OPTICAL APPARATUS FOR IMAGE OVERLAYING ONTO A REAL WORLD SCENE

Abstract: Optical apparatus (2) for allowing a pre-recorded three dimensional image (6) to be overlaid onto a real world scene (8) such that the image (6) appears to be part of the real world scene (8), which optical apparatus (2) comprises a housing (10), storage means (32) containing the pre-recorded three-dimensional image (6), and viewing means (16) for viewing the real world scene (8) through the pre-recorded three-dimensional image (6) such that the pre-recorded three-dimensional image (6) is overlaid onto the real world scene (8), the storage means (32) being a cassette or a liquid crystal display storage means (32).

Description: OPTICAL APPARATUS FOR IMAGE OVERLAYING ONTO A REAL WORLD SCENE This invention relates to optical apparatus for image overlaying onto a real world scene. More especially, this invention relates to optical apparatus for allowing a pre-recorded three dimensional image to be overlaid on to a real world scene such that the image appears to be part of the real world scene. Optical apparatus for image overlaying onto a real world scene is known. The known apparatus is in the form of a military helmet mounted display which utilises a complex optical system, and which does not use a pre-recorded three dimensional image contained in storage means in the form of a film cassette or a liquid crystal display. Optical apparatus in the form of virtual reality apparatus is also known but the virtual reality apparatus does not usually overlay a prerecorded three dimensional image on to a real world scene . It is an aim of the present invention to provide optical apparatus for image overlaying onto a real world scene, which optical apparatus is relatively simple and inexpensive to construct as compared with known military helmet mounted displays and with virtual reality apparatus. Accordingly, in one non-limiting embodiment of the present invention there is provided optical apparatus for allowing a pre-recorded three dimensional image to be overlaid on to a real world scene such that the image appears to be part of the real world scene, which optical apparatus comprises a housing, storage means containing the pre-recorded three dimensional image, and viewing means for viewing the real world scene through the pre-recorded three dimensional image such that the pre-recorded three dimensional image is overlaid on to the real world scene, the storage means being a cassette or a liquid crystal display storage means. The optical apparatus of the present invention may be especially useful in the fields of architecture and archeology. Thus, for example, in architecture, the optical apparatus may be advantageous to show the appearance and the effects of buildings, constructions, extensions, restorations and interior decorations in a chosen site before any work has actually started. Thus, for example, the effect of buildings in the form of houses, factories or shops may be shown in a chosen site before any construction has been started. Similarly, the effect of constructions such for example as bridges, towers and power plants can be seen and appreciated before work is actually started. Thus the use of the optical apparatus of the present invention could be used to facilitate and improve the decisions of town planners, or the acceptance of a particular building or commercial development by the public. Modifications and improvements may be more easily thought of using the optical apparatus of the present invention. All this may be achieved at an early stage during the design phase of the buildings, constructions and the like. In the field of archeology, the optical apparatus of the present invention may allow ancient buildings to be seen in situ as they were before the destructive effects of time. Thus the optical apparatus of the present invention may facilitate the understanding of past civilisations, and the enjoyment of cultural visits to historical sites . The optical apparatus may stimulate the study of archeological re-constructions. The optical apparatus of the present invention may be such that it includes adjustor means for adjusting the distance at which the pre-recorded three dimensional image is placed on the real world scene, thereby allowing the pre-recorded three dimensional image to be placed at will on a natural field of view at any distance from a user of the optical apparatus. The image may be any suitable and appropriate image, for example of one or more objects and/or one or more persons and/or one or more animals. Preferably, the optical apparatus is one in which the housing is such as to enable the optical apparatus to be hand-holdable for ease of use. Thus, for example, the housing may be in the form of a housing for a pair of binoculars. The housing may however be in other forms if desired. In one embodiment of the invention, the optical apparatus may be one in which the viewing means comprises a beam splitter and reflective lenses, the beam splitter and the reflective lenses being spaced in air from each other. Such optical apparatus may be constructed to be light and inexpensive. Such optical apparatus will however have a relatively small horizontal field of field of 40°. in another embodiment of the present invention, the optical apparatus is one in which the viewing means comprises a beam splitter and reflective lenses, the beam splitter and the reflective lenses being enclosed in a transparent plastics material. Such optical apparatus will be heavier and more costly to manufacture than the above mentioned air-spaced beam splitter and reflective lens arrangement. However, the solid system utilizing the transparent plastics material enclosure gives a wider horizontal field of view of 48°, and the optical apparatus is also potentially more robust. The transparent plastics material may be an acrylic material . In both embodiments of the invention, the interocular spacing may be fixed, but the optical correction may be maintained over a large pupil size resulting in an effective interocular range of 53 - 75mm, which will satisfy 98% of the adult population. If the field of view is increased, the effective interocular range would be more restricted as the pupil size has to be scaled down to maintain the same level of optical correction. In practice this means that people at extremes of the interocular range are likely to notice some distortion of the image which they may find difficult to accommodate. If desired, the optical apparatus may include focusing means for catering for situations where the real world scene is less than 15m distant from the viewer. In this situation, the overlaid image can appear to move with respect to the real world scene, due to parallax with the two images being at a slightly different focus. The optical apparatus may be one in which the reflective lens has an inner concave surface coated with a partially reflecting coating to give a see- through ability. The viewing means may include a field correction lens. The pre-recorded three dimensional image may be on roll film in the cassette. The roll film will usually contain a plurality of the pre-recorded three dimensional images with each image being composed of two slightly different perspectives of the scene in order to generate the three dimensional image. Alternatively, the pre-recorded three dimensional image may be in the form of two slides in the cassette, with each slide having a slightly different perspective of the scene in order to generate the three dimensional image. In a further alternative, the pre-recorded three dimensional image may be in the form of a glass transparency. 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 a person using optical apparatus of the present invention; Figure 2 shows a pre-recorded three dimensional image overlaid onto a real world scene by the person shown in Figure l using the optical apparatus shown in Figure 1; Figure 3 illustrates the use of optical apparatus with a 48° field of view; Figure 4 is a perspective view of optical apparatus giving a 48° field of view and utilising cylindrical film guides; Figure 5 is a plan view of the apparatus shown in Figure 4; Figure 6 is a perspective view of optical apparatus giving a 48° field of view and utilising flat film guides; and Figure 7 is a plan view of the optical apparatus shown in Figure 6. Referring to Figures 1 and 2, there is shown optical apparatus 2 being used by a person . The optical apparatus 2 allows a pre-recorded three dimensional image 6 to be overlaid onto a real world scene 8. As can be seen from Figure 2, the image 6 is of a temple and the real world scene 8 is of countryside. The image 6 appears to be part of the real world scene 8. The optical apparatus 2 comprises a housing 10 which is a hand holdable housing 10 somewhat like a pair of binoculars. The optical apparatus 2 also includes storage means containing the image 6, and viewing means for viewing the real world scene 8 through the image 6 such that the image 6 is overlaid onto the real world scene 8. The storage means and the viewing means are not shown in Figures 1 and 2 for simplicity of illustration. Figure 3 shows part of the face 12 of the person 4 utilising the optical apparatus 2 which has been constructed in the form of a slide viewer giving a 48° field of view. As can be seen from Figure 3, the optical apparatus 2 has the image 6 in the form of a slide. The slide surface may be plane or cylindrical. Illumination of the image 6 comes from overhead ambient light as shown by arrows 14. Figure 3 shows viewing means 16 comprising a beam splitter 18 and a reflective lens 20. As can be seen from the annotation on Figure 3, the eye 22 of the person 4 is able to see a direct view of the outside world via the beam splitter 18 and the reflective lens 20 on line 24. The eye 22 is also able to see a combined view of the outside world and the image 6 on lines 26. Referring to Figures 4 and 5, there is shown optical' apparatus 2 utilising a 50:50 beam splitter 18 and two positions 28 which act as focal planes for images on slides (not shown) . The slides are placed face upwards of the positions 28 in order to collect ambient overhead illumination. Figure 4 shows the use of optical correction means 30. This optical correction means 30 over large pupils gives an effective interocular range of 53- 75mm, thus catering for over 98% of the adult population whilst obviating the need for interocular adjustment. The optical apparatus 2 utilises reflective lenses 20 as shown. The reflective lenses each have an internal surface which acts as a concave mirror to enable the image 6 to be set anywhere between 2.5m and infinity. The person 4 can see the outside world through the reflective lenses due to the use of a semi-transmissive coating on the internal surface of the reflective lenses 20. Thus the image 6 is able to be superimposed upon the real world. As can be seen from Figure 5, the image 6 is wound on a cassette 32 having a winding mechanism 24 and guide spools 36, 38. Light for illuminating the image 6 comes from overhead ambient illumination as indicated by the arrows 14. The image 6 on the film passes through cylindrical film guides 40, 42 which give a film gate aperture of 36 x 24mm. The cylindrical film guides 40, 42 have a cylinder radius of 50mm. 10 Figures 6 and 7 show optical apparatus 2 which gives a 48° field of view and which utilises flat film guides . As can be seen from Figures 6 and 7, the beam splitter 18, the reflective lenses 20 and the optical correction means 30 are the same as the optical apparatus shown in Figures 4 and 5. In the various embodiments of the optical apparatus 2 shown in the drawings, the use of the reflective lenses 20 may give approximately 2 dioptres of. over-correct field curvature, which most persons 4 can accommodate when using conventional optical instruments such as binoculars and magnifiers. However, where the image 6 of the slide is seen against the real world background or scene 8, the field of curvature could prove a little too excessive for some persons 4 comfortably to fuse the two images together. For this reason, the cylindrical slide surface and the field correction lens are shown which reduce the field curvature to approximately 0.6 and i.o dioptres respectively. In the drawings, the winding mechanism for the cylindrical gate system has been shown in a simplified manner and it is more complicated due to the additional role as required to hold the film in the correct location. In high brightness environments, it may be necessary to dim the real world scene in order to 99/46626 11 enhance the contrast of the virtual image 6. This can be achieved using a polarising surface applied to the external surface of the reflective lenses 20. Alternatively, the reflective lenses 20 may be made of a photochromic material . With the use of the polarising surface, an adjustable voltage can be applied to the polarising surface in order to vary the degree of polarisation and hence the attenuation of the external scene brightness. If an adjustable voltage is required, then the optical apparatus 2 will normally be battery powered. It will be appreciated from the drawings that the optical apparatus of the present invention has a see- through capability in order that virtual images can be overlaid onto a real world scene. The images can be of high resolution photographic quality, produced by computer aided design techniques. The optical apparatus 2 is preferably hand held and in its most simple embodiment does not require a source of power. The optical apparatus may give a minimum horizontal field of view of 40°. Long eye relief may be provided in order to cater for spectacle wearers . The optical apparatus may provide a large effective interocular range, for example of 53 - 75mm, with no adjustment being required. The optical apparatus provides good optical correction. A slide surface may be provided 12 at the top of the apparatus, angled away from the person's forehead, in order to gain maximum collection of overhead ambient illumination. 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, in more complicated embodiments, a focus adjustment can be provided, for example for use in situations where the real world is relatively close to the viewer, for example less than 15m. In more complicated embodiments, the slide containing the image may be replaced by a liquid crystal display. A polarising surface on the external surface of the reflecting lenses, or alternatively a photochromic material, may be used as a means of adjusting scene brightness as mentioned above. For indoor applications of low ambient brightness, artificial illumination may be provided. This artificial illumination may be external to the optical apparatus of the invention, or it may form part of the optical apparatus being, for example, battery operated. The optical apparatus operates such that an intermediate level of field curvature correction is desirable as the person 4 is actively overlaying the generated image 6 with a real world background for a visual 99/46626 13 effect rather than the determination of an accurate co-ordinate measurement. Preferably, in the optical apparatus of the invention, the two images which give the three dimensional image are arranged to overlap entirely. However, if only a central part of the viewed image overlaps, then the three dimensional effect is limited to the overlapping area but a wider field of view is obtained.

Claims: 14 CLAIMS 1. Optical apparatus for allowing a pre-recorded three dimensional image to be overlaid on to a real world scene such that the image appears to be part of the real world scene, which optical apparatus comprises a housing, storage means containing the prerecorded three dimensional image, and viewing means for viewing the real world scene through the prerecorded three dimensional image such that the pre- recorded three dimensional image is overlaid on to the real world scene, the storage means being a cassette or a liquid crystal display storage means. 2. Optical apparatus according to claim 1 and which is such that it includes adjustor means for adjusting the distance at which the pre-recorded three dimensional image is placed on the real world scene, thus allowing the pre-recorded three dimensional image to be placed at will in any part of a natural field of view of a user of the optical apparatus. 3. Optical apparatus according to claim 1 or claim 2 in which the housing is such as to enable the optical apparatus to be hand-holdable for ease of use. 15 . Optical apparatus according to claim 3 in which the housing is in the form of a housing for a pair of binoculars . 5. Optical apparatus according to any one of the preceding claims in which the viewing means comprises a beam splitter and reflective lenses, the beam splitter and the reflective lenses being spaced in air from each other. 6. Optical apparatus according to any one of claims 1 - 5 in which the viewing means comprises a beam splitter and reflective lenses, the beam splitter and the reflective lenses being enclosed in a transparent plastics material. 7. Optical apparatus according to claim β in which the transparent plastics material is an acrylic material . 8. Apparatus according to any one of claims 5 - 7 in which the reflective lenses have an inner concave surface coated with a partially reflecting coating to give a see-through ability. 16 9. Apparatus according to any one of claims 5 - 8 in which the viewing means includes a field correction lens. 10. Optical apparatus according to claim 1 and substantially as herein described with reference to the accompanying drawings .

Inventors: BUSINARO TIZIANO VINICIO, HUXFORD ROGER BRIAN, BUSINARO, TIZIANO, VINICIO, HUXFORD, ROGER, BRIAN
Applicants: BUSINARO LUCA, BUSINARO TIZIANO VINICIO, HUXFORD ROGER BRIAN, BUSINARO, LUCA, BUSINARO, TIZIANO, VINICIO, HUXFORD, ROGER, BRIAN
Application year: 1999
Main classification: G02B27
IPC codes: G02B27