GB2467944A - Stereoscopic effect without glasses - Google Patents

Abstract

A two dimensional image is modified by selectively distorting the area surrounding certain objects 1. When the image is displayed so it extends to the peripheral vision (figure 2) of an observer, the modified areas 2 will cause the objects within to appear physically distinct from the background 3, 4. A series of related images prepared and displayed with the same features would provide a moving stereoscopic image observable with normal vision. The modification of areas may comprise horizontally distorting the image, changing the focus or changing the brightness level.

Description

Stereoscopic Effects Without Glasses This invention relates to a method of creating stereoscopic effects with two-dimensional displays which can be viewed without visual aids.

Stereoscopic perception is a consequence of a number of conditions, both physical and intuitive. Because eyes are displaced horizontally in respect to each other an observer sees three-dimensional space slightly differently in each eye. When this visual information is processed by the brain the observer sees the space in three dimensions or stereoscopically.

Existing methods of creating a stereoscopic effect do so by presenting concurrent 2-dimensional images to an observer, which attempt to duplicate the differences found in nature and each employs a device of some kind to selectively present the related 2D images to the left and right eye of the observer. Examples of methods of achieving this include the use of coloured or polarized filters or shutters, which selectively block one image and not the other so that the appropriate image is only visible by either the left or right eye.

A common factor in each of these methods is that the vision of the observer is modified in some way by the device, or is limited to a specific viewing position in order to view the stereoscopic effect. It is also the case that as the vision of the observer is distorted, continuous use of some of these devices can become uncomfortable.

Large 2-dimensioinal displays which fill the field of view of an observer have also been used as a means to duplicate reality and special cameras, films and projectors have been developed to provide the large focussed images necessary to fill the display. However, when these large displays are used for stereoscopic projection, they also employ a dual image and special glasses to see the effect.

The aim in presenting images stereoscopically has been to more closely represent real life.

However it is fair to say that the inherent complexity of the techniques used has caused public displays to be limited in creative content, and in many cases it is the stereoscopic effect which the audience pays to see. It might therefore be an improvement and an advantage if some of the negative factors in creating stereoscopic effects could be avoided by employing a method which provides stereoscopic effects for public display, which can be viewed with normal vision.

The present invention achieves this aim by selectively employing visual aspects of stereoscopic perception which are present in real-life binocular vision, but are currently excluded in traditional means of dual-image capture, dual-image creation and their display.

These alternative cues, when combined in a single image, can create a stereoscopic effect on a two-dimensional surface which does not require an observer to use any device or take a specific point of view in order to see the effect.

Visual cues of significance to the invention and their display will now be described together with reference to the accompanying diagrams and illustrations.

Figures 1 and 2 illustrate the peripheral limits of human vision and the binocular stereoscopic zone.

Figure 3 is a 2-dimensional image with a significant artefact' in focus, within a context' which is out of focus.

Figures 4 and 5 show a number of significant artefacts' in focus bounded by areas of modified focus within a context' in focus.

Human binocular vision has horizontal peripheral vision extending to approximately 180 degrees and about half of that vertically and these boundaries are the limits of an observer's field of view. Within this field of view is a central area which is seen by both eyes and is the visual zone in which stereoscopic vision is possible. Figures 1 and 2.

In order to experience stereoscopic perception in real life, an observer must constantly scan their field of view by fixing their vision at least momentarily on an artefact of interest' within their stereoscopic zone. When an artefact is selected' it automatically becomes a single focussed image with all other artefacts on different planes within the zone, both in front and behind distorted horizontally, with the degree of distortion proportional to the space between each plane. As the eye is a lens, artefacts on these planes will also be out of focus. The observer then shifts his vision to fix on a different artefact of interest' which might be on a different plane and this will automatically become the focussed image with artefacts on other planes becoming horizontally distorted and out of focus.

The brain when presented with visual data which extends to the periphery of an observer's vision and contains at least one artefact in focus and one or more other artefacts as horizontally distorted images and or out of focus, will automatically infer that different planes exist and therefore present these data to the observer as a stereoscopic view. Note. 2-D images are often dimensionally enhanced by having objects in focus against an out of focus background as shown in Figure 3. However these images are not stereoscopic as their boundaries are also visible.

The present invention describes the preparation of images to incorporate the visual cues described above, which when displayed provide a stereoscopic view to an observer when viewed with normal vision.

Two-dimensional mages which are presented for entertainment or to provide information generally have specific visual content which can be described as significant' and context'. It is usually an aim to ensure that an observer is drawn to the significant parts of the image, which is supported by its context.

An image or a series of images is prepared so that any artefact or artefacts, which have some significance at any particular moment in the narrative of the presentation, will he in sharp focus and might be selectively illuminated. Other parts of the same image -the context -at least immediately around the significant image, will be selectively dual images being displaced horizontally in respect to each other and or out of focus and might also have modified lower light intensity. Figures 4 and 5. The whole image is presented to an observer employing a display which extends without a boundary to beyond their peripheral vision.

The observer views the image with normal vision and may move his view freely to any part of the display, but when his view is of the significant parts of the display, which have been prepared as described above, artefacts in focus and bounded by a distorted area will appear to be physically distinct from their contextual background and therefore a stereoscopic effect will have been created.

In a series of related images the degree of light intensity of artefacts or displacement of their boundaries might be varied in subsequent images which correspond to changes in the relative spatial positions of an artefact or artefacts. In this case these images, when displayed in the manner described above, would form a moving stereoscopic image.

Images incorporating the features of the invention described above could be created using existing means of image capture or digital creation, including those which simultaneously capture visual and depth data. These methods could be used to create a series of complex two-dimensional images to include the visual cues and means of display described above. Even existing images could he modified digitally to include the features described above with an objective of introducing a stereoscopic effect. As the stereoscopic effect can be experienced with normal vision, the invention can be selectively introduced into any part of a conventional 2 dimensional display which extends to the peripheral vision of an observer.

Modifying images and their display as described above would enable directorsleditors to readily manipulate any 2-dimensional elements of an image -including in real-time, and at any moment in a narrative, to create a stereoscopic effect which can be viewed by an observer using only normal vision.

The invention can he applied in many forms of display including those for advertising and entertainment.

For example the visual aspects of a movie might be enhanced by selectively introducing a stereoscopic effect in response to sounds or other artefacts which have significance at any moment in the narrative and might add to the dramatic effect of the presentation. An advertisement might be presented which selectively enhances the dimensionality of a product or any text which relates to it, and at any moment in the presentation.

Another application is in the presentation of live events where significant parts of the action could be dimensionally enhanced in real-time. A soccer game for example could have a player or players or the ball dimensionally enhanced to improve clarity even if these elements are on the same plane as the contextual elements of the image, such as the field of play.

Another application might be in the field of interactive video games, where a display is provided which extends to the peripheral vision of the player or players and the images are enhanced as described above with an aim of adding realism or dramatic effects to aspects of the game.

The invention provides additional creative opportunities for those preparing images for methods of public displays some of which are used as backdrops in live theatre and existing venues which are designed specifically to display giant screen images. Some of these displays are modular and can be readily extended to fill the whole field of view of observers. Modules with enhanced clarity levels could he reserved for the central parts of the display which correspond to the stereoscopic zone in binocular vision.

Another advantage of the invention is that in some cases the same equipment and venues currently in use for two-dimensional presentations can be used to display and view these images. In cinemas for example relatively simple modification of existing layout and projection equipment would he required, which would not affect the projection and screening of conventional movies. Existing cinema screens of existing size and shape could continue to be employed, requiring only the surfaces of the proscenium which connect to it, to he simply modified to provide a continuous surface to the peripheral vision of observers Existing movies or other images could apply the invention retrospectively, by digitally modifying their visual content to selectively include the features of the invention. The framing aperture of a conventional projector, which is normally employed to provide a crisp border to images, could be removed and replaced with a lens, which modifies only the contextual parts of an image to extend its boundaries to beyond the peripheral vision of the observer. In this example, those parts of the image projected towards the periphery might become heavily distorted and be of lower light levels but without significant penalty as they would tend to draw the observer's attention to the dimensionally modified parts of the image, which it is intended they should watch.

Claims (10)

1. Claims 1. Images which create a stereoscopic effect when viewed with normal vision.
2. 2. Images as in claim 1 where parts of an image have modified focus or horizontal distortion or illumination.
3. 3. Images as in claim 2 where the modified focus or horizontal distortion is around a focussed part of the image.
4. 4. Images as in claim 2 where the enhanced illumination is a focussed part of the image.
5. 5. Images as in claim 2 where reduced illumination is around a focussed part of the image.
6. 6. Images as in claims 1 to 5 which are displayed to the peripheral vision of an observer.
7. 7. Images as in claims 1 to 6 which when displayed sequentially provide a moving stereoscopic effect.
8. 8. Images as in claims 1 to 7 in which the moving images have sections in 2-dimensions and other sections which are stereoscopic.
9. 9. Images as in claims 1 to 8 which are created or modified in real time'.
10. 10. Images as in claim 9 where modifications are made by an observer or observers.