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Title:
CAMERAS AND METHODS OF CLEANING CAMERAS
Document Type and Number:
WIPO Patent Application WO/2005/096091
Kind Code:
A1
Abstract:
A camera (100) has a lens (2) and a cover (8) for protecting the lens, and also drive means (21) for moving the lens cover in a rapid repeated manner which is sufficient to dispel any extraneous matter from the lens cover, thereby to clean the cover. The lens cover may be form a hollow unit, the interior of which defines a protective space (12) for housing the lens, and the axis of rotation of the cover unit is disposed such that the cover is arranged to rotate around the enclosed lens. This allows not only the view through the camera lens to be kept clear by the repeated movement of the cover, but also the lens apparatus to be used at the same time.

Inventors:
Harmon, David William (31 Hillside Way, Welwyn, Herts AL6 0TY, GB)
Application Number:
PCT/GB2005/001253
Publication Date:
October 13, 2005
Filing Date:
March 31, 2005
Export Citation:
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Assignee:
Harmon, Bonnie Maureen (31 Hillside Way, Welwyn, Herts AL6 0TY, GB)
Harmon, David William (31 Hillside Way, Welwyn, Herts AL6 0TY, GB)
International Classes:
G03B11/00; G03B17/08; G03B17/12; (IPC1-7): G03B11/00; G03B17/08; G03B17/12
Domestic Patent References:
WO2001061406A1
Foreign References:
US5315333A
US6322258B1
US3879742A
US5418567A
Other References:
WPI WORLD PATENT INFORMATION DERWENT, DERWENT, GB PA - ANDREW M CREAGH PN - AU1507495 A, 3 October 1996 (1996-10-03), XP002152790
Attorney, Agent or Firm:
Pickin, Susan Evis (20 Heathfield, Royston, Herts SG8 5BW, GB)
Download PDF:
Claims:
CLAIMS
1. A camera comprising an imagecapturing device, a cover for protecting the imagecapturing device, and drive apparatus which is operable to move the cover in a repeated manner which is sufficient to get rid of any extraneous matter from the cover.
2. A camera according to claim 1, wherein the drive apparatus is operable to move the cover in a continuous series of forceful movements so as to throw off extraneous matter.
3. A camera according to claim 1 or 2, having a hollow chamber below the cover, the chamber providing an enclosed protective space for housing the image capturing device, which is surrounded by the cover, whereby the cover is operable to move in the series of repeated movements freely with respect to the enclosed imagecapturing device.
4. A camera according to any one of claims 1 to 3, wherein the drive apparatus is operable to move the cover independently of movement of the imagecapturing device.
5. A camera according to any one of claims 1 to 4, wherein the drive apparatus is operable to move the cover in cyclical movements so as to throw off extraneous matter.
6. A camera according to any one of claims 1 to 5, wherein the drive apparatus is operable to move the cover in rapid repeated movements so as to throw off extraneous matter .
7. A camera according to claim 6, wherein the drive 5 apparatus is operable to rotate the cover so as to throw off extraneous matter.
8. A camera according to claim 7, wherein the drive apparatus is operable to rotate the cover at a maximum 10 speed of about 500 about 2000 revolutions per minute.
9. A camera according to any preceding claim, wherein the cover comprises a projecting cap portion having a continuous side wall attached to a base face, which is 15 rotatable by the drive apparatus.
10. A camera according to claim 9, wherein the image captur±ng device is supported by a camera base and the base face of the cover is supported on this camera base 20 for rotation over the camera base.
11. A camera according to any preceding claim, wherein the cover is domeshaped.
12. 25 12.
13. A camera according to any preceding claim, wherein the cover is made from a lightweight synthetic material.
14. A camera according to any preceding claim, for use in surveillance. 30.
15. Camera cleaning apparatus comprising a camera according to any preceding claim, further including a device for controlling the repeated movement of the cover, and a power source for supplying power to the cover.
16. 5 15. A method of cleaning a camera having a cover for protecting an imagecapturing device, comprises operating drive apparatus to move the cover in a repeated manner which is sufficient to get rid of any extraneous matter from the cover, thereby to keep the cover clean. 10 16. A method according to claim 15, further comprising operating the drive apparatus to move the cover in a continuous series of forceful movements so as to throw off extraneous matter from the cover. 15 17. A method according to claim 15 or 16, comprising moving the cover in cyclical movements so as to throw off extraneous matter.
17. 20 18. A method according to claim 15, 16 or 17, comprising moving the cover in rapid repeated movements so as to throw off extraneous matter.
18. 19 A method according to claim 17, comprising rotating 25 the cover so as to throw off extraneous matter.
19. 20 A method according to claim 19, comprising increasing the rotational speed of the cover to a maximum speed of about 500 to about 2000 revolutions per minute. 30 20. A method according to any one of claims 15 to 19, comprising moving the cover independently of movement of the imagecapturing device .
Description:
TITLE: CAMERAS AND METHODS OF CLEANING CAMERAS

DESCRIPTION

TECHNICAL FIELD

The present invention relates to cameras, especially to cameras used in environments liable to change such as outdoors, and to methods of cleaning such cameras. By cameras is meant apparatus for recording and/or displaying images.

BACKGROUND OF THE INVENTION

The problem of keeping camera lenses free of solid particles, like dust and dirt, is common. It is possible to clean lenses before use but this is less effective in dynamic environments, such as outdoors, for example when taking a photograph, recording a film, or using a monitoring system, where dirt or moisture from the air can land on the lens. Moreover, the problem is worse while on the move, since the environment is changing and an air flow occurs, which may increase the dirt and moisture. It is even more difficult in poor conditions such as bad air quality or bad weather, for instance rain or snow, because the lens gets sullied by the dirt and/or moisture and the view through the lens is even more likely to be obscured and diminished.

Cameras having covers fixed over the lens to provide a protective environment are well known, particularly in the field of surveillance. However, this still does not solve the problem of unwanted foreign matter, such as rain or dirt, sullying the cover and impeding the field of view of the lens and consequently masking what should be seen and/or recorded.

It is therefore an object of this invention to be able to improve the field of view of cameras including a lens with a cover for protecting the lens, for example such cameras for use in changing environmental conditions.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, a camera comprises an image-capturing device, a cover for protecting the image-capturing device, and drive apparatus which is operable to move the cover in a repeated manner which is sufficient to get rid of any extraneous matter from the cover.

Throughout this specification the term image- capturing device may refer to at least one lens; it may also refer to digital image-viewing devices.

The repeated manner of movement of the cover acts to both dislodge and dispel any extraneous material from the exterior of the cover. This provides a clearer field of view so that the image-capturing device may operate without interruption. It may also stop extraneous matter in the surroundings from settling on the cover.

The camera may be used in all kinds of photography, covert and overt surveillance and monitoring, in CCTV, in filming and broadcasting. The camera may be deployed as and when required since the camera may be controlled using remote control equipment.

The drive apparatus may be operable to move the lens cover in a continuous series of forceful movements so as to throw off extraneous matter.

The speed of movement of the cover may be adjustable.

The drive apparatus may be operable to move the lens cover in cyclical movements so as to throw off extraneous matter.

The drive apparatus may be operable to move the lens cover in rapid repeated movements so as to throw off extraneous matter.

The drive apparatus may be operable to rotate the lens cover so as to throw off extraneous matter.

The drive apparatus may be operable so as to move the lens cover in rapid cycles. For instance, the cover may be repeatedly rotated i.e. spun round, or oscillated to-and-fro or up-and-down.

The applicants have appreciated that moving the cover in rapid cyclical motion not only clears the cover and provides an improved view from the image-capturing device but it also allows the camera to continue operating without adverse effects thereto such as vibration.

The drive apparatus may rotate the cover at a maximum speed of about 500 - about 2000 revolutions per minute, which results in highly effective cleaning of the lens cover without disturbing the image-capturing device.

The rotation may be manually and/or automatically started. The rotational speed may be held at or about the maximum as long as necessary to clean the cover. Alternatively, the dislodging motion can be activated occasionally or at a pre-set time interval. The rapid movement may be carried out continuously for as long as required by the external conditions. Means may be included to pre-select or vary the speed of rotation and/or the timing of the operation of the rotating cover. The whole of the image-capturing device and any associated apparatus may be disposed beneath the cover.

The cover may comprise a hollow chamber below the cover, the chamber providing an enclosed protective space for housing the image-capturing device, which is surrounded by the cover, whereby the cover is operable to move in the series of repeated movements freely with respect to the enclosed image-capturing device. The chamber may be closed to the external environment to keep the image-capturing device clean.

The drive apparatus may be operable so as to move the cover independently of movement of the image- capturing device i.e. the cover and the image-capturing device may be selectively moved independently of each other. This allows not only the view through the image- capturing device to be kept clear by the repeated movement of the cover, but also the image-capturing device to be used at the same time.

The camera may be associated with a switch for remote control of the motor causing the repeated action of the cover to dispel extraneous matter from the exterior of the cover.

In one embodiment in particular, the cover may comprise a projecting cap portion having a continuous side wall attached to a base face, which is rotatable by the drive apparatus. Also, the image-capturing device may be supported by a camera base and the base face of the cover may be supported on this camera base for rotation over the camera base.

Thus, the projecting cover portion and side wall may provide a canopy over the protective chamber in which the image-capturing device is housed and the image-capturing device (and some or all associated apparatus) may be enclosed so that the rotation of the cover is around the enclosed image-capturing device. Rotation of the base face of the cover by the drive will provide the rotation of the attached cover and impart the dislodging action thereto.

The image-capturing device may be supported by a planar surface of a camera base such that the base face of the cover lies on this planar surface face-to-face therewith for rotation over the camera base. In particular, the image-capturing device may be mounted on a rigid support, which is also supported by the planar base.

The side wall may be vertical, inclined or curved. In particular, the cover may be dome-shaped or have cylindrical sides with a curved or flat upper end. The protective chamber may be closed to the environment. The base face may be integral with the dome or fastened thereto, such that the canopy and lower planar face together providing a sealed chamber.

The cover may be transparent or translucent to visible light according to the image required to be viewed by the camera. If the surroundings are dark, the image may be provided by infra-red electromagnetic waves. The cover may be made from a lightweight synthetic material, for instance polycarbonate .

Cameras according to the invention may be disposed in use in any required orientation: for example they may¬ be employed with the cover extending downwards from a mounting above or upwards from a support beneath.

According to a further aspect of the invention, a method of cleaning a camera having a cover for protecting an image-capturing device, comprises operating drive apparatus to move the cover in a repeated manner which is sufficient to get r.id of any extraneous matter from the cover, thereby to keep the cover clean.

The method of cleaning may comprise operating the drive apparatus to move the cover in a series of forceful movements so as to throw off extraneous matter from the cover.

The method may comprise moving the cover in cyclical movements so as to throw off extraneous matter.

The method may comprise moving the cover in rapid repeated movements so as to throw off extraneous matter.

The method may comprise rotating the cover so as to throw off extraneous matter.

The method may comprise increasing the rotational speed of the cover to a maximum speed of about 500 to about 2000 revolutions per minute.

The method may comprise moving the cover independently of movement of the image-capturing device.

The camera may have means for mounting it on a vehicle and/or under remote-control, for example for use in any of the following: surveillance, inspection, dangerous locations, and inaccessible situations.

The camera may further include a low voltage light under the cover to aid the recording or viewing of an image.

Thus, it has been found that the dislodging motion imparted to the cover according to the invention does not adversely affect the performance of the camera, which can continue to function while the cover is being cleared. This would, for example, allow a pan, tilt and zoom lens to be independently adjusted while the cover is moving. This minimises any interruption in viewing by the image- capturing device and thus allows improved monitoring or recording of still or motion photography.

In the cameras and methods of cleaning cameras according to this invention the cover is moved sufficiently to dislodge extraneous matter if the force dislodges matter from the exterior of the cover and dispels the extraneous matter i.e. allows it to fall down and/or be thrown off.

We further propose camera cleaning apparatus comprising a camera comprising an image-capturing device, a cover for protecting the image-capturing device, and drive apparatus which is operable to move the cover in a repeated manner which is sufficient to get rid of any extraneous matter from the cover, the apparatus further including a device for controlling the repeated movement of the cover, and a power source for supplying power to the cover.

Cameras and methods of cleaning cameras according to this invention may be used for viewing and/or recording surroundings, including covert and overt surveillance, typically outdoors. They may be used where extraneous matter in the air might settle on the exterior of the lens cover, such as spray, water droplets, dust, insects, debris, sand, at airports, seaports, on moving vehicles and installations, stationary vehicles and installations, and factories or industrial areas. For instance, they may be used to remotely survey the bodies of aircraft prior to take off. Other locations include film studios and smoky rooms.

According to another aspect of the invention, a camera comprises a lens assembly, a cover for protecting the camera lens, and drive means for moving the lens cover sufficiently to dislodge extraneous matter from the lens cover.

According to yet another aspect of the invention, a method of operating a camera having a lens assembly and a cover for protecting the camera lens, comprises moving the lens cover sufficiently to dislodge extraneous matter therefrom.

Thus extraneous matter can be removed from the exterior of the cover in order to provide a clearer field of view through both the lens and cover. At the same time the lens is protected under the cover and may be kept clean and dry.

This can be employed with different types of lens, for instance a pan, tilt and zoom camera, and in changing conditions in dynamic environments such as outdoors, where the air around is moving and/or where the camera is moving.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of this invention is now described, by way of example, with reference to the drawings, in which:

Figure 1 is a diagrammatic cross sectional view of a camera according to the invention, with a single pan, tilt and zoom lens;

Figure 2 is a schematic side view of the apparatus of Figure 1;

Figure 3 is a diagrammatic view from above of the camera of Figures 1 and 2; Figure 4 is a diagrammatic view of a control unit for the camera of Figures 1 to 3;

Figure 5 is a diagram showing the camera of Figures 1 to 3 on the roof of a surveillance vehicle;

Figure 6 is a block diagram showing a schematic arrangement of surveillance apparatus used with the vehicle of Figure 5; and

Figure 7 is a flow diagram showing a method of cleaning a camera having a cover for protecting the camera lens in accordance with the invention.

BEST MODE OF CARRYING OUT THE INVENTION

A camera (100) has pan, tilt and zoom lens apparatus (2) for remotely recording a view of the surroundings. The lens apparatus (2) is angularly movable on a rigid bracket (3), which is mounted for rotation about a central axis (A-A) by a stepper motor (4) via a bearing (5) in an upper, first bearing case (6) .

The camera (100) has a solid, approximately hemi¬ spherical camera cover unit(8), which provides a projecting dome-shaped canopy (9) having a closed curved upper end cap portion (10) and an adjoining continuous curved side wall portion (11) , the lower edge of which is attached to an annular planar base face (14) . The whole lens apparatus is housed within a sealed hollow protective chamber (12) formed by the enclosed space beneath the canopy. Provided the chamber is as clean as possible the lens can be kept clean as it is closed to the external environment. The cover (8) is made of polycarbonate, which is transparent in this embodiment although it may be translucent. The cover is approximately 25 cm tall and 70cm wide.

The base face (14) of the cover unit is fixed on a lightweight annular plate of aluminium (15) . This plate (15) is attached to a lower, second bearing case (16) below the lower face (14) of the cover for rotation about the central axis (A-A) on a lower, sealed, double ball bearing (17, 18) around a central, stationary, rigid, metal rod (19), which is fixed and enclosed in a rigid camera support base (20) . (The lower end (19' ) of the rod is rigidly mounted in the base (20) , perpendicularly thereto.) The axis of rotation (A-A) of the cover is perpendicular to the base and the base face (14) of the cover unit confronts the camera support base (20), whereby in use the cover rotates around the lens. Only one of the plate (15) and the lower face (14) is essential as either one could be omitted and the other could be directly attached to the lower bearing case.

The lower bearing case and thereby the attached dome cover is rapidly rotatable by a 12V DC, 3A electric motor (21) , housed in the base (20) . This motor (21) is connected with the dome only and as mentioned above, the separate motor (4) is used to carry out pan, tilt and zoom of the lens assembly.

However, the pan, tilt and zoom of the lens and the dislodging motion of the cover are all controllable remotely by a person using a portable control unit (described below) .

A schematic view of the camera is shown in Figure (2), which shows the lens apparatus (2) in the housing chamber (12) . A low voltage light (22) is disposed under the cover next to the lens apparatus to assist the lens.

Use of the camera on a surveillance vehicle (50) is now described:

The camera (100) has four rigid supporting legs (51) bolted to a fixing (52) on the roof (53) of the surveillance vehicle (50) . The camera is controlled using a portable laptop control unit (54), which may be kept in a hand-held case (56), which is stored (when not in use) in the vehicle (50) and which is controlled by a person (P) in the vehicle, seated facing the control unit (54) . With reference to Figure 6, a separate power distribution unit (57) is housed in the rear of the vehicle for supplying power, taken from the car battery (58) , to the control unit via data cable (60) and power to the camera via data and power cable (59) .

The control unit (54) has a keyboard (62) and a screen (64) for viewing the image sensed by the camera lens apparatus (2) . The keyboard includes conventional camera controls and also has :

an on-off switch (66) for remote control of the motor causing movement of the cover to dislodge unwanted material, such as water from rain, snow or other precipitation;

an on-off switch (68) for remote control of a light 5 to assist the camera;

an on-off switch (70) for the power to the control unit; and

0 a joy-stick (72) for remote control of the pan, tilt and zoom of the camera lens.

In adverse environmental conditions, such as rain, once the operator presses the switch (66) for the motor 5 (21) for the cover, the whole dome cover unit starts spinning about axis A-A, with the annular base face of the dome rotating over the adjacent support base. The speed increases to a rotational speed of about 800 revolutions per minute. As a result of rotating the 0 cover unit, any extraneous matter is thrown off the exterior of the dome cover until the monitor shows a clearer view, at which point the operator switches off the motor and the cover stops spinning.

5 The cover can freely spin around the enclosed lens. The spinning of the dome does not adversely affect the view or the stability of the camera lens, which can continue to record while the dome is spinning. The pan, tilt and zoom may also be adjusted while the dome is O spinning; pan, tilt and zoom of the lens are controlled separately. The control unit may optionally include a timer to spin the cover at preselected times or a pre-set time interval for precautionary cleaning the outside of the cover to ensure it is kept clean.

Operation of the movement of the cover is independent of the operation of the movement of the lens. This can be carried out as known to the skilled man.

In the embodiment described herein the spinning dome part of the unit is electronically and physically separate from the camera and camera control system.

Spinning Dome Control

The spinning dome is actuated by a power switching mechanism on the laptop control device (54) and when switched on feeds power to the motor (21) below the dome mechanism. This motor then spins the dome via a pair of two rubber belts (30) disposed around the lower bearing case and the motor shaft (21' ) .

Camera Control Unit

The camera control unit is separate, having a telemetry receiver unit (32) located below the dome assembly. The joystick (72) on the laptop camera control unit (54) is moved and rotated as required to control the position of the camera lens and the zoom/focus of the camera. This positioning information is sent in a protocol of electrical signals on a wire from the joystick to the telemetry receiver unit (32) located below the dome camera.

Once received, these signals are processed by the telemetry receiver and sent as individual electrical signals to the different parts of the camera (pan and tilt motors, zoom and focus motors) by use of a 16 way slip ring (34), allowing the camera to rotate 360 degrees continuously, without the twisting of the cables.

Note: 360 degree pan for the camera is driven by the electric motor (4) connected by a toothed drive belt (36) to the camera assembly.

Finally, operation of the cover of the above camera may be summarised thus: when the image on the monitor is unclear, the motor of the cover is switched on, the cover spins at a maximum speed from about 500 to about 2000 revolutions per minute, the movement of the cover both removes foreign material, such as water, from the cover and throws it from the external surface of the cover, and once the image on the monitor screen is clearer, the motor for trie cover is switched off.

Thus, the steps of a method of cleaning a camera having a cover for protecting its image-capturing device are illustrated in Figure 7. These steps comprise:

STEP ONE switch on drive apparatus for cover of image-capturing device of camera to start moving cover in a repeated manner sufficient to get rid of extraneous matter from the cover

STEP TWO

allow drive apparatus to move the cover in the repeated manner so as to get rid of any extraneous matter from the cover

AND

STEP THREE

switch off drive apparatus for the cover to stop moving the cover in the repeated manner.