Abstract: The present invention refers to a surround-view imaging system for time-of-flight (TOF) depth sensing applications and a time-of-flight sensing based collision avoidance system comprising such an imaging system. The imaging system for time-of-flight depth sensing applications comprises a lens system, adapted for imaging angles of view (AOV) larger than 120° in an image on an image plane; a sensor system, adapted to convert at least a part the image in the image plane into an electronic image signal; and an evaluation electronics, adapted to analyze the electronic image signal and to output resulting environmental information; wherein the lens system and/or the sensor system are designed for specifically imaging fields of view (FOV) starting at zenithal angles larger than 60°.

Abstract: An apparatus for displaying still and moving images on a three-dimensional projection screen includes a gas-inflatable envelope made of flexible material with an inner surface serving as three-dimensional projection screen, a gas inlet opening, a fan connected to the gas inlet opening and which generates a gas flow that inflates the envelope, an interior surrounded by the envelope, a projector emitting a projector beam and a reflection mirror set up in the zenith of the envelope, said reflection mirror having a curved mirror surface for deflecting the projector beam onto the inner surface of the envelope. The image generated by the projector beam is visible on the outer surface of the envelope. The projector is configured within the interior of the envelope and aligned in such a way that the projector beam is reflected onto the inner surface serving as a three-dimensional projection screen via the reflection mirror.

Abstract: Methods and compositions for creating an immersive experience within wellness studios, rooms and enclosures, and methods of physically organizing a wellness center or studio and conducting the business of a wellness center or studio. In some embodiments the invention concerning enclosures for conducting wellness activities, such as yoga, pilates, meditation and the like. In preferred embodiments the enclosure comprises at least one interior space and at least one mirrored surface that reflects images projected from one or more projector component onto a curved, projection wall and or ceiling opposing the mirrored surface.

Abstract: A camera device includes a supporter, a plurality of camera units, a cover and a lens driving mechanism. The camera units are movably disposed on the supporter. The cover covers the supporter and the camera units. The lens driving mechanism includes a base, a pivoting component and a fixer. The base is disposed on the supporter. The pivoting component is disposed on the base. The fixer has a top surface and two supporting surfaces connected with each other. The supporting surfaces are used to support the camera units. The fixer includes a connective block disposed on a side of the supporting surface opposite to the top surface. The pivoting component is rotatably assembled with the connective block, so the fixer can rotate relative to the base and the camera units can be moved synchronously.

Abstract: The lens apparatus includes: a first optical unit (FOU) changes a field curvature amount of a projection optical system (POS) by shifting in an optical axis direction (OAD) of POS, a second optical unit (SOU) including a focus adjustment unit moves during focusing and a zoom adjustment unit moves during zooming, the SOU changing projection magnification and focus position of POS by shifting in OAD of POS, a first detection unit (FDU) detecting a position of FOU, a memory stores change information regarding changes in projection magnification and focus position of POS through shift of FOU and a control unit controls SOU to shift so as to reduce changes in projection magnification and focus position of POS at the same time caused due to shift of FOU, when field curvature amount of POS is changed, based on position of FOU detected by FDU and change information stored in memory.

Abstract: A camera system includes a camera mounting frame having a plurality of camera mounts. Each camera mount is configured to hold a respective camera at a respective lens orientation such that mounted cameras provide different respective lens orientations relative to each other, with each mounted camera providing a different field of view facing outward from the mounting frame. The camera system may provide obstruction-free, fully spherical image and video capture to record spherical images or spherical videos in which the nadir hole and/or a physical support element of the camera system is eliminated or reduced in size during the digital stitching process of the image or video.

Abstract: The present disclosure relates to a holographic reproducing apparatus comprising: a light source configured to supply a reproducing light beam to be incident to a photorefractive crystal, wherein the photorefractive crystal has holographic images recorded therein in a plurality of different angles respectively; a reflective mirror configured to reflect the reproducing light beam emitted from the light source to the photorefractive crystal; and a driving mechanism connected to the reflective mirror and configured to drive the reflective mirror to move on a plane elliptical arc, the plane elliptical arc is defined by using the light source and the photorefractive crystal as two mathematical focuses and using a predetermined constant, so that an incident angle of the reproducing light beam to be incident to the photorefractive crystal varies to form a plurality of reproducing light beams in different angles to be incident to the photorefractive crystal in sequence.

Abstract: Embodiments of the present application provide a display screen, wherein the display screen is in a fully-closed or partially-closed housing structure, an interior of the housing structure being configured to provide continuous images with a view angle of 180 degrees to 360 degrees in a horizontal direction; wherein the housing structure includes a cylindrical portion, a side wall of the cylindrical portion being arranged in a smooth arc line or straight line on an axial cross section, and if the side wall of the cylindrical portion is arranged in the arc line, the radius of a circle corresponding to the arc line is greater than a maximum vertical distance from the arc line to an axial line. According to the present application, the audiences feel comfortable in watching and the cost is saved, while a strong sense of immersion is achieved for the audiences.

Abstract: Panoramic imaging systems and devices are disclosed. In one aspect, a disclosed panoramic imaging system includes a housing which has a substantially spherical shape and a set of cameras mounted on and enclosed by the housing. The housing is further composed of a first hemispherical substructure which receives a first subset of cameras and a second hemispherical substructure substantially identical to the first hemispherical substructure to receive a second subset of cameras. Each of the first and second hemispherical substructures has a closed boundary, and the contour of the closed boundary resembles the contour of the seam of a tennis ball. Moreover, each of the first and second hemispherical substructures has a shape which resembles the shape of one half of the tennis ball. In some embodiments, the disclosed panoramic imaging system includes eight normal-lens or wide-angle-lens cameras.

Abstract: Various embodiments of systems for improving shooting performance, as well as, carriers configured for that purpose, are disclosed and described herein. In some such embodiments, such systems may comprise: at least one projector, at least one screen, at least one carrier, and at least one pathway. The at least one projector may project one or more images upon at least some portion of the at least one screen. The at least one screen may receive and display the one or more images. The at least one carrier may house the at least one projector; and in some embodiments, may also house at least one screen mount for removably mounting the at least one screen. The at least one carrier may travel along the at least one pathway. A shooter may aim and shoot a firearm at the one or more images displayed upon the at least one screen.

Abstract: Various examples are directed to a panoramic camera system comprising a first image sensor, a second image sensor and an enclosure. The first image sensor may have a first in-air field-of-view and the second image sensor may have a second in-air field-of-view. The first in-air field-of-view may overlap the second in-air field-of-view by greater than a threshold amount. The enclosure may comprise a curved outer surface. An alternate medium field-of-view of the first image sensor may overlap an alternate medium field-of-view of the second image sensor by greater than the threshold amount. The panoramic camera system may also comprise an image processor that is programmed to determine that the first image sensor and the second image sensor are within the enclosure. The panoramic camera system may stitch frames captured by the first and second image sensors considering an alternate medium stitching parameter.

Abstract: A curvilinear projection screen and acoustic system includes a curvilinear structural frame having a first side and a second side, a plurality of glass fiber reinforced gypsum (GRG) surface panels secured to the first side of the curvilinear structural frame, and a plurality of acoustic panels secured to the first side of the structural frame and interspersed between the plurality of GRG surface panels. In addition, the system includes a projection coating over the pluralities of GRG surface panels and acoustic panels to define a curvilinear projection surface.

Abstract: A timer mount system is configured for use with a camera and a camera mount to capture panoramic videos or photographs in multiple rotational directions. The timer mount system comprises a housing, a drive shaft, a panning mechanism, a first mount component, and a second mount component. Within the housing, the drive shaft is coupled to the panning mechanism, which stores rotational energy when wound in a rotational direction and then causes the drive shaft to rotate in a reverse rotational direction when released. The first mount component is configured to secure to and rotate with the drive shaft, while the second mount component is configured to remain stationary while allowing the drive shaft to rotate freely. A first configuration allows the first mount component to rotate in a first rotational direction, and a second configuration allows the first mount component to rotate in a second rotational direction.

Abstract: Methods and apparatus for producing images having variable lateral magnification. One example of such a method includes receiving a first image having a first level of magnification and representing a first field of view, simultaneously receiving a second image having a second level of magnification and representing a second field of view, the second level of magnification being higher than the first level of magnification and the second field of view being narrower than the first field of view, and digitally processing the first and second images to produce a composite image having a variable lateral magnification derived from the first and second levels of magnification.

Abstract: A camera system includes a camera mounting frame having a plurality of camera mounts. Each camera mount is configured to hold a respective camera at a respective lens orientation such that mounted cameras provide different respective lens orientations relative to each other, with each mounted camera providing a different field of view facing outward from the mounting frame. The camera system may provide obstruction-free, fully spherical image and video capture to record spherical images or spherical videos in which the nadir hole and/or a physical support element of the camera system is eliminated or reduced in size during the digital stitching process of the image or video.

Abstract: An eye examining instrument comprises a projection device and a concave screen. The eye examining instrument furthermore comprises a convex reflector, wherein an image can be projected by the projection device onto the convex reflector and reflected by the convex reflector onto the concave screen.

Abstract: A method of making a panoramic image includes capturing a first image (30) defining a first overlap region (115) capturing a second image (40), and defining a second overlap region (215). Two points (150, 151) in the first overlap region are identified and a first vector (175) overlap region connecting the two points is defined. Two points (250, 251) in the second overlap region which correspond to the two points in the first overlap region are identified and a second vector (275) the two points is defined. If points in the first vector match points in the second vector, determine if the first and second vectors are parallel. If the vectors are not parallel, rotate the second vector image until the second vector is parallel to the first vector.

Abstract: Disclosed are an unmanned monitoring system and a monitoring method for performing 360° unmanned monitoring work in equipment having a low storage capacity, such as a robot, by using one omni-directional camera. When an image is input through the omni-directional camera, a movement of an object is detected from the image. Then, the movement region is sampled by tracing the object and the image for the movement region is rotated into a frontal image while compensating for inclination of the image in order to allow a user to easily view the image. Thus, the frontal image is transmitted to a mobile communication terminal of a user, such as a mobile phone or a PDA.

Abstract: A mirror assembly adapted for use in a panoramic imaging system for capturing a panoramic image includes a mirror for optically coupling to a fisheye lens having a first field of view, the mirror configured for reflecting an image of a second field of view through the fisheye lens. A housing has a first end and a second end, the mirror being secured proximate to the first end, and the second end having an engagement portion for securing the mirror assembly to the panoramic imaging system. When the mirror assembly is secured to the panoramic imaging system, the mirror is optically coupled to the fisheye lens and a detector for capturing a first portion of the panoramic image and a second portion of the panoramic image, the first portion of the panoramic image having a portion overlapping the second portion of the panoramic image.

Abstract: A method of making a panoramic image includes capturing a first image (30) defining a first overlap region (115) capturing a second image (40), and defining a second overlap region (215). Two points (150, 151) in the first overlap region are identified and a first vector (175) overlap region connecting the two points is defined. Two points (250, 251) in the second overlap region which correspond to the two points in the first overlap region are identified and a second vector (275) the two points is defined. If points in the first vector match points in the second vector, determine if the first and second vectors are parallel. If the vectors are not parallel, rotate the second vector image until the second vector is parallel to the first vector.

Abstract: A system for displaying an anamorphic image on a viewing surface comprises a screen having a viewing surface and an image source configured to display the anamorphic image on the viewing surface such that an image viewed on the viewing surface appears undistorted from a viewing point. In addition, the system may also include a reflective lens having a convex exterior surface and a refractive lens having a plurality of surfaces to redirect light toward an image capture device. Further, the system may include an image conversion module for converting a non-anamorphic image into the anamorphic image suitable for displaying on the viewing surface and a selected portion of the anamorphic image into at least one non-anamorphic image.

Abstract: An entire-visual-field projection device which projects image information relating to an entire-visual-field image onto a spherical screen to provide the entire-visual-field image to a viewer positioned inside the screen. The projection device is provided with the spherical screen, a pair of projectors which project the entire-visual-field image onto the screen and are arranged opposite each other with the center of the screen therebetween, and a double-convex mirror for projection which reflects luminous fluxes from the projectors toward the screen and is disposed in the vicinity of the center of the screen. A projection luminous flux from one of the projectors is emitted to one of the convex surfaces of the mirror, and that from the other projector to the other convex surface of the mirror.

Abstract: The invention relates to an optical system adapted to project a cylindrical, spherical, conical or other three-dimensional display surface onto every direction in the distance or receive images from every direction at such a three-dimensional imaging surface. The optical system is adapted to project a three-dimensional object surface 3 onto a full circle in the distance, and comprises at least one rotationally symmetric reflective surface 2.

Abstract: A pair of rotation plates 10 are provided on an upper surface and a lower surface of a camera body 30. The rotation plates 10 are rotatable with respect to the camera body 30. During panorama imaging, a user holds the pair of rotation plates 10 with their fingers to hold a camera 9. An actual rotation angle of the camera body 30 with respect to the rotation plate 10 is detected by an encoder provided inside the camera. When the actual rotation angle reaches a target rotation angle, an image capturing process of an element image is automatically executed.

Abstract: A projection apparatus comprising a three-dimensional screen, a convex mirror, two or more projectors, and an assemblage of flat mirrored surfaces that share at least one common edge or apex that faces the convex mirror. The flat mirrored surfaces fold the images from separate projectors into a common image that has single optical axis aligned with principal axis of the convex mirror so that the combined image is reflected from the convex mirror onto the three dimensional screen.

Abstract: Systems and methods for maintaining orientation of a non-cylindrical panorama is described wherein an initial magnetometer reading is obtained for a panoramic camera. If the panoramic camera is rotated from an initial position, a new magnetometer reading is obtained and a magnitude of rotation is determined. The magnitude of rotation is factored into an image stitching and warping process to create a panoramic image that maintains the initial orientation.

Abstract: A panoramic camera design that is lower cost, robust, stable and more user friendly than prior art designs. The camera design makes use of a unified molded structure of optical material to house a mirror, aligned sensor, and lens assembly. The unified molded structure of the camera keeps the sensed optical path enclosed to minimize dust and user's fingers and maintain optical alignment.

Abstract: Improved camera calibration techniques, including an improved up look angle and an improved method for calibrating a virtual center of projection. By using a view camera technique for the up look angle, the image sensors can be mounted flat to a Printed Circuit Board (PCB). By using a sub-region of the image sensor for the active area of the camera it is possible to calibrate the virtual center of projection (C?).

Abstract: A dynamic wide angle image viewing technique is presented which provides a way to view a wide-angle image while zooming between a wide angle view and a narrower angle view that employs both perspective and non-perspective projection models. In general, this involves first establishing the field of view for a view of the wide angle image that is to be displayed. The view is then rendered and displayed based on the established field of view, such that the projection transitions between a perspective projection associated with narrower angle views and a non-perspective projection (e.g., cylindrical, spherical or some other parameterization) associated with wider-angle views.

Abstract: In order to prevent the upper part of a subject such as a multistoried building or the like from being photographed in a short form when a wide angle shot is carried out, image pick-up means 5 are provided at intervals of 90 degrees on a base 4. The image pick-up means 5 respectively have front convex lenses 8 and image pick-up parts 7 along vertical planes parallel to each other. The front convex lenses 8 are displaced along the vertical planes so as to be provided at higher positions than those of the image pick-up parts 7. The NP points of the image pick-up means 5 are arranged to respectively correspond to each other so that a parallax is reduced.

Abstract: The invention provides systems and methods for generating a visual image that is made to appear to be situated behind an architectural structure, such as a wall of a building, and is viewed through windows thereof. The image appears as an oversize object relative to the actual object. The system and method include an image recorder and/or a pre-recorded image, an image display apparatus, and a mask. Sound can be provided as required to complete the illusion. The image can be a still image or a moving image. In some embodiments, two viewers can see the image from opposite sides of the structure, each perceiving the image as being on the side opposite to the viewer. The system includes a video capture device and a display and an optional audio system for showing the person whose image is being projected the giant image as seen and heard by a viewer.

Abstract: A display system includes a single image-projection device, and a reflective surface optically coupled to the image-projection device, wherein the reflective surface is configured to reflect a plurality of images projected by the image-projection device onto a plurality of display surfaces, the projection being along a same path as a collection of the plurality of images.

Abstract: Methods of and equipment for converting existing standard motion picture theatres to one having highly immersive, large fields of view are addressed. Aspects of the methods including moving motion picture screens closer to the audience and employing different projection equipment to avoid or minimize appearance of unrealistic or non-natural image artefacts. Alternative sound systems too are detailed.

Abstract: The invention provides systems and methods for generating a visual image that is made to appear to be situated behind an architectural structure, such as a wall of a building, and is viewed through windows thereof. The image appears as an oversize object relative to the actual object. The system and method include an image recorder and/or a pre-recorded image, an image display apparatus, and a mask. Upon being projected, the image of interest is masked so that illumination falls on one or more regions of a display surface, and no illumination reaches the architectural structure outside the display region(s). Sound can be provided as required to complete the illusion. The image can be a still image or a moving image. In some embodiments, two viewers can see the image from opposite sides of the structure, each perceiving the image as being on the side opposite to the viewer.

Abstract: A panoramic display system includes a curved projection screen, a panoramic projector, and a substantially conically shaped barrier. The projector is configured to project an image onto the projection screen from a projection point located substantially above the projection screen. The conical barrier has a base disposed toward the bottom of the projection screen, and an apex region disposed toward the projection point. The barrier blocks scattered light from reflecting from portions of the curved screen to other portions thereof.

Abstract: Apparatus and methods for recording and projecting images on curved screens in a manner that imparts to an audience a sense of immersion in the projected scene. The screen is usually a segment of a spherical dome, with a large portion of the segment located below the horizontal viewing line of an audience. During recording of the images, the camera lens longitudinal axis is maintained in a substantially horizontal orientation. During projection, the projector lens longitudinal axis is maintained in a substantially horizontal orientation, and the image is positioned on the screen by horizontal and/or vertical movement of the projector lens relative to the film. The image is projected to appear to the viewer to be in substantially the same position as it was to the camera lens during recording.

Abstract: A process for adjusting the content of a digitized image file used in printing an interlaced image on a lenticular lens material to substantially eliminate ghosting effects which might otherwise occur when the printed image is viewed by an observer. A pixel address within the image file is selected, as is a preselected number of pixel addresses adjacent the selected address on both sides thereof. Percent color values contained at each of the addresses within the resulting range of addresses are added together and the result divided by the total number of addresses to compute an average color percent value. The percent color value at the selected address is compared with the computed average and is changed by a predetermined amount if the percent color value is greater or less than the computed average. The revised percent color value is then stored at the selected address. The process is repeated for each pixel address within the file.

Abstract: A panoramic imaging and display system for the imaging and displaying of visual-media content, comprising a screen configured for the display of panoramic imagery, having an interior surface-perimeter and an exterior surface-perimeter, wherein each of said surface-perimeters are substantially contiguous in appearance and are sized and shaped to have a display area on which, substantially contiguous panoramic visual-media content and segmented visual-media content can be imaged. The system provides support and positioning of the display to at least one height relative to a viewing audience to provide circumnavigable viewing, and a multitude of vantage points from which to view at least one of the surface-perimeters of the panoramic display. Embodiments of the system can have an array of speakers positioned around a perimeter of the system's screen as a sound-system providing a panning of audible sound which can be synchronized with the movement of objects seen moving on the screen.

Abstract: An interactive theater for creating a perception on the part of the audience that they are immersed in a boundless environment. The projection surface surrounds the audience platform and the ceiling to form a cavity providing a full or apparent 360° projected environment horizontally and apparent 360° projected environment vertically.

Abstract: A visual and audio system for theaters includes a spherical screen having a desired radius of curvature while having a surface reflectivity of 5-50%, and a projector located at a focal point of the spherical screen. The curvature radius of the spherical screen corresponds to the projection distance of the projector. The image projected from the projector at the focal point of the spherical screen is reflected from the spherical screen in a horizontal direction. Accordingly, viewers can view images projected on the screen corresponding to 5-50 time the brightness of images viewed on conventional theaters screens. Central speakers are arranged at the focal point of the spherical screen, so that viewers perceive the sound effect as coming directly from the spherical screen. This visual and audio system can be effectively used in theaters for stereoscopic moves, theaters for high resolution images, and theaters for viewing of images at a higher brightness such as sports arenas, and restaurant theaters, etc.

Abstract: A tactical display unit having a set of abutting viewing screens with each of the viewing screens located at an angle of at least 60 degrees to each other and each having an identical image thereon with the screens positioned either above or below a lateral head region of the viewers to create a communications zone where each of the viewers can both visually and orally communicate with one another even if viewers are on the opposite side of the viewing screens.

Abstract: A multi-layer image display system and method thereof, in which liquid crystal type image display units for displaying the images according to depth necessary for obtaining the stereoscopic image are arranged according to layers at a predetermined interval without overlapping each other along the rotary axis and rotated as displayed the layer image corresponding to each image display unit, by which the screen is on to express the stereoscopic image when each image display unit arrives at the user's position; and another method in which the reflector or half mirror is installed instead of the image display unit and the layer image corresponding to the relative depth of the reflector or half mirror is synchronized with the rotation speed to express the stereoscopic image in the fixed high speed display device.

Abstract: An image alignment system for rear projection in which a portion of the normally changing pixel pattern contains a pixel reference mark, which appears in each of the side-by-side pixel images projected onto a screen. A camera having a field of view large enough to encompass the pixel reference mark of each of the images on the screen captures the location of the pixel reference marks to enable a computer to determine the coordinates of the each of the pixel reference marks and generate a deviation signal represented of the visual misalignment of the side-by-side images. A drive member controllable by the deviation signal from the computer repositions one of the side-by-side images with respect to the other to thereby align the images to produce a single visually seamless image. The camera and computer can continually monitor both of the pixel reference marks to continually generate a deviation signal so that the side-by-side images can automatically be brought into a single visually seamless image.

Abstract: An embodiment of the invention provides a theater having a first screen and a second screen movable relative to the first screen. The first and second screens are typically designed for different movie formats. The second screen is mounted to a frame in sections, and a rotating member is operable to move sections of the second screen away from the first screen. A projection system disposed in front of one of the screens is operable to project screen images alternatively on the first screen or on the second screen. A plurality of speakers are mountable to the frame to provide a sound system.

Abstract: A panoptic camera system that can be used to capture all the light from a hemisphere viewing angle is disclosed. The panoptic camera comprises a main reflecting mirror that reflects light from an entire hemisphere onto an image capture mechanism. The main reflecting mirror consists of a paraboloid shape with a dimple on an apex. The surface area around the dimple allows the main reflector to capture light from behind an image capture mechanism or a second reflector. When two panoptic camera systems that capture the light from an entire hemisphere are placed back to back, a camera system that “sees” light from all directions is created. A stereo vision panoramic camera system is also disclosed. The stereo vision panoramic camera system comprises two panoramic camera systems that are separated by a known distance. The two panoramic camera systems are each placed in a “blind spot” of the other panoramic camera system.

Abstract: A multiplexed motion picture camera comprising a sturdy plate for supporting a plurality of camera mechanisms, each camera mechanism provided with an adjustable support device, and connected to a common objective lens through an arrangement of lenses, beam splitters, multiple axis optical relays, and additional shutter devices. Each camera mechanism and its associated optical relays, shutters, and lenses can be individually controlled and adjusted to allow an operator a broad range of photographic settings to achieve a smooth, continuous, natural motion moving image recording.

Abstract: A projector 3 is provided for casting light toward the inside of a spherical screen 2. A first reflecting mirror 4 is arranged inside the spherical screen 2 on the optical axis 15 of the projector 3, and a second reflecting mirror 5 of a convex mirror on the optical axis 15 is arranged adjacent to a body tube 16 of the projector 3. The light emitted from the projector 3 is cast onto the entire surface of the spherical screen 2 via the first and second reflecting mirrors 4, 5. Images with virtual presence can be projected onto the entire surface of the spherical screen by the simple structures using the single projector.

Abstract: According to one aspect of the invention there is provided a panoramic imaging arrangement comprising a transparent component and a reflective material. The transparent component has a first surface about a vertical axis of revolution, a second surface about the axis of revolution, and an opening formed therein to define a third, internal surface about the axis of revolution. The third surface has a concave profile in a plane of the axis of revolution. The reflective material is located on the second surface to provide a reflective surface against the second surface. The first surface, the reflective surface and the third surface are positioned relative to one another so that light from a 360° surrounding panoramic scene enters the transparent component through the first surface, whereafter the light is reflected from the reflective surface, whereafter the light exits the transparent component through the third surface.

Abstract: A projection system having multiple screens for image display includes at least two screens arranged to form a polygon and a multi-projector comprised of at least two sub-projector units for projecting an image to the rear side of each of the screens. Thus, since multiple screens for displaying an image are disposed in at least two directions, the image can be viewed in various directions.

Abstract: An omnidirectional or panoramic viewer/projector uses a single camera and a mirror with a curved surface. The curved mirror provides a single virtual optical center or viewpoint.