WO2005041591A1

WO2005041591A1 - Apparatus for enabling stereoscopic viewing

Info

Publication number: WO2005041591A1
Application number: PCT/GB2004/004043
Authority: WO
Inventors: John Alexander Christian; Alan Thomas Scrase
Original assignee: Stereoscopic Image Systems Limited
Priority date: 2003-10-13
Filing date: 2004-09-23
Publication date: 2005-05-06
Also published as: GB0323964D0; GB2428155B; GB2428155A; GB2428155A8; GB0603776D0

Abstract

Apparatus (8) for enabling stereoscopic viewing, which apparatus (8) comprises a first screen (10) for being viewed by a first eye of a person, and a second screen (12) for being viewed by a second eye of the person, and the apparatus (8) being such that each screen is rotated 900 clockwise from a position required if the apparatus (8) were to be driven by a video input signal giving non-stereoscopic viewing, each screen has during use a first image (6) for the first eye and a second image (7) for the second eye, a first mask (14) for the first screen (10) masks one of the first (6). and second images (7) on the first screen (10), a second mask (16) for the second screen (12) masks one of the first (6) and second images (7) on the second screen, and the first and second screens (10, 12) are displaced with respect to each other such that the displacement and the masks ensure that there is only one image (6) or (7) on each screen that is viewable by each eye, and the image (6) that is viewable on the first screen (10) is on an axis for the first eye, and the image (7) that is viewable on the second screen (12) is on an axis for the second eye, whereby the apparatus (8) is able to be driven by a video input signal giving the stereoscopic viewing.

Description

APPARATUS FOR ENABLING STEREOSCOPIC VIEWING

This invention relates to apparatus for enabling stereoscopic viewing. Accordingly, in one non-limiting embodiment of the present invention there is provided apparatus for enabling stereoscopic viewing, which apparatus comprises a first screen for being viewed by a first eye of a person, and a second screen for being viewed by a second eye of the person, and the apparatus being such that each screen is rotated 90° clockwise from a position required if the apparatus were to be driven by a video input signal giving non-stereoscopic viewing, each screen has during use a first image for the first eye and a second image for the second eye, a first mask for the first screen masks one of the first and second images on the first screen, a second mask for the second screen masks one of the first and second images on the second screen, and the first and second screens are displaced with respect to each other such that the displacement and the masks ensure that there is only one image on each screen that is viewable by each eye, and the image that is viewable on the first screen is on an axis for the first eye, and the image that is viewable on the second screen is on an axis for the second eye, whereby the apparatus is able to be driven by a video input signal giving the stereoscopic viewing. The apparatus may be one in which the first mask is on the first screen and in which the second mask is on the second screen. If desired however, the masks may be remote from the first and second screens. In one embodiment of the invention, the first and the second screens are displaced vertically with respect to each other. In this case, the apparatus is preferably one in which the first screen is displaced vertically upwardly, and in which the second screen is displaced vertically downwardly. Other types of displacement for the first and the second screens may be employed. In another embodiment of the invention, the apparatus is one in which the first and second screens are displaced angularly with respect to each other such that the first and second screens are perpendicular to each other. The apparatus of the present invention may be one in which one image is seen by transmission, and in which the other image is seen by reflection from a half silvered mirror. With such apparatus, electrical or software reversal of the image to be seen by reflection is necessary. This may be an on-board menu choice on the appropriate screen. In one embodiment of the invention, the apparatus may include mounting means for mounting the apparatus on the person's head. In another embodiment of the apparatus of the invention, the apparatus is self-standing for location and viewing remote from the person. In this case, superimposed images are segregated to each eye by means of polarising spectacles. Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows images that would be seen on a first screen and a second screen if the images were provided by a video input signal from a single camera giving non-stereoscopic viewing; " Figure 2 shows what would happen to the images of Figure 1 if the images were recorded by the above camera with a stereoscopic encoding attachment fitted; Figure 3 illustrates part of apparatus of the present invention whereby the images on the first and second screens are each masked; Figure 4 shows first driving apparatus for providing a video input signal giving stereoscopic viewing; Figure 5 shows second driving apparatus for providing a video input signal giving stereoscopic viewing; Figure 6 shows apparatus for enabling stereoscopic viewing, the apparatus utilising the arrangement shown in Figure 3, and the apparatus including mounting means in the form of a pair of spectacles for enabling the apparatus to be mounted on a person's head; and Figure 7 shows apparatus of the present invention for enabling stereoscopic viewing, the apparatus being self-mounted and being for viewing remote from a person via a pair of polarising spectacles. Referring to Figure 1 , there is shown a first screen 2 for being viewed by a first eye of a person, and a second screen 4 for being viewed by a second eye of the person. The first and the second screens 2, 4 each have the same image 6, this image being of a vehicle and the vehicle being the correct way up. Referring now to Figure 2, there is shown how the images 6 are rearranged if they are provided by a video input signal giving stereoscopic viewing. More specifically, the first screen 2 has a pair of stereoscopic images 6 and 7, one being for a right eye view as shown and one being for a left eye view as shown. Similarly, the second screen 2 has a pair of stereoscopic images 6 and 7, one being for a right eye view as shown and one being shown for a left eye view as shown. Figure 3 illustrates the operating principle of apparatus 8 of the present invention for enabling stereoscopic viewing. More specifically, the apparatus 8 comprises a first screen 10 for being viewed by the first eye of a person, and a second screen 12 for being viewed by a second eye of the person. In comparison with the first and second screens 2, 4 shown in Figure 2, it will be seen that each of the first and second screens 10, 12 is rotated 90° clockwise from a position required if the apparatus were to be driven by a video input signal giving non-stereoscopic viewing, which is the case with the apparatus shown in Figure 2. In the apparatus 8, each screen has during use a first image for the first eye and a second image for the second eye. This can be appreciated from the two images 6 and 7 shown in Figure 2 for each screen. As shown in Figure 3, there is a first mask 14 for the first screen 10. This first mask 14 masks the upper one of the first and the second images 6 and 7 on the first screen 14. Also provided is a second mask 16 for the second screen 12. This second mask 16 masks the lower image 6 of the two images 6 and 7 on the second screen 12. As can be seen from Figure 3, the first and the second screens 10, 12 are displaced vertically with respect to each other. More specifically, the vertical displacement is such that the first screen 10 is displaced vertically upwardly, and the second screen 12 is displaced vertically downwardly. The displacement and the masks 14, 16 ensure that there is only one image 6 or 7 on each screen 10, 12 that is viewable by each eye of the person. The image 6 that is viewable on the first screen 10 is on an axis for the first eye. The image 7 that is viewable on the second screen 12 is on an axis for the second eye. Thus the apparatus 8 is able to be driven by a video input signal giving the stereoscopic viewing. The apparatus 8 is such that the first mask 14 is on the first screen 10. The second mask 16 is on the second screen 12. In an alternative arrangement (not shown) the first mask 14 could be remote from the first screen 10, and the second mask 16 could be remote from the second screen 12. Referring now to Figure 4, there is shown first driving apparatus 18 for driving the apparatus 8 with a video input signal giving the stereoscopic viewing. The driving apparatus is disclosed in European Patent Application No. 01947011.1. The driving apparatus 18 may be in the form of an endoscope. The driving apparatus 18 comprises an optical arrangement 20 comprising two similar tubular optical channels side by side each containing repeated pairs of lenses 24, 88 or 26, 28. Each pair of lenses share a common focal point, for example 30 for lenses 24, 88 and convey a left eye image 32 and a right eye image 34 from a remote target object 36 to a camera, via optical arrangement 38. The purpose of optical arrangement 38 is to rearrange the two landscape images from being side by side to being one above the other in order to fit within the frame of a single camera. This is achieved by two periscopes, one acting vertically (40, 42) and one acting horizontally 44, 46). There are pairs of lenses down the whole endoscope length. For example 24 and 88 is just one typical pair of lenses in diagrammatic form. In practice endoscope lenses are cylindrical rods. The optical arrangement 20 captures a left eye image 32 and a right eye image 34 of a target object 36. Images of the object 36 are reflected as shown via an optical arrangement 38 comprising four reflective surfaces 40, 42, 44 and 46 as shown. The left eye image 108 and the right eye image 106 then appear as shown. The left eye image 108 and the right eye image 106 appear on top of one another to a camera looking at lenses 32 and 34 as shown in Figure 4. Figure 5 shows second driving apparatus 48 for providing a video input signal giving the stereoscopic viewing. The driving apparatus is disclosed in PCT/GB03/02021. The driving apparatus 48 comprises a housing 50 having a first aperture 52 through a wall 54, a second aperture 56 and a third aperture 58 in a wall 60 opposite the wall 54. The first, second and third apertures contain lenses. The optical path length to the lens in the first aperture is the same for the second and third aperture lenses. A camera located at the first aperture 52 sees a rearranged pair of stereoscopic images one above the other. The housing 50 contains an optical arrangement 62. The optical arrangement 62 comprises mirrors 64, 66, 68, 70, 72, 74. The mirrors 64 - 74 have been shown in imaginary cubes in order that their respective inclination can easily be appreciated. The optical arrangement 62 provides left and right eye images as is required for the apparatus 8. Figure 6 shows how apparatus 76 of the present invention may be constructed like the apparatus 8 shown in Figure 3 with the first screen 10 moved vertically upwardly and with the second screen 12 moved vertically downwardly. The apparatus 76 is shown provided with mounting means 78 for mounting the apparatus 76 on a person's head. The mounting means 78 comprises a bridge piece 80 for fitting on a person's nose, and a pair of side arms 82, 84 for enabling the apparatus 76 to fit behind a person's ears. Thus the entire apparatus 76 takes the form of a pair of spectacles. Figure 7 shows apparatus 86 of the present invention. The apparatus 86 comprises a single half silvered mirror 88, and separate screens 90 and 92. The apparatus 86 is for being viewed via polarising spectacles 94 giving left and right eye images as shown. Liquid crystal display screens are polarised in their light output before stereoscopic segregation of images is considered. This viewing arrangement is to exploit the inbuilt polarisation of the two display screens for the segregation of the left and right image to each eye without the need for additional polarising filters. Where the two display screens are of such size that the image length does not exceed the distance between the eyes, then the direct viewing arrangement shown in Figure 6 is appropriate. For larger screens the images may be brought together and superimposed on a 45° glass plate δ

which half transmits light and half reflects light, hereafter called a half- silvered mirror. In Figure 7 the right eye image is viewed directly through the half- silvered mirror, and the left eye image which also appears on that screen is physically masked off. The left eye image also appears on the half-silvered mirror by reflection from the second display screen which is horizontal. However the reflection also changes the plane of polarisation 90° so that the right eye cannot see it, because of crossed polarisation with the polarising spectacles, whereas the left eye can. The right eye image appearing on the horizontal screen is also masked off by the structure, as the half-silvered mirror is not above it. For this viewing arrangement to work, the horizontal display screen needs its images visually reversed across the screen's shortest side, either electronically or using software, such that the second inversion caused by reflection off the half-silvered mirror causes both images to be correct with respect to each other for stereoscopic combination. Images 6 and 7 could be swapped in position with this version of viewing. For this change to work it would then be necessary to reverse the polarities of the viewing spectacles. The stereoscopic viewing window is shown diagrammatically but the housing which excludes ambient light and dust is omitted for clarity. Ideally the viewing window is covered by anti-reflection coated glass. It is to be appreciated that the embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected. Thus, for example, mounting means other than the spectacles shown in Figure 6 may be employed for mounting the apparatus of the invention on a person's head^* and it is advantageous to enclose the screens and gap to the face, such that ambient light is excluded from affecting the images.

Claims

1. Apparatus for enabling stereoscopic viewing, which apparatus comprises a first screen for being viewed by a first eye of a person, and a second screen for being viewed by a second eye of the person, and the apparatus being such that each screen is rotated 90° clockwise from a position required if the apparatus were to be driven by a video input signal giving non-stereoscopic viewing, each screen has during use a first image for the first eye and a second image for the second eye, a first mask for the first screen masks one of the first and second images on the first screen, a second mask for the second screen masks one of the first and second images on the second screen, and the first and second screens are displaced with respect to each other such that the displacement and the masks ensure that there is only one image on each screen that is viewable by each eye, and the image that is viewable on the first screen is on an axis for the first eye, and the image that is viewable on the second screen is on an axis for the second eye, whereby the apparatus is able to be driven by a video input signal giving the stereoscopic viewing.

2. Apparatus according to claim 1 in which the first mask is on the first screen, and in which the second mask is on the second screen.

3. Apparatus according to claim 1 or claim 2 in which the first and the second screens are displaced vertically with respect to each other.

4. Apparatus according to claim 3 in which the first screen is displaced vertically upwardly, and in which the second screen is displaced vertically downwardly.

5. Apparatus according to claim 1 or claim 2 in which the first and second screens are displaced angularly with respect to each other such that the first and second screens are perpendicular to each other.

6. Apparatus according to any one of the preceding claims in which one image is seen by transmission, and in which the other image is seen by reflection from a half silvered mirror.

7. Apparatus according to any one of the preceding claims and including mounting means for mounting the apparatus on the person's head.

8. Apparatus according to claims 1 , 5 and 6 in which the superimposed images are segregated from each other by means of polarising spectacles.