1. Field of the Invention
This invention generally relates to the display of stereoscopic images on a three-dimensional display and more specifically to the three-dimensional display of images obtained from a stereoscopic imaging system.
2. Description of Related Art
As known, humans have a natural stereoscopic image viewing capability. The separation of their left and right eyes causes them to view an object from two directions of view. Likewise, electro-optical devices today can produce a three-dimensional stereoscopic image by viewing an object simultaneously from two separate directions. The resulting images from the two optical viewing directions are overlaid on a stereoscopic display such that one image is observed by the right eye and the other by the left eye. The human brain then perceives depth from the lateral displacement, or parallax, between corresponding parts of the images. Many devices in use today have the capability of generating image pairs that form three-dimensional stereoscopic images viewable to a user on three-dimensional (3D) displays. The use of this technology is becoming prevalent in the movie and entertainment industry. It is also becoming an important feature in health care surgical diagnostic devices such as stereoscopic endoscopes and camera systems.
As will be appreciated, surgical stereoscopic endoscopes and camera systems are precision optical instruments. Each creates matched image pairs of an object inside the body during surgical procedures that are displayed for stereoscopic viewing. The better the quality and alignment of the stereoscopic images, the better the three-dimensional perception will appear to the medical personnel using the device. The variables for matching image quality include focus, magnification, field of view and distortion. The variables for matching alignment include “dipvergence” and “convergence” of the stereoscopic image pair.
“Dipvergence” is vertical line-of-sight misalignment between the images in an image pair when viewed on 3D display. Stated differently, it is a vertical angular disparity between the lines of sight of the left and right images as displayed on a 3D display. Depending upon the context, in the following discussion “dipvergence shift” and “dipvergence error” represent the magnitude of the misalignment.
“Convergence” is the horizontal alignment of the images of an object at a specific desired distance when viewed on a 3D display. Proper convergence is defined as a perfect overlay of the images in the image pair at the desired object distance or “convergence point.” Depending upon the context, in the following discussion “convergence shift” and “convergence error” represent the distance between the actual convergence point for the stereoscopic endoscope assembly and the ideal convergence point for the object being viewed.
As between dipvergence and convergence error, a user's eyes are more sensitive to misalignments in dipvergence between the stereoscopic image pair. Therefore it will be apparent that any three-dimensional system, particularly such systems for use in medical applications, should optimize the optics to minimize the effects of dipvergence errors. Also, because the same stereoscopic endoscope system may be used for different procedures, it is desirable to be able to easily modify the convergence point of the system depending on the expected location of objects for each specific procedure.
Today a typical stereoscopic endoscope system includes a stereoscopic endoscope assembly, a stereoscopic camera assembly and a stereoscopic image display assembly. Each assembly comprises many subassemblies and internal components, all of which contribute to a wide range of inherent manufacturing tolerances that can accumulate to introduce noticeable dipvergence shift or misalignment and an improper convergence shift or misalignment in a 3D display.
It is common practice to manufacture stereoscopic endoscope systems by fabricating components and assemblies to very tight tolerances so that endoscopes and camera assemblies can be interchanged without causing a noticeable perceived misalignment from system to system. However, even if a manufacturer adopts the use of and accepts the costs of tightly controlled manufacturing tolerances, there may still be cumulative misalignments that contribute to noticeable dipvergence and convergence errors between the images of image pairs when viewed on 3D displays.
U.S. Pat. No. 6,191,809 (2001) to Hori et al. discloses one method for changing dipvergence and convergence alignment by electronically adjusting the overlapping video displays of one channel relative to the other channel in the display electronics. For simplicity and cost, many display systems do not incorporate this capability.
What is needed is a system that facilitates the correction of errors in dipvergence and allows easy adjustment of convergence, that can be constructed economically, and that is easy to use thereby to facilitate the adjustments as different assemblies are substituted or exchanged in a given stereoscopic imaging system, such as a stereoscopic endoscope system and when a given stereoscopic imaging system is used for different procedures.
Therefore, it is an object of this invention to provide an adjustment system for use in stereoscopic imaging system that corrects dipvergence errors, convergence errors or both.
Another object of this invention is to provide an adjustment system for use in a stereoscopic imaging system that corrects dipvergence errors, convergence errors or both and that is economical to construct and easy to use.
Still another object of this invention to provide an adjustment system for use in a stereoscopic endoscope imaging system that corrects dipvergence errors, convergence errors or both.
Yet another object of this invention is to provide an adjustment system for use in a stereoscopic endoscope imaging system that corrects dipvergence errors, convergence errors or both and that is easy to use.
In a stereoscopic imaging system constructed in accordance with one aspect of this invention, first and second images are directed along first and second image paths for being viewed on a three-dimensional display wherein the displayed images are subject to misalignment in the direction of a first of two orthogonal displayed image axes. An image adjuster mechanism adjusts the misalignment. More specifically, an optical structure in the first of the image paths is angularly tiltable about a first tilt axis that corresponds to the second orthogonal displayed image axis. An exiting light beam from the optical structure deviates in a direction that corresponds to the first orthogonal display image axis to a path that is parallel with and offset from an entering light beam. A first tilt control structure connects to the optical structure to adjust the tilt of the optical structure about the first tilt axis thereby to adjust the misalignment of the first and second displayed images in the direction of the first orthogonal displayed image axis.
The appended claims particularly point out and distinctly claim the subject matter of this invention. The various objects, advantages and novel features of this invention will be more fully apparent from a reading of the following detailed description in conjunction with the accompanying drawings in which like reference numerals refer to like parts, and in which:
More specifically, the stereoscopic endoscope 11 defines a right viewing image path 17 and a left viewing image path 18 along which a stereoscopic image pair transfers from an object 20 being viewed. Each of the detectors 14 and 15 in this particular embodiment comprises a charged coupled device (CCD) but other detector types can be substituted in other embodiments of this invention. System electronics 16 process the signals from the detectors 14 and 15 to produce an image 21 for being viewed on the 3D display 13. Such systems are known in the art.
Although an object generally is a three-dimensional object, for purposes of understanding this invention the object 20 in
As previously indicated, misalignments between images 25 and 26 of the stereoscopic image 21 are a direct result of the manufacturing tolerances and misalignments of the stereoscopic endoscope system. These include the affects of tolerances and misalignments beginning with the orientations of the right side image path 17 and the left side image path 18, the optical elements within the stereoscopic endoscope assembly 11 and the stereoscopic camera assembly 12 including the position of the detectors 14 and 15. Also contributing are electronic signal mapping errors introduced by the system electronics 16.
As shown in
In use, stereoscopic endoscopes and cameras are intended to be interchangeable. The perceived dipvergence shift 23 and convergence shift 24 may be different for each combination of an individual stereoscopic endoscope assembly 11 and stereoscopic camera assembly 12. In order to adjust the dipvergence shift 23 and convergence shift 24 for optimal use in accordance with this invention, the embodiment in
Plano-plano windows constitute a category of optical beam adjuster used in the optical industry. When a plano-plano window in the optical path tips, the light beam deviates in the plane of tip based on the angle of tip, the window material and the window thickness. However, the exiting light beam remains parallel to the entrance light beam thereby preventing image tilt on a sensor and maintains a constant magnification during adjustment. The optical properties of a tipped plano-plano window are ideally suited to the performance of the required adjustment needed in the matched stereo image pair. Other types of window may create image distortion that has a negative effect on the quality of the displayed image. However, a true plano-plano window placed within an optical path designed to accommodate such a window introduces virtually no negative image effects over the small range of tipping encountered in the applications for which this invention is useful.
Plano-plano windows 37 and 40 used in this embodiment of the adjustment mechanism 30 are sized so that such a window can be tipped without clipping the image path. Each of plano-plano windows 37 and 40 is held in a separate window bezel 41. Each window bezel 41 has pivot post 42 fixedly mounted to the outside of the bezel side wall and each window bezel 41 has a gear mounting shaft 43 fixedly mounted to the outside of the bezel wall in axial alignment with axis of the pivot post 42.
When the components are assembled, turning the control knob 33 adjusts the tip angle of the right side plano-plano window 40 by rotating it about a horizontal tilt axis to adjust the right-side image path 17. The horizontal tilt axis corresponds to the vertical displayed image axis thereby to produce a desired exiting beam axis 17b relative to the left side image path 18b to correct dipvergence shift or error. Likewise, turning the control knob 31 adjusts the tip angle of the attached plano-plano window 37 to adjust the left side image path 18 to produce a desired exiting beam along an axis 18b to correct convergence shift or error relative to the right-side image path 17b. In this case the second tilt axis is vertical to correspond to the horizontal one of the orthogonal displayed image axes to adjust the convergence misalignment 24 of the displayed images 25 and 26.
More specifically,
In
The worm gear sets used in embodiment of
However, in many cases the worm gear diameters may be so large as to prevent their use in a compact enclosure as encountered in a stereoscopic endoscope system.
It is also possible to adjust the tip and tilt of a single plano-plano window positioned in one image path for adjustment of both dipvergence and convergence. In
A multi-gear assembly carried by a frame 114 is adapted to tip plano-plano windows 112 and 113 toward or away from each other about vertical axes in
A mirrored adjustment is created by two worm gear sets, As the worm 126 turns, it rotates segmented worm gear 129 on the gear mounting shaft 117 thus tipping plano-plano window 112 in a plane axially centered with hole 118. As the worm 127 turns, it rotates segmented worm gear 130 mounted to the gear mounting shaft 117 thus tipping plano-plano window 113 in a plane axially centered with hole 125.
Since the pivots for the worm gears 129 and 130 are on opposite sides of the worm gear sets, the plano-plano windows 112 and 113 undergo opposite tipping. Thus, in use an adjuster knob 134 attached to the adjusting shaft 124 simultaneously adjusts the convergence of the image paths 110 and 111 to produce output image paths 110a and 111a. This adjustment mechanism has an advantage. This allows for the adjustment of the convergence point along the mechanical axis of the stereoscopic endoscope without displacing the convergence point laterally. Moreover adding a single adjustment mechanism for dipvergence in one of the image paths 110 or 111 would provide full adjustment of dipvergence and convergence of the image pair.
Lens cells 156 and 157 in
A fixed window mount 162 intermediate the lens cell 156 and camera system passage 153 supports a plano-plano window 163 in a fixed position. A tiltable window mount 164 intermediate the lens cell 157 and camera system passage 154 supports a plano-plano window 165 for being tilted about an axis 166 thereby to offset the image arriving through the camera system passage 154 vertically and minimize or otherwise adjust dipvergence shift. In this embodiment the axis 166 corresponds to the vertical one of the orthogonal displayed image axes. Rotation about the axis 166 is achieved by shafts, such as a shaft 167A that extends from the mount 164 in the form of a yoke, block or equivalent component to be supported for rotation about the axis 166. A central block 171, also mounted to the horizontal extension 170, acts as a journal for a second shaft 167B from the mount 164.
As previously indicated, the control knob 155 provides adjustment by tilting the mount 164 about the horizontal axis that intersects both image paths within the camera system 150 because that is the axis that corresponds to the dipvergence displayed image axis. Referring to
Rotation of the control knob 155 causes the bevel gear 175 to rotate the worm 177 and a segment 182 that pivots about a horizontal axis in the block 171 attached to the shaft 167B extending from the tiltable mount 164 through the segment gear. As a result, the tiltable window 164 rotates about the axis 166 and causes the image path to deviate as previously described to bring the image paths into vertical alignment and to minimize the effects of dipvergence on the displayed image.
As will now be apparent, there have been disclosed a number of specific mechanisms that can implement a stereoscopic imaging system that meets the objectives of this invention. Each of the various embodiments provides an adjustment system for use in a stereoscopic imaging system that corrects unwanted dipvergence, convergence or both. Each adjustment system is economical to construct an easy-to-use. Moreover each adjustment system is readily adapted for use in stereoscopic endoscope imaging systems.
This invention has been disclosed in terms of certain embodiments. It will be apparent that many modifications can be made to the disclosed apparatus without departing from the invention. For example, other mechanisms could be constructed that incorporate the features of various specific embodiments of this invention in alternative and equivalent assemblies. Each of the specifically disclosed embodiments assumes that there is a direct correspondence between tilt axes and orthogonal displayed image axes and more specifically that the orthogonal displayed image axes are horizontal and vertical and that the tilt axes are also horizontal and vertical. However this invention is not limited to such a direct correspondence. Other arrangements can be implemented so long as there is a predetermined correspondence or relationship between the displayed image orientation and the various tilt axes. As previously indicated, other optical assemblies might be substituted for the preferred plano-plano lenses with the attainment of some or all of the advantages of the specifically disclosed embodiments. All of the tilt control structures have been disclosed with conventional gear apparatus; other non-gear apparatus might be substituted to provide the limited rotary motion of the plano-plano windows. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the true spirit and scope of this invention.
This application claims priority from copending U.S. Provisional Application Ser. No. 61/445,997 filed Feb. 23, 2011 for an Adjustment System for Dipvergence and/or Convergence of a Stereoscopic Image Pair.
Number | Date | Country | |
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61445997 | Feb 2011 | US |