KR20000076414A - Method and apparatus for volumetric displaying - Google Patents

Abstract

Three-dimensional images based on a series of two-dimensional images are generated and displayed. Frame 20 comprising a series of image displays 22 lying at different radial distances from the center 39 of the frame rotates above 60 Hz. While each display rotates past the viewer, different cross-sectional slices of the three-dimensional image are displayed. And, the complete rotation of the frame gives the viewer a complete view of the 3D image. The high rotational speeds of the system match the slices and the radial displacement of the display provides depth to the image. This combination presents a real three-dimensional image without the need for a visual aid. In addition, several people may view the same or different three-dimensional images.

Description

3D stereoscopic display system and method {METHOD AND APPARATUS FOR VOLUMETRIC DISPLAYING}

In the last 100 years, advances in the display and presentation of electronically generated images, from photographic technology to television displays, have focused on the early technology displaying two-dimensional (2-D) images. Although an important step, this system was not enough to replicate real 3D images.

Initial attempts to generate three-dimensional electronically generated images have been primarily limited to stereoscopic imaging techniques such as two-dimensional and two-and-half dimensions, or at most shuttered and polarized lens systems. In a shutter system, the observer must wear special shuttered glasses to view the image. Liquid crystal shutters, which alternate between transparent and opaque positions, are mounted in each lens. The display shows the other image sequence given the correct perspective for one eye and then the other. The control system adjusts the shutter position so that only suitable eyes see the image. This switching takes place at approximately 120 hertz (Hz) and provides the viewer with the sense of viewing a polarization-dimensional image. See Stereo Monitors Put Images In Perspective, Laser Focus World, 41, October 1989, and S. Wixson's Three-Dimensional Presentations, Information Display, 24-26, July / August 1989.

In polarized systems, observers wear special glasses that are polarized in opposite directions (horizontal / vertical or clockwise / counterclockwise). Display devices are also fitted with polarizing filters that switch between different directions. In a circular polarization system, the polarization filter alternates between two circular polarization states (clockwise and counterclockwise). If the polarization of the screen matches the polarization of one of the lenses, then the image on the screen can be seen. If the polarization is shifted, the image is hidden. Linear polarization systems operate in the same way as filters and glasses with vertical and horizontal polarization states. However, in the circular polarization system, the observer can see the three-dimensional effect even when the head is tilted, while the head must be positioned near the vertical to view the image in the linear polarization system. The disadvantage of circular systems is that the cost for lenses and screens is usually about 20% more than the cost of linear systems. See Stereo Monitors Put Images In Perspective, Laser Focus World, 41, October 1989, and S. Wixson's Three-Dimensional Presentations, Information Display, 24-26, July / August 1989.

The lens system can be implemented in various forms. For example, a common approach is to mount the same series of cameras next to each other and focus them on the desired object, which produces a series of object images at slightly different angles. These images are multiplexed and applied to the image projector series in a one-to-one correspondence with the camera. The image projector simultaneously projects the image onto a lens display screen that produces a stereoscopic image of the image that produces a three-dimensional effect. N. Nithiynadam, K. Balasubramonian, K.P. Rajappan's A Real-Time 3-D TV By Autostereoscopic Methods of Imaging, Journal of Optics, vol. 11, No. 1, 6-8, March 1982, and R. Borner, 3D TV Projection, Electronics and Power, June 1987, pages 379-382.

Although the above systems are better than standard two-dimensional images, they still do not provide real three-dimensional images. In addition, these systems typically require observers to use vision aids such as glasses or goggles. Therefore, subsequent studies have been made in an attempt to develop a real three-dimensional visual system without these limitations.

B. Daviss, Boob Cube, Discover, 30, December 1995, and P. Soltan, M. Lasher, W. Dahlke, N. Acnatilado, M. Mcdonald, Laser Projection 3-D Volumetric Displays, Naval Command, Control and Ocean Surveillance Center, February 1996, discloses a rotating spiral system that allows display in three-dimensional form without special glasses. In a rotating helical system, the double helix rotates in a glass cylinder. The spiral rotates at a rate of approximately 20 Hz sufficient to provide a flicker free image when written. A mirror is placed on top of a glass cylinder to reflect a pulse of laser light received over a spiral-generating visible light spot where the light crosses a spiral from a series of red, green and blue lasers. This intersection is known as voxels. The rotating helix sweeps through the cylindrical envelope to produce a three-dimensional image. Although the system produces real three-dimensional images, the system is of lower resolution than desired for most three-dimensional display applications. In addition, the system is sensitive to visual artifacts and is quite complex and expensive.

RL Hotz, A 3-D System That Works without Glasses, Los Angles Times, A1, A3a, August 30, 1996, describes a visual cube developed at Stanford University that includes multilayer glass coated with rare earth oxide fluorescent components. have. A computer-series controlled laser projects each ray through this cube to produce an emitting point where the two rays intersect. The laser quickly scans the cube to produce a real three-dimensional image. This visual cube has been limited to very small displays of about 3 cm ³ or less. In addition, the development of larger displays is not advanced because they develop adequate materials in sufficiently large volumes and cannot scan with lasers at sufficiently high rates.

J.C. Ruses, The Image Processing Handbook, CRC Press, 1992, pp. 406-408, discloses a multifocal mirror system in which a cathode ray tube (CRT) display projects a series of three-dimensional image slices. This image slice is not directly visible to the viewer but is reflected by a moving mirror. As each different slice is projected, the speaker voice coil moves the mirror slightly to give a sense of depth to the mirror. This technique is typically limited to simple outline drawings since the system cannot provide a complete image slice quickly enough. If the slice is not perpendicular to the x, y, and z axes, the trigonometric calculations required to fill the image further reduce system performance.

Although the techniques described above provide real 3D images, these systems are very complex and expensive and generally do not adapt well to the opposite environment. In addition, all three systems are very likely to produce display artifacts such as ghost images, spots, and unwanted defects.

The present invention relates to a projection of a two-dimensional image that can provide a three-dimensional image to an observer without a special visual aid such as polarized glasses or a shutter.

1 is a block diagram of a three-dimensional volumetric display system in accordance with the present invention.

2 is a partial cross-sectional view of a three-dimensional stereoscopic display system showing the rotation of the system in the vertical direction.

3 is a cross-sectional view of a three-dimensional stereoscopic display system operating in a given vertical direction along line 3-3 of FIG.

4 is a timing diagram illustrating sequential video display by a three-dimensional stereoscopic display system.

5 is a cross-sectional view of an alternative rotation frame design of a three-dimensional stereoscopic display using counterweights viewed from the same direction as in FIG.

6 is a cross-sectional view of a second alternative design of a rotating frame of a three-dimensional stereoscopic display using a curved display screen viewed from the same direction as FIG.

7 is a cross-sectional view of a third alternative design of a rotating frame of a three-dimensional stereoscopic display using only an image display circle viewed from the same direction as in FIG.

8 is a partial cross-sectional view of a three-dimensional stereoscopic display system operated in a horizontal direction.

9 is a cross-sectional view of a three-dimensional stereoscopic display system operated in a given horizontal shape along line 9-9 of FIG.

The present invention relates to a system and method for generating complex high resolution three dimensional images from two dimensional images.

An image source generates a sequence of two-dimensional images and transmits them to a series of display image sources mounted around a rotational frame structure. The display image source projects an image, which is concentrated on a plurality of display screens located around the frame with varying radii. The viewer sees a sequence of two-dimensional images visually fused by the depth given by the radial displacement and the rotational speed of the system. The binocular fusion and depth together provide a true three-dimensional image. With this system, an observer can see a real three-dimensional image without a special visual aid.

Although initially assumed that the display screen is flat, in an alternative form the display screen may be curved. Furthermore, the display screen itself can be a visual display source and eliminates the need for intermediate optics and subsequent display screens.

Although initially assumed that the frame rotates in a vertical manner around the horizontal axis, this may rotate horizontally around the vertical axis. This direction will allow several people to use the system. If there are multiple observers, they will be placed in different locations around the system and can see the same or different images.

These and other features, forms, and advantages of the present invention will become apparent to those skilled in the art from the following detailed description with reference to the accompanying drawings.

The present invention provides a system and method for the presentation of three-dimensional images based on a series of two-dimensional images. Frames containing a series of imange displays placed at different radial distances from the center of the frame should be at a frequency sufficient to prevent display flicker around an axis extending through the center of the frame, for example 60 Hz or more. Rotate As each display rotates past the viewer, another sectional depth slice of the three-dimensional image is displayed. When the frame is completely rotated, the viewer is provided with a 3D image of a desired object or scene. The high speed of rotation of the system visually fits the slices and the radial separation of the display provides depth for the image. This combination provides real 3D stereoscopic images that can be seen without a visual aid. In addition, several people can view the same or different three-dimensional images in a stereoscopic presentation.

As shown in FIG. 1, the three-dimensional system 19 includes a rotatable frame 20 that includes an image display 22. Each image display 22 includes a display image source 24, an intermediate optics series 26, and a display screen 28. The display image source 24 is preferably a flat panel display device that receives an image from the image source 30 and projects it onto the intermediate optics 26, wherein the intermediate optics 26 are preferably translucent. Focus the image on display screen 28, which is a rear projection display screen.

Depending on the scheme, the image source 30 may receive the image from the external image source 38 or may generate it internally using an image generating software package. For each image display 22, the display screen 28 lies at a different radial distance from the center of the frame 20. This arrangement provides another depth layer of the three-dimensional image to be displayed. The number of video displays 22 determines the depth resolution of the system, and the larger the number, the higher the depth resolution.

As shown in FIG. 2, mounting structure 32 supports frame 20 and causes frame 20 to rotate about its axis. The rotary motor 34 on the mounting structure 32 rotates the frame 20. A system controller 36, which is a suitably commercially available numerical or servo controller, maintains the speed of the frame 20 and adjusts the motor 34 and image source to adjust the projection of the image by the display 22. Control 30. The external image source 38 provides the image source 30 with the image received from the outside to the system.

As further shown in FIG. 2, in a preferred shape, the frame 20 is mounted in a vertical manner with a rotation axis horizontal to the mounting structure 32. Motor 34 rotates frame 20 relative to a central hub 40 that includes a rotating electrical connector (not shown). Hub 40 includes two portions, one portion mounted to mounting structure 32 and a second portion mounted to frame 20. The rotary electrical connector series is positioned between the two parts to pass electrical signals between the two parts. The electrical signal received from the image source 30 passes through the rotary connector and is provided to the corresponding display image source 24.

The frame 20 and mounting structure 32 are preferably located in a housing 42 having one or more viewing locations. The housing 42 is preferably kept near or near vacuum to minimize the air resistance experienced by the frame 20 during rotation. The housing 42 may be sealed to prevent vacuum loss or may be connected to a series of vacuum pumps (not shown) used to maintain vacuum levels. A cabinet 46 surrounds the housing 42 and provides a series of viewing positions 48 in a direction corresponding to the housing viewing position 44.

The series of electrical connectors 50 and 52 passes through the housing 42. A connector 50 is connected between the image source 30 and the first half of the central hub 40. The signal transmitted from the image source 30 is then passed through the housing 42 and received by the central hub 40, which then provides the signal to the corresponding display image source 24. The connector 52 is connected to the system controller 36, passes through the housing 42, and is connected to the motor 34.

As shown in FIG. 3, each image display includes a display image source 24 mounted radially close to the center of the frame 20. It is preferable to place the display image source 24 as close to the center of the frame 20 as possible to minimize the centrifugal effect on the display image source. The display image source 24 is not limited to this, but a liquid crystal display (LCD), a field emission display (FED), an electroluminescent display (ELD), a plasma display The panel PDP can be a variety of flat panel displays. It is better that these displays are high resolution with more than 1280 x 1024 pixels (horizontally and vertically), which is also valid for low resolution applications. The display image source 24 is connected to the second portion of the central hub 40 by an electrical lead 54. Moving radially out of the display image source 24 lies the intermediate optics 26. Moving further radially lies the display screen 28. Like the display image source 24, the intermediate optics 26 are also mounted in the frame 20. They receive the image projected by the display image source 24 and then concentrate this image on the display screen 28.

Each display screen 28 is located at a different radial distance from the center of the frame 20. This varying radial distance provides different depth layers of a given image, providing a true three-dimensional image. Display screen 28 may be any of a variety of commercially available rear projection display devices including, but not limited to, flexible and rigid diffusion screens, and hybrid systems including a combination of lens systems or holographic elements. . The transparent sheet 56 series is mounted parallel to the display screen 28 to balance the system and prevent shaking during rotation. Sheet 56 allows an image provided to / from display screen 28 to be passed to the viewer. If desired, a series of counterbalance weights (not shown) can be used to further balance the rotating system.

In operation, the motor 34 rotates the frame 20 at a speed of 60 Hz or more. While frame 20 is rotating, image source 30 internally generates or receives from external image source 38 a three-dimensional image to display. In both cases, the image source 30 cuts the three-dimensional image thinly into two-dimensional portions. The number of parts is in a one-to-one relationship with the number of video displays 22 used in the system. The input may initially include a layered database, so that “slicing” may not be necessary.

If the image is received from an external image source 38, the image includes various shapes of series or three-dimensional data points for the same image that must be matched by the image source 30 to produce a three-dimensional image. For example, if a three-dimensional stereoscopic display system is used for aircraft traffic control purposes, then the image source 30 will at least receive information about the altitude and latitude longitude position of each aircraft relative to a fixed position-route. will be. Image source 30 collects this data to generate a three-dimensional model of the airport area showing the location of the aircraft. The model is then thinly cut into a series of numbers of two-dimensional images that correspond one-to-one to the number of image displays 22 used by the system.

The image source 30 provides the corresponding image slice to each display image source 24. In particular, the image source 30 passes the signal through the housing 42 and through the electrical connector to the hub 40. Within the hub 40 electrical signals are passed by electrical leads 54 to individual display image sources 24. The image is transmitted to intermediate optics 26 where it is concentrated on the corresponding display screen.

Just before the display screen reaches the viewing position 44/48, the image is projected onto the display screen 28. At a minimum, the image is maintained throughout the entire time the display screen is visible through the viewing position 44/48. When the next image display 22 approaches the viewing position 44/48, it is also activated in a similar manner to display the corresponding image slice. This ordering is the responsibility of the controller 36, which not only controls which image display 22 receives but also controls the rotational speed of the frame 20.

This ordering for the individual image displays is specified in the timing diagram shown in FIG. The image display time (W) for each display image source 24 is a function of the minimum number of displays (N) and the time required for the frame to be fully rotated. And W ≦ T / N. While frame 20 rotates, the viewer views each slice of the image in an orderly manner. A complete series of three-dimensional image slices is presented for each complete rotation of the frame. The high speed of rotation of frame 20 visually matches the slices and the radial displacement of display screen 28 provides depth to the image. This combination provides a real three-dimensional image presentation to an observer located at position 44/48. While FIG. 4 specifies a dynamic display, if a static image is to be displayed, display 22 may be active throughout frame 20 rotation.

In an alternative form of three-dimensional stereoscopic display system as shown in FIG. 5, the sheet 56 is not used. For balancing purposes a series of counterweights (not shown) is mounted to the frame 20 to prevent shaking during rotation. This alternative approach has the advantage that the projected and concentrated image is not attenuated as it passes through the transparent sheet 56.

In a second alternative form of three-dimensional stereoscopic display system as shown in FIG. 6, display screen 28 and transparent portion 56 are formed of a single cylinder as opposed to a polyhedral polygonal structure. This alternative form has the advantage that the system can be easily balanced and also reduces the number of individual parts required to manufacture the system.

In a third alternative form of the three-dimensional stereoscopic display system as shown in FIG. 7, the display image screen 24 is mounted to the frame 20 at the point where the display screen 28 is normally positioned. This system has the additional advantage of eliminating the need for intermediate optics and display screens. However, in this form, the selection of the display image source 24 is important. As the display image source 24 moves further radially out, the centrifugal force experienced by the individual display image source 24 is greater. Therefore, a display, for example an LCD, may experience liquid flow of the display under rotation. In addition, balancing may be required to eliminate shaking during rotation.

In a fourth alternative form of a three-dimensional stereoscopic display system as shown in FIGS. 8 and 9, the frame 20 rotates in a horizontal form where the axis of rotation is vertical. In this form, several people can be arranged to view the same or different three-dimensional images around the system. And several people can be placed around the system to view completely different images, each of which is all three-dimensional.

Although the system of the present invention was initially described for the use of a single three-dimensional object in a display, the present invention is applicable to a variety of different display scenarios. For example, the system can be used for command and control applications such as for display and vessel traffic control, aircraft traffic control, computer assisted design and manufacturing, medical imaging, simulation and / or training appropriate for navigation.

Although the present invention has been described and illustrated by way of specific example, the present disclosure has been presented by way of example only, and one skilled in the art will recognize that many changes in the combination and arrangement of parts may exist without departing from the spirit and scope of the claimed invention. You will know.

Ship / aircraft traffic control, computer aided design and manufacturing, medical imaging.

Claims (10)

In a three-dimensional volumetric display system 19, Frame 20, A plurality of image displays 22 disposed around the frame with different radial distances from the center of the frame 20, An image source 30 that provides a two-dimensional image to the image display, A motor 32 for rotating the frame about the center of the frame, and A controller 36 for synchronizing the rotation of the motor with the display of the image so that an observer can see a sequence of the image that is given a depth and visually matched to provide a real three-dimensional image. Three-dimensional stereoscopic display system comprising a. The display apparatus of claim 1, wherein each of the image displays comprises: A display image source 24 disposed within the frame to receive and project the image; A display screen 28 disposed in the frame at a position radially further from the center of the frame than the position of the display image source, and Intermediate optics 26 disposed within the frame between the display image source and the display screen and focusing the image on the display screen. Three-dimensional stereoscopic display system comprising a. A vacuum conditioner as set forth in claim 1, wherein said frame is mounted in a housing (42) having a transparent surface (44) for viewing said image display, said housing having a vacuum to reduce air resistance to said rotating frame. Three-dimensional stereoscopic display system characterized in that for providing. The 3D stereoscopic display system according to claim 1, wherein the motor rotates in the frame by 60 Hz or more. In the method for providing a three-dimensional image, Rotating a frame 20, around which the plurality of image displays 22 having radially different distances from the center of the frame are arranged around the frame, Providing different two-dimensional sectional slices of a three-dimensional image to each of the image displays, Displaying each cross-sectional image slice on its corresponding image display while the frame is rotating, and Synchronizing the rotation of the motor with the display of the image so that an observer can see a given depth and visually matched sequence of images to provide a real three-dimensional image Method for providing a three-dimensional image comprising a. 6. The method of claim 5, further comprising displaying each of the cross-sectional image slices to the viewer in a sequential manner such that the viewer can recognize the three-dimensional image. The method of claim 5, wherein the displaying of the image display slice comprises: Providing the section image slice to an image source 30, and Projecting the cross-sectional image slice through intermediate optics 26, and Concentrating the projected image on a display screen 28 Method for providing a three-dimensional image comprising a. 6. The method of claim 5, wherein the cross-sectional image slice is displayed at a frequency of about 60 Hz or higher. 7. A method according to claim 6, wherein the cross-sectional image slice is displayed at one or more positions (44). The method of claim 5, wherein the cross-sectional image slice is provided by an image source.