3D-VIEWING

Abstract: In a 3D-viewing method, two different images (IM1, IM2) are alternately displayed on a screen (SCR). Each of the two different images (IM1, IM2) is passed to a viewer's right eye (RE) or a viewer's left eye (LE), respectively. In order to allow a wide variety of applications, there is provided, on the screen (SCR), an indication (IND) as to which eye an image should be passed.

Description: 3D-VIEWING The invention relates to a method and a system for three-dimensional (3D) viewing in which two different images are alternately displayed on a screen, and in which each of the two different images is passed to a viewer's left eye or to a viewer's right eye, respectively. The invention also relates to a pair of 3D-viewing glasses, a video signal for alternately displaying two different images on a screen, and an information carrier on which such a signal has been stored. The miro 3D Games Set is a prior-art system for 3D-viewing which is intended for personal computers (PCs). It comprises a graphics board and a pair of 3D shutter glasses, using liquid crystal display (LCD) technology. The graphics board includes a high-speed graphics accelerator and drivers for Windows 95. The 3D shutter glasses are provided with a connection cable, a VGA adapter plug, and a driver disk. In the prior-art system, two different images are displayed on a monitor as alternating frames and together these form the 3D image. The lenses of the glasses, which are controlled by a graphics board in the PC, are switched from a transparent to an opaque state and back again for each image. This happens too quickly to be perceived by the eye, depending on the refresh rate of the image displayed. Thus, the person wearing the glasses perceives, the images as a single, 3D image. The invention seeks, inter alia, to provide 3D-viewing which, with respect to the prior art, is better suited for a wide variety of applications. Claims 1 and 4 define a 3D-viewing method and system, respectively, in accordance with the invention. Claims 7, 8 and 9 define a pair of 3D- viewing glasses, a video signal, and an information carrier respectively in accordance with the invention. Additional features, which may be optionally used to implement the invention to advantage, are defined in the dependent claims. The invention takes the following aspects into consideration. The prior-art system can only be used if certain conditions are met. First of all, a device in the form of a PC is required in which the graphics board can be fitted. Moreover, the PC must be able to co-operate with the graphics board. To this end, it must work under one of the operating systems, for example Windows 95, for which the graphics board has been designed. In accordance with the invention, there is provided, on the screen, an indication as which eye an image should be passed. For example, a pair of 3D-viewing glasses, may use this indication for passing each of the two different images, which are alternately displayed on the screen, to a viewer's left eye or to a viewer's right eye, respectively. Consequently, there is no need for any specific graphics board in order to control the pair of 3D-viewing glasses. The invention may be used in any application as long as there is a screen and suitable hardware and software for alternately displaying two different images on the screen. In principle, it does not matter on what basis the hardware and software operate. For example, the invention may be used, without great difficulty, in PC applications as well as in dedicated game machine applications, whereas the prior-art system is ill-suited for these purposes. Thus, 3D-viewing in accordance with the invention allows a wide range of applications. The invention and additional features, which may optionally be used to implement the invention to advantage, are apparent from and will be elucidated with reference to the drawings described hereinafter. In the drawings, Fig. 1 is a conceptual diagram illustrating basic features of the invention; Figs. 2 and 3 are conceptual diagrams illustrating additional features which may be optionally used to implement the invention to advantage; Fig. 4 is an abstract diagram illustrating an example of a 3D-viewing system in accordance with the invention; Figs. 5a to 5e are diagrams illustrating a mode of operation of the Fig. 4 3D-viewing system, which mode includes the Figs. 2 and 3 additional features; and Fig. 6 is a block diagram of an example of a shutter controller in the Fig. 4 3D-viewing system. First, some remarks will be made on the use of reference signs. Similar entities are denoted by an identical lettercode throughout the drawings. In a single drawing, various similar entities may be shown. In that case, a numeral is added to the lettercode, to distinguish similar entities from each other. The numeral will be between parentheses if the number of similar entities is a running parameter. In the description and the claims, any numeral in a reference sign may be omitted if this is appropriate. Fig. 1 illustrates basic features of the invention. A basic feature is that two different images IMl and IM2 are alternately displayed on a screen SCR. In Fig. 1, two different situations SI and S2 are depicted. In situation SI, an image IMl is displayed on the screen SCR whereas, in situation S2, an image IM2 is displayed on the screen SCR. With time, situations SI and S2 repetitively succeed one another, which may be expressed as: Sl- S2-S1-S2-S1-S2..., and is illustrated by means of two arrows pointing in opposite directions between the situations SI and S2. It should be noted that the images IMl and IM2 need not be static. That is, the images IMl and IM2 may be formed by respective sequences of pictures for the purpose of showing motion. Fig. 1 also illustrates the following basic feature. Each of the two different images IMl and IM2 is passed to a viewer's left eye LE or a viewer's right eye RE, respectively. In Fig. 1, this is illustrated by means of an arrow pointing away from the screen SCR and towards the relevant viewer's eye LE or RE. In situation SI, the image IMl is displayed on the screen SCR and passed to the viewer' left eye LE, whereas, in situation S2, the image IMl is displayed on the screen and passed to the viewer's right eye RE. Fig. 1 also illustrates the following basic feature. There is provided, on the screen SCR, an indication IND as to which eye, LE or RE, the image IMl or IM2 should be passed. In Fig. 1, this is illustrated in a way as if the indicator were a comic figure saying a text which refers to the relevant eye and is followed by an exclamation mark. Fig. 2 illustrates the following additional feature. The indication IND is in the form of two different spots SP1 and SP2 which are alternately displayed on the screen SCR. Fig. 2 depicts two situations SI and S2 which correspond to those in Fig. 1. In situation SI, the spot SP1 is displayed to indicate, for example, that the image IMl should be passed to the viewer's left eye LE as illustrated in Fig. 1. In situation S2, the spot S2 is displayed to indicate, for example, that the image IMl should be passed to the viewer's right eye RE as illustrated in Fig. 1. In Fig. 2, the spot SP1 or SP2 which is not displayed in situation S2 or SI, respectively, is shown in broken lines. If the Fig. 2 feature is applied, two opto-electric transducers may be used, for example, one to detect the spot SP1 and the other to detect the spot SP2. The two opto- electric transducers will provide electric signals which directly indicate as to which viewer's eye an image should be passed. Therefore, any control circuitry for controlling which viewer's eye an image is passed to, may be relative simple. Thus, the Fig. 2 feature contributes to cost efficiency. Fig. 3 illustrates the following additional features. The two different images IMl and IM2 are displayed as alternating frames FR1 and FR2, respectively, formed by a plurality of lines L(1)..L(X) which are sequentially written on the screen SCR. The indication IND is provided in at least one of the last lines of a frame. Fig. 3 depicts two situations SI and S2 which correspond to those in Fig. 1. Line L(l) represents the first line of the frames FR1 and FR2, and L(X) represents the last line. If the Fig. 3 feature is applied and, for example, an opto-electric transducer is used to convert the indication IND into an electric signal, the electric signal will comprise one or more pulses. These pulses will occur a relatively short time before the start of a new frame and, consequently, therefore, a relatively short time before the display of a new image which should be passed to the other eye. Consequently, any control circuitry for controlling which viewer's eye an image is passed to, may be relatively simple because it needs to bridge a relatively small time-gap only between the pulses and the start of a new image. Thus, the Fig. 3 feature contributes to cost efficiency. Fig. 4 illustrates an example of a 3D-viewing system in accordance with the invention. The Fig. 4 3D-viewing system comprises three main elements: an information- processing assembly IPA, a picture display device PDD and a pair of 3D-viewing glasses GLS be worn by a viewer VWR who is also shown in Fig. 4. In more detail, the information-processing assembly IPA comprises a read-out unit ROU for retrieving 3D-video information which is stored on an information carrier ICR, and a video-processing circuit VPC for providing the 3D-video information to the picture display device PDD in a suitable form. The picture display device PDD includes a screen SCR on which the 3D-video information is displayed. The pair of 3D-viewing glasses GLS comprises two controllable shutters SHI and SH2 in front of the viewer's left eye LE and the viewer's right eye RE, respectively, and a shutter controller CON for controlling the two controllable shutters. It also comprises an opto-electric transducer arrangement OET which is attached to the screen SCR by means of a suction cup SUC. A connection cable CC provides an electrical connection between the opto-electric transducer arrangement OET and the shutter controller CON. The Fig. 4 3D-viewing system may operate in accordance with a method incorporating the Figs. 2 and 3 features. That is, two different images are displayed on the screen SCR as alternating frames formed by a plurality of lines which are sequentially written, as illustrated in Fig. 3. On the screen SCR, an indication as to which eye, LE or RE, an image should be passed is provided in at least one of the lines of the frames, as also illustrated in Fig. 3. The indication is in the form of alternately displaying two different spots, as illustrated in Fig. 2. Accordingly, the opto-electric transducer arrangement OET, shown in Fig.4, may comprise two opto-electric transducer sections, one section for each of the two spots displayed on the screen SCR. An opto-electric transducer section may comprise, for example, an opto-electric transducer of the type BPW 34 produced by Philips, or of the type PPC-12S produced by Photonic Power systems. The latter type can provide a relatively high output voltage which may also be obtained, for example, by coupling a plurality of opto-electric transducers of the former type in series. It is to be noticed that the indicator to which edge the information concerned has to be sent can be accomplished in several ways. For example, is it also possible to display on the screen a light intensity variation according to a known pattern. In that case it is possible that the light sensor does not need to be placed on the screen. So, a wireless solution is possible and the light sensor can be part of the 3D-glasses. Figs. 5a to 5e further illustrate the operation of the Fig. 4 3D-viewing system in accordance with the above-described method. Figs. 5a to 5e are diagrams which have corresponding horizontal time (t) axes. Fig. 5a illustrates a signal Srgb which with, reference to Fig. 4, is received by the picture display device PDD from the video-processing circuit VPC on the basis of the 3D-information retrieved from the information carrier ICR. Figs. 5b and 5c illustrate a signal Stl and a signal St2, respectively, supplied by the two opto-electric transducer sections mentioned hereinbefore. Figs. 5d and 5e illustrate whether the two controllable shutters SHI and SH2, shown in Fig. 4, are transparent TRP or opaque OPQ at a certain point of time. In more detail, Fig. 5a illustrates the signal Srgb at a transition between frames FR(N-l) and FR(N) and at a transition between frames FR(N) and FR(N + 1). Each frame comprises a plurality of successive active line components LC(1),..LC(X-1),LC(X). There is a time gap ΔTl between two successive active line components of a frame, and there is a time-gap ΔTf between the last active line component of a frame and the first active line component of a successive frame. The last two active line components LC(X-l) and LC(X) of the frame FR(N-l) comprise left-indication components LIC, and the last two active line components LC(X-l) and LC(X) of frame FR(N) comprise right-indication components RIC. In response to the left- indication components LIC and the right- indication components RIC, the picture display device PDD provides an indication, on the screen SCR, that the image formed by the frame FR(N) should be passed to the viewer's left eye LE and that the image formed by the frame FR(N-t- l) should be passed to the viewer's right eye RE, respectively. Figs. 5b and 5c illustrate that pulses P occur in the signals Stl and St2 as a result of the left- indication components LIC and the right- indication-components RIC, respectively shown in Fig. 5a. Thus, the pulses P in the signal Stl indicate to the shutter controller CON, shown in Fig. 4, that a new image formed by the frame FR(N) will be displayed shortly, and that it should be passed to the viewer's left eye LE. Likewise, the pulses P in the signal St2 indicate to the shutter controller CON that a new image formed by the frame FR(N+ 1) will be displayed shortly, and that it should be passed to the viewer's right eye RE. Figs. 5d and 5e illustrate that the controllable shutter SHI in front of the viewer's left eye LE is opaque OPQ during the frame FR(N-l), and that the controllable shutter SH2 in front of the viewer's right eye RE is transparent TRP. In response to the pulses P in the signal Stl shown in Fig. 5b, the shutter controller CON, shown in Fig. 4, switches the controllable shutter SHI from the opaque state OPQ to the transparent state TRP, and the controllable shutter SH2 from the transparent state TRP to the opaque state OPQ. The shutter controller CON ensures that the two controllable shutter SHI and SH2 are transparent TRP and opaque OPQ, respectively, during the frame FR(N). As a result, the image which is formed by the frame FR(N) will be passed to the viewer's left eye LE. In response to the pulses P in the signal St2 shown in Fig. 5c, the shutter controller CON switches the two controllable shutters SHI and SH2 back to the opaque OPQ and transparent states TRP, respectively. Consequently, the image which is formed by the frame FR(N + 1) will be passed to the viewer's right eye RE, which was also the case for the frame FR(N-l). The shutter controller CON, shown in Fig.4, may be implemented in numerous different ways, depending on, for example, the type of controllable shutters used. The two controllable shutters SHI and SH2, shown in Fig. 4, may comprise, for example, liquid crystal display (LCD) devices. An LCD device can be switched to the transparent or opaque state, depending on whether a voltage is applied or not applied to it. The polarity of the voltage should be changed regularly to prevent the LCD device from receiving an average non-zero voltage which could cause malfunctioning of the LCD device. Thus, a controllable shutter op het LCD type is preferably rendered alternately transparent and opaque by means of AC signal bursts. Fig. 6 shows an example of a shutter controller which is suitable for use in the Fig. 4 3D-viewing system operating as described hereinbefore, using controllable shutters of the LCD type. The Fig. 6 shutter controller supplies two shutter control signals Sshl and Ssh2 to the two controllable shutters SHI and SH2, respectively, in response to the signals Stl and St2 which are illustrated in Figs. 5b and 5c, respectively. The Fig. 6 shutter controller comprises an energy source ENS, which may be for example a battery, a switching circuit SWC and two DC- AC converters DACl and DAC2. The Fig. 6 shutter controller operates as follows. If pulses P occur in the signal Stl, as illustrated in Fig. 5b, the switching arrangement SWC will connect the energy source ENS to the DC-AC converter DACl and, consequently, disconnect the energy source ENS from the DC-AC converter DAC2. If, however, pulses P occur in the signal St2, the switching arrangement SWC will do the opposite. As a result, the shutter control signals Sshl and Ssh2 will alternately comprise AC signal bursts provided by the two DC-AC converters DACl and DAC2, respectively. The AC signal bursts in the shutter control signals Sshl and Ssh2 should preferably coincide with the frames which are displayed on the screen. To achieve this, the switching circuitry SWC may comprise, for example, timing circuitry. This timing circuitry may effectively delay a switching of the energy source ENS, shown in Fig. 6, with respect to the occurrence of pulses P in the signals Stl and St2, shown in Figs. 5b and 5c, such that the two controllable shutters SHI and SH2 are switched from the opaque to the transparent state, or vice versa, as illustrated in Figs. 5d and 5e, in the time-gap ΔTf shown in Fig. 5a. The drawings and their description hereinbefore illustrate rather than limit the invention. It will be evident that there are numerous alternatives which fall within the scope of the appended Claims. In this respect, the following closing remarks are made. There are numerous ways of physically spreading functions or functional elements over various units. In this respect, the drawings are very diagrammatic and represent only one possible embodiment of the invention. As an example, the information- processing assembly IPA and the picture display device PDD, both shown in Fig. 4, may be integrated into one unit so as to form, for example, a game computer. In that case, the information carrier ICR, also shown in Fig. 4, on which a 3D-video game may be stored, may be in the form of a cartridge which can be plugged into the game computer. As another example, the shutter controller CON, shown in Fig. 4, may be combined with the opto- electric transducer arrangement OET so as to form one unit. Any technique may be used to display the two different images IMl and IM2. The picture display device PDD in the Fig. 4 3D-viewing system may comprise, for example, a picture tube, an LCD display, a plasma display, or a projector. Any type of visual information may be provided by the two different images IMl and IM2. For example, the two different images IMl and IM2 may represent a still picture. The two different images IMl and IM2 may also represent a motion picture. In that case, each of the two different images IMl and IM2 will be formed by a sequence of pictures which are successively displayed on the screen SCR. Any form of visual representation may be used for the purpose of indicating as to which viewer's eye an image should be passed. For example, the indication IND illustrated in Fig. 1 may be provided in the form of a blinking bar. The blinking bar may cause a relatively large variation in light intensity. In that case, an opto-electric transducer, which is relatively distant from the screen, may be able to provide suitable shutter control signals. Referring to Fig. 4, this may allow the opto-electric transducer arrangement OET to be placed near the controllable shutters SHI and SH2, thereby dispensing with the connection cable CC. Accordingly, a wireless pair of 3D-viewing glasses may be obtained. It goes without saying that the opto-electric transducer arrangement OET may supply one or more electric output signals which are different from the signals Stl and St2 shown in Figs. 5b and 5c, depending on, for example, the type of display device, the form of the indication, and/or the type of opto-electric transducer used. The term shutter should be broadly construed so as to include any type of device which is capable of preventing a viewer's eye from perceiving an image. Scattering shutters may be used, for example, in the pair of 3D-viewing glasses GLS shown in Fig. 4. In that case, the light coming from the screen SCR will not be blocked, but will rather be diffused in order to prevent an image from being passed to the relevant viewer's eye LE or RE. Scattering shutters have certain advantages in terms of cost, robustness, and longevity. They may also be more pleasant to the user, because the light from the screen reaches his eyes in a substantially uninterrupted manner. Any source of energy may be used for controlling the controllable shutters SHI and SH2 shown in Fig. 4. For example, energy may be obtained from the opto-electric transducer arrangement OET. A resonant circuit may be used, for example, to convert an electric signal supplied by the opto-electric transducer arrangement OET into suitable shutter control signals, without the use of any battery or other form of DC voltage supply. Alternatively, rectifier circuitry may be used for converting the electric signal supplied by the opto-electric transducer arrangement OET, into a suitable DC supply voltage. This DC supply voltage may then be used, for example, to power DC-AC converters like the DC-AC converters DACl and DAC2 in the Fig. 6 shutter controller. Energy may be alternatively obtained from the electro-magnetic stray field of a picture display device of the electron-tube type. To this end, a pick-up coil may be included in a pair of 3D-viewing glasses to obtain an induced signal, as well as circuitry for deriving a suitable DC supply voltage from the induced signal. The induced signal may also be suitably processed for the purpose of controlling shutters. Any reference signs between parentheses shall not be construed as limiting the Claim concerned.

Claims: Claims: 1. A method of three-dimensional viewing, comprising the steps of: alternately displaying two different images (IM1,IM2) on a screen (SCR); and passing each of the two different images (IM1,IM2) to a viewer's left eye (LE) or a viewer's right eye (RE), respectively, characterized in that the method comprises the step of providing, on the screen (SCR), an indication (IND) as to which eye an image should be passed. 2. A method as claimed in Claim 1, characterized in that it comprises the step of providing the indication in the form of alternately displaying two different spots (SP1.SP2). 3. A method as claimed in Claim 1, characterized in that it comprises the steps of: displaying the two different images as alternating frames (FR1,FR2) formed by a plurality of lines (L(1)..L(X)) which are sequentially written; and providing the indication (IND) in at least one of the last lines of a frame. 4. A system of three-dimensional viewing, comprising: means (IPA, PDD) for alternately displaying two different images (IM1,IM2) on a screen (SCR); and means (GLS) for passing each of the two different images (IM1,IM2) to a viewer's left eye (LE) or a viewer's right eye (RE), respectively, characterized in that the system comprises means (ICR) for providing, on the screen, an indication as to which eye an image should be passed. 5. A pair of three-dimensional viewing glasses comprising two controllable shutters (SH1,SH2), one for a viewer's left eye (LE) and one for a viewer's right eye (RE), characterized in that the pair of three-dimensional viewing glasses comprises an opto-electric transducer arrangement (OET) for supplying control signals to the controllable shutters (SH1.SH2). 6. A pair of three-dimensional viewing glasses as claimed in Claim 5, characterized in that it comprises means (SUC) for attaching the opto-electric transducer arrangement (OET) to a screen (SCR). 7. A pair of three-dimensional viewing glasses as claimed in Claim 6, characterized in that the attaching means (SUC) include a suction cup. 8. A video signal (Srgb) for alternately displaying two different images (IM1,IM2) on a screen (SCR), characterized in that the video signal (Srgb) includes one or more components (LIC, RIC) for providing an indication (IND) on the screen (SCR) for distinguishing the two different images (IM1 M2). 9. An information carrier (ICR) on which a video signal as claimed in Claim 8 has been stored.

Inventors: DRAAIJER MAURICE HERMAN JOHAN, DRAAIJER, MAURICE, HERMAN, JOHAN
Applicants: KONINKL PHILIPS ELECTRONICS NV, LMILIPS NORDEN AB, KONINKLIJKE PHILIPS ELECTRONICS N.V.
Application year: 1998
Main classification: H04N13
IPC codes: G02B27, H04N13