WO1998030989A1

WO1998030989A1 - Surveillance device

Info

Publication number: WO1998030989A1
Application number: PCT/GB1997/000033
Authority: WO
Inventors: Mark Gregory Pitts
Original assignee: Texecom Limited
Priority date: 1997-01-08
Filing date: 1997-01-08
Publication date: 1998-07-16
Also published as: AU1387797A; GB9915969D0; GB2337656A

Abstract

A covert surveillance device comprising a housing (10) for a PIR unit, a lens (14) in the housing consisting of a mesh (16) an opaque sheet (18) behind the lens. A camera (22) is disposed in the housing with the camera lens (24) in register with an aperture (20) in the opaque sheet (18).

Description

SURVEILLANCE DEVICE

This invention relates to a surveillance device and more particularly a device for covert surveillance.

Surveillance by means of instruments such as closed circuit television systems are now commonly used for the purposes of watchin-g members of the public and to provide recorded images of members of the public which can be used for the detection and identification of criminals. These systems are overt. They can clearly be seen and frequently there are notices drawing attention to the fact that the system is installed. However, there can be circumstances where it is desired that the existence of a surveillance system should not be evident to persons being watched. It is with this latter type of system that this invention is particularly concerned.

One of the problems about covert surveillance is that the equipment must be capable of surveying a desired area or site, but at the same time that must not be apparent to the person or persons being watched. So closed circuit television, cameras and the like cannot be used. The present invention has been made in order to deal with this problem.

According to the invention there is provided a covert surveillance device comprising a housing for a sensor, characterised in that a camera is disposed within the housing and the housing includes a lens, said lens comprising opaque portions for reflecting light and transparent portions defined by said opaque portions, said transparent portions permitting the transmission of light from outside the housing to the camera, and the camera including a lens, said camera lens being dimensionally larger than the opaque portions.

In a preferred embodiment of the invention the housing has the appearance of a passive infra red (PIR) sensor of the kind which are commonly installed in burglar alarm systems for detecting the presence of an intruder. The public are now quite used to seeing PIR units installed in places such as shops, cafes, offices and so on and will not, therefore, suspect that such units may be there for a different purpose, namely surveillance. The lenses of such units appear somewhat opaque when viewed from outside the unit in normal lighting conditions. It is preferred that in the unit of the invention the lens of the housing behind which the camera is disposed should, as far as possible, resemble the lens of a PIR unit. Preferably the lens is in the form of an opaque mesh.

Preferably an opaque mask extends behind the partially opaque lens of the housing, the mask having an aperture or transparent portion therein which corresponds to the location of the lens of the camera inside the housing. Because the level of illumination within the housing is lower than the level of illumination outside it an observer will see light reflected from the opaque lens and not see into the housing and as a result cannot identify the presence of a camera therein.

The camera in the device of the invention can be linked to a monitor at some remote location and/or means can also be linked to the camera to record what the camera observes much in the same way as known closed circuit systems.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which:-

Fig.l is a front exterior elevation of a device of the invention;

Fig.2 is a view of the interior of the front face of the device of Fig.l; and

Fig.3 is a vertical section through the device.

Referring to the drawing the covert surveillance device comprises a housing 10 having the appearance of a PIR sensor. An aperture 12 is provided in the front face of the housing into which a lens 14 is fitted. The lens comprises a fine opaque mesh 16 formed, for example, by perforating a metal sheet. The outer side of the mesh is preferably white or light coloured so as to reflect incident light.

On the inner side of the front face of the housing an opaque sheet 18 extends over the lens 14. An aperture 20 is provided in the opaque sheet 18. The purpose of the aperture is to enable a camera 22 within the housing to take pictures. To that end the aperture needs to be only the same size as the camera lens 24.

The provision of the opaque sheet helps to ensure that an observer cannot see into the housing and identify the camera therein. The area where light passes into the housing is through the aperture in the opaque sheet and with the camera lens close up to the part of the mesh adjacent the aperture, vision into the housing through the aperture is virtually impossible.

The opaque sheet may have one or more additional apertures to provide through vision to an LED or to permit sound to reach a microphone. These items would be disposed in a tube or the like so that again an observer could not see the camera in the housing.

The dimensions of the opaque lines forming the mesh and their relative spacing should be such that they are relatively small compared to the dimensions of the camera lens so that they do not seriously impair the image that is received by the camera lens. Further because the camera lens will be focussed to a distance well beyond the mesh, the image received by the camera will not include the mesh. In this connection the camera response is similar to the human eye which will not see a fine mesh placed closely in front of it when focussed on a point some distance away.

The invention is not restricted to the above described embodiment and many variations and modifications can be made. For example the lens for the housing can be made of a transparent sheet of plastics or glass having an opaque mesh formed thereon as by printing, etching or other method.

Claims

1. A covert surveillance device comprising a housing for a sensor, characterised in that a camera is disposed within the housing and the housing includes a lens, said lens comprising opaque portions for reflecting light and transparent portions defined by said opaque portions, said transparent portions permitting the transmission of light from outside the housing to the camera, and the camera including a lens, said camera lens being dimensionally larger than the opaque portions.

2. A device as claimed in Claim 1, wherein the lens comprises an opaque mesh.

3. A device as claimed in Claim 2, wherein the mesh comprises a perforated sheet.

4. A device as claimed in Claim 2 or Claim 3, wherein the mesh comprises a perforated metal sheet.

5. A device as claimed in any preceding claim, wherein the opaque portions are light coloured on the exterior of the lens.

6. A device as claimed in any preceding claim, wherein the camera lens is focussed at a location spaced from the housing.

7. A device as claimed in any preceding claim, wherein an opaque sheet extends over the inner surface of the lens, an aperture for the camera lens being provided in the opaque sheet .

8. A device as claimed in Claim 7, wherein the aperture in the opaque sheet is substantially the same size as the camera lens.