GB2385480A

GB2385480A - Hidden image viewing

Info

Publication number: GB2385480A
Application number: GB0200624A
Authority: GB
Inventors: Jeremy Edward Hibbert
Original assignee: HIBBERT RALPH HOLDINGS Ltd
Current assignee: HIBBERT RALPH HOLDINGS Ltd
Priority date: 2002-01-11
Filing date: 2002-01-11
Publication date: 2003-08-20
Also published as: GB0200624D0

Abstract

An image 14 is recorded in one colour on a record medium 8 within a background 16 of random shapes 17 of one or more substantially opposite colours of the same or similar tone as the colour of the image. When the image 14 is displayed to an observer, the background 16 confuses the naked eye of the observer and hides or obscures the image 14 unless the latter is viewed through filter means of a substantially opposite colour to the colour of the image.

Description

IMAGING TECHNIQUE The present invention relates to an imaging technique and, more particularly, to an imaging technique in which a moving image to be displayed to an observer is hidden or obscured unless the observer views the display through a predetermined colour filter.

FR-A-2 724 325 discloses a game in which hidden information can be read by viewing it through a colour filter. In this game, an envelope, into which a card can be inserted, has a transparent window formed by a colour filter. The card has a zone which is positioned to cooperate with the window and is printed with a coded inscription. When the card is inserted into the envelope, the inscription is revealed when viewed through the window. The filter colours may, for example, be red, blue or green and the colours of the inscription follow the same principle.

It is an object of the present invention to provide a technique for hiding or obscuring an image so that the image is only clearly visible when viewed through a predetermined colour filter.

The invention relies on the principle of colour filtration. This principle involves the fact that a displayed colour appears as black when viewed through a coloured filter of a colour from the diametrically opposite side of the colour spectrum, as represented by a colour wheel, whilst the same colour when viewed through a colour filter of the same colour appears as that original colour. For example, green when seen through a red filter appears black and red when seen through a red filter appears red. For a more detailed explanation, reference is made to Figure 1 of the accompanying drawings, which illustrates the successive colours of the spectrum, that is, red 1, orange 2, yellow 3, green 4, blue 5 and purple 6, arranged in the form of a wheel or ring 7 with the colour gradually changing between these main colours as is usual in a colour spectrum. The colours which are diametrically opposite each other on the ring 7 are said to be on opposite sides of the spectrum and are

referred to herein as opposite colours. For example, red 1 and green 4 are opposite colours. When a colour image is viewed through a coloured filter which is of the opposite colour, the displayed image appears black as light of one colour cannot travel through a filter of an opposite colour. However, any opposite colour viewed through a filter of the same colour appears unchanged in colour.

Within the context of this invention, opposite colours which have the same level or degree of colour brightness will be referred to as being of the same tone.

From one aspect, the present invention consists in a method of displaying an image, wherein the image is produced in one colour within a background comprising one or more substantially opposite colours of the same or similar tone as the colour of the image, such that, when displayed to an observer, the background confuses the eye of the observer and hides or obscures the image unless the image is viewed through coloured filter means of a substantially opposite colour to the colour of the image.

With the invention, a coloured image, for example a green image, is hidden from the naked eye by surrounding it with a background of dots, splashes, squiggles, lines and/or marks of other shapes of a substantially opposite colour, for example, red where the image is green, and of an identical or similar tone to the colour of the image. The fact that the tones of the colours are identical or nearly so confuses the eye and therefore serves to disguise the image. In the example just given, the green image would appear dark and the background markings would appear red when viewed through a red filter, thus rendering the image tonely discernible.

Preferably, the image is a moving image. A moving image comprises still images shown on frames of, say, a film or pictures on, say, a television, shown in quick succession so that to the observer of

the film or television, the image appears to move. The moving image may be, for example, an animation. One example of the use of the invention is to display a programme having a hidden animated image, such as fairies on say, a television or film projection screen. This hidden image would be for viewing only by specific people, such as children, given the required colour filter device in order to detect it visually.

Whilst a still image may still be identifiable through the background "fog"of marks etc, the addition of random or designed animation, (that is, a series of still images shown in quick succession), to the background of marks turns the "still image" into a "moving image". This makes the hidden image impossible to detect by an observer without the aid of an appropriate filter of the opposite colour. It is also important for the background to be of an opposite tonely similar colour to the colour of the image otherwise an observer would be more easily be able to distinguish the image from the background.

Hence, preferably, the background is formed from shapes which move or change as the image is displayed. At least one of the background shapes may be arranged to move in a random or a predetermined fashion.

From another aspect, the present invention consists in an imaging system wherein an image is recorded in one colour on a record medium within a background of one or more substantially opposite colours of the same or similar tone as the colour of the image, whereby, when displayed to an observer, the background confuses the naked eye of the observer and hides or obscures the image unless the latter is viewed through filter means of a substantially opposite colour to the colour of the image.

In order that the present invention may be more readily understood, reference will now be made to the accompanying drawings, in which :-

Figure 1 illustrates the colour spectrum in the form of a ring, Figure 2 illustrates one frame of an animation to which the present invention is to be applied, Figure 3 illustrates colour filter means for use with the invention, and Figures 4 and 5 illustrate the invention applied to the frame of Figure 2.

Referring to the accompanying drawings, Figure 2 illustrates one frame 8 of a moving picture to be displayed, for example, on a television screen and, at least part of which is to be hidden or obscured in accordance with the imaging technique provided by the present invention. Successive frames animate the images 14,15 shown in the picture.

In the embodiment described, the left hand side 10 of the frame, as delimited by the broken line, is to be hidden or obscured by the technique of the invention, the right hand side remaining visible to the naked eye of an observer. In order to achieve this, at least the image 14 appearing on the left hand side of the frame is produced in a green colour and is mixed with a background 16 of random shapes 17, such as, lines, dots, splashes and squiggles, which are of a red colour or of a colour close to red and of an identical or similar tone to the green colour of the image, as is schematically illustrated in Figure 4. The background 16 confuses the naked eye of an observer and hides or obscures the green image 14 from the naked eye. So as to enhance the effect, the background shapes are animated in a random fashion in successive frames 8 of the video recording. The movement of the background 16 distracts an observer's eyes and renders the green image 14 on the left hand part of the frame even more difficult to detect.

The image 15 on the right hand side 9 of the frame may simply be recorded as a black image on a white background.

In order for an observer to see the image on both sides 9,10 of each successive frame and be able to view the whole picture, it is necessary to observe the picture through red colour filter means which may, for example, be incorporated in a pair of spectacles as illustrated in Figure 3. As is conventional, the spectacle frame 11 mounts two eye pieces 12 of red transparent material. When an observer wearing such spectacles views a moving picture displayed on a television screen and produced with a hidden image, as described above, the whole picture is rendered tonely discernible to the observer and the left hand image 14 is no longer hidden. The whole picture appears in the form of black images on a red background as schematically illustrated in Figure 5. The green image on the left hand side of each frame is seen as black through the red eye pieces of the spectacles, red being of opposite colour to green, whilst the image on the right hand side is seen in its original black colour.

Preferably, the animated background shapes are animated at speeds of between 12 images or frames per second and 60 images per second. At speeds of less than 12 images or frames per second, the effect of distracting the eye and disguising the image may be less pronounced.

The moving picture with the hidden image may be recorded on video tape for playback by a video machine and display on a television screen. The picture need not necessarily be animated but may, alternatively, comprise recorded footage of "live" events which have subsequently been processed in accordance with the invention so as to have hidden images which can only be observed when viewed through appropriate colour filters.

While a particular embodiment has been described, it will be understood that modifications can be made without departing from the scope of the invention. For example, some of the background shapes 17 may be of different colours and not be of a colour substantially opposite

to that of the image. The variation of colours for the background shapes confuse the eye and serves to further disguise the image. The closer the colour of the background shapes are to the colour of the filter, the less discernible they will be to an observer viewing the image through the filter means.

The background shapes 17, instead of being animated, may be a moving background"texture"such as a moving image of a mass of wriggling squiggles or swirling water.

Claims

CLAIMS : 1. A method of displaying an image, wherein the image is produced in one colour within a background comprising one or more substantially opposite colours of the same or similar tone as the colour of the image, such that, when displayed to an observer, the background confuses the eye of the observer and hides or obscures the image unless the image is viewed through coloured filter means of a substantially opposite colour to the colour of the image.
2. The method as claimed in claim 1, wherein the image comprises still images shown in quick succession so that to the observer the image appears to move.
3. The method as claimed in claim 1 or 2, wherein the background comprises dots, splashes, squiggles, lines and/or marks of other shapes.
4. The method as claimed in claim 3, wherein the background comprising said shapes comprises still images shown in quick succession so that to the observer at least one of the shapes appear to move or change.
5. The method as claimed in claim 4, including arranging at least one of the background shapes to appear to the observer to move in a random or a predetermined fashion.
6. An imaging system wherein an image is recorded in one colour on a record medium within a background of one or more substantially opposite colours of the same or similar tone as the colour of the image, whereby,

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when displayed to an observer, the background confuses the naked eye of the observer and hides or obscure the image unless the latter is viewed through filter means of a substantially opposite colour to the colour of the image.
7. A method for displaying an image substantially as hereinbefore described with reference to the accompanying drawings.
8. An imaging system constructed substantially as hereinbefore described with reference to the accompanying drawings.