JPH08280620A - Simulation apparatus for eye optical system - Google Patents

Abstract

PURPOSE: To enable simulation of a wide-angle scene including the effect of chromatic aberration when an optical lens is mounted by a method wherein a monochromatic scene image data per wavelength is generated from an image data set in a range of view possible with the turning of eyes and a monochromatic scene image data is synthesized to generate a scene image. CONSTITUTION: An original image data 1 is divided by an image analyzing means 2 into monochromatic image data 3a-3c per wavelength set in plurality and optical system data 12c-14c are set on PSF calculating parts 12-14 of a scene image generating section 10a with human eyes being turned so that images at corresponding visual points are focused on a retina. The PSF computing means 12b-14b determine PSFs 12a-14a based on the optical system data 12c-14c and the scene image computing means 11 perform a convolution integral of the corresponding monochromatic image data 3a based on the PSFs 12a-14a to obtain a monochromatic scene image data 4a. A scene image synthesization means 5 synthesizes the obtained monochromatic scene image data 4a-4c to generate a scene image data 6.

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 eyeglass lenses having different optical characteristics are sold. The spectacle lenses are roughly classified according to optical specifications, and 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 monofocal lens is divided into a spherical lens and an aspherical lens. The design of the aspherical lens depends on the manufacturer. Similarly, there are many types of multifocal lenses. For example, there are bifocal lenses, trifocal lenses, and progressive multifocal lenses, and these lenses are further subdivided.

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

[0004] However, it is actually difficult to own a plurality of types of lenses having different optical specifications having a power suitable for a wearer in an eyeglass store because the number of types is huge. On the other hand, the method in which the store clerk asks the wearer for his / her desire and makes a selection requires skill of the store clerk. Furthermore, it is difficult for the store clerk to make an accurate judgment at all times because he 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 wearing spectacles or the like. First, in the first simulation apparatus for the eye optical system, the parallel light rays from the light source screen are traced in the optical system such as the optical lens and the cornea to obtain the PSF.
(Point Spread Function) is calculated. PSF is a function representing how the light emitted from one point on the object is distributed on the image plane. Retinal image data is calculated from this PSF and original image data. By displaying the retinal image data thus obtained on the screen of the display device, it is possible to objectively judge how the image looks. As such an example, the present applicant has filed Japanese Patent Application No. 7-2693.
I am applying for No. 6.

A further simulation apparatus for a second eye optical system, which takes the influence of chromatic aberration of light into consideration, is also considered. That is, the refractive index of an optical material such as a lens depends on the wavelength, and the shorter the wavelength, the higher the value. Therefore, PSFs at a plurality of wavelengths are obtained, and monochromatic retinal image data for each wavelength is generated from the original image data and the PSF for each wavelength. By synthesizing these monochromatic retinal image data, a retinal image including chromatic aberration can be simulated. As an example of this, the applicant of the present invention has filed Japanese Patent Application No.
-71502 has been filed.

On the other hand, the above-described first eye optical system simulation apparatus can only simulate an image within a range in which the retina can be focused when the human eye is facing a certain direction. However, when the glasses are actually worn, it is possible to focus on an arbitrary image in a wide range by rotating the eyes. Therefore, a third ocular optical system simulation device capable of simulating a scene image in a range in which the human eye can be rotated and overlooked has been considered.

In the third simulation apparatus for the eye optical system, a large light source screen that allows the entire eye to be viewed by rotating the eye is assumed, and the viewpoints arranged in a grid pattern are set on the light source screen. PSF when looking at this viewpoint
Respectively, and the retinal image is generated using PSFs corresponding to all viewpoints. This makes it possible to simulate a scene image when the eyes are rotated to look around. As such an example, the present applicant has applied for Japanese Patent Application No. 7-71503.

[0009]

However, in contrast to the case where the influence of chromatic aberration becomes remarkable when the rotation angle is large, the conventional eye-optical system simulation apparatus rotates the eye and looks around the periphery. The scene image in this case could not be simulated by taking into consideration chromatic aberration.
Therefore, even if you simulate the appearance of a scene image,
The characteristics including the influence of the chromatic aberration of the optical lens could not be accurately recognized.

The present invention has been made in view of the above points, and it is possible to simulate a wide-angle scene involving the rotation of the human eye when an optical lens such as spectacles is worn, including the effect of chromatic aberration. The purpose is to provide an academic simulation device.

[0011]

In order to solve the above-mentioned problems, the present invention provides a simulation apparatus of an eye optical system for simulating a retinal image when an optical lens is worn, with a light source screen placed at a predetermined position. A plurality of viewpoints are defined, at each of a plurality of set wavelengths, based on the optical lens and the optical system data about the human eye in a state where the human eye is rotated so that the image at the viewpoint is focused on the retina. PSF (Point Spre) for each viewpoint
for each wavelength within the range that can be overlooked by the rotation of the human eye based on the PSF calculation means for calculating ad Function), the original image data, and the PSF for each viewpoint corresponding to each wavelength. And a scene image synthesizing means for synthesizing the monochromatic scene images for each of the wavelengths to generate a scene image. Provided.

[0012]

In the PSF calculating means, a plurality of viewpoints are defined on the light source screen placed at a predetermined position, and the human eye is rotated so that the image at the viewpoint focuses on the retina at each of the plurality of set wavelengths. Based on the optical lens and the optical system data for the human eye, the PSF (Point Sp
read Function) is calculated. The scene image calculation means uses the original image data and P for each viewpoint corresponding to each wavelength.
Based on the SF, a monochromatic scene image is calculated for each wavelength in the range that can be overlooked by the rotation of the human eye.
The scene image synthesizing means synthesizes monochromatic scene images for each wavelength,
Generate a scene image.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram of a simulation apparatus for an eye optical system according to the present invention. In this simulation device, it is assumed that the light source screen is large enough that the whole body cannot be seen without turning the human eye. The viewpoints arranged in a grid pattern are set on the light source screen. Then, the original image data 1 drawn on this light source screen is set.

The image decomposing means 2 decomposes the original image data 1 into monochromatic image data 3a to 3c for each set wavelength. The monochromatic image data 3a to 3c are image data obtained by extracting only the spectrum of a certain wavelength from the original image data 1. That is, the original image data 1
Of the monochromatic image data 3a to 3 for each wavelength by spectrally decomposing the image data and obtaining image data obtained by a spectrum of a preset wavelength at all wavelengths.
c is generated. The wavelength set at this time can be set arbitrarily, and for example, can be set at intervals of several nm in the visible light wavelength region.

When the original image data 1 is drawn in a constant color like black and white data, the shapes of the images obtained by each spectrum when the spectrum is decomposed are the same. At this time, the original image data 1 can be directly converted into the monochromatic image data 3a to 3c of each wavelength without being decomposed. That is, in this case, the image decomposing means 2 is unnecessary.

The monochromatic image data 3a thus generated
~ 3c respectively corresponding to the scene image generation unit 10a ~ 10.
c is provided. The scene image generation unit 10a includes a PSF (Poin) corresponding to each viewpoint set on the light source screen.
t Spread Function) calculators 12 to 14 are provided. For example, when the light source screen is divided into m in the vertical direction and n in the horizontal direction, m × n PSF calculation units are provided.

Optical system data 12c, 13c, 14c in a state in which the human eye is rotated so that the image at the corresponding viewpoint is focused on the retina is set in each PSF calculation unit 12-14. This optical system data 12c, 13c, 14
c is position data of the corresponding viewpoint, data regarding the optical lens, and data regarding the human eye. The data regarding the optical lens is the curvature of the convex surface, the curvature of the concave surface, the refractive index, etc. of the lens. These data can be obtained from the design values of the lens. The data regarding the human eye is data such as the cornea, the pupil, the lens, the retina, and the rotation angle. These data are basically obtained using the Gullstrand model, and the axial length or the value of the radius of curvature of the convex surface of the cornea is determined according to the visual acuity of the wearer. The refractive index of each medium at this time is the refractive index of the light of the corresponding wavelength.

PSF calculation means 12b, 13b, 14b
Is the PSF based on the optical system data 12c, 13c, 14c.
12a, 13a, and 14a are calculated. PSF 12a, 13
a and 14a are functions that represent how the light emitted from a certain viewpoint is distributed on the image plane. Scene image calculation means 11
Corresponds to the corresponding monochromatic image data 3a to the PSFs 12a, 13
Convolutional integration is performed with a and 14a to obtain monochromatic scene image data 4a.

Similarly, the other scene image generators 10b, 10
Also in c, the monochromatic scene image data 4b and 4c are generated based on the optical system data at the corresponding wavelengths. The scene image synthesizing means 5 generates the generated monochromatic scene image data 4a, 4a.
b and 4c are combined to generate the scene image data 6. The display control means 7 displays an image obtained from the scene image data 6 on the display device 8. As a result, the entire scene that can be recognized by moving the line of sight up, down, left, and right is displayed on the display screen in consideration of the influence of chromatic aberration. In this way, a scene image simulation including the influence of chromatic aberration can be performed.

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

FIG. 2 is a diagram showing a light source screen. On the light source screen 20, a plurality of viewpoints arranged in a grid pattern are set. The light source screen 20 is a plane perpendicular to the X axis, and the central portion is on the X axis. Then, m pieces (y ₁ ~
decompose y _m), it is decomposed into n (y ₁ ~y _n) in the Z axis direction. Therefore, m × n viewpoints are provided on the light source screen. By giving light intensity at each viewpoint on the optical screen 20, original image data of an arbitrary shape is set.

The original image data is decomposed into spectra for each preset wavelength. The wavelengths set at this time may be three lines of d line (He), F line (H), and C line (H), or three lines of e line, F ′ line, and C ′ line. May be. It is also possible to decompose into more wavelengths including the wavelength of the previous period or into a spectrum of 5 nm intervals from 380 nm to 780 nm.

Furthermore, optical system data for viewing the light source screen while the human eye rotates is set for each wavelength. At this time, in order to obtain the optical system data to be set, the refractive index at each wavelength of the spectacle lens is necessary. The refractive index of an optical lens is specified by the material, and in general, the characteristics of the lens are shown using the Abbe number, which is the reciprocal of the dispersive power. Some Abbe numbers are based on the d line and some are based on the e line. Recently, the Abbe number based on the e-line (Hg) is often used, but the difference between the case based on the e-line and the case based on the d-line is the case based on the e-line. Is only slightly smaller,
It is the same in the meaning of expressing the degree of dispersion.

The Abbe number ν _{d based on the} d line is defined by the following equation.

[0025]

Ν _d = (n _d −1) / (n _F −n _C ) where n _d is the refractive index of the medium for the d line (589 nm), and n _F is the medium for the F line (486 nm). , And n _C is the refractive index of the medium with respect to the C line (656 nm).

On the other hand, the Abbe number (ν _e ) based on the e line
Is defined by the following formula.

[0027]

Ν _e = (n _e −1) / (n _{F ′} −n _{C ′} ), where n _e is the e-line (540.07 nm) and n _{F ′} is F ′.
Line (479.99 nm), n _{C ′} is the C ′ line (643.85)
nm).

The smaller the Abbe number, the larger the change in the refractive index with the change in wavelength. Conversely, the larger the Abbe number displayed on each type of spectacle lens manufactured and sold, the smaller the chromatic aberration, that is, the color shift, at the periphery of the lens. Generally, when used as a spectacle lens,
It is said that the Abbe number is preferably 40 or more (based on the d-line), and conversely, the influence of chromatic aberration becomes remarkable when the lens power is 1/10 or more of the Abbe number. Has been done.

From the Abbe number as described above, the refractive index of the optical lens to be simulated for an arbitrary wavelength can be calculated. Then, by using the refractive index at each wavelength, optical system data when the human eye rotates and the viewpoint set on the light source screen is viewed is created.

FIG. 3 is a diagram showing changes in the optical system when viewing the light source screen. This figure shows a case where the turning angle in the Z-axis direction is kept constant and the angle in the Y-axis direction is changed. Here, the straight line connecting the center of rotation O of the human eye and the center of the spectacle lens is defined as the reference axis 37.

(A) is an optical system for viewing the upper end of the light source screen. The human eye 30 rotates upward, and the light source screen 20
Is oriented straight with respect to any upper-end viewpoint (y _m , z _i ). That is, it is rotated upward by the angle α ₁ from the reference axis 37. Therefore, the light 36 at the upper end of the light source screen 20
a is incident on the spectacle lens 21 from an obliquely upper direction. The light 36a that has passed through the spectacle lens 21 enters the human eye and the image is recognized. From this state, the human eye 30 is Y
Turn in the negative direction of the axis.

(B) is an optical system for viewing the center of the light source screen. The human eye 30 does not rotate, but faces straight to the center of the light source screen 20. That is, the reference axis 37 and the direction of the line of sight of the human eye match. Therefore, the light source screen 20
The light 36b at the center of is incident on the spectacle lens 21 perpendicularly. The light 36b that has passed through the spectacle lens 21 enters the human eye and the image is recognized. From this state, it is further rotated 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 30 rotates downward, and the light source screen 20
It is facing straight to the bottom edge of. That is, the reference axis 3
It is rotated downward by an angle α ₂ from 7. Therefore, the light 36c at the lower end of the light source screen 20 enters the spectacle lens 21 from an obliquely lower direction. The light 36c that has passed through the spectacle lens 21 enters the human eye and the image is recognized.

In this way, optical system data for all viewpoints when rotated in the Y-axis direction are obtained. As described above, when the human eye rotates, the values of various data change. For example, the distance from the spectacle lens to the cornea changes with rotation. Also, if the spectacle lens is a multifocal lens, with the change in the position where light enters the lens,
The radius of curvature of the concave surface and the convex surface also changes.

FIG. 3 shows an optical system in the case where the value of the Z axis on the optical screen is fixed and the human eye rotates in the vertical direction. Further, the values of the Z axis are changed from z ₁ to z _n. By changing it, the optical system data corresponding to all the viewpoints including the case of rotating the light source screen in the left-right direction can be obtained.

Next, the optical system data when the human eye is rotated will be described in detail. FIG. 4 is a diagram showing an optical system in which the human eye is rotated. This example is a case of looking at a viewpoint in a direction below the reference axis 37. The light 36 output from the viewpoint obliquely passes through the lower peripheral portion of the spectacle lens 21 and enters the human eye 30. The human eye 30 rotates, faces straight to the viewpoint, and has a cornea 31 acting as a lens on the front surface. A pupil 32 is provided behind the cornea 31 and serves to reduce the amount of incident light. Behind the pupil 32 is a lens 33 which acts as a lens.
The vitreous body 34 is behind the crystalline lens 33, and the retina 35 is located behind it.

In this optical system, the radii of curvature of the convex and concave surfaces and the refractive index are set as data regarding the spectacle lens 21. The data regarding the human eye 30 includes the radii of curvature of the respective surfaces of the cornea and the crystalline lens, the cornea 31, and the crystalline lens 3.
3. Set the refractive index of the vitreous body 34. The refractive index inside the human eye 30 is obtained from the Gullstrand model, and the refractive index of the spectacle lens 21 is obtained by actually measuring. Further human eyes 3
The distance between the cornea in 0, the pupil 32, the lens 33, and the retina 35 is set. The data for the human eye is basically the data of the Gullstrand model, and the distance to the retina or the curvature of the convex surface of the cornea is set according to the visual acuity of the human eye to be simulated.

Then, the position of the viewpoint of the light source screen is set. By performing ray tracing of the light from that position, the angle θ formed by the light 36 incident on the spectacle lens 21 and the reference axis 37 and the turning angle α can be obtained. In addition,
The angle θ formed by the light 36 and the reference axis 37 is not the same as the turning angle α. This is because the traveling direction of the light 36 slightly changes when the light 36 passes through the spectacle lens 21.

As described above, optical system data at any wavelength can be obtained. This optical system data is obtained for all preset wavelengths. This makes it possible to obtain optical system data in a state in which the human eye is facing an arbitrary viewpoint, for all the set wavelengths at all viewpoints.

Further, each monochromatic image data is subjected to convolution integration by the PSF obtained by the corresponding wavelength to obtain monochromatic scene image data. The light intensity distribution of the ideal image on the image plane is f (y, z), PSF at the point (y, z)
Is p (x, y, u, v), the point (y,
The light intensity in z) can be represented by the following formula.

[0041]

(Equation 3)

Here, p (u, v, u-y, u-z) is the value of PSF at the point (u-y, v-z) away from each point (u, v). Further, a is the spread radius of the PSF. Using this formula, the light intensity of a point on the retina is obtained for each rotation angle of the human eye, whereby monochromatic scene image data can be obtained. This monochromatic scene image data is obtained at all wavelengths.

Next, all the generated monochromatic scene image data are combined. In the RGB color matching system, which is a basic color matching function, R (700.n) is used to determine how much stimulus is given to eye cells when light of a specific wavelength reaches the retina.
m), G (546.3 nm), and B (435.8 nm). In other words, this color matching function converts light of any color into light of three colors (R
It is possible to specify the RGB light intensities to be perceived by humans by replacing them with GB).

However, in the RGB color matching system, one of the three values may be a negative value. Therefore, in general, XY using the original stimuli X, Y, and Z that can be color-matched by a positive additive color mixture of the original stimuli in RGB.
The Z color matching system is used. In this case, after stimulating the stimulus values in the XYZ color matching system for each of the F line, d line, and C line, RG
The intensities of the RGB spectral lines are obtained by converting the values into the B color matching system. That is, the scene image data is created by converting each monochromatic scene image data into RGB spectral line data and adding the intensities for each coordinate value for each RGB spectral line.

When the original image is separated into three colors, the image of each color is R (700.nm), G
(546.3 nm) and B (435.8 nm) are considered as three color spectral lines. For example, in the case of separating into three colors of d line, F line, and C line, d line, F line, and C line are respectively G,
Considered as B and R spectral lines. Also, e line, F'line,
In the case of a combination of C ′ lines, the e line, F ′ line, and C ′ line are regarded as G, B, and R spectral lines, respectively. From this, when displaying the screen on the display device, three colors are displayed by CRT (CRT
It is possible to correspond to each RGB dot of the athode Ray Tube), and the screen display can be easily performed.

The scene image data obtained as described above is a continuous display of images projected on the retina when the person wearing the glasses looks around by turning his eyes. The image also considers the influence of chromatic aberration.

In this way, it is possible to simulate an image recognized by a human when a wide range is viewed by rotating the eye in consideration of chromatic aberration. Therefore, even in the case of a multifocal lens, it is possible to accurately recognize the characteristics including the influence of the chromatic aberration of the lens. As a result, the spectacle wearer can easily select the lens suitable for himself. On the other hand, even when designing or evaluating a lens of a complex optical system such as a progressive multifocal lens, the characteristics of the lens can be accurately known by inputting the data of the optical system of the lens.

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

As shown in the figure, the workstation is
Processor 61, graphic control circuit 64 and display device 65, mouse 66, keyboard 67, hard disk device (HDD) 68, 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 centrally controls the entire workstation. The read-only memory 62 stores a program required at startup. The main memory 63 stores a simulation program or 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.

A system program and a simulation program are stored in the hard disk device 68, and 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 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 the simulation data on the magnetic tape as required. A high-performance personal computer or a general-purpose computer other than the workstation may be used.

[0055]

As described above, according to the present invention, a single-color scene image data for each of a plurality of set wavelengths is created from the image data set in the range that can be seen by rotating the eye. Since the scene image is generated by combining the monochromatic scene image data,
It has become possible to simulate a wide-angle scene involving the rotation of the human eye when wearing an optical lens such as spectacles, including the effect of chromatic aberration. As a result, even with an optical lens having a complicated optical system such as a multifocal lens, it is possible to objectively recognize the lens characteristics including the influence of chromatic aberration.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing changes in an optical system when viewing a light source screen.

FIG. 4 is a diagram showing an optical system in which a human eye is rotated.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 original image data 2 image decomposition means 3a, 3b, 3c monochromatic image data 4a, 4b, 4c monochromatic scene image data 5 scene image composition means 6 scene image data 7 display control means 8 display devices 10a, 10b, 10c scene image generation unit 11 Scene Image Calculation Means 12, 13, 14 PSF Calculation Units 12a, 13a, 14a PSF 12b, 13b, 14b PSF Calculation Means 12c, 13c, 14c Optical System Data

Claims (5)

[Claims] 1. In a simulation device of an eye optical system for simulating a retinal image when an optical lens is worn, a plurality of viewpoints are defined on a light source screen placed at a predetermined position, and a plurality of set wavelengths are respectively set. Based on the optical system data regarding the optical lens and the human eye in a state where the human eye is rotated so that the image at the viewpoint is focused on the retina, a PSF (Point Spread Fun) for each viewpoint is used.
ction), a PSF calculation unit, original image data, and the PSF for each viewpoint corresponding to each wavelength, for each wavelength within a range that can be overlooked by rotation of the human eye. An eye-optical system simulation apparatus comprising: a scene image calculation unit that calculates a single-color scene image; and a scene image combination unit that combines the single-color scene images for each wavelength to generate a scene image. 2. In a simulation device of an eye optical system for simulating a retinal image when an optical lens is worn, a plurality of viewpoints are defined on a light source screen placed at a predetermined position, and at each of the wavelengths, the viewpoints A PSF (Point Spread Function) for each viewpoint based on the optical lens and the optical system data on the human eye in a state where the human eye is rotated so that the image is focused on the retina.
And an image decomposing means for decomposing the original image data placed at a predetermined position into monochromatic image data for each of a plurality of set wavelengths, and the monochromatic image data corresponding to each wavelength. And the PSF for each viewpoint, a scene image calculation means for calculating a monochromatic scene image for each wavelength within a range that can be overlooked by the rotation of the human eye, and the monochromatic scene image for each wavelength. A scene image synthesizing means for synthesizing to generate a scene image, and a simulation device for an eye optical system, comprising: 3. The plurality of set wavelengths are at least a combination of e-line, F ′ line, C ′ line, or d-line, F-line.
3. A combination of a line and a C line is included.
The described eye optical system simulation device. 4. The eye optical system simulation apparatus according to claim 2, further comprising display control means for displaying the scene image on a display device. 5. The scene image composition means includes R (red), G (green), and B (blue) for the single color scene image for each wavelength.
The eye-optical system simulation apparatus according to claim 2, wherein the scene image is generated by obtaining the intensity of the primary colors of the above using a color matching function.