Computer graphics processing and selective visual display system – Computer graphics processing – Adjusting level of detail
Reexamination Certificate
1999-10-12
2001-12-11
Manuel, George (Department: 3737)
Computer graphics processing and selective visual display system
Computer graphics processing
Adjusting level of detail
Reexamination Certificate
active
06329989
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The invention relates to an ocular optical system simulating method and a simulating apparatus for simulating how things are seen when the outside world is observed through a lens system placed in front of the eyes.
(b) Related Art
An apparatus has been described in Japanese Patent Laid-Open No. Hei. 8-266473 applied for previously by the assignee of the present application. In this prior application, there are described an ocular optical system simulating method and a simulating apparatus for simulating how things are seen when the outside world is observed through a lens system placed in front of eyes.
The apparatus described in the above-mentioned publication simulates an image of scenery in a scope which can be visualized by turning eyes while wearing spectacle lenses, by computations including computing the Point Spread Function (PSF). The disclosed apparatus and method have enabled simulation of the sight of scenery in a wide angle involving rotation of human eyes while wearing optical lenses such as spectacle lenses.
Unpleasant sensations of fluctuation, deformation and blur in wearing progressive addition lenses (PAL) are obtained in certain cases, even though these lenses fulfill the function of accommodating far and near distances. Therefore, suppression of these unpleasant sensations to the greatest degree possible while accommodating for the far and near is desirable in designing a progressive addition lens. To this end, it is most desirable for a designer himself to know whether the designed lens is accompanied by unpleasant fluctuation, deformation and blur. The above-mentioned conventional ocular optical system simulating method is very useful for certain purposes because it can simulate scenery in a wide angle involving the rotation of human eyes in wearing optical lenses such as spectacles. However, the above system cannot simulate the deformation, blur, etc., which the wearer may feel in reality by also taking human perception into consideration. Therefore, these methods have not always been sufficient to fulfill the purpose of allowing the designer himself to know in advance what kind of deformation and blur the wearer actually perceives when the wearer wears the designed lenses. Still more, this system cannot deal at all with the fluctuation, which is considered to be the most serious problem in actually wearing lenses.
An image of the outside world perceived by a human through the eyes is not considered to be an optical image formed on the retina of the eye in accordance with optical principles. That is, the distribution density of photoreceptors on the retina is high around the fovea and is low at peripheral parts. Accordingly, if a strictly optical image formed on the retina is perceived, it must be perceived as an image which is clear only around the center and is unclear at the periphery even when the optical image is ideally formed. However, one can sense that one can see clearly anywhere within a field of vision as long as one has healthy eyes. This is because the operation of perception is not a simple operation of detecting the optical image projected on the retina as it is, but is based on the result of a complex system of processing neural information on and after the retina.
According to the research of the inventors, although such perception may not be simulated directly, it has become clear that the result of the perception may be reproduced approximately by image processing based on certain assumptions found by the inventors.
The present invention has been devised based on the background described above and its object is to provide an ocular optical system simulating method and a simulating apparatus which enables simulation of how things are seen, with fluctuation, deformation, blur and the like, while wearing a lens system such as a progressive addition lens.
SUMMARY OF THE INVENTION
In accordance with the above objects, the present invention provides a method for simulating how things are seen through a lens system placed in front of the eye whose center of rotation is placed at a specific position and whose central visual line is directed to a specific direction, comprising the steps of:
(1) Creating an original image within a field of view centered with said central visual line; (2) Creating a deformed original image to approximate deformation occurring when the original image is seen through said lens system;(3) Determining point spread functions (PSF), defined as the distribution of luminance on the retina originated from the corresponded object point, for each object point within the original image;(4) Convoluting the deformed original image with the point spread functions to create a rotation-based retinal image.
In yet another preferred embodiment, the invention provides an apparatus for simulating an apparatus for simulating how things are seen through a lens system placed in front of the eye whose center of rotation is placed at a specific position and whose central visual line is directed to a specific direction comprising: (1) Means for creating an original image within a field of view centered with said central visual line; (2) Means for creating a deformed original image to approximate deformation occurring when the original image is seen through said lens system; (3) Means for determining point spread functions (PSF), defined as the distribution of luminance on the retina originated from the corresponded object point, for each object point within the original image;
(4) Means for convoluting the deformed original image with the point spread functions to create a rotation-based retinal image; (5) Means for displaying the rotation based optical image.
As means for solving the above-mentioned problems, one further embodiment of invention provides an ocular optical system simulating method for simulating how things are seen when the outside world is observed through a lens system placed in front of eyes by creating, not an optical image projected on the retinal surface of the eye, but a rotation-based retinal image, defined as an image obtained by turning the eye-ball with respect to all object points within a field of vision and by connecting images caught at the fovea by computer simulation. The result is a simulated image perceived by the eye through the lens system.
According to this embodiment, the rotation-based retinal image is created through steps of:
creating an original image having a specific angular field of vision and entering the eye which has a specific rotational center point;
creating, by using ray tracing, a deformed original image containing deformation occurring when the original image is seen through the lens system;
determining the PSF on the retina of an eye-model caused by light from the object points of the original image in an optical system composed of the lens system and a spectacle model; and
convoluting the deformed original image found in the deformed original image creating step and the PSF of each pixel of the original image found in the PSF obtaining step.
A further embodiment of the invention is characterized in that in an ocular optical system simulating method for simulating how things are seen when the outside world is observed through a lens system placed in front of an eye, comprising the steps of:
creating an original image by placing a virtual object in a virtual three-dimensional space by computer graphics, creating an image of the virtual object defined within a specific angular field of vision, entering the eye which has a specific rotational center point, and having a central line of sight of a specific direction, and obtaining an object point distance which is a distance between the position of the object point related to each pixel of the original image and the rotation center point of the eye;
creating a deformed original image containing deformation caused by the lens system by setting a passing point of the central line of sight on the lens system placed in front of the eye, by finding a ray which is emitted from the object
Qi Hua
Tanaka Ikuka
Griffin & Szipl, P.
Hoya Corporation
Manuel George
LandOfFree
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