WO2010062257A1

WO2010062257A1 - An apparatus for imaging

Info

Publication number: WO2010062257A1
Application number: PCT/SG2008/000452
Authority: WO
Inventors: Hong Lim Wilson Tan; Ming Xing Lu; Wee Kok Andy Tan; Yeok Koon Joseph Tan; Chai Lay Lee
Original assignee: Stelop Pte. Ltd.
Priority date: 2008-11-28
Filing date: 2008-11-28
Publication date: 2010-06-03

Abstract

An apparatus (1) for imaging, the apparatus (1) including a first and a second lens system (20A, 20B) for generating first and second images in an image plane (12), the image plane (12) being positioned between the first and second lens systems (20A, 20B), a reflector (10) positioned in the image plane (12) for reflecting the first and second images, and a detector (15) for imaging the reflected first and second images.

Description

AN APPARATUS FOR IMAGING

Field of the Invention

The present invention relates to an apparatus for imaging, and in particular, to an apparatus that is particularly suited to be used for imaging at night.

Description of the Background Art

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Imaging apparatus often include the use of one or more cameras, detectors, or the like to image a particular region. However, when re-imaging a region, it has become evident that the re-imaged region is often of low quality, especially when imaging at night. It will be appreciated that this can have severe consequences in numerous applications, such as imaging for security surveillance.

Accordingly, the present invention seeks to substantially overcome, at least ameliorate one or more disadvantages of existing arrangements, or to provide alternatives to existing arrangements.

Summary of the Present Invention

It will be appreciated that the broad forms of the invention may be used individually or in combination.

According to a first broad aspect, there is provided an apparatus for imaging, the apparatus including: a) first and second lens systems for generating first and second images in an image plane, the image plane being positioned between the first and second lens systems; b) a reflector positioned in the image plane for reflecting the first and second images; and, c) a detector for imaging the reflected first and second images.

In one particular example, the reflector has the shape of a triangular prism with an apex, the apex of the triangular prism lying within the image plane and on an optical axis of first and second lens systems.

According to another example, the triangular prism has a first and second reflecting surface for reflecting respective first and second images.

With respect to a further example, the detector receives a single image formed from the reflected first and second images.

In accordance with another aspect, an edge between the first and second images is sharp and clear.

With respect to another form, the apparatus includes a re-image lens system between the reflector and the detector, for transferring the reflected images to the detector surface.

According to another example, the detector includes a camera.

With respect to yet another example, the reflector includes one or more mirrors.

According to a further aspect, the apparatus is combined into a modular device with other similar apparatus sharing a common housing.

In another example, the apparatus includes a processing system for image processing the reflected first and second images.

According to a second broad form, there is provided, a method for detecting an image, the method including the steps of: a) generating first and second images from respective first and second lens systems in an image plane, the image plane being positioned between the first and second lens systems; b) reflecting the first and second images by a reflector in the image plane; and, c) detecting the first and second images reflected by the reflector. According to a third broad form, there is provided an apparatus for imaging, the apparatus including: a) first and second lens systems for generating first and second images in an image plane, the image plane being positioned between the first and second lens systems; b) a reflector positioned in the image plane for reflecting the first and second images; and, c) a re-image lens system for transferring the first and second the images produced by first and second lens systems to a detector plane; and, d) a detector, positioned in the detector plane for imaging the reflected first and second images.

Brief Description of the Drawings

An example of the present invention will now be described with reference to the accompanying drawings, in which: -

Figure 1 is a schematic diagram of a side view of an example of an apparatus for imaging;

Figure 2 is a schematic diagram of a plan view of the apparatus of Figure 1 ;

Figure 3 is a photograph of an example apparatus for imaging;

Figure 4 is a functional block diagram of an example processing system that can be utilised to embody or give effect to a particular example;

Figure 5A is a schematic diagram of a plan view of a plurality of apparatus for imaging, being configured to divide detector images horizontally;

Figure 5B is a schematic diagram of a example images that can be obtained from the apparatus of Figure 5A;

Figure 6A is a schematic diagram of a plan view of a plurality of apparatus for imaging, being configured to divide detector images vertically; and,

Figure 6B is a schematic diagram of example images that can be obtained from the apparatus of Figures 6A.

Detailed Description Including Best Mode

Figures 1 and 2 show an example of an apparatus 1 for imaging.

In particular, the apparatus 1 of Figures 1 and 2 includes first and second lens systems 2OA and 20B respectively, which generate respective first and second images in an image plane 12. The image plane 12, in this example, is positioned between the first and second lens systems 2OA, 2OB. The apparatus 1 further includes a reflector 10 which, in this example, includes two mirror surfaces 9 A and 9B positioned in the image plane 12 for reflecting the first and second images to a detector 15.

As shown in Figure 1, the respective first and second images can be obtained from receiving radiation from the areas 5A and 5B respectively. Accordingly, the lens systems 2OA and 2OB can generate images, by focusing the radiation onto the image plane 12. The reflector 10, is shaped as a triangular prism, with each side 9A and 9B having a reflecting surface that reflects the respective first and second images generated by the respective lens systems 2OA and 2OB. The reflector 10 is positioned so that an apex 11 of the reflector 10 lies substantially within the image plane 12 and optical axis of the lens systems 2OA and 2OB.

Accordingly, the reflector 10 reflects radiation received from the lens systems 2OA, 2OB, providing the reflected radiation to the detector 15, so that the detector 15 receives radiation corresponding to each of the first and second images, with this radiation being used to form a single image that effectively combines the first and second images. By positioning the reflector in the image plane 12 of the two lens systems 2OA, 2OB, this means that the first and second images formed by the lens systems 2OA, 2OB are effectively re-imaged by lens group/system 25 to the detector 15.

By re-imaging the first and second images, and in particular, by having the apex of the reflector 10 positioned in the image plane 12, this ensures that the final image, formed from a combination of each of the first and second images can have a edge between the first and second images that is sharp and clear, separating the two images from regions 5 A and 5B.

This is particularly advantageous in use in night vision and other scenarios as it ensures that the final combined image is clear over the entire extent of the first and second images, and avoids the loss of visual clarity that can otherwise occur.

Notably, it can be seen from the examples of Figures 1 and 2 that the lens systems 2OA and 2OB include three lens structures in order to generate the images from regions 5 A and 5B. However, it will be appreciated by persons skilled in the art that other suitable lens systems and variations are considered to fall within the scope of the present application. Additionally, in order to direct the image received by the detector 15, the apparatus 1 can also include an additional lens system 25 (also referred to herein as a re-image lens system) placed between the reflector and the detector and aligned with the image plane, for transferring the image to the detector surface, which can be used to ensure that the detector 15 is accurately focussed on the surfaces of the reflector 10, thereby ensuring accurate focus and hence clarity in the re-image process.

It will be appreciated that the combination of the detector 15 and the lens system 25 can be implemented similar to that described in the applicant's prior application, WO 2007/084082. Notably, in this particular example, the lens system 25 is a finite system.

It will further be appreciated that in one specific example, the detector 15 can be or include a camera and that the reflector 10 can be or include one or more mirrors that are placed in a re- imaging region 8. Accordingly, the above-described apparatus 1 can act to provide the imaging effect of two cameras directed towards the areas 5 A and 5B. In this example, however, by using the reflector 10 positioned in the image plane of the lens systems 2OA, 2OB, this allows the same effect to be achieved whilst only requiring a single detector 15.

Notably, it will be appreciated by persons skilled in the art that any sensors/cameras/detectors 15 can be used in the apparatus 1. Furthermore, the reflector 10 can be formed of any suitable shape.

However, this is particularly advantageous in night vision applications where detectors generally need to more optically sensitive, to allow images to be captured in low light level scenarios, which typically results in the detectors being more expensive. Accordingly, this arrangement, allows two expensive detectors to be replaced by a single detector, and a cheaper lens and reflector arrangement. Furthermore, by ensuring that the reflector is positioned in the image plane 12, this ensures that resolution and clarity is maintained in the final image.

Figure 3 shows a photographic example of the apparatus 1 being a part of a modular device 30. Accordingly, in this particular example, device 30 includes three separate apparatus for imaging 1 in a common housing 32. The device 30 can be installed for numerous purposes, including but not limited to security surveillance or the like. Moreover, imaging processing may be used to further process the images obtained by the detector 15. The image processing can, in one example, be performed by any suitable processing system, an example of which is shown in Figure 4.

In particular, Figure 4 shows a processing system 50 including a processor 52, a memory 56, an input/output (I/O) device 54, such as a keyboard, and display, and an external interface 58, coupled together via a bus 60 as show. The processing system can include or is able to communicate with a data store or the like 62.

Thus, in a particular example, an image can be displayed on the display or any other I/O device 54, and in surveillance applications, the images displayed can be recorded and stored in the data store 62, either prior to, or post manipulation.

Accordingly, it will be appreciated that the processing system 50 can be formed from any suitable processing system, such as a suitably programmed PC, Internet terminal, lap-top, handheld PC, or the like, which is typically operating applications software to enable image manipulation, recordal and display.

In a further example, Figures 5 A to 6B show the apparatus 1, in configurations where the images obtained by the detector 15 are divided horizontally (Figures 5 A and 5B) and vertically (Figure 6A and 6B). In particular, Figures 5 A and 6 A show the modular design of Figure 3 being implemented such that three separate apparatus 1 (in these examples, referred to as cameras 1, 2, and 3) can form three separate images. As shown in Figures 5B and 6B, each image detected by the apparatus 1 is split into first and second images. For example, camera 1 forms images Ia and Ib, camera 2 forms images 2a and 2b, and camera 3 forms images 3a and 3b.

It will be appreciated that the above-described apparatus/system can provide numerous advantages, including but not limited to being effective in night or low-light imaging, and being able to provide clearer images of the region between two cameras. Furthermore, the image created is often clear and the distortion is minimal, thereby facilitating visualisation. The apparatus 1 is also generally easy to set up, simple and easy to implement. Additionally, the image processing implemented is generally straightforward and simple, thereby improving the efficiency of the system. In a further example, the particular design of the apparatus/system can allow for the system to be constructed in such a way so as to limit the size of the apparatus/system as well as limiting the effect on the image overlap. Thus, in one particular example, the system can be sized such that the distance between the ends of the lens system 2OA and 2OB (as indicated by "A" in Figure 1), is approximately 53mm. Additionally, the length of the system from the detector 15 to the lens systems 2OA and 2OB (as indicated by "B" in Figure 1) can be approximately 70mm. Furthermore, the length of the lens systems 20A, 2OB (as indicated by "C" in Figure 2) can be approximately 22mm.

This can allow, in one particular example, a f# of 1.8mm. where effective focal length (EFL) of the modular design of Figure 3 is 8.5mm (for the three sets used). Accordingly the field of view (FOV) for each apparatus can be 2 x (64° x 24°), where the total FOV can be 360° x 24° for the modular system of Figure 3.

Accordingly, it will be appreciated that the present apparatus/system is particularly suited for night applications (or use in situations where limited light is available).

The foregoing describes only some embodiments of the present invention, and modifications and/or changes can be made thereto without departing from the scope and spirit of the invention, the embodiments being illustrative and not restrictive.

In the context of this specification, the word "comprising" means "including principally but not necessarily solely" or "having" or "including", and not "consisting only of. Variations of the word "comprising", such as "comprise" and "comprises" have correspondingly varied meanings.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1) An apparatus for imaging, the apparatus including: a) first and second lens systems for generating first and second images in an image plane, the image plane being positioned between the first and second lens systems; b) a reflector positioned in the image plane for reflecting the first and second images; and, c) a detector for imaging the reflected first and second images.

2) The apparatus of claim 1, wherein the reflector has the shape of a triangular prism with an apex, the apex of the triangular prism lying within the image plane and on an optical axis of first and second lens systems.

3) The apparatus of claim 2, wherein the triangular prism has a first and second reflecting surface for reflecting respective first and second images.

4) The apparatus of any one of claims 1 to 3, wherein the detector receives a single image formed from the reflected first and second images.

5) The apparatus of claim 4, wherein an edge between the first and second images is sharp and clear.

6) The apparatus of any one of claims 1 to 5, wherein the apparatus includes a re-image lens system between the reflector and the detector, for transferring the reflected images to the detector surface.

7) The apparatus of any one claims 1 to 6, wherein the detector includes a camera.

8) The apparatus of any one of claims 1 to 7, wherein the reflector includes one or more mirrors.

9) The apparatus of any one of claims 1 to 8, wherein the apparatus is combined into a modular device with other similar apparatus sharing a common housing.

10) The apparatus of any one of claims 1 to 9, wherein the apparatus includes a processing system for image processing the reflected first and second images.

H)A method for detecting an image, the method including the steps of: a) generating first and second images from respective first and second lens systems in an image plane, the image plane being positioned between the first and second lens systems; b) reflecting the first and second images by a reflector in the image plane; and, c) detecting the first and second images reflected by the reflector. 12) An apparatus for imaging, the apparatus including: a) first and second lens systems for generating first and second images in an image plane, the image plane being positioned between the first and second lens systems; b) a reflector positioned in the image plane for reflecting the first and second images; and, c) a re-image lens system for transferring the first and second the images produced by first and second lens systems to a detector plane; and, d) a detector, positioned in the detector plane for imaging the reflected first and second images.