GB2293712A

GB2293712A - CRT lighting display

Info

Publication number: GB2293712A
Application number: GB9419000A
Authority: GB
Inventors: Nicholas Constant Velissarides
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-09-21
Filing date: 1994-09-21
Publication date: 1996-04-03
Also published as: GB9512287D0; GB9419000D0; GB2293714A; GB2293714B

Abstract

A sequence of computer generated graphic frames (R1, R2) comprise a series of pages (P1 - P5) with a Window (W) whose size and/or colour and/or brightness changes discontinuously between successive pages which are recorded as corresponding frames onto a video recording medium. The recording medium is then played back e.g. through a domestic video recorder coupled to a television set to generate a stroboscopic lighting effect. The invention provides a low cost alternative to the hire of stroboscopic equipment for parties and discotheques. <IMAGE>

Description

LIGHTING DISPLAY The present invention relates to light displays such as are used in discotheques and nightclubs. Conventionally such displays utilise coloured stroboscope lights which are flashed on and off in a pre-determined sequence, for example, in time with the music. Such lighting apparatus is available for hire but the hiring cost is usually prohibitive for use in private parties and the like An object of the present invention is to provide a less expensive alternative which nevertheless produces a similar lighting effect.

In accordance with the present invention, a Cathode Ray Tube (CRT) display is used to produce a stroboscopic lighting effect.

Preferably the CRT display is driven by the output of a video playback device playing a video recording medium on which a recording simulating a stroboscopic lighting effect has been recorded. The CRT display is suitably the display of a domestic television set and the video recording medium is suitably a videotape played back on a domestic video recorder which is connected to the television set.

Although the maximum brightness of a television screen is usually less than the brightness of a stroboscopic light, the area is of course much greater and hence a comparable lighting effect can be obtained.

Preferably the CRT display displays a bright window composed of a block of colour, the size and/or colour and/or brightness of the window changing discontinuously between successive frames. Preferably the size and/or colour and/or brightness changes periodically at the frame rate (25 Hz in the case of European television systems) or a sub-multiple of the frame rate.

Unlike conventional applications of CRT displays, wherein moving images, text or other information is displayed, the present invention utilises a CRT display as a specialised illumination source. Whereas "flicker" is a disadvantage in applications involving the display of information, the present invention takes advantage of the rapid changes in brightness obtainable from a CRT display.

In the use of the present invention, preferably there is at least one sequence of discontinuous change in size and/or colour and/or brightness which has a duration of at least three and preferably five minutes. In preferred embodiment, at least one sequence of discontinuous change in size and/or colour and/or brightness is repeated.

The invention also provides a method of producing a video recording for use with a CRT display to produce a stroboscopic lighting effect, wherein a set of video frames is generated by a computer, the frames each comprising a bright window composed of a block of colour, the frames are formed in a sequence wherein the size and/or colour and/or brightness of the window changes discontinuously between successive frames, and the sequences are recorded onto a video recording medium.

Additionally, the invention provides a method of producing a video recording for use with CRT display to produce a stroboscopic lighting effect, wherein an image of a periodically flashing light is recorded onto a video recording medium.

The video recording medium is preferably a video tape, however it may alternatively be a computer - readable hard disk, an optical recording medium such as a Compact Disc, or a magneto-optic disk micro chip, or other semiconductor A preferred embodiment of the invention is described below by way of example only with reference to Figures 1 to 3 of the accompanying drawing, wherein: Figure 1 is a schematic block diagram showing apparatus for producing a video recording by a method in accordance with the invention; Figure 2 illustrates two computer-generated sets of video frames which are combined into respective sequences for incorporation into the above video recording, and Figure 3 illustrates the combination of the above sequences in the video recording.

Referring to Figure 1, a desktop computer 1 is connected via a Y-C Genlock video adaptor 2 to an input of a video mixer 3 which has another input connected to output of a video camera 4 and its output connected to an input of a video recorder 6. Graphics pages are generated by means of a suitable software package on the computer 1, temporarily recorded in a pre-recorded sequence on a hard disk of the computer and then fed via the video adaptor 1 to the video mixer 3 under the control of the computer.

The video adaptor converts the graphics data from the computer into PAL video format. The video camera 4 also records a flashing stroboscopic light 5 and feeds the resulting video signal to the video mixer 3. At the video 3, either of the two input video signals is selected and recorded onto a master video tape in the video recorder 6.

In one arrangement which has been used for making a recording in accordance with the method of the invention, the computer 1 was an Amiga (Registered Trade Mark 4000 computer the video adaptor 2 was a Y.C. Genlock adaptor, the video mixer 3 was a Panasonic Betacam (Registered Trade Mark). WJ - MX5000 mixer and the video camera 4 was a Sony (Registered Trade Mark) DXC 3000 camera. The software package used was the Scala Multimedia 300 editing package.

However, various other desk top video production and editing arrangements can be used to make a recording in accordance with the invention. In particular, "Avid's Media Suite Pro" a complete hardware and software package based on an Apple Macintosh (Registered Trade Mark), Quadra (Registered Trade Mark) computer and obtainable from Avid Technology Limited, 20 -28 Kingly Court, London WIR 5LE can be used optionally in conjunction with a suitable video camera and stroboscopic light. A variety of graphics programs are available for the Macintosh (Registered Trade Mark) such as Adobe Photo Shop for example, which are suitable for creating the graphics packages which are recorded as video frames on the video tape.

Depending on the arrangement used to generate the video recording, some enhancement of the luminance and chromanence of the graphics output from the computer may be desirable in order to improve the impact of the lighting effect recorded onto the video tape.

Background information on desk top production is contained in a series of articles at pp 31 - 41 of the magazine "MAC FORMAT" issue 14, July 1994 and in the article "Movies, Macs and videos" by a Hoffer at pp 90 to 104 of the magazine "Mac World", June 1994.

The production of a video recording using the apparatus of Figure 1 or a similar apparatus will now be described with reference to Figure 2 and Figure 3. It will be assumed purely for the sake of example that the computer 1 is an Amiga 4000 computer running the "Scala Multi Media 300" software package although it will be apparent that the method may easily may be implemented using other video and graphics hardware and software.

A page P1 is created, having a circular window W which is filled with an appropriate colour eg red in this case. The background is set at black. Then further pages P2, P,3 and P4, P5 are created in a similar manner, with the windows of adjacent pages preferably having contrasting colours, e.g.

red against yellow, blue against orange and green against yellow. It is not essential for the window to be circular and each page may have more than one window formed thereon.

Furthermore, some or all of the windows can entirely fill the page.

Once the pages P1 to P5 have been generated and assembled into an appropriate sequence, a transition between adjacent pages is selected which would normally be a wipe or a so-called "cut" with a zero pause time so that each page appears as a successive video frame or multiple of frames on the recording. However, other transitions are available; for example a transition called "Black" inserts a black blank page momentarily before the next page which gives the effect of instantaneously plunging the room into darkness before the next page is displayed and "Cccut" is a transition that rapidly alternates two adjacent pages with increasing speed before moving onto the next page which alternates in the same manner with the previous page.

Once the sequence of pages and the transitions between them have been generated, the resulting routine 1 is saved as a sequence of frames R1 as illustrated in Figure 2 (a).

A slightly different sequence of pages P6 to P10 is illustrated in Figure 2 (b) and it will be seen that the window begins as a small red window W in P6, expands to a large red window in P7 and contracts to a small red window in P8. In this example P9 consists solely of background and P10 appears with a large yellow window against a black background. This sequence with appropriate transitions between adjacent pages is then saved as a further routine R2.

As illustrated in Figure 3, a further routine S can be inserted between Routine R1 and R2. In this example Routine S is generated by filming a standard stroboscopic light 5 with a video camera 4 (Fig. 1) with the stroboscopic frequency being between 10 and 20 pulses per second. This sequence is recorded directed onto the video master tape using the video recorder 6 (Fig. 1).

Preferably routines R1 and R2 are of five minutes' duration. Further routines similar to R1 and R2 but with different transitions and/or different windows are then generated in the same way and are recorded onto the video tape in a similar manner so that the entire video tape is ultimately filled with computer-generated sequences alternating with sequences of filmed stroboscopic light.

It is not essential to use filmed stroboscopic light in the recording; instead the entire recording may consist of computer-generated graphics sequences such as R1 and R2.

However, in order to maximise the stroboscopic effect when the recording is played, the brightness of the windows should be maximised and the transitions between the pages should be as varied as possible.

The tape recorded in the video recorder 6 is suitably a Betacam master tape which can be used to make multiple copies in VHS format. In use, such a VHS tape is played back through a video recorder connected to a domestic television set in a darkened room and produces a stroboscopic lighting effect. A sound track may optionally be recorded on the video tape, preferably in synchronism with the recorded video.

Claims

1. Use of a CRT display to produce a regular or irregular lighting effect.

2. Use of a CRT display according to claim 1 wherein the lighting effect is produced stroboscopically.

3. Use as claimed in claim 1 wherein said CRT display displays a bright window composed of a block of colour, the size and/or colour and/or brightness of the window changing discontinuously between successive frames.

4. Use as claimed in claim 3 wherein said size and/or colour and/or brightness changes periodically at the frame rate or a sub-multiple of the frame rate.

5. Use as claimed in claim 3 or claim 4 wherein the background region of the frame surrounding said window is substantially black.

6. Use as claimed in any of claims 3 to 5 wherein a dark frame in which the window is absent is interspersed between frames having differently sized and/or coloured windows and/or windows of different brightness.

7. Use as claimed in any of claims 1 to 6 wherein a sequence of discontinuous changes in size and/or colour and/or brightness has a duration of at least 3 minutes.

8. Use as claimed in any preceding claim wherein at least one sequence of discontinuous changes in size and/or colour and/or brightness is repeated.

9. Use as claimed in any preceding claim wherein said CRT display is driven by the output of video playback device playing a video recording medium on which a recording simulating stroboscopic lighting effect has been recorded.

10. Use as claimed in claim 9 wherein said CRT display is the display of a domestic television set.

11. A method of producing a video recording for use as claimed in claim 8 or claim 9 wherein a set of video frames is generated by a computer, the frames each comprising a bright window composed of a block of colour, the frames are formed into a sequence wherein the size and/or colour and/or brightness of the window changes discontinuously between successive frames, and the sequence is recorded onto a video recording medium.

12. A method as claimed in claim 11 wherein a dark frame in which the window is absent is interspersed between frames having differently sized and/or coloured windows and/or windows of different brightness.

13. A method of producing a video recording for use as claimed in claim 9 or claim 10 wherein an image of a periodically flashing light is recorded onto a video recording medium.

14. A method as claimed in any of claims 11 to 13 wherein a recorded sequence of discontinuous changes in window size and/or colour and/or brightness has a duration of at least 3 minutes.

15. A method as claimed in any of claims 11 to 14 wherein at least one recorded sequence of discontinuous changes in window size and/or colour an/or brightness is repeated.

16. A method as claimed in any of claims 11 to 15 wherein said recording medium is a videotape.

17. A method of producing a video recording for use in producing a stroboscopic lighting effect, substantially as described hereinabove with reference to Figures 1 to 3 of the accompanying drawings.