Image analysis – Applications – Range or distance measuring
Reexamination Certificate
1998-09-23
2002-05-14
Boudreau, Leo (Department: 2721)
Image analysis
Applications
Range or distance measuring
C356S614000, C356S615000, C356S623000, C356S624000
Reexamination Certificate
active
06389153
ABSTRACT:
RELATED APPLICATIONS
This application is based on Application No. HEI 9-261268 filed in Japan, the content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device for displaying images, for example, to generate a distance image in real space relative to the viewpoint of an observer in augmented reality (AR), and to display an AR image based on a generated distance image.
2. Description of the Related Art
The art of influencing human perception to present an environment as if in the real world by presenting computer-generated information to a person is known as virtual reality (VR). The art of virtual reality allows a person to enter and experience an virtual environment as if in the real world. Virtual reality is also known as artificial reality.
Augmented reality (hereinafter referred to as “AR”) is one area in the field of virtual reality technology. In the field of augmented reality, real space and computer-generated virtual space are mixed and presented to the viewer. In augmented reality, real space is enhanced by virtual space.
In AR technology the purpose is to heighten the quality of real space by suitably arranging an virtual environment in a real environment, whereas the purpose of VR technology is to completely immerse a person in a virtual environment. The presentation of a image as an virtual environment is visual AR. Hereinafter AR refers to to as “visual AR.”
Examples of the uses considered for AR technology include systems which superimpose the image from a patient's brain CT scan on the actual brain of the patient during surgery, systems supporting work such as assembly and repairs and the annotation of parts of an actual mechanical device by computer graphics, systems which evaluate the impression of how furniture will look in an actual room, and systems which evaluate sights at actual locales and at actual size when urban redevelopment programs build new buildings.
AR technology typically uses a head-mounted display (HMD) to present both actual space and virtual space to a person simultaneously. Head-mounted displays include those using optical systems and those using video signals.
FIG. 13
illustrates the principle of AR system
80
using a conventional optical system type head-mounted display, and
FIG. 14
illustrates the principle of AR system
90
using a conventional video signal type head-mounted display. In AR system
80
shown in
FIG. 13
, a real space image is transmitted through a half mirror
81
arranged on the line of sight in front of the eyes of an observer so as to be viewed by the observer, and a virtual space image projected by a projector
82
is viewed via half mirror
81
so as to be viewed by the observer. In this way a virtual space image overlaps a real space image. A position/posture sensor
83
is provided to detect the observation point of the head of an observer; the signals of a virtual space image are transmitted from a workstation
84
to projector
82
based on the output of the position/posture sensor
83
.
In AR system
90
shown in
FIG. 14
, a real space image is projected by double mirror
91
to two image sensors
93
arranged at conjugate positions relative to the right and left eyes of an observer. The projected real space image and a virtual space image are combined by workstation
95
, and the composite image is projected by projector
92
. As a result, the composite image of the combined real space image and the virtual space image is presented to the observer via double mirror
91
.
To realize augmented reality (AR), there is, in addition to the conventional problem of specifying positional matching of the images, the requirement of accurately expressing the screening relationship. In both the aforesaid AR system
80
and
90
, there must be accurate expression of the screening relationship wherein space and objects far from the observer are screened by space and objects near the observer.
In the former AR system
80
, real space is visible behind objects in virtual space, such that an observer sees both the images of virtual space and real space simply overlapped. In this system, however, the screening relationship cannot be expressed completely.
In the latter AR system
90
, there is no distance relationship and objects in virtual space typically hide objects in real space, such that a screening relationship cannot be accurately expressed. That is, although the screening relationship is accurate when objects in virtual space are nearer than objects in real space, objects in virtual space block objects in real space such that the objects in real space appear far away even when they are at near positions, and the screening relationship is reversed.
According to opinion in perceptual psychology, in the state wherein a screening relationship cannot be accurately manifested, stereo vision is obstructed and unexpected stereo vision results due to the contradiction between vergence-parallax information and the screening relationship. In other words, accurate expression of the screening relationship is extremely important in the art of augmented reality.
The present applicants have come up with a head-mounted display capable of accurately expressing screening relationship. In this head-mounted display, the distance of a virtual space image and the distance of a real space image are compared relative to the pixels of the virtual space image and pixels of the real space image at the same position so as to select and display the pixels nearer to the observer.
FIG. 15
is a perspective view of the exterior of the previously mentioned head-mounted display (HMD)
70
.
In HMD
70
, slit projectors
71
R and
71
L are respectively arranged at positions near the right and left eye of an observer to measure the distance to an observation object from the viewpoint of the observer. The reflected light of slit light UR and UL projected from the two slit projectors
71
R and
71
L is received by photoreceptors
73
R and
73
L disposed at each image sensor
72
R and
72
L of HMD
70
, so as to obtain accurate distance information of each pixel of a the right and left two-dimensional images (real space images). The screening relationship can be accurately expressed based on the right and left distance information.
In the HMD
70
of
FIG. 15
, however, the slit projectors
71
R and
71
L must be positioned near the right and left eye, respectively thereby complicating the construction of the disposition and mounting, and enlarging the overall head-mounted device
70
.
In particular, since the HMD
70
is an active type device, photoreceptors
73
R and
73
L are required which are separate from the photoreceptor device for inputting the two-dimensional images so as to receive the slit light UR and UL projected from slit projectors
71
R and
71
L, thereby making it difficult to accurately match the lines of sight.
SUMMARY OF THE INVENTION
An object of the present invention is to eliminate the previously described disadvantages.
A further object of the present invention is to provide a distance image generating device capable of increasing the freedom of arrangement of a distance detector, and capable of obtaining distance information which matches the line of sight of an input two-dimensional image based on distance information from a different position than the line of sight of the input two-dimensional image by generating other necessary distance information based on distance information measured by a single distance detector.
A still further object of the present invention is to provide a compact head-mounted device capable of obtaining binocular distance information from distance information measured by a distance detector provided at a position near one eye.
The invention itself, together with further objects and attendant advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4136949 (1979-01-01), Hayamizu et al.
patent: 4556
Imai Shigeaki
Ishida Tokuji
Kondo Takashi
Sato Akira
Boudreau Leo
Choobin M B
Minolta Co. , Ltd.
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