Optical: systems and elements – Stereoscopic – Stereo-viewers
Reexamination Certificate
1999-06-25
2003-07-08
Robinson, Mark A. (Department: 2872)
Optical: systems and elements
Stereoscopic
Stereo-viewers
C359S471000, C396S324000
Reexamination Certificate
active
06590704
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-eye image sensing apparatus having a plurality of image sensing systems.
2. Description of Related Art
Conventionally, as a method of sensing a three-dimensional image of an object, a method using a multi-eye image sensing apparatus having a plurality of image sensing optical systems is known. In this image sensing method, an object is sensed using a plurality of image sensing systems, e.g., two, right and left image sensing systems, and the three-dimensional shape of the object is recognized by disparity produced between the right and left image portions of the object sensed by the right and left image sensing systems. Such three-dimensional shape recognition works in basically the same way a person recognizes the shape of an object as a three-dimensional shape due to disparity produced upon capturing the object by the right and left eyes.
In image sensing using the multi-eye image sensing apparatus, the base length (spacing between the right and left image sensing systems) and convergence angle (the angle the optical axes of the right and left image sensing systems make with each other) are changed depending on the distance to an object (i.e., a far object or near object). This is done to capture the overlapping region between the right and left images since the region changes depending on the distance to the object (i.e., a far object or near object). For example, when the right and left image sensing systems are placed parallel to each other, the overlapping region becomes narrower as the object becomes closer. In order to assure this overlapping region upon image sensing, the optical axis directions of the right and left image sensing systems must be adjusted.
When the distance between the two, right and left image sensing systems is short, the right and left images have no disparity with respect to a far object, and sufficient stereoscopic sense cannot be obtained. Hence, in such case, the distance between the two, right and left image sensing systems must be increased. In this manner, upon image sensing using the multi-eye image sensing apparatus, to adjust the base length and convergence angle in correspondence with each object is an important technical requirement.
The image sensing optical systems of the aforementioned multi-eye image sensing apparatus will be explained below with reference to FIG.
27
.
FIG. 27
depicts the layout of the image sensing optical systems in the conventional multi-eye image sensing apparatus.
In the conventional multi-eye image sensing apparatus, as shown in
FIG. 27
, the optical axis spacing (base length) and the angle the optical axes make with each other (convergence angle) are changed by mechanically moving the right and left image sensing optical systems. The conventional multi-eye image sensing apparatus is capable of sensing a so-called panoramic image, which has a broader angle in the horizontal direction, using two or more image sensing systems. Upon sensing the panoramic image, the plurality of image sensing optical systems are placed to be capable of sensing different fields of view by nearly matching their viewpoints each other, and minimizing the overlapping region between images required for joining the images sensed by the image sensing optical systems in an image process. In this case, the optical axis spacing and the angle the optical axes make with each other in the image sensing optical systems are mechanically adjusted.
On the other hand, recently, even in a non-coaxial optical system, an optical system in which aberrations can be satisfactorily corrected using an asymmetric aspherical surface as a constituent surface can be built by introducing the concept “reference axis”, as disclosed in Japanese Patent Laid-Open Nos. 9-5650, 8-292371, and 8-292372. Japanese Patent Laid-Open No. 9-5650 discloses the design method of such optical system, and Japanese Patent Laid-Open Nos. 8-292371, and 8-292372 disclose its design examples.
Such non-coaxial optical system is called an offaxial optical system, which is defined as an optical system in which, assuming a reference axis along a light ray passing through the image center and pupil center, a normal to the surface at the intersection of a constituent surface with the reference axis contains a curved surface (offaxial surface) which is not present on the reference axis, and the reference axis at that time has a bent shape.
In this offaxial optical system, in general, since its constituent surfaces are offaxial and no eclipse is produced on a reflecting surface, an optical system using the reflecting surface can be easily build. Also, the optical path can be laid out relatively freely, and a one-piece optical system can be easily formed by forming constituent surfaces by one-piece molding.
However, in the above-mentioned conventional multi-eye image sensing apparatus, since the convergence angle and base length of its image sensing optical systems are changed by moving and rotating these optical systems, the entire apparatus becomes bulky if the image sensing optical systems are comprised of coaxial optical systems.
Especially, upon sensing a panoramic image, the right and left viewpoints must be nearly matched (i.e., the base length as the spacing between the centers of the entrance pupils of the respective image sensing optical systems must be set to be nearly zero). However, since the entrance pupil position cannot be largely moved toward the object side, when the convergence angle becomes equal to or larger than a predetermined angle, lenses in the respective image sensing optical systems may interfere with each other. As a consequence, the base length cannot become smaller than a predetermined length. Or if the base length is set at an appropriate length, a large convergence angle cannot be set.
In case of the multi-eye image sensing apparatus, the right and left image sensing systems must have uniform magnification and imaging performance. However, in the conventional apparatus, since a plurality of lenses are built in lens barrels in the right and left image sensing systems, the optical characteristics of the right and left image sensing systems suffer variations. Hence, the magnifications and the like in the right and left image sensing systems must be adjusted.
Furthermore, upon switching to the panoramic image sensing mode by increasing the convergence angle of the image sensing optical systems, since “central viewpoints” (“central viewpoint” means a point on a line obtained by extending the reference axis of each image sensing optical system toward the object, and such point will be referred to as a “central viewpoint” hereinafter) of the right and left image sensing optical systems are different from ideal ones of a synthesized image, an image process for removing apparent trapezoidal distortion arising from the “central viewpoint” difference must be done upon joining the right and left images.
An example upon sensing a panoramic image will be described below with reference to
FIGS. 28A
to
28
C.
FIGS. 28A
to
28
C are views showing images sensed by panoramic image sensing of the conventional multi-eye image sensing apparatus, and an ideal synthesis result of those images.
Upon sensing a panoramic image using the two, right and left image sensing optical systems, since these systems have a convergence angle, as shown in
FIG. 28A
, they have different “central viewpoints” with respect to an object to be sensed, as shown in
FIGS. 28B
and
28
C. More specifically, since the “central viewpoints” of the right and left image sensing optical systems are different from an ideal “central viewpoint” of a synthesized image shown in
FIG. 28C
, an image process for removing apparent trapezoidal distortion arising from the “central viewpoint” difference must be done upon joining the right and left images. However, when the trapezoidal distortion is removed by only the image process, the image quality deteriorates.
SUMMARY OF THE INVENTION
It is the first object of the prese
Araki Keisuke
Sunaga Toshihiro
Yano Kotaro
Fineman Lee
Robinson Mark A.
LandOfFree
Multi-eye image sensing 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 Multi-eye image sensing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-eye image sensing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3081881