GB2131645A - Television network and receivers - Google Patents

Abstract

In a television transmission network, the information within the transmitted line signals is time- multiplexed and the line signals are in a format for displaying a three- dimensional image. Thus chrominance signals (U or V) in each of the two lines A and B is split into two equal parts ULA and URA (or VLB and VRB) corresponding to the chrominance information for an image L (left) or R (right). The luminance signal in each line is likewise split into two parts LLA and LRA (or LLB and LRB) for images L and R respectively. These two images are then used to produce a three-dimensional image. <IMAGE>

Description

SPECIFICATION Television network and receiver The present invention relates to a television transmission network and to a television receiver for use with such a network.

The present invention provides a television transmission. network in which the information within the transmitted line signals is time-multiplexed and the line signals are in a format for displaying athree- dimensional image.

in one form, the present invention provides a television transmission network in which a line of the transmitted video information has time-multiplexed chrominance and luminance signals for two separate pictures to thereby provide a three-dimensional image.

Preferably, the chrominance and luminance signals in a line are each divided into two portions, each portion being the relevant information for one of two pictures to form the three-dimensional image.

The transmitted signals may include information identifying thattheirformat allows three-dimensional display; preferably this identification information is a modification of the field synchronising information.

The present invention further includes apparatus for generating signals suitable for use in such a network, a transmitterfortransmission of these signals, and a television receiver for receiving, processing and displaying these signals.

A network according to the present invention may involve the transmission of television signals along cable transmission lines and/or by broadcasting (whether by satellite or otherwise).

In orderthatthe invention may more readily by understood, a description is now given, by way of example only, reference being made to the accompanying drawings, in which: Figure lisa schematic diagram ofthe video information in two successive scanning lines of a signal used in a network embodying the present invention; and Figure 2 is a block diagram of the switching and storage circuits used in a television receiver for use in a network embodying the present invention.

In this specific description of a network embodying the presentinvention,thevideosignalsare in the time-multiplexed format recently proposed by the Independent Broadcasting Authority (and having the name the Multiplexed Analogoue Component (MAC) system), wherebythe chrominance component of information within each line is separated in time from the luminance component.Thus, taking a line of 64 secsofvideo information in the correct sequence of transmission, there is an initial line sone word and a clamping period, then a chrominance signal of 20u secs duration containing all the necessary colour informationforthat line; therefollowsanother clamping period, succeeded by a luminance signal of 40secscontaining all the necessary brightness (or contrast) information forthat line and terminated by another line sync word. Each television receiver has an information store into which the lines of information are put as they are received and a processor to take out each line, when required, from the store.

As the chrominance signal in each line is a colour-difference component (U orV), it must be present on the successive line.

The distinction of the signals ofthe present invention overthe standard MAC signals is clearly illustrated in Figure 2 which shows that the chromi- nace signals (U orV) in each ofthe two lines and B is split into two equal parts ULA and URA (orVLs and VRB) corresponding to the chrominance information for a picture L (left) or R (right) to be displayed; the luminance signal in each line is likewise split into two parts LLA and LRA (or LLB and LRB) for use in producing the pictures Land R respectively. These two pictures can then be used in a conventional way, e.g. by viewing through spectacles with polarised lenses, to produce a three-dimensional image.

Taking nowthetime durations shown in Figure lit is evident from the above description that

The switching circuits and stores of a television receiver able to process the signals suitably are shown in Figure 2. Video signals broadcast from a transmission station operating on the MAC system are received at aerial A and are passed to a switch S1 which can selectively direct them to one of eight memory stores LRA, LONE, LLA, LLB, URA, ULA, VRB, VLB as required.Clearly, in orderto ensurethateach part of the signal of Figure 1 is received atthe approprate memory store, switch S1 starts a two-line period in the position as shown, i.e. it contacts with terminal 1; after a time interval t3, switch S1 moves to terminal 2 fort4 secs, thereafter to terminal 3 fort5 secs, and so on.Each ofthe stores URA, ULA, VRB and VLB have two outputs, one for signals to be immediately (i.e. during the same line period) processed for display and the other as an input to a second store (e.g. for ULA it is ULB) in which the information is stored for processing in the next line period; in the case ofthe V component stores, the succeeding line (and corresponding stores) has been designated as A+ (and VLA+, VRA+).

The appropriate clocking operations to achieve this switching are generated in the sync and counter system H. This system also has the facility to detect a modificationinthefieldsyncwhich indicatesthatthe signals being received are of the standard twodimensional format. When the signals are ofthis standard format, then switches S5 and S6 operate as shown in the chart below to provide U andVsignals of full bandwidth, i.e. the stores are used in pairs each providing half of a display line. As the control signals are derived from counters referenced to the sync signals in unit H, which also generates the clock speeds of clocks C1 to C6, the switch edges and clock cycle starts can readily be synch ronised.

Table of clocking operations SIGNAL FORMAT CLOCK NO. FUNCTION TIME 2-D or 3-D C1 LIN t2 2 3-D C2 L OUT t7 2-D or 3-D C3 U or V IN tl 2 2-D C4 UorVOUT t7 2-D C5 L OUT t7 2 2-D C6 U or V OUT t7 2 Details ofthe operations for imparting signals into the memory stores and their subsequent extraction for matrixing, are shown in the following table.

TADLE OF INPUT AND EXTRACTION OPERATIONS FOR STORES

SIGNAL LINE S1 S2 S10 S7 S5 S6 CLOCKS FORMAT AND TO TO AND LRA LRR LLA LLR URA VRR ULA ILR FILTERS CONTACT CONTACT | Sli LINE A 2 FOR t6 21 FOR t7 CLOSE 27 12 16 C1 C2 C1 C2 C3 C4 C3 C4 53 S4 3 FOR t5 FOR FOR FOR FORFOR | FOR | FOR | FOR | FOR | FOR | FOR 3D S8, S9 4 FOR t4 t7 t7 t6 t7 t5 t7 t4 t7 t3 t7 OPEN 5 FOR t3 NARROW LINE B 6 FOR t6 20 FOR t7 CLOSE 26 13 17 C2 C1 C2 C1 C4 C4 C4 S3, S4 7 FOR t5 FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR 3D S8, S9 8 FOR t4 t7 t7 t7 t7 t6 t7 t5 t7 t7 t7 t7 OPEN 9 FOR t3 =NARROW LINE A 21 FOR t8 OPEN 25 12 18 c1 c5 c1 c5 c3 c6 c3 c6 AS LINE FOR 23 FOR t9 S3, S4 AABOVE t8 FOR FOR FOR FOR FOR FOR FOR FOR 2D 11 t6 t8 t5 t9 t4 t8 t3 t9 S8, S9 FOR CLOSED t9 =WIDE LINE B AS LINE 20 FOR t8 OPEN 25 13 18 C1 c5 C1 C5 c6 C3 c6 C3 S3, S4 22 FOR t9 FOR FOR FOR FOR FOR FOR FOR FOR B ABOVE t8 S8, S9 t6 t8 t5 t9 t8 t4 t9 t4 CLOSED 14 = WIDE FOR t9 The stores are of the charge coupled memory type, and the clock rates for clocks C1 to C6 are chosen in relation to the number of elements in the stores which depends on the maximum frequencies required in the outputs. Filters F1 to F4 remove all frequencies above the required base band; when three-dimensioned format signalsare being received, then the filter bandwidth is relatively narrow, and when standard format signals are being received the bandwidth is extended by closing switches S3, S4, S8 and Sg.

Ifthe networkwas operated with full luminance definition and with the stores holding alternate lines, there would be some reduction ofthevertical definition.

Atelevision receiver without the three-dimensional facilities can still receive and utilize the special format signalsfortwo-dimensional display by employing, for example, the right hand channel data. Thus a simplified store system would be utilized,with the signals fed into the stores at twice the normal speed once the field sync modification indicating a three- dimensional format signal has been received; alter nativelythesignalsarefed intothestoresatthe normal speed and are read out at halfthe normal speed.

If the U and V signals do not have to be processed in separate areas, a single store to hold alternatively U and V signals can be used in place oftwo separate stores, thereby enabling the number of U and V stores to be reduced from 4 each to 3 each.

During three-dimensional display, the definition may be reduced. Thus methodsto improvethe definition may be added.

Modifications and alterations of the network within the scope of the invention would be evident to a person skilled in the art.

Claims (12)

1. Atelevision transmision network in which the information within the transmitted line signals is time-multiplexed and the line signals are in a format for displaying a three-dimensional image.

2. Atelevision transmission network in which a line ofthetransmitted video information has time- multiplexed chrominance and luminance signals for two separate pictures thereby to provide a threedimensional image.

3. Anetworkaccordingtoclaim 1 orclaim2, wherein chrominance and luminance signals in a line are each divided into two equal portions, each portion being the relevant information for one oftwo pictures to form the three-dimensional image.

4. A network according to any one of the preceding claims, wherein the transmitted signals include information identifying thattheirformatallows three-dimensional display.

5. Anetwork according to claim4whereinthe identification information is a modification of the field synchronising information.

6. Apparatus for producing video signals in which the information within the transmitted line signals is time-multiplexed and the line signals are in a format for displaying a three-dimensional image.

7. Apparatus for producing video signals in which a line ofthe video information transmitted has time-multiplexed chrominance and luminance sig nalsfortwoseparate pictures thereby to provide a three-dimensional image.

8. Atelevision receiver for receiving, processing and displaying video signals in which the information within the transmitted line signals is time-multi- plexed and the line signals are in a format for displaying athree-dimensional image.

9. A television receiver for receiving, processing and displaying video signals in which a line ofthe video information has time-multiplexed chrominance and luminance signals for two separate picturestherebyto provide a th ree-dimensional image.

10. Atelevisiontransmission networksubstantially as hereinbefore described with reference to the accompanying drawings.

11. Apparatus for producing signals of a format fortransmission in a network according to claim 10.

12. A television receiver for receiving, processing and displaying signals of a formatfortransmission in a networkaccording to claim 10.