radius of curvature.

(28) FIG. 6 presents an illustration of an example implementation of the distortion correction. The figure uses two color bars as the displayed image. This image is useful to showcase the distortion correction as well as is used in the refraction measurement device in a PVT system. The figure presents on the first line the image presentation on the display. The second and third lines present the two bars as can be seen through the attached device in two different positions of the bars on the display. The last line shows the case where, thought the attached device, the lines seem to be overlapping. This is the case for 0D refraction as an example. It shows the potential ambiguity of the overlapping condition that is required in the refraction measurement of [PVT patent]. FIG. 6A shows the distortion present in the device where the image on the display is what is expected through the system without any correction. This figure shows the fact that straight lines on the display correspond to curved lines through the device optics. This would then lead to errors and ambiguity for the user while they are observing the image and performing the refraction test. FIG. 6B presents a form of prior art of controlling the distortion in the image. The solution used was reduction of the bar length to minimize the effect of the curvature of the lines due to the distortion of the optical system. The disadvantages of this method are clear as the curvature has not been diminished but rather is only less apparent. The shorter length of the lines causes many users to have problems observing the lines and performing the test (aligning the bars). FIG. 6.c. presents an implementation of the solution of the current invention where the lines on the display are pre-distorted to create a clear image through the optics. The procedures describe hitherto are used to create a mapping of the curvature of the bar as a function of the distance between the bars to create straight lines as they are observed through the optics of the attached device (lines 2-4 in the figure).

(29) The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform routines having steps in a different order. The teachings of the invention provided herein can be applied to other systems, not only the systems described herein. The various embodiments described herein can be combined to provide further embodiments. These and other changes can be made to the invention in light of the detailed description.

(30) Any and all the above references and U.S. patents and applications are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions and concepts of the various patents and applications described above to provide yet further embodiments of the invention.

(31) Disclosed items include:

(32) 1. A method to measure refraction error of an optical system, the method comprising the steps of:

(33) a) using a first lens for demagnification;

(34) b) using a second and third lens, with the second and third lens each defining one slit; and wherein the second lens is of a different color as compared to the third lens;

(35) c) using a view screen to project a first line through the first and second lenses and using the view screen to project a second line through the first and third lenses, wherein the first and second lines are pre-distorted so as to project relatively straight lines as perceived by a user;

(36) d) using meridian angles to rotate the first and second lines projected by the view screen;

(37) e) using a first meridian angle to initially dispose the first and second lines projected by the view screen and using the optical system being tested to adjust the first line and second line to alignment to derived a first distance of line movement for the first meridian angle;

(38) f) using a second meridian angle, the second meridian angle being a predefined angular difference from the first meridian angle; adjusting the first line and second line, as perceived by the optical system being tested, such that the first and second lines are aligned to derived a second distance of line movement for the second meridian angle;

(39) g) using the first and second distance of line movement in conjunction with the first and second meridian angles, to derive the refractor error of the optical system.

(40) 2. The method of 1 further including the step of projecting a view port indicia (430) upon the view screen; the user adjusting the view port screen to comport with a view port of the first and second lens lines.

(41) 3. The method of 2 further including the step of calculating a display resolution of the display screen by use of the size of the view port screen size, as adjusted by the user.

(42) 4. The method of 2 further including the step of calculating display resolution by

(43) $\mathrm{PPI}=\frac{d_p}{D_D}$

(44) 5. A system to measure refraction error of an optical system, the system comprising:

(45) a) a first lens used for demagnification;

(46) b) a second and third lens, with the second and third lens each defining one slit; and wherein the second lens is of a different color as compared to the third lens;

(47) c) a view screen to project a first line through the first and second lenses and using the view screen to project a second line through the first and third lenses, wherein the first and second lines are pre-distorted so as to project relatively straight lines as perceived by a user;

(48) d) using meridian angles to rotate the first and second lines projected by the view screen;

(49) e) a first meridian angle employed to initially dispose the first and second lines projected by the view screen and using the optical system being tested to adjust the first line and second line to alignment to derived a first distance of line movement for the first meridian angle;

(50) f) a second meridian angle being a predefined angular difference from the first meridian angle; adjusting the first line and second line, as perceived by the optical system being tested, such that the first and second lines are aligned to derived a second distance of line movement for the second meridian angle;

(51) g) using the first and second distance of line movement in conjunction with the first and second meridian angles, to derive the refractor error of the optical system.

(52) 6. The system of 5 further comprising of a view port indicia (430) disposed upon the view screen; the view port screen adjusted to comport with a view port of the first and second lens lines.

(53) 7. The system of 5 wherein display resolution is derived by use of the size of the view port screen size.

(54) 8. The system of 6 wherein display resolution is derived by

(55) $\mathrm{PPI}=\frac{d_p}{D_D}.$