GB2436409A

GB2436409A - Camera with reflector for forming images on different sensor portions

Info

Publication number: GB2436409A
Application number: GB0605443A
Authority: GB
Inventors: Adrian Marc Simon Jacobs; David James Montgomery
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2006-03-20
Filing date: 2006-03-20
Publication date: 2007-09-26
Also published as: GB0605443D0

Abstract

A camera (11) comprises an image capture layer (7), image forming means (8) for forming a first image of an object on a first portion (13) of the image capture layer, and an optical arrangement for forming, in combination with the image forming means (lens, 8), a second image of the object on a second different portion (14) of the image capture layer. The optical arrangement comprises a single reflector (10), being arrangeable in at least a first configuration in which it is laterally spaced from and inclined with respect to a principal axis (12) of the camera (11). The first and second images obtained by the camera may form a stereoscopic image pair of the object. Planar reflector 10 may be detachable from camera 11. Inclining the reflector (10) towards the principal axis (12) of the camera (11) increases the field of view of the second image or, alternatively, allows a given field of view for the second image to obtained using a shorter reflector. The camera may be on a mobile phone, with mirror 10 folding (see Figure 6).

Description

A Camera The present application relates to a camera, in particular to

a camera for obtaining a pair of related images of an object. It particularly relates to a camera for obtaining a pair of related images of an object such that the two images may be used in, for example, a 3-dimensional display.

Displays that are able to display a 3-dimensional image are well known. One type of 3-D display is the autostereoscopic 3D display, which achieves a 3-D effect by displaying a pair of related images of a scene. One image corresponds to a left eye viewpoint of the scene and the other image corresponds to a right eye viewpoint of the scene. The display is arranged to display the two images in different directions from one another, such that the left eye image is displayed to a left eye viewing window and the right eye image is displayed to a right eye viewing window. If an observer positions their head such that their left eye is in the left eye viewing window and their right eye is in the right eye viewing window, the observer will see the left eye viewpoint of the scene in their left eye and the right eye viewpoint of their right eye and so will perceive a 3-D image.

In order for an autostercoscopic display to provide a 3-D image, it is necessary first to obtain a pair of related images of a scene, such that one image corresponds to the left eye view of the scene and the other image corresponds to the right eye view of the scene. Such a pair of related images of a scene is generally referred to as a "stereoscopic image pair". In the case of a photographic image (which may be a still image or a moving image), this can be achieved by mounting two nominally identical cameras side-by-side, to form a "stereoscopic camera". The left camera of the camera pair captures the left eye view of a scene, and the right camera of the camera pair captures the right eye view of the scene. However, the use of a pair of cameras necessarily increases cost, size and complexity compared to the use of a single camera.

Moreover, in practice there will be slight differences between two nominally identical cameras, and these differences will degrade the quality of the image pair obtained.

Furthermore, it is necessary to ensure that the cameras are correctly mounted with their axes parallel to one another, and this can again be difficult to achieve in practice.

There has therefore been considerable effort directed to obtaining a stereoscopic image pair using a single camera. As an example, US patent No. 2 736 250 discloses a camera provided with an optical arrangement that can direct two "bundles" of light, that have been emitted by an object in slightly different directions from one another, onto the camera film. The optical arrangement comprises mirror and a beam splitter, and directs one bundle of light on to a first area of the film and directs the second bundle of light on to a second, different area of the camera film so that a stereoscopic image pair can be recorded. However, optical systems of the type described in US Patent No. 2 736 250 tend to be bulky and expensive, and are therefore not suitable for use with the current generation of small digital cameras and, in particular, mobile phone cameras. It is not generally possible to reduce the size of these prior art optical systems, owing to the need for the arrangement to capture images of the object from two different directions.

US patent application No. 2003/0156187 discloses a camera in which light emitted by an object in one direction is captured directly on the camera film, and light travelling in another direction from the object is reflected by a reflector so as to be captured on a second, different region of the camera film. This prior art camera is shown schematically in figure 1. Light emitted in a first range of directions, shown schematically by ray path 1, from an object 2 is captured by a camera 3, and is focused on to the camera's film or image capture layer by the camera's optical system. Light propagating from the object in a second range of directions, shown as ray path 5, is reflected by a mirror 4 so as to be incident on the camera 3, and is focused on to a second part of the camera's film or image capture layer by the camera's optical system.

The reflector 4 is arranged to be parallel to the principal axis of the camera 3. The effect of the reflector 4 is to create a virtual second camera 6, positioned at a lateral separation b from the camera 3. The virtual camera 6 and the camera 3 thus simulate a stereoscopic camera pair.

The camera of US 2003/0156187 does, however, have the disadvantage that the mirror 4 is required to be large enough to ensure that the field of view for the image reflected in the mirror is equal in size to the field of view for the image captured directly by the camera. The teaching of US 2003/0156187 is therefore unsuitable for use with a small camera such as a mobile telephone camera, since either the minor 4 would be unduly large for a mobile device or, if the minor were made small, one image of the image pair

would have a restricted field of view.

The present invention provides a camera comprising:-an image capture layer; image forming means for forming a first image of an object on a first portion of the image capture layer; an optical arrangement for forming, in combination with the image forming means, a second image of the object on a second portion of the image capture layer, the second portion being different from the first portion; wherein the optical arrangement comprises a single reflector, the reflector being arrangeable in at least a first configuration to which it is laterally spaced from and inclined with respect to a principal axis of the camera.

Since the optical arrangement comprises only a single reflector, it can be made lightweight and the invention may therefore be applied to a small portable camera such as a mobile telephone camera. Placing the reflector at an angle to the axis of the camera means that, for a given minor size, the present invention will provide a greater field of view than will a minor arranged parallel to the camera axis as in US 2003/0156187.

These factors mean that an optical arrangement of the invention may be made much smaller and lighter than a prior art optical arrangement, so that the invention may be applied to a small digital camera, and in particular to a mobile telephone camera.

For the avoidance of doubt, the term "mobile telephone camera" as used herein refers to a mobile telephone device provided with an integral camera, such as is well-known in the art.

The reflector may be inclined towards the principal axis of the camera. It may be inclined towards the principal axis of the camera by at least 2 or by at least 100. There are typical angles of inclination that may be used where the invention is applied to a mobile telephone camera, given the normal dimensions of a mobile telephone.

The reflector may be substantially planar.

The reflector may be detachable from the camera. If the reflector is detached, the camera can be operated in a 2-D mode. Moreover, detaching the reflector may allow easier storage and transportation of the camera. For example, the camera may have a camera body, and the reflector may attachable to and detachable from the camera body.

Alternatively, the reflector may be arrangeable in the first configuration or in a second configuration different from the first configuration.

Alternatively, the camera may have a camera body, and the reflector may be rotatably mounted on the camera body. The reflector may then be changed from the first configuration to the second configuration, or vice versa, by rotation.

In the second configuration, the reflector may not be effective to direct light from the object on to the image capture layer. This again allows the camera to be operated in a conventional 2-D mode, by putting the reflector in the second configuration. In the second configuration, the reflector may be inclined at substantially 90 away from the axis of the camera.

The optical arrangement may consist solely of the reflector. This minimises the weight and physical size of the optical arrangement. However, the optical arrangement may in principle comprise, in addition to the reflector, further components (which are not reflectors).

The first image of the object and the second image of the object may form a stereoscopic image pair. This allows the first and second images to be displayed on a 3-D display to give a 3-D image.

The camera may be a mobile telephone camera.

The camera may further comprise a display operable at least in a 3-D display mode.

This allows the user to display a stereoscopic image pair captured by the camera to obtain a 3-D image.

Preferred embodiments of the present invention will now be described by way of illustrative example with reference to the accompanying figures, in which: Figure 1 is a schematic view of a prior art camera that can simulate a stereoscopic camera pair; Figure 2 is a schematic illustration of a camera of the present invention; Figures 3(a) to 3(d) illustrate operation of the prior art camera of figure 1(a); Figures 4(a) and 4(b) illustrate operation of a camera of the present invention; Figure 5 illustrates an image obtained by a camera of the present invention; Figures 6(a) and 6(b) illustrate an embodiment of a camera according to the present invention; Figures 7(a) and 7(b) illustrate another embodiment of a camera according to the present invention; Figures 8(a) and 8(b) illustrate the effect of modifying the camera of figure 2(a); and Figures 9(a) and 9(b) illustrate possible viewfinder configurations for a camera of the present invention.

Figure 2 is a schematic view of a camera 11 according to a first embodiment of the present invention. The camera comprises an image capture layer 7 for capturing an image. The invention will be described with reference to a digital camera in which the image capture layer 7 may be, for example, an array of charge-coupled devices (CCDs) as indicated in figure 2. However, the invention is not so limited and the image capture layer 7 may be any other suitable image capture layer.

The camera further comprises image-forming means 8 for forming an image of an object on the image capture layer 7. In figure 2 the image-forming means 8 are represented as a single lens for clarity of description, but the camera of the invention is not limited to this particular image-forming means.

The image capture layer 7 and the image-forming means 8 are respectively enclosed in and mounted on a camera body 9, shown schematically in figure 2.

The camera 11 further comprises a reflector 10 that is laterally separated from the principal axis 12 of the camera. The principal axis 12 of the camera is the axis of symmetry of the image forming system 8. This will normally be the axis that passes perpendicularly through the image capture layer 7 and also passes through the optical centre of the image-forming means 8. As in the camera of figure 1, one image of an object 2 is formed on a first portion 13 of the image capture layer 7 directly by the image-forming means 8, and a second image of an object 2 is formed on a second, different portion 14 of the image capture layer 7 by light that undergoes a reflection at the reflector 10. The action of the reflector 10 is to create a virtual image of the camera body 9, image-forming means 8 and image capture layer 7, and this virtual image is schematically denoted at 15 in figure 2.

A practical implementation of the camera 11 may comprise other features such as, for example, a shutter for selectively blocking the path of light to the image capture layer, a power supply, focusing means for adjusting the image forming means 8 to compensate for different distances of an object away from the camera, etc. These features are not relevant to the present invention, and will not be described further in this application.

In the present invention, in contrast to US 2003/0156 187, the reflector 10 is not parallel to the principal axis 12 of the camera. In the invention, the reflector 10 is inclined with respect to the principal axis 12 of the camera.

The reflector 10 is tilted towards the principal axis 12 of the camera, as shown in figure 2. By tilted "towards" the principal axis 12 of the camera, it is meant that the separation between the reflector 10 and the principal axis 12 of the camera decreases moving from camera body 9 towards the object 2.

The effect of the present invention is illustrated in figures 3(a) -3(d) and figures 4(a) and 4(b). Figure 3(a) shows a camera in which the reflector 10 is arranged parallel to the principal axis of the camera, as taught in US 2003/0156187 in order to provide a rectified image pair. This has the disadvantage that, if the reflector 10 is small, the field of view for the image obtained via reflection at the reflector 10 is restricted, and is much less than the field of view of the image obtained directly without reflection. This is shown in figure 3(b), in which 16 denotes the image obtained directly without reflection and 17 denotes the image obtained by reflection at the reflector 10. It can be seen that the restricted field of view for the image 17 obtained by reflection means that the lateral extent of the image 17 obtained by reflection is much less than the lateral extent of the image 16, so that the image 17 obtained by reflection is incomplete. As a result, a proper stereoscopic image pair cannot be obtained.

Figure 3(c) again corresponds to the camera of figure 1, but shows a mirror having a much larger extent a2 (where a2 > a) parallel to the axis 12 of the camera. Figure 3(d) shows the two images obtained by the camera of figure 3(c), and it can be seen that the greater field of view for the image 17 obtained by reflection means that the image 16 obtained directly and the image 17 obtained by reflection now have the same lateral extent as one another. it is therefore possible to obtain a stereoscopic image pair.

However, the need to make the mirror large in order to obtain a stereoscopic image pair means that it is difficult to apply the teaching of US 2003/0156187 to a small portable camera such as a mobile telephone camera.

The effect of inclining the reflector 10 towards the optical axis 12 of the camera is to increase the field of view for the image 17 obtained via reflection at the reflector 10. As a result, for a given size of reflector, the field of view for the second image 17 is increased. This is shown schematically in figure 4(a) and 4(b). Figure 4 (a) shows a camera of the invention, in which the reflector 10 is inclined towards the principal axis 12 of the camera and figure 4(b) illustrates the images 16, 17 recorded on the image capture layer of the camera of figure 4(a). It can be seen that the increased field of view for the second image that is obtained by tilting the reflector 10 means that, even though a small minor is used as in figure 3(a), the present invention allows a proper stereoscopic pair to be obtained.

The present invention thus enables a stereoscopic image pair to be obtained using a smaller reflector 10 than in US 2003/0156187. The present invention thus allows the size and weight of the reflector to be reduced, and the invention is therefore particularly suited for use with a small portable camera such as a mobile telephone camera.

Conversely, for a given size of reflector, a camera of the invention will provide a greater field of view for the image obtained by reflection than will a camera of US 2003/0156187.

A camera of the present invention captures two images that correspond to the images that would be obtained by a pair of cameras arranged such that their axes converge on the object. It is sometimes preferred to use a stereoscopic image pair in which the views correspond to the views that would be obtained by a pair of cameras aligned with their axes parallel to one another. In this case, the images obtained by a camera of the present invention may be processed after acquisition in order to correct for the converging camera viewpoints. Suitable processing techniques are known, for example, as described in European patent application No. 02251251.1.

Figure 5 shows that the general form of a pair of images that would be obtained by the camera of figure 2. The left hand image 16 shown in figure 5 is the image captured on the first portion 13 of the image capture layer 7 of the camera. The image 16 shows the object 2 from the viewpoint that is captured directly by the camera. The right-hand image 17 in figure 5, which is captured on the second portion 14 of the image capture layer, shows the object from the viewpoint as captured by the camera after reflection by the reflector 10. The image 17 is therefore reversed, as a result of the reflection in the reflector 10, compared to the image 16. Known image processing techniques may be used to separate the composite image recorded on the image capture layer 7 into the left and right images 16, 17, and mirror reverse the image 17 captured after reflection in the reflector 10. The result of this processing step is to provide images of the object 2 taken from two different viewpoints, as required for use in a 3-D stereoscopic display.

Analysis of the position of the separator line 18 that separates the image 16 obtained directly from the image 17 obtained via reflector 10 may be used to obtain information about the tilt angle a of the reflector 10 relative to the axis 12 of the camera. If it is found that the tilt angle a varies from the design value, the variation in tilt angle may be accounted for during the processing of the reversed image 17. Suitable processing techniques, for example such as edge-detection techniques, are well-known in the art.

The tilt angle a of the reflector 10 is preferably at least 2 , may be at least 5 , and may be at least 10 .

In many cases it is desirable if a camera can be operated in a 3-D mode, in which it captures a pair of related images of an object, or in a conventional 2-D mode. Figures 6(a) and 6(b) illustrate one way in which a camera of the present invention may provide a 3-D mode or a 2-D mode. In the embodiment of figure 6(a), the reflector 10 is mounted on the camera, for example on the camera body 9, such that it is can be arranged in one configuration as shown in figure 6(a) and another second configuration as shown in figure 6(b). In the configuration shown in figure 6(a), the reflector is not effective to direct light from an object into the image forming means 8 of the camera -the reflector has been removed from the field of view of the image forming means 8 of the camera. In the configuration shown in figure 6(b), the reflector is arranged to be laterally spaced from, but tilted with respect to, the camera axis, as shown in figure 2.

With the reflector 10 arranged as shown in figure 6(b), the camera may operate in a 3-D mode.

The embodiment of figure 6(a) and 6(b) may conveniently be effected by rotatably mounting the reflector 10 on the camera body 9. The camera may then be switched between a 2-D mode and a 3-D mode simply by rotating the mirror so as to place it in either the folded "position" shown in figure 6(a) or the "unfolded" position shown in figure 6(b).

In this embodiment, the reflective surface of reflector 10 will be uppermost when the reflector is folded out of the field of view of the image forming means 8 to give the 2-D mode, as shown in figure 6 (a). In this case, the reflector 10 may function as a normal cosmetic mirror.

The embodiment of figures 6(a) and 6(b) is particularly convenient when the invention is applied to a mobile telephone camera. The body of a mobile telephone is generally elongate, so that the mirror can be received against the body of the mobile telephone in its folded configuration as shown in figure 6(a).

The mirror may be formed of, for example, a hard plastics material, with one face coated with a reflective coating, for example a thin metallic layer. The reflective coating may be covered by a transparent protective coating as protection against damage. A rotation stop is preferably provided to ensure that the mirror is rotated into the correct tilt angle for the 3-D mode.

En a modified embodiment, the reflector 10 may be detachably mounted on the camera, so that the reflector can be removed completely in order to provide a 2-D mode. The reflector may be attachable to or detachable from the camera body and, for example, may be a clip fit on to the camera body 9.

Figures 7(a) and 7(b) show a further embodiment of the present invention. In this embodiment, the reflector 10 may again be arranged in a first configuration in which it can provide a 3-D mode or a second configuration in which the reflector is outside the field of view of the image-forming means of the camera. Digital cameras or mobile telephone cameras are provided with batteries as a source of electrical power, and these are contained within the camera body 9. A conventional camera or mobile telephone camera is therefore provided with a battery cover 19 in its body 9 -the battery cover 19 is intended to be openable, or to be removable from the camera body, to allow access to the batteries when they require changing or re-charging. In the embodiment of figures 7(a) and 7(b), the reflector 10 is attached to the inner surface of the battery cover 19 of the camera. When the battery cover 19 is in its normal or "closed" position as shown in figure 7(a) the battery cover 19, and hence the reflector 10, are outside the field of view of the camera image forming means 8, so that the camera operates in a conventional 2-D mode. In order to convert the camera to a 3-D mode, the battery cover 19 is positioned as shown in figure 7(b) so that the reflector 10 is within the field of view of the image forming means, and is tilted with respect to the camera axis as shown in figure 2. This embodiment is generally similar to the embodiment of figure 6(a) and 6(b), but has the advantage that it is not necessary to provide a mount specifically for the reflector 10. A camera or mobile telephone camera will almost always have a battery cover, and making use of the battery cover as the mounting for the reflector 10 avoids the need to provide any further mounted means for the reflector.

This embodiment may be effect by making the inner surface of the battery cover reflective, or by attaching a separate reflector to the inner surface of the battery cover.

To change the camera of figures 7(a) and 7(b) from the 2-D mode to the 3-D mode, the battery cover 19 is initially rotated about an axis perpendicular to the plane of the paper in figure 7(a). This places the battery cover 19 in a configuration similar to that shown in figure 7(b), but with the reflector 10 on the opposite side of the battery cover to the image forming system 8. The battery cover is then rotated about its longitudinal axis (i.e., about an axis in the plane of the paper in the figures), so as to put the reflector 10 on the same side of the battery cover as the image forming system 8.

The reflector 10 could alternatively be provided on the outer surface of the battery cover 19, although providing the mirror on the inner surface of the battery cover has the advantage that the battery covers protects the mirror when the battery cover is in its closed position (to give a 2-D mode).

Figures 8(a) and 8(b) illustrate how the position and size of the reflector 10 determine the effective position of the virtual camera 15 of figure 2. In figure 8(a) the reflector 10 is spaced a relatively large distance from the axis 12 of the camera, so that the centre-to-centre separation dl between the camera body 9 and the virtual camera position 15 is relatively large. If the separation between the reflector 10 and the camera axis 12 is reduced, the separation between the camera body 9 and the virtual camera position 15 is reduced as shown in figure 8(b) -in figure 8(b) the spacing between the reflector 10 and the camera axis is less than the spacing between the reflector 10 and the camera axis in figure 8(a), so that the separation d2 between the virtual camera position 15 and the camera body 9 in figure 8(b) is smaller the separation dl between the virtual camera position 15 and the camera body 9 in figure 8(b).

The position of the virtual camera 15 in turn determines the apparent depth that is seen in a 3D image created from a pair of related images obtained by the camera. The reduced separation between the effective camera position 15 and the axis 12 of the camera in figure 8(b) compared to figure 8(a) will mean that a 3-D image formed using an image pair obtained by the camera of figure 8(b) will have a lower apparent depth than a 3-D image formed using an image pair obtained by the camera of figure 8(a).

Thus, the apparent depth of a 3-D image formed using an image pair obtained by a camera of the present invention will depend on the separation between the reflector 10 and the camera axis 12.

As explained with reference to figures 3(a) to 3(d) above, the field of view of the image 17 (that is, the spatial or angular extent of the scene captured) obtained via a reflection at reflector 10 is determined by the axial extent a of the reflector 10.

The axial extent a of the reflector, and its separation from the camera axis 12 may be chosen so as to provide the best 3-D result. Alternatively, where the invention is applied to a small portable camera, such as a mobile telephone camera, the reflector size and position may be chosen to fit the size of the camera, possibly at the expense of a lower 3-D image quality.

The position of the reflector may be chosen as the result of a trade-off between reflector size and the required apparent depth of a 3-D image formed using an image pair obtained by the camera. The greater is the separation between the reflector 10 and the camera axis 12 the greater will be the apparent depth -but the axial extent of the reflector 10 required to obtain a given field of view will also be greater.

In a preferred embodiment, the separation between the reflector 10 and the camera axis 12 may be adjustable, so that the separation can be changed between acquiring one pair of images and acquiring a subsequent pair of images. For example, the reflector may be mounted on the camera body so that the reflector 10 can be translated in a direction generally perpendicular to the camera axis 12. This can be done, for example, by mounting the reflector on a slider that can slide relative to the camera body.

The image processing steps described above may be carried out within the camera, or externally to the camera. In the second case, the captured images could be uploaded to a server, and the processing could be carried out in the server -after which the processed images could be down-loaded to the camera if desired. Processing the images externally to the camera is particularly advantageous in the case of a small mobile camera, which is designed to be as small as possible and to have a low power consumption.

In addition to the effects described above, the image processing may also allow other effects to be added. For example, if there should be any error in the angular position of the mirror (which would introduce a relative rotation between the viewpoint for one image 16 and the viewpoint for the other image 17), this rotational error could be rectified during post-processing of the images. For example, the techniques described in European Patent Application No. 02251251.1 may be used.

If the reflector 10 were an ideal reflector with 100% reflectance, thebrightness of the image 17 obtained via reflection at the reflector 10 would be the same as the brightness of the image 16 obtained directly. In any practical implementation of the invention the reflector 10 will of course have a reflectance of less than 100%, so that the brightness of the image 17 obtained via reflection at the reflector 10 will be lower than the brightness of the image 16 obtained directly. Given knowledge of the reflectance of a reflector used in a practical implementation of the invention, the difference between the brightness of one image and the brightness of the other image may be compensated for during a further post-processing step.

Similarly, defects or blemishes in the image 17 obtained via reflection at the reflector 10 that arise from defects in the reflector 10, for example from scratches in the surface of the reflector 10, may be detected by comparing the two images 16, 17 with one another.

Any detected defects or blemishes may be removed during post-processing of the images.

To aid a user of the camera who is recording images with the camera in a 3-D mode, it may be advantageous to provide an indication in the camera's viewfinder to indicate where the scene should be centred, to ensure that a high quality stereoscopic image pair may be obtained for a desired object. For example, the area of the viewfinder corresponding to one image may be outlined by means of a cursor 22, as shown in figure 9(a). Alternatively, the directly viewed image 16 may be entirely blacked out in the viewfinder image, as shown in figure 9(b). (In the case of a digital camera the viewfinder is a display such as an LCD panel, and it is straightforward to drive the display to black out the directly viewed image 16.) When the directly viewed image 16 is blacked out the camera user will see just the reflected image 17 in the viewfinder, and can determine whether or not the full field of view has been obtained for the reflected image. If the user determines that the scene is not correctly centred, so that the field of view of the reflected image 17 is less than the field of view of the direct viewed image 16, the user may adjust the camera position so that the scene is correctly centred.

Alternatively, it may be possible to compensate during processing, by cropping the directly viewed image to remove the extra part of the scene that is present in the directly viewed image 16 but is not present in the reflected image 17.

A mobile telephone camera is generally provided with a display screen so that, when operating in camera mode, a user can display a captured image. (When operating is telephone mode the display is used to display information relating to a telephone call such as the number dialled, a received text message etc.) Where the invention is applied to a mobile telephone camera having a display that is operable in at least a 3-D display mode, a user can display a captured image pair to obtain a 3- D image. By displaying a captured image pair, a user can obtain an idea of whether a pair of captured images form an acceptable stereoscopic pair, or whether they need to re-take the images. In principle, the pair of images may be displayed before any processing of the images has taken place (except for reversing the image 17 obtained via reflection), or the pair of images may be displayed after any of the processing steps described above have been performed either within the camera or external to the camera.

In the embodiments described above, the optical arrangement consists solely of the reflector 10. In principle however, the optical arrangement may comprise, in addition to the reflector, further components (but not including further reflectors). If any further components are provided in the optical arrangement, they are preferably light and physically compact, to keep the size and weight of the optical arrangement low.

Claims

CLAIMS: 1. A camera comprising: an image capture layer; image forming

means for forming a first image of an object on a first portion of the image capture layer; and an optical arrangement for forming, in combination with the image forming means, a second image of the object on a second portion of the image capture layer, the second portion of the image capture layer being different from the first portion of the image capture layer; wherein the optical arrangement comprises a single reflector, the reflector being arrangeable in at least a first configuration in which it is laterally spaced from and inclined with respect to a principal axis of the camera.

2. A camera as claimed in claim 1 wherein the reflector is inclined towards the principal axis of the camera.

3. A camera as claimed in claim 2 wherein the reflector is inclined towards the principal axis of the camera by at least 2 .

4. A camera as claimed in claim 2 wherein the reflector is inclined towards the principal axis of the camera by at least 10 .

5. A camera as claimed in any preceding claim wherein the reflector is substantially planar.

6. A camera as claimed in any preceding claim, wherein the reflector is detachable from the camera.

7. A camera as claimed in claim 6 and having a camera body, wherein the reflector is attachable to and detachable from the camera body.

8. A camera as claimed any of claims I to 5 wherein the reflector is arrangeable in the first configuration or in a second configuration different from the first configuration.

9. A camera as claimed in claim 8 and having a camera body, wherein the reflector is rotatably mounted on the camera body.

10. A camera as claimed in claim 8 or 9 wherein, in the second configuration, the reflector is not effective to direct light from the object onto the image capture layer.

11. A camera as claimed in claim 8, 9 or 10 wherein, in the second configuration, the reflector is inclined at substantially 900 away from the principal axis of the camera.

12. A camera as claimed in any preceding claim wherein the optical arrangement consists solely of the reflector.

13. A camera as claimed in any preceding claim, wherein the first image of the object and the second image of the object form a stereoscopic image pair.

14. A camera as claimed in any preceding claim wherein the camera is a mobile telephone camera.

15. A camera as claimed in claim 14 and further comprising a display operable at least in a 3-D display mode.