GB2392546A

GB2392546A - Generation of a three dimensional video display

Info

Publication number: GB2392546A
Application number: GB0319132A
Authority: GB
Inventors: Rutger Forss; Jan-Ake Andersson
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-28
Filing date: 2003-08-14
Publication date: 2004-03-03
Anticipated expiration: 2023-08-14
Also published as: GB0319132D0; GB2392546B; SE0202541L; SE0202541D0; SE524855C2

Abstract

The present invention relates to an arrangement for three-dimensional video displays. The arrangement comprises two video cassette recorders 3, 3', which during use contains video tapes with identical display information. One of the video cassette recorders comprises a stereo base regulator 10 for lengthening the video tape path of one of the video tapes, such as to be able to vary the length of that video tape path. The stereo base regulator comprises one or more rollers 13, 14 , which during use are arranged on opposite sides of the video tape. The present invention further relates to a method for generation of a three-dimensional video display.

Description

1 2392546

GENERATION OF A THREE-DIMENSIONAL VIDEO DISPLAY

FIELD OF INVENTION

The present invention relates generally to three-dimensional video displays and particularly to three-dimensional video 5 displays recorded by the use of one video camera.

BACKGROUND

There are many known recording techniques that are utilized to get the possibility of three-dimensional video displays.

These techniques include special setups with separate 10 recordings for the left eye and the right eye, respectively.

However, such setups have a drawback in that they are complex and thus expensive.

It is further known that it is possible to obtain a three-

dimensional video display of a video recorded by only one 15 video camera. This may be obtained by electronically shifting a video signal to one eye parallel to the video signal to the other eye. Examples of such solutions are presented in JP 07-250349, SANYO ELECTRIC CO LTD, and JP 08-

256360, HITACHI DENSHI LTD, respectively. However, such 20 solutions have a drawback in that they need complex electronic control equipment and are thus expensive in design. SUMMARY OF THE INVENTION

An object of the present invention is to provide an 25 arrangement that overcomes the above-mentioned drawbacks.

This object, among others, is obtained by arrangements and methods as claimed in the appended claims.

With utilization of two identical video tapes run in two video cassette recorders, in parallel, started simultaneously, it is possible to increase the video tape path for one of the video tapes by means of a mechanical 5 device and thus being able increase or decrease the distance in time or tape run between the two video tapes having been started simultaneously. A simple solution is thus achieved to provide a three- dimensional display from a two-

dimensional recording, which solution also is rugged and 10 attainable with common video cassette recorders and a device for varying the stereo base according to the present invention. The fundamental principle for this conversion from 2D to 3D to be possible is that there exists a horizontal lateral 15 movement between the camera and the object/background being

depicted. The lateral speed may range from above zero and upwards. Preferably the lateral speed is as constant as possible, which facilitates the reproduction as variations in lateral speed give rise to a need of a varied stereo 20 base.

An arrangement according to the present invention is possible to utilize in areas such as underwater scanning in a midget submarine and infrared scanning from a helicopter.

It is also possible to utilize three-dimensional viewing of 25 other images than TV (video) images, such as infrared images, sonar images, and also cinema films.

Varying the stereo base easily changes the focus distance of a threedimensional video picture, displayed according to the present invention.

30 Further features and advantages of the present invention will be evident from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description of embodiments given below and the

accompanying figures, which are given by way of illustration 5 only, and thus, are not limitative of the present invention, wherein: Fig. 1 schematically illustrates the creation of two video cassette tapes containing identical information; Fig. 2 illustrates a schematic representation of a preferred 10 embodiment of the present invention; Fig. 3 illustrates a schematic representation of another method of displaying compared to Fig. 2; Fig. 4 illustrates a video cassette in a run position in a video cassette recorder; 15 Fig. 5 illustrates a stereo base regulator according to the present invention; Fig. 6 illustrates two modes of movements in connection with the stereo base regulator in Fig. 5; Fig. 7 illustrates two modes of movements, reverse those of 20 Fig. 6; Fig. 8 illustrates the stereo base regulator of Fig. 4 in a positioning position in area V in Fig 3; and Fig. 9 illustrates the stereo base regulator in Fig. 5 in a operating start position.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, for purpose of explanation and

not limitation, specific details are set forth, such as particular techniques and applications in order to provide a 5 thorough understanding of the present invention. However, it will be apparent for a person skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed description of well-known methods and apparatuses

10 are omitted so as not to obscure the description of the

present invention with unnecessary details.

Throughout this description a term "left image" will be used

to denote an image that is displayed to the left eye of a viewer. A term "right image" will be used to denote an image 15 that is displayed to the right eye of a viewer. A term "left video signal,' will be used to denote a signal to be displayed as a left image. A term "right video signal" will be used to denote a signal to be displayed as a right image.

A term "left printer" will be used to denote a printer for 20 printing pictures to be displayed to the left eye of a viewer. A term "right printer" will be used to denote a printer for printing pictures to be displayed to the right eye of a viewer.

A preferred embodiment of the present invention will now be 25 described with reference to the figures.

Fig. 1 schematically illustrates how one video tape of a video cassette 1 is copied to two video tapes of two video cassettes 2 and 2' thus containing identical information. It is further illustrated that recording of the information to 30 the video cassette 1 may be performed before copy, as denoted by ALT 2. The recording of information directly to

the two video cassettes 2 and 2' may alternatively be performed, as denoted by ALT 1. It is further possible to record according to both ALT 1 and ALT 2 simultaneously.

In Fig. 2 is an arrangement for generation of a three-

5 dimensional display schematically illustrated. A first video cassette recorder 3 contains a first video tape of the video cassette 2. A second video cassette recorder 3' contains a second video tape of the video cassette 2', containing identical information compared to the first video tape.

10 A video signal from the first video cassette recorder 3 goes through a selector 4 to a left image generator 5. The left image generator 5 displays the video signal from the first video cassette recorder to the left eye of a viewer. A video signal from the second video cassette recorder 3' also goes 15 through the selector 4 to a right image generator 6. The right image generator 6 displays the video signal from the second video cassette recorder to the right eye of the viewer. The means to obtain a three-dimensional display to the eyes 20 of a viewer may be obtained in a plurality of ways. The image generators may e.g. be two video projectors with different polarization of their respective displays. The two displays are superimposed on common area of a projection screen, as illustrated in Fig. 2. The viewer then uses 3D 25 glasses with corresponding polarization for his respective eyes. Another example of image generators may e.g. be utilization of virtual glasses to display the respective video signals directly to the respective eyes. Yet another example may e.g. be to utilize different color codes for the 30 respective eyes, instead of different polarizations. A further example may e.g. be to use two monitors combined

with a mirror stereoscope, to transform the displayed images JO a desirable size, as illustrated in Fig. 3.

A video tape 9 of the first video cassette 2 loaded into the video cassette recorder 3 (a regular VCR) is schematically 5 illustrated in Fig. 4. The video tape 9 is drawn out of the video cassette 2 by means of two guides 7 to bring the video tape 9 against the video head drum 8 and the audio sensor head. The video tape 9 during run travels from the left to the right in the figure. The area V is an area with ample 10 free space for a stereo base regulator according to the present invention. A stereo base regulator 10 as illustrated in Fig. 5 is positioned around the video tape 9 after that the video tape 9 of the video cassette 2 is loaded into run position in the video cassette recorder 3. The stereo base 15 regulator 10 is removed from around the video tape 9 before that the video tape 9 is unloaded, as illustrated in the right part of Fig. 7.

The stereo base regulator 10 comprises two rollers 13 and 14, to be positioned on opposite sides of the video tape 9.

20 It further comprises a rotation shaft 11, to vary the stereo base of a three-dimensional video display, and a plate 12 connecting the three parts 11, 13 and 14. The two rollers 13 and 14 are positioned symmetrically around the axis of rotation of the rotation shaft 11, and parallel to the 25 rotation shaft, as illustrated in the left part of Fig. 6, two get a possibility to achieve a linear conversion between turning of the rotation shaft 11 and varying of the stereo base of the three- dimensional video display, which will be explained in greater detail below.

30 In Fig. 8 the area V in Fig. 4 is blown up and illustrates the initial positions of the two rollers 13 and 14 on opposite sides of the video tape 9, which position

hereinafter is designated the positioning position. The rotation shaft 11 is then turned clockwise 180 degrees, as illustrated in the right part of Fig. 6, and the new position of the-stereo base regulator is illustrated in Fig. 5 9, which new position hereinafter is designated the operating start position. It is possible to instead turn the rotation shaft 11 counter clockwise 180 degrees. A difference is that the counter clockwise operating start position may give a higher friction against the audio sensor 10 of the video cassette recorder (at least in some types of video cassette recorders) than that of the clockwise operating start position. On the other hand the clockwise start position may give poorer sound than that of the counter clockwise start position, due to poorer contact 15 against the audio sensor in maximum direction of the stereo base regulator.

The friction clutch between the left storage wheel of a the video cassette and the recorder drive system has less braking effect than the clutch between the right drive wheel 20 of a video cassette and the recorder drive system, which makes it possible to attain the desired increased video tape path in a controlled way.

The second video cassette recorder 3' is a regular video cassette recorder without any stereo base regulator.

25 Preferably, both video cassette recorders 3 and 3' are identical regular video cassette recorders, apart from that the first video cassette recorder 3 comprises the additional stereo base regulator 10.

In an alternative embodiment of the present invention the 30 stereo base regulator has two or more rollers positioned non-symmetrically relative to the axis of rotation of the stereo base regulator. An advantage with the preferred

embodiment of the present invention is that with symmetrically positioned rollers the varying or the stereo base is essentially linear. With the rollers 13 and 14 symmetrically positioned on opposite sides of the video tape 5 9 and positioned in the start position an essentially linear conversion between the turning of the rotation shaft 11 and the stereo base of the three-dimensional video display is achieved up to +90 degrees, from the operating start position. 10 In another alternative embodiment of the present invention the stereo base regulator has four or more rollers positioned symmetrically relative to the axis of rotation of the stereo base regulator. The difference to the preferred embodiment of the present invention is that a greater 15 difference between the video tape paths of the video cassette recorders are achieved, and thus a greater possibility of varying the stereo base.

In yet another alternative embodiment of the present invention the stereo base regulator has only one roller 20 positioned on one side of the video tape, preferably on the outside of the video tape, i.e. on the same side as the audio sensor. In this embodiment the roller may instead of being positioned around a rotating axis be positioned on a linear or curved track that deflects and changes the video 25 tape path more or less perpendicular to the video tape. An advantage compared to the preferred embodiment is that the stereo base regulator may be kept in the operating start position during loading and unloading of the video cassette and video tape without vertical transitions. A disadvantage 30 compared to the preferred embodiment is that a much smaller difference between the video tape paths of the video

cassette recorders are achieved, and thus a smaller possibility of varying the stereo base.

A method of operating the arrangement for generation of a threedimensional display will next be described.

5 A 2D-video recorded in a conventional way by means of one video camera is copied to two identical video tapes. The two identical video tapes are loaded into the two identical video cassette recorders 3 and 3'. The first video cassette recorder 3 is equipped with the stereo base regulator 10.

10 The stereo base regulator 10 is lowered into the positioning position on opposite sides of the video tape 9 after that the video tape 9 is brought into run position by the guides 7, as illustrated in the left part of Fig. 6. The stereo base regulator 10 is then turned clockwise 180 degrees to be 15 positioned in the operating start position, to lengthen the video tape path, as illustrated in the right part of Fig. 6.

Thus, the video tape of the first video cassette recorder 3 is displaced a number of frames relatively to the video tape loaded into run position in the second video cassette 20 recorder 3'. Thereafter the video tape of the second video cassette is synchronized in tape position, such that identical frames are displayed simultaneously for the left and right eyes of the viewer. Identical frames refer to frames with the same time stamp (the same frame number).

25 With a diameter of 6 mm of the rollers 13 and 14, a center to-center distance of 10 mm between the rollers 13 and 14, and the rollers 13 and 14 in the operating start position the left video signal has a lead of approximately 25 frames compared to the right video signal, before the second video 30 tape is synchronized.

To position the stereo base regulator around the video tape 9 it may be moved along its axis of rotation (i.e. from above and downwards). Alternatively the stereo base regulator 10 may be rotated from a horizontal position to a 5 vertical position to be positioned around the video tape 9.

It is further possible to arrange parts of the stereo base regulator 10, such as one of the rollers 13 or 14, movable relatively to the other parts such as to provide a clear path for the video tape 9 to be loaded into the video 10 cassette recorder 3. However, the more straightforward a chosen solution is the more rugged the solution is.

Firstly we assume that a recorded object/background has a

component moving laterally to the right in an image display, equivalent to that the camera moves to the left. Both video 15 cassette recorders 3 and 3' are started simultaneously, preferably by means of a common control unit, such as a remote control that may control both video cassette recorders by means of common buttons. The first video cassette recorder 3 transmits a left video signal through 20 the selector 4 to the left image generator 5 for display to the left eye of the viewer. The second video cassette recorder 3' transmits a right video signal through the selector 4 to the right image generator 6 for display to the right eye of the viewer. Together the left and right video 25 signals now display a three-dimensional picture to the viewer. The left video signal will now, due to the stereo base regulator 10 being turned clockwise, be advanced some frames, during tape run, relatively to the right video 30 signal. The number of frames to advance the left video signal is chosen in dependence on the desired focus depth and the stereo base, which will be further described below.

To increase the focus depth of the displayed picture the rotation shaft 11 of the stereo base regulator 10 is turned counter clockwise and to decrease the focus depth the rotation shaft 11 is turned clockwise. It is only possible 5 to turn the stereo base regulator 10 90 degrees clockwise from the operating start position, since thereafter the video tape 9 will brush against itself and thus decelerate itself. It is further only possible to turn the stereo base regulator 10 90 degrees counter clockwise, from the 10 operating start position, since thereafter the rollers 13 and 14 will not touch the video tape 9 and it is thus not possible to vary the video tape path any longer.

The stereo base is varied in dependence on the lateral movement speed of the scenery displayed on the video 15 picture. With a lateral movement to the right the left eye of the viewer should be displayed the left video signal and with a movement to the left of the scenery the right eye of the viewer should be displayed the left video signal. With an increased lateral movement of the scenery the stereo base 20 is increased and with a decreased lateral movement of the scenery the stereo base is decreased. When the lateral movement direction is reversed the selector 4 is switched such that the displays to the eyes of the viewer are interchanged, thus switching the first video cassette 25 recorder 3 to the right image generator 6 and the second video cassette recorder 3' to the left image generator 5.

Further, objects on different depth distances in the three-

dimensional display require different stereo base adjustment, as explained above. Thus the operator may choose 30 the focus depth of the three-dimensional display by turning the stereo base regulator.

12 Before the unloading of the video cassette is performed the stereo base regulator 10 is turned back to its positioning position, as illustrated in the right part of Fig. 7.

Thereafter the stereo base regulator 10 is raised form the 5 positioning position, as illustrated in the left part of Fig. 7, such as to allow the guides 7 to move freely during unloading of the cassette.

With the above-described setup for a three-dimensional video display it is possible to provide a utility for achieving 10 three-dimensional snapshots of the recording. With a left eye frame grabber in a left printer connected at the left image generator 5 and a right eye frame grabber in a right printer connected at the right image generator 6 a control signal simultaneously to the two printers provide two 15 pictures; one for the left eye of the viewer and the other for the right eye of a viewer. The pictures may then be viewed in a conventional way to experience the 3D effect.

Without consideration to the setup of the present invention it is possible to provide one or more printers including 20 frame grabbers directly in connection with a video camera during recording, where a first image is printed for a first eye of a viewer and some frames later a second image is printed for the other eye of the viewer. This may be obtained during real time video camera operation, but there 25 will be a time delay command for the printer(s) to print the Images. It will be obvious that the present invention may be varied in a plurality of ways. Such variations are not to be regarded as departure from the scope of the present 30 invention. All such variations as would be obvious for a person skilled in the art are intended to be included within the scope of the present invention.

One example of a variation obvious for a person skilled in the art is that recording by means of one video camera is equivalent to recording by means of any other type of camera and thereafter converting the recording to a video tape.

5 Another example of a variation obvious for a person skilled in the art is that the rotation shaft described above may be turned by hand or by a servo actuator controlled by e.g. a remote control.

Claims

1. An arrangement for generation of a three-dimensional video display, said arrangement comprising a first (3) and a second (3') video cassette recorder, wherein 5 - said first video cassette recorder comprises a compartment for receiving a first video cassette (2) and a first drum (8) for reading video signals to be displayed to a first eye of a viewer; said second video cassette recorder comprises a 10 compartment for receiving a second video cassette and a second drum for reading video signals to be displayed to the other eye of the viewer; and À said arrangement being c h ar ac t e r i z e d i n that said first video cassette recorder comprises a stereo base 15 regulator (10) for increasing the video tape path of a video tape (9) of said first video cassette, which first video cassette during operation is arranged in said first video cassette recorder, wherein said stereo base regulator comprises at least two rollers (13, 14), which rollers 20 during operation are arranged on opposite sides of said video tape and being movable such as to vary the length of the video tape path.

2. The arrangement as claimed in claim 1, comprising a selector (4) arranged to receive the video signals from said 25 first and said second video cassette recorders and to display the video signals to the respective eyes of the viewer.

3. The arrangement as claimed in claim 2, wherein said selector is controllable to interchange the display between the eyes of the viewer.

4. The arrangement as claimed in any of claims 1-3, wherein 5 said at least two rollers are positioned symmetrically on opposite sides of an axis of rotation of said stereo base regulator and parallel to said rotation axis, and on which axis of rotation a rotation shaft (11) is arranged.

5. The arrangement as claimed in any of claims 1-4, wherein 10 said first and second video cassettes contain video tapes with identical information to be displayed as said three-

dimensional video display.

6. The arrangement as claimed in any of claims 1-5, comprising: 15 - a first frame grabber in a first printer connected at a left image generator (5) that display said video signals to be displayed to the left eye of the viewer; - a second frame grabber in a second printer connected at a right image generator (6) that display said video signals to 20 be displayed to the right eye of the viewer; and - a control unit that simultaneously activates said first and second printers.

7. The arrangement as claimed in any of claims 1-6, comprising a control device that may control said first and 25 said second video cassette recorders simultaneously.

8. A method for generation of a three-dimensional video display, wherein said method is c h ar ac t e r i z e d b y the following steps:

- displaying a first video signal from a video tape of a first video cassette to the left eye of a viewer; - displaying a second video signal from a video tape of a second video cassette to the right eye of the viewer, 5 wherein said second video cassette contains the same information as said first video cassette; - lengthening the video tape path of said first video cassette, - synchronizing said second video signal with said first 10 video signal; and - varying said video tape path depending on lateral movement speed of said three-dimensional display.

9. The method as claimed in claim 8, wherein said first video signal is changed to be displayed to said right eye 15 and said second video signal is changed to be displayed to said left eye depending on a change of lateral movement direction of said three-dimensional display.

10. The method as claimed in claim 8 or 9, comprising the following steps: 20 - grabbing a left frame of said first video signal displayed to said left eye of the viewer; - grabbing a right frame of said second video signal displayed to said right eye of the viewer simultaneously with said grabbing a left frame; and 25 - printing said left and right frames, to produce a three-

dimensional snapshot picture of said three-dimensional display.

11. An arrangement for generation of a three-dimensional video display, said arrangement comprising a first (3) and a second (3') video cassette recorder, wherein - said first video cassette recorder comprises a compartment 5 for receiving a first video cassette (2) and a first drum (8) for reading video signals to be displayed to a first eye of a viewer; - said second video cassette recorder comprises a compartment for receiving a second video cassette and a 10 second drum for reading video signals to be displayed to the other eye of the viewer; and - said arrangement being c h a r a c t e r i z e d i n that said first video cassette recorder comprises a stereo base regulator (10) for increasing the video tape path of a video 15 tape (9) of said first video cassette, which first video cassette during operation is arranged in said first video cassette recorder, wherein said stereo base regulator comprises one roller, which roller during operation is arranged on one side of said video tape and being movable, 20 preferably generally perpendicularly to the video tape, such as to vary the length of the video tape path.