Optical: systems and elements – Stereoscopic
Reexamination Certificate
1997-05-29
2001-11-27
Chang, Audrey (Department: 2872)
Optical: systems and elements
Stereoscopic
C359S464000, C348S051000, C345S111000
Reexamination Certificate
active
06324001
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to stereo image display apparatuses capable of displaying stereo images to the viewer with left eye and right eye images with a binocular parallax and, more particularly, to improvements in the stereo image display apparatus for alleviating the departure from the natural sense of viewing and fatigue of the viewer viewing stereo image.
2. Discussion of the Related Art
As visual display apparatuses or systems, various stereo image display apparatuses for displaying images viewed as stereo image have been proposed.
FIG. 18
is a perspective view showing a head-mounted display (HMD)
700
as an example of such stereo image display apparatus. The illustrated HMD
700
is a binocular stereo display. The HMD
700
has a frame
702
, which is mounted on the viewer's head and supports a left and a right display element and also a left and a right enlarging optical system
701
in front of the viewer's left and right eyes. Thus, a left eye image is displayed to the left eye, while a right eye is displayed to the right eye, whereby the viewer can view the image as a stereo image. The frame
702
has a sensor support
703
supporting a head motion sensor
704
, which is located on the head and detects motion of the head. Thus, the viewer can view the image in correspondence to the motion of his or her head. A data processor
720
is connected via a cable
722
to a connector
706
, which is supported on a connector support
705
provided on the frame
702
. A loudspeaker
709
for outputting sound is provided in each air. The data processor
720
has operating buttons
720
a
which are operable by the user for various operations. With the usual stereo image display apparatus such as the HMD, the viewing distance and the verging distance fail to coincide with each other, as will be described later in detail, thus resulting in a departure from the natural sense of viewing.
FIGS.
19
(
a
) to
19
(
c
) are views for describing how a left eye image and a right eye image are viewed as a stereo image in the stereo image display apparatus. These figures show an example of a stereo image viewed by the left and right eyes. The image includes two objects, i.e., a sphere and a triangle pyramid, the sphere becoming closer to the viewer. In this case, the left eye and right eye images are changed from those shown in FIG.
19
(
a
) to those shown in FIG.
19
(
b
) and then to those shown in FIG.
19
(
c
). As shown, the sphere is moved toward the center while being gradually increased in size. This means that the binocular parallax is being gradually increased.
FIG. 20
shows the way in which the images shown in FIGS.
19
(
a
) to
19
(
c
) are viewed with the two eyes. Increasing binocular parallax leads to verging for merging, (i.e., reaching or going to reach a viewer's state of perceiving one image on the basis of a plurality of images), so that the viewer's eyeballs are turned inward. This rotation of the eyes is called vergence, and the angle of the rotation is called vergence angle in the illustrated definition. Also, the distance between the optical axes of the eyeballs in vergence and each eye is called parallax distance. In the HMD, the parallax distance is equal to the distance between the point of intersection of the main beans of the left and right images and the main plane of the eyepiece optical system. Thus the vergence of the eyeballs immediately causes accommodation. With increasing vergence angle, the accommodation tends to be closer. Conversely, with reducing the vergence angle, the accommodation tends to be further apart. In the stereo image display, the plane in which image can be viewed with the best contrast is fixed. In the HMD, the distance from this plane to each eyeball is the viewing distance. In this connection, inconsistency has heretofore taken place. Specifically, the above phenomenon occurs not only in the HMD but also in various stereo television sets, such as those of a shutter switching system, a lenticular system, etc. In these systems, the viewing distance of stereo television is the distance from the display surface of the display such as a CRT, to each eyeball of the viewer.
Viewing an image with great verging distance changes as a stereo image in a state that the viewing distance and the verging distance do not coincide, leads to unnatural viewing. This problem may be avoided by producing an image with less fly-out changes. Doing so, however, weakens the impact of image as a stereo image.
To solve this problem, Japanese Patent Publication Heisei 6-85590 proposes an HMD, in which the viewing distance is varied according to the image motion or the like through mechanical driving of the eyepiece lens. Japanese Laid-Open Patent Publication Heisei 3-292093 discloses a method of varying the viewing degree by detecting a point viewed by the viewer and moving the lenses according to depth information at the viewed point. These systems permit one to obtain coincidence of the viewing degree and the verging angle with each other.
Japanese Laid-Open Patent Publication Heisei 7-167633 shows a method of controlling the optimum viewing point, which permits the viewer to perceive the depth world of an object in the broadcast range, by calculating the point from the binocular parallax of image, such as the point is reproduced on the surface of a stereo image display unit or at a specified distance from the surface. As a specific means, a parallax map is calculated from left and right images by using a correlation matching map, and then the mean value of parallax of the entire image or weighted mean parallax of a central part of the image is calculated. Using this mean parallax, a parallax controller controls the horizontal read timing of left and right images to cause parallel movement of the image in the horizontal direction. This method does not require any mechanical drive system, and it is thus possible to prevent size increase.
FIGS.
21
(
a
) to
21
(
c
) are views showing left eye and right eye images displayed in a stereo image display apparatus, which was proposed earlier by the inventor (Japanese Patent Application Heisei 8-28856). Like the case of FIGS.
19
(
a
) to
19
(
c
), two objects, i.e., a sphere and a triangular pyramid, are displayed, the sphere becoming closer to the viewer. In this case, the left eye and right eye images are changed from those shown in FIG.
21
(
a
) to those shown in FIG.
21
(
b
) and then to those shown in FIG.
21
(
c
). In this apparatus, the parallax of the left eye and right eye images is substantially fixed irrespective of the motion of the sphere toward and away from the viewer.
FIG. 22
shows the way of viewing of the images shown in
FIG. 21
displayed on an HMD with the two eyes. In this case, the verging distance L with respect to the sphere is unchanged although the image of the ball is increased as the ball becomes closer. The triangular pyramid, on the other hand, is moved apart from the viewer although its size is unchanged. In other words, the distance difference between the triangular pyramid and the sphere is increased as in the prior art case. Nevertheless, the verging distance L with respect to the sphere is substantially fixed.
This is owing to the fact that the person's eyes are not so sensitive with respect to the change in the absolute distance although they are sensitive to changes in the relative distance. Experiments conducted by the inventor prove that the viewer viewing a stereo image of only a single object with changing binocular parallax (background being black), cannot perceive distance changes. However, the sense of stereo arises when objects in different motions are displayed simultaneously. This means that it is difficult to recognize a change in the distance of a single object, although changes in the distance between two objects can be recognized. According to the proposal noted above, with the distance difference between the sphere and the triangular pyramid changing as usual and also the s
Chang Audrey
Olympus Optical Co,. Ltd.
Pillsbury & Winthrop LLP
LandOfFree
Stereo image display apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Stereo image display apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stereo image display apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2579737