JP3328096B2 - Eye optical system simulation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eye optical system simulation apparatus, and more particularly to an eye optical system simulation apparatus for simulating a retinal image when an optical lens such as a spectacle lens is worn.

[0002]

2. Description of the Related Art Optical lenses such as spectacle lenses are used to maintain normal vision. Many spectacle lenses with different optical characteristics are sold. When the classification of spectacle lenses is roughly classified by optical specifications, they are classified into a single focus lens having one focus in one lens and a multifocal lens having a plurality of focuses in one lens. Further, the single focus lens is divided into a spherical lens and an aspheric lens. The design of the aspherical lens varies from manufacturer to manufacturer. Similarly, multifocal lenses are also classified into many types. For example, there are a bifocal lens, a trifocal lens, and a progressive multifocal lens, and these lenses are further subdivided.

When selecting an optical lens, a lens suitable for a wearer is selected from lenses having various optical specifications. As a judgment material in the selection, a clerk makes a selection by preparing a plurality of types of lenses having a lens power suitable for the wearer and actually wearing the lens, or a clerk of an eyeglass store listening to the request of the wearer. There was a way.

[0004] However, it is actually difficult to own a plurality of lenses having different powers suitable for the wearer according to optical specifications in a spectacle store because of the large number of types. On the other hand, the method in which the clerk asks the wearer for his / her request and makes a selection requires skill of the clerk. Further, it is difficult for the clerk to always make an accurate judgment because the clerk cannot know what the wearer actually looks like.

In order to solve such a problem, there is an eye optical system simulation apparatus capable of simulating a retinal image when an optical lens is worn. In the eye optical system simulation apparatus, first, a parallel light beam from a light source screen is traced in an optical system such as an optical lens and a cornea to obtain a PSF (Point Spread Function). P
The SF is a function representing how light emitted from one point on the object is distributed on the image plane. Retinal image data is calculated from the PSF and the image data. By displaying the retinal image data corresponding to the image data thus obtained on the screen of the display device, it is possible to objectively determine how the image is viewed. As such an example, the present applicant has filed Japanese Patent Application No. 7-26936.

[0006]

However, the conventional ophthalmic optical system simulation apparatus can only simulate an image in a range where the retina can be focused when the human eye is facing a certain direction. There was a problem.

[0007] That is, when the eyeglasses are actually worn, only a limited area in the center can focus on an image that enters the field of view, and other areas cannot focus. Rotating the eye can focus on a wider range of arbitrary images. Nevertheless, with the conventional simulation device, it was possible to simulate only an image in a limited area where the focus can be focused with the direction of the line of sight fixed.

In addition, among spectacle lenses, there are many lenses, such as a multifocal lens, whose optical characteristics greatly differ between when an image is viewed through the center of the lens and when an image is viewed through the periphery of the lens. is there. A conventional simulation apparatus cannot perform a simulation for such a multifocal lens so that the characteristics of the lens can be sufficiently understood. Therefore, after all, the lens must be selected based on the vague criteria based on the knowledge of the clerk.

The present invention has been made in view of the above points, and provides a simulation apparatus for an eye optical system capable of simulating a wide angle scene involving rotation of a human eye when wearing an optical lens such as eyeglasses. The purpose is to do.

[0010]

According to the present invention, in order to solve the above-mentioned problems, in an eye optical system simulation apparatus for simulating a retinal image when an optical lens is worn, a light source screen placed at a predetermined position is provided. A plurality of viewpoints are determined, and the PS for each viewpoint is based on the optical lens and optical system data on the human eye in a state where the human eye is rotated so that the image at the viewpoint focuses on the retina.
PSF calculating means for calculating F (Point Spread Function), image data and the P at each viewpoint.
Performs convolution integral by SF, continuous image that is projected on the retina when the human eye was MiWataru by rotation
And a scene image calculating means for calculating the scene image displayed in the image processing apparatus.

[0011]

The PSF calculation means includes an optical lens and a human eye in a state where a plurality of viewpoints are defined on a light source screen placed at a predetermined position, and the human eye is rotated so that an image at the viewpoint is focused on the retina. Calculates a PSF (Point Spread Function) for each viewpoint based on the optical system data related to. Scenery image calculating means, continuous image that is projected on the retina when subjected to convolution integral by PSF in the image data and the respective viewpoint, the human eye has MiWataru by rotation
Calculate the scene image that is displayed on the screen .

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating the principle of the eye optical system simulation apparatus according to the present invention. In this simulation device, you can not see the whole without turning the human eye,
Assume a sufficiently large light source screen. On this light source screen,
The viewpoints arranged in a grid are set. PSF (Point Spread Function) calculators 10a to 10c for each viewpoint
10c is provided. For example, when the light source screen is decomposed into m in the vertical direction and n in the horizontal direction, m × n PSF calculation units are provided.

In each of the PSF calculation units 10a to 10c, optical system data 13a to 13c in a state where the human eye is rotated so that the image at the corresponding viewpoint is focused on the retina is set. The optical system data 13a to 13c are position data of a corresponding viewpoint, data on an optical lens such as a curvature of a convex surface and a concave surface, a refractive index, and the like, and data on a human eye such as a cornea, a pupil, a crystalline lens, a retina, and a rotation angle. . Data on the optical lens can be obtained from the design value of the lens. The optical system data on the human eye is basically obtained using a gulstrand model, and the value of the axial length is determined according to the eyesight of the wearer. Note that the measurable data can be obtained by actually measuring the eye of the wearer.

The PSF calculating means 12a to 12c obtain PSFs 11a to 11c based on the optical system data 13a to 13c. The PSFs 11a to 11c are functions representing how light emitted from a certain viewpoint is distributed on an image plane.

The scene image calculation means 2 performs convolution integration of the image data 1 drawn on the light source screen by the PSFs 11a to 11c to obtain scene image data 3. The display control means 4 displays an image obtained from the scene image data 3 on the display device 5. Thereby, the entire image that can be recognized by moving the line of sight up, down, left, and right is displayed on the screen.

Next, the procedure of the simulation in the eye optical system simulation apparatus of the present invention will be described in more detail. First, image data to be displayed by simulation is set. This image data is drawn on the light source screen within a range that can be focused by rotating the human eye.

FIG. 2 shows a light source screen. A plurality of viewpoints arranged in a grid are set on the light source screen 20. The light source screen 20 is a plane perpendicular to the X axis, and has a central part on the X axis. In this example, the light source screen 20 is set at infinity from the human eye. Then, it is decomposed into m pieces (y _{1 to} y _m ) in the Y-axis direction and n pieces (y
It is decomposed into ₁ ~y _n). Therefore, on the light source screen, m
× n viewpoints are provided. By giving light intensity at each viewpoint on the optical screen 20, image data of an arbitrary shape is set. The light at this time may be monochromatic light or light of a plurality of wavelengths.

FIG. 3 shows the human eye. This figure is a view of the human eye 40 viewed from the direction of the light source screen (positive direction of the X axis). The rotation center of the human eye 40 at this time is set on the X axis. Therefore, when the direction of the human eye 40 is parallel to the X axis, the user is looking at the center of the light source screen. Then, when viewing an arbitrary viewpoint on the light source screen, the human eye 40 is
Rotate in the axial direction. Assuming that the rotation angle in the Y-axis direction is θ _y and the rotation angle in the Z-axis direction is θ _z , the rotation angles (θ _y , θ _z ) corresponding to all viewpoints on the light source screen are obtained.

FIG. 4 is a diagram showing changes in the optical system when viewing the light source screen. This figure shows a case where the rotation angle in the Z-axis direction is fixed and the angle in the Y-axis direction is changed.
(A) is an optical system for viewing the upper end of the light source screen.
The human eye 41 rotates upward and is directed straight to a viewpoint (y _m , z _i ) at an arbitrary upper end of the light source screen 21. Therefore, the light 51 at the upper end of the light source screen 21 is
Incident from above. This spectacle lens 31
The light 51 that has passed through enters the human eye, and the image is recognized.
From this state, the human eye 41 rotates in the negative direction of the Y axis.

FIG. 2B shows an optical system for viewing the center of the light source screen. The human eye 42 does not rotate, and faces straight toward the center of the light source screen 22. Therefore, the light 52 at the center of the light source screen 22 is perpendicularly incident on the spectacle lens 32. The light 52 that has passed through the spectacle lens 32 enters the human eye, and an image is recognized. From this state, further rotation is performed in the negative direction of the Y axis.

(C) is an optical system for viewing the lower end of the light source screen. The human eye 43 rotates downward and the light source screen 23
Faces straight at the lower end of the. Therefore, the light 53 at the lower end of the light source screen 23 enters the spectacle lens 33 from a diagonally lower direction. Light 5 passing through this spectacle lens 33
3 enters the human eye, and the image is recognized.

In this manner, the optical system data at all viewpoints when rotating in the Y-axis direction is obtained. Thus, when the human eye rotates, the values of various data change. For example, the distance from the spectacle lens to the cornea is
It changes with rotation. If the spectacle lens is a multifocal lens, the radius of curvature of the concave surface and the convex surface also changes as the position where light enters the lens changes.

Note that the angle between the light 51, 53 from the light source screen and the X axis is not exactly the same as the rotation angle θy. This is because the direction changes when light passes through the spectacle lenses 31, 33.

FIG. 4 shows an optical system in the case where the rotation angle in the Z-axis direction on the optical screen is constant and the human eye rotates vertically, but it rotates in the Z-axis direction and the position of the viewpoint is changed. To z ₁
To z _n, optical system data corresponding to all viewpoints is obtained, including the case where the light source screen is rotated in the left-right direction. Then, the PSF calculating means obtains a PSF for each viewpoint based on the optical system data obtained as described above. Therefore, m × n PSFs are obtained.

Further, the scene image calculating means performs a convolution integration of the image data set on the light source screen by the PSF to obtain the scene image data 3. Assuming that the light intensity distribution of the ideal image on the image plane is f (y, z) and the PSF at the point (y, z) is p (x, y, u, v), the point (y, z) on the retina is The light intensity can be represented by the following equation.

[0026]

(Equation 1)

Here, p (u, v, uy, uz) is the value of the PSF at a point (uy, vz) apart from each point (u, v). A is the spreading radius of the PSF. By obtaining the light intensity at a point on the retina for each rotation angle of the human eye using this equation, scene image data can be obtained. The scene image data obtained in this way is a continuous display of an image projected on the retina when a person wearing glasses looks around by rotating his or her eyes.

In this way, by rotating the eye, it is possible to simulate an image recognized by a human when looking over a wide range. Therefore, even in the case of a multifocal lens, it is possible to objectively recognize the characteristics of the lens. As a result, the spectacle wearer can easily select a lens that suits him. On the other hand, when designing or evaluating a lens of a complicated optical system such as a progressive multifocal lens, if the data of the optical system of the lens is input, the characteristics of the lens can be accurately known.

Next, hardware for performing the above-described simulation will be briefly described. FIG. 5 is a block diagram of the hardware of the workstation for performing the above simulation.

As shown in the figure, the workstation is:
A processor 61, a graphic control circuit 64, a display device 65, a mouse 66, a keyboard 67, a hard disk device (HDD) 68, a floppy disk device (FD)
D) 69, a printer 70, and a magnetic tape device 71. These elements are connected by a bus 72.

The processor 61 controls the whole workstation. The read-only memory 62 stores a program required at the time of startup. The main memory 63 stores a simulation program and the like for performing a simulation.

The graphic control circuit 64 includes a video memory, converts the obtained scene image data into a display signal, and displays it on the display device 65. The mouse 66 is a pointing device for controlling the mouse on the display device and selecting various icons and menus. Hard disk drive 6
8 stores a system program and a simulation program, and is loaded into the main memory 63 after the power is turned on. In addition, simulation data and the like are temporarily stored.

The floppy disk device 69 inputs necessary data such as original image data from the floppy 69a, and saves the data to the floppy 69a as necessary. The printer device 70 is used to print out PSF, scene image data, and the like.

The magnetic tape device 71 is used to save simulation data to a magnetic tape as required. Note that a high-performance personal computer or a general-purpose computer other than the workstation may be used.

In the above description, the light source screen is assumed to be a plane at infinity, and the light rays are parallel. However, the light source screen can be set near. In this case, the simulation is performed assuming that the light beams are diffused.

In the above description, only the case where one scene image data is displayed on the display device is described. However, a plurality of scene images generated using optical system data of a plurality of optical lenses having different specifications are described. Can be displayed on the same screen of the display device.

[0037]

As described above, according to the present invention, the PSF for each rotation angle is determined in consideration of the rotation of the human eye when viewing a wide light source screen, and the PSF corresponding to each point of the image data is used. Since a scene image is calculated in this way, it is possible to simulate an image of a scene that is perceived by a human when the user rotates his eyes and looks over a wide range.

[Brief description of the drawings]

FIG. 1 is a principle diagram of an eye optical system simulation apparatus according to the present invention.

FIG. 2 is a diagram showing a light source screen.

FIG. 3 is a diagram showing a human eye.

FIG. 4 is a diagram showing a change in an optical system when viewing a light source screen.

FIG. 5 is a hardware block diagram of a workstation for performing a simulation according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 image data 2 scene image calculation means 3 scene image data 4 display control means 5 display device 10a, 10b, 10c PSF calculation units 11a, 11b, 11c PSF 12a, 12b, 12c PSF calculation means 13a, 13b, 13c Optical system data

Continuation of the front page (56) References JP-A-3-121412 (JP, A) JP-A-1-40926 (JP, A) JP-A-4-327831 (JP, A) JP-A-6-201990 (JP) JP-A-7-100107 (JP, A) JP-A-6-215084 (JP, A) JP-A-2-198547 (JP, A) JP-A-4-195019 (JP, A) 2-305544 (JP, A) JP-A-4-50813 (JP, A) JP-A-61-85917 (JP, A) JP-A-61-10740 (JP, A) Pablo Artal, Javier Santamaria, Julian Bescos, Optical-digital Procedure for the Retinal Image of a Point Test, Optical Engineering ING, Vol. 28, No. 6, p. 687-690, Rafael Navarro, Manuel Ferro, Pblo Artal, Israel Miranda, Modulation trans fer functions of the Institute of the United States of America. 32, No. 31, p. 6359-6367 Shunichi Kaneko, Rinko Ohya, Yogo Ohta, Modeling of Blur Characteristics in Vision and Binocular Stereoscopic Display Using It, Proc. Of the 40th National Convention of IPSJ (p. I), p. 109 -110 (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 3/00-3/16 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. An ophthalmic optical system simulation apparatus for simulating a retinal image when an optical lens is worn, wherein a plurality of viewpoints are defined on a light source screen placed at a predetermined position, and the image at the viewpoint is focused on the retina. Based on the optical lens and the optical system data on the human eye in a state where the human eye is rotated so as to connect
int Spread Function) to calculate the image data and the PSF at each viewpoint.
Therefore it performs convolution integral, continuously displaying the image to be projected on the retina when the human eye was MiWataru by rotation
And a scene image calculating means for calculating the calculated scene image. 2. The eye optical system simulation apparatus according to claim 1, further comprising display control means for displaying the scene image on a display device. 3. The display control unit according to claim 2, wherein the plurality of scene images generated using the optical system data of the plurality of optical lenses having different specifications are displayed on the same screen. 3. The eye optical system simulation apparatus according to 2.