GB2257257A - Security apparatus - Google Patents

Abstract

The invention provides security apparatus (10) comprising a covertly operating infra-red light source (12), imaging means (14) capable of forming an image in infra-red light, and means (16) to cause operation of said light source (12) in response to a triggering input. The triggering input is provided by sensor means operative in response to the presence or activity of an unauthorised person or which may be in the form of switch means operable by a user. The invention also provides an imaging system comprising a rotating mirror (M). prism or the like which is rotatable about an axis (A) to direct light (visible or other) to image-sensing locations (40a, 40b, 40c, 40d) distributed around said axis (A). <IMAGE>

Description

Title: "Security apparatus" Description of Invention This invention relates to security apparatus.

Many premises, both domestic and commercial, and vehicles, are equipped with security apparatus in the form of burglar alarms, generally arranged to activate an audible alarm, and sometimes a visual alarm, in the event of being triggered by the presence or activity of an unauthorised person, and although such alarms can have a deterrent effect, they suffer from the disadvantage that owing to the large number of such alarms now fitted to premises and vehicles, the incidence of false alarm indications, due to triggering of the alarms by spurious inputs of one sort or another, is comparatively great, causing neighbours, passers by or bystanders to take little or no notice of such alarms when they sound, or to delay taking action until it is too late to catch any such unauthorised person.

It has been indicated by a police statement that about three-quarters of break-ins are conducted by known criminals, and that compared with the above alarms it would be preferable, alternatively or additionally, to provide means for obtaining identification evidence.

Systems exist for providing visual identification evidence, employing, for example video cameras such as are commonly installed in retail shops.

However such video cameras cannot work in poor light conditions or darkness.

For larger premises, permanent illumination, photo-multipliers and image intensifiers may be used, but such systems are so highly priced as to be out of the range of domestic and small commercial users. The common features of such known systems are that they are expensive, rely heavily on electronics, require expert installation and servicing, and are too bulky to be installed in a hidden manner.

It is an object of the invention to provide new and improved security apparatus, for providing visual identification evidence in any ambient lighting conditions including complete darkness, with the advantages of relative cheapness and relative simplicity, for example so as easily to be within the range and competence of domestic, small commercial, and vehicle users.

According to the invention, there is provided security apparatus comprising a covertly operating infra-red light source, imaging means capable of forming an image in infra-red light, and means to cause operation of said light source in response to a triggering input.

Operation of said light source may be caused directly, or may be caused indirectly such as through the intermediary of causing operation of a shutter means which in turn causes operation of said light source.

Such apparatus by virtue of its covert infra-red operation may be utilised to provide visual identification evidence, such as in relation to an unauthorised or undesirable person, in any ambient lighting conditions, including complete darkness.

In preferred embodiments of the invention the apparatus further comprises or is adapted for use with, sensor means operative to provide said triggering input.

Said sensor means may be so operative in response to the presence or activity of a burglar or other unauthorised person, or may be in the form of switch means (e.g. a "panic button") operable by a user.

Preferably said light source is arranged to operate only in response to such triggering input (other than optional provision of a "test" function).

Preferably light which emerges from said light source is at least substantially devoid of visible light.

Preferably said infra-red light source comprises a photographic flash (e.g. a xenon flash tube) in front of which there is positioned an optical filter having a spectral transmission characteristic providing good or fair transmission of infra-red light but which at least substantially blocks transmission of all visible light.

In this manner, the flash is able to operate in covert manner.

The infra-red light source and the imaging means may be provided in a single unit if desired, or may be provided at distinct locations. In one preferred embodiment, there is provided, in a single unit, the infra-red light source, the imaging means, and sensor means.

Preferably the apparatus provides for recordal of said image on a photographic emulsion sensitive to infra-red light.

Thus the apparatus may be adapted to accommodate at least a portion of photographic emulsion sensitive to infra-red light, and may further comprise shutter means adapted for operation in synchronism with operation of said light source, for operating the light source and exposing the emulsion at least substantially contemporaneously.

Alternatively the apparatus may provide for recordal of said image by way of electronic means (e.g. a CCD-charge coupled device) sensitive to infra-red light.

If desired, shutter means, either at least partly mechanical or at least largely electronic (e.g. by way of controlling a time or times of sampling image data from such CCD) may be provided, adapted for operation in synchronism with operation of said light source, whereby operation of the light source, and sampling of image data for recordal, may be caused to occur at least substantially contemporaneously.

In one embodiment, for example, electronic recordal is effected on a video tape which continuously records the output of the imaging means, the infrared light source being arranged to operate only in response to a triggering input, whereby a video recording which is at least largely blank, but with occasional images due to individual triggerings of the light source by respective inputs. Such occasional images may easily be found during fast-playing of the tape.

Apparatus in accordance with the invention may be utilised in any convenient place, and is particularly useful for example in domestic or smaller commercial premises or in vehicles, in each of which its comparatively small size, low cost and covert nature are advantageous.

The invention also provides an imaging system, comprising a rotating mirror, prism or the like which is rotatable about an axis to direct light (visible or other) to image sensing locations distributed around said axis.

Several embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURES 1 to 3 are respective cross-sectional side elevational views of three examples of security apparatus in accordance with the invention; and FIGURE 4 is a schematic perspective view showing parts of a fourth example of security apparatus in accordance with the invention.

In each of Figures 1, 2 and 3 of the drawings, the respective security apparatus 10, 110, and 210 illustrated is expressly in accordance with the invention, comprising (like parts in each example being designated by like reference numerals) a covertly operating infra-red light source 12, imaging means 14 capable of forming an image in infra-red light, and means 16 to cause operation of said light source in response to a triggering input.

In the examples of Figures 1 and 2, said means 16 comprises an electrical input terminal into which an electrical triggering input may be supplied from an externally located sensor responsive to the presence or activity of a burglar or other unauthorised person, whilst in Figure 3 said means 16, and a sensor 30 of "passive infra-red" type which provides the input, are each accommodated within the housing of the main apparatus 210.

The apparatus 10, 110, and 210 is designed to be capable of recording, for visual identification purposes in relation to an unauthorised or undesirable person, infra-red images of such person or persons formed by the imaging means under any ambient visible lighting conditions, including low light conditions and even complete darkness, and is specifically designed to be difficult to detect in operation, being small and silent or comparatively silent, and having said light source 12 adapted for covert operation.

In relation to the examples of Figures 1 and 2, a triggering input to cause operation of the apparatus may be provided by an electrical signal derived from, for example, (floor) pressure pads, door switches, passive infra-red detectors, user-operated "panic buttons" or the like, whereas in Figure 3 said input is derived from the in-built passive infra-red detector 30. Each such apparatus may be arranged to be capable of being triggered by any one of a number of inputs from different sensors simultaneously connected to, or otherwise in communication with, the apparatus.

In each of the illustrated embodiments, the infra-red light source 12 is provided by a photographic flash device, in these examples comprising a xenon flash tube 18 in front of which there is positioned an optical filter 20 having a spectral transmission characteristic providing good or fair transmission of infra-red light but which at least substantially blocks transmission of all visible light.The xenon flash tube 18 which may be of any straight-forward commercially available type such as might be used for a flash gun for ordinary photography, has the characteristic that when the xenon ionises and conducts electricity, in response to receipt by the apparatus of said triggering input, the radiation it emits has a duration of roughly 1/2000 of a second and it is roughly 50% in the visible spectrum i.e. wavelengths from about 400 nm (violet) to about 800nm (deep red) and roughly 50% in the infra-red spectrum.

The optical filter 20 has a sharp edged spectral transmission characteristic, and when placed in front of the flash tube 18 the filter 20 blocks transmission of substantially all of the visible light emitted by the flash tube, but allows the infra-red radiation emitted by the flash to pass through, to illuminate the scene under surveillance. For example, such filter 20 may have a spectral transmission edge point at a wavelength of around 800 to 840 nm, so as to provide good or fair transmission of infra-red light of wavelength greater than that "edge point" but such as to have nearly zero transmittance for "visible" wavelengths shorter than said "edge point".

Thus, from the point of view of the visual spectral sensitivity of the eyes of a burglar or other unauthorised person, through use of the filter 20, the flash 18 is able to operate in covert manner, so as to constitute an at least substantially undetectable source of infra-red illumination.

In the basic example of Figure 1, the filter 20 extends only over the front of the flash tube 18, whereas in Figure 2 the filter 20 extends over the imaging means 14 also. In the case of Figure 3, the filter 20 again extends over the imaging means also, and if desired may be replaced by a larger such filter which extends in front of the passive infra-red detector also. Thus the latter embodiments may be given a substantially monolithic front appearance, from which the nature of the apparatus is not apparent.

Although in the illustrated embodiments, the infra-red light source 18 and the imaging means 14 are provided in a single unit, they could instead be provided at distinct electrically connected or otherwise inter-communicating locations if desired.

The preferred embodiments 10, 110 and 210 illustrated provide for recordal of the image formed by the imaging means 14, being an image of the scene illuminated by the infra-red light from the light source 12, on a photographic emulsion sensitive to infra-red light.

The photographic emulsion 40 used in the preferred embodiments is "Kodak" (Registered Trade Mark) high speed infra-red film No.2481 and is mounted either in single pieces (Figures 1 and 2) or as a transportable roll (Figure 3) behind the imaging means, which in these examples includes a conventional camera shutter, adapted for operation in synchronism with operation of the light source 12, thereby providing for operation of the light source 12 and exposure of the emulsion at least substantially contemporaneously.

In the single exposure models shown in Figures 1 and 2 the individual piece or portion of film (which is also sensitive to visible light) should be inserted into the unit in conditions of complete darkness and zero or minimal ambient infra-red illumination or may be inserted into the unit/camera in a light proof holder, from which a front panel is then withdrawn, in much the same manner as light-sensitive glass plates are customarily inserted into visible-light "plate" cameras. In preferred embodiments, the front panel may be ejected automatically, for example by a spring loaded or motorised action, as the film holder is pressed into the unit/camera, and the act of pressing home the holder may be effective to cock the shutter.

The more comprehensive, multi-shot version of Figure 3 includes suitably silent motorised wind-on means to enable the film to be wound-on by one frame between exposures, and may be arranged to take for example 6 photographs in sequence, with the film preferably contained in a removable cassette or cartridge 45 of the type having a basic film spool on one side and a take-up spool on the other side, and may for example be afforded by a "126" size film cartridge, loaded with infra-red-sensitive film.

In the examples illustrated, when the shutter is open the infra-red image of the scene illuminated by the flash is focused onto the film by the lens L of the imaging means, said lens preferably being of about 35 to 40mm focal length (giving a field of view coverage approaching 800), positioned for correct focusing of light of infra-red wavelength for the most likely camera-to-subject distance expected.

The shutter employed is electrically operated, whereby said synchronisation between the shutter and the flash may most conveniently be achieved.

Units such as the units 10, 110 and 210 may be battery-operated if desired, and it is believed that by suitable electronics design a battery powered flash may be kept continuously charged for about a year or so. Where for example the shutter is basically spring-loaded and cocked by insertion of the film holder, a comparatively small solenoid may then be utilised to operate (i.e.

release) the shutter, such a small solenoid being well within a power range conducive to battery operation. Alternatively the units may be adapted to be basically mains-operated, although a battery back-up may be incorporated or otherwise provided if desired.

Optionally the flash (when mains powered) may be arranged to be permanently electrically charged, ready for immediate operation in response to a triggering input, or if powered by a battery (e.g. battery B in Figure 2) may be arranged to charge up (typically taking a few seconds) in response to a triggering input, and operate as soon as sufficient charge has built up.

In the multi-shot version of Figure 3, the flash could be arranged to operate in a variety of ways, one of which for example could follow a sequence whereby in response to a triggering input, two photographs would be taken in quick succession, and then the unit/camera would wait a further five seconds or so before it would respond to a further triggering input. In such a way, it should be possible to avoid, for example, photographing the back of an intruder's head, and furthermore it may be possible to catch more than one intruder on film.In relation to the single shot variants of Figures 1 and 2, it may be arranged that at least one useful photograph of an intruder's face is obtained by arranging a number of the single-shot units at different locations, covering the room or other area under surveillance from respective different directions, and arranging them to be triggered from a common source, or separately. Electronic control means may be provided for effecting the above sequencing and control.

In the unit of Figure 3, the passive infra-red detector is responsive to changes in the scene viewed thereby, such as burglar-movement for example, and in a more elaborate arrangement, the apparatus in accordance with the invention may comprise a plurality of such units 210 provided at different locations in a building, wired back to, or otherwise communicating with, a central control console or the like on which information may be displayed as to when and which one or more of the units has or have been triggered.

In a further unit embodying the invention, selected parts of which are illustrated in Figure 4, multiple shot operation is achieved by disposing a number of single pieces 40a, 40b, 40c, 40d of emulsion at respective locations distributed around the optical axis A of the lens L of the imaging means, and moving the image location from one emulsion location to another, in azimuthal succession about said axis or in some other order, by rotating a mirror M (or alternatively a prism capable of transmitting infra-red light) about said axis A In Figure 4 there are shown four emulsion locations, but any other number of emulsion locations may be utilised if desired.In Figure 4 the mirror M is carried (at an angle of 45 degrees) on an axial shaft S on which there is formed a pinion P, through which drive is received from a wormwheel (not shown) and a generally circular cam C having indentations to define the four angular positions utilised by the mirror in this example.

The invention is not restricted to use of photographic emulsion, and instead the apparatus in accordance with the invention may provide for recordal of said image by way of electronic means (e.g. a CCD sensitive to infra-red light) which may include for example wholly electronic shutter means controlling a time or times of sampling of image data, so as to be at least substantially contemporaneous with operation of the light source, and the image or images so sensed may for example be recorded on a video tape which may be operated in accordance with each triggering of the apparatus or which may be set to run continuously for a period of time, with images being recorded if and when a triggering input is sensed.

If desired, the unit comprising the imaging means may be provided with an electronic "databack" such as are available on conventional cameras, for recording, for example, a date and time at which the image is recorded which may be of assistance for purposes of evidence against criminals.

Preferably electronic means is provided to allow an authorised person to deactivate said apparatus by remote control, or there may be a built-in delay between sensing an input and operating the light source, such as may be desirable if the authorised person needs to cross an area protected by the apparatus, in order to switch off the apparatus (such as when arriving home, or when arriving at commercial premises, or when getting into a car or other vehicle).

In domestic or small-commercial installations, the apparatus is arranged to view an area where an intruder or other unauthorised or undesirable person is likely to appear, for example adjacent to valuables or cabinets or the like containing valuables, for example. In a shop or an office reception, for example, the apparatus may survey a suitable area and a "panic button" operated by a shop assistant or receptionist may trigger operation of the apparatus either because a person is perceived to be clearly undesirable, or potentially undesirable.

In domestic or small commercial premises, or vehicles, the comparatively small size, low cost and covert nature of the units 10, 110 and 210 are advantageous.

It is envisaged that even for the multi-shot version of Figures 3 and 4, external dimensions as small as approximately 75mm height with an approximately 50mm square base could be achieved, or smaller dimensions could be achieved with subsequent development, and this allows such units to be concealed in (say) household ornaments or mounted discretely in a room where an ordinary passive infra-red detector of a conventional burglar alarm system would be fitted.

Separation (not illustrated) of the flash unit from the imaging means further assists concealment, in that in the unlikely event of an intruder detecting the flash, the intruder may still not be able to find and destroy the imaging means containing the film.

In relation to vehicles such as cars, a suitably compact security apparatus in accordance with the invention could be concealed, for example, in the steering wheel or facia of the vehicle, and could be programmed (unless previously deactivated by an authorised person) to take a photograph (say) one minute after starting the vehicle engine: in this manner, it is believed that photographic evidence particularly useful against "joy riders" who steal a car and then drive it for only a short distance, before dumping it, could be obtained, with the apparatus again operating in covert manner.

As an alternative to a data-back, the apparatus could of course be arranged so as to face a wall clock, for recording as part of the image the time at which a photograph is taken Thus, it will be appreciated that in general terms, the apparatus in accordance with the invention is relatively inexpensive and simple to install and permits visual identification evidence of unwanted persons to be obtained, in any ambient lighting conditions, including complete darkness, without the person concerned being able to detect what is happening. Furthermore, there will be the deterrent effect of warning potential intruders, such as by way of a sticker or other sign on a door or window, that they will be photographed by concealed cameras if they proceed.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (23)

CLAIMS:

1. Security apparatus comprising a covertly operating infra-red light source, imaging means capable of forming an image in infra-red light, and means to cause operation of said light source in response to a triggering input.

2. Security apparatus according to claim 1 wherein operation of said light source is caused directly.

3. Security apparatus according to claim 1 wherein operation of said light source is caused indirectly.

4. Security apparatus according to claim 3 wherein operation of said light source is caused indirectly through the intermediary of causing operation of a shutter means which in turn causes operation of said light source.

5. Security apparatus according to any one of the preceding claims further comprising or being adapted for use with, sensor means operative to provide said triggering input.

6. Security apparatus according to claim 5 wherein said sensor means is so operative in response to the presence or activity of a burglar or other unauthorised person.

7. Security apparatus according to claim 5 wherein said sensor means is in the form of switch means operable by a user.

8. Security apparatus according to any one of the preceding claims wherein said light source is arranged to operate only in response to such triggering input (other than optional provision of a "test" function).

9. Security apparatus according to any one of the preceding claims wherein light which emerges from said light source is at least substantially devoid of visible light.

10. Security apparatus according to claim 9 wherein said infra-red light source comprises a photographic flash in front of which there is positioned an optical filter having a spectral transmission characteristic providing good or fair transmission of infra-red light but which at least substantially blocks transmission of all visible light.

11. Security apparatus according to any one of the preceding claims wherein the infra-red light source and the imaging means are provided in a single unit.

12. Security apparatus according to claim 11 where directly or indirectly dependent upon claim 5 wherein there is provided, in a single unit, the infra-red light source, the imaging means, and sensor means.

13. Security apparatus according to any one of claims 1 - 11 wherein the infra-red light source and the imaging means are provided at distant locations.

14. Security apparatus according to any one of the preceding claims wherein the apparatus provides for recordal of said image on a photographic emulsion sensitive to infra-red light.

15. Security apparatus according to claim 14 adapted to accommodate at least a portion of photographic emulsion sensitive to infra-red light.

16. Security apparatus according to claim 15 further comprising shutter means adapted for operation in synchronism with operation of said light source, for operating the light source and exposing the emulsion at least substantially contemporaneously.

17. Security apparatus according to any one of claims 1 - 13 wherein the apparatus provides for recordal of said image by way of electronic means sensitive to infra-red light

18. Security apparatus according to claim 17 wherein shutter means, either at least partly mechanical or at least largely electronic is provided, adapted for operation in synchronism with operation of said light source, whereby operation of the light source, and sampling of image data for recordal, may be caused to occur at least substantially contemporaneously.

19. Security apparatus according to claim 17 wherein electronic recordal is effected on a video tape which continuously records the output of the imaging means, the infra-red light source being arranged to operate only in response to a triggering input.

20. An imaging system, comprising a rotating mirror, prism or the like which is rotatable about an axis to direct light (visible or other) to image sensing locationsdistributed around said axis.

21. Security apparatus substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.

22. An imaging system, substantially as hereinbefore described with reference to and/or as illustrated in the accompanying drawings.

23. Any novel feature or novel combination of features described herein and/or illustrated in the accompanying drawings.