FR2789253A1 - Video surveillance remote sensor/commercial broadcast camera dome cover having ogive shaped dome camera rotating having folded back plate edge liquid filled channel inserted. - Google Patents

Abstract

The dome unit carries a video camera. The video camera is held in an ogive shape (10) and rotates around the support shaft (11) with the camera (12). Rotation is achieved with a support plate (17) with edges in a channel in the support shaft (15) which is filled with liquid (16). The optical window (13) includes a vertically down camera position.

Description

The present invention relates to a dome method for receiving a

video camera,

  intended for the remote monitoring or the diffusion of commercial images.

  A dome differs from a conventional turret in that it allows 360 rotation of the camera without a stop. This rotation without stop is authorized by the use of a rotating joint system. The rotating joint transmits the video information + the power supply to the motors by

  friction and not by wire. This allows a permanent rotation called "without stop".

  Example of a conventional dome: see plate 1/3 (Figure 1) A dome consists of a horizontal support plate (1) which, on its upper face, supports the electronic control cards (2). A rotary joint (3) allows information to be transmitted to the rotary assembly (4) located on the underside. Using 2

  motors, the camera (5) can pivot on the horizontal axis and on the vertical axis.

  The domes work most of the time in the hanging position, i.e. upside down, so

  to allow the camera to take all positions, from horizontal to vertical.

  (Figure 2) The assembly is protected by a barrel (6) in which the dome is installed. In order to protect the camera while allowing vision, a transparent optical quality half-sphere (7) seals the lower part of the barrel at the level of the camera. This half sphere is

  fixed and integral with the barrel. The camera rotates inside this hemisphere.

  In outdoor use, a very good seal is necessary in order to protect the electronic modules and the camera. An internal heating system makes it possible to maintain a sufficient ambient temperature for the operation of the electronics and to prevent

  fogging on the transparent hemisphere.

  Currently, the existing domes allow little or no view above the horizontal.

  Indeed, the optical half-sphere does not allow the camera to go beyond the horizontal without hindering

  the vision of the objective by the lower edge of the barrel (8).

  (Figure 3) To remedy this drawback, it is possible to replace this half-sphere with a 3/4 of a sphere (9), but the cost of producing such a part in optical quality is very

  expensive. Figure 3: Example of an SFE dome mounted in a barrel with% of optical sphere.

  In outdoor use, the half-sphere and especially the 3/4 of a sphere, are subject to

  bad weather and cannot be protected from spray, flakes or external contamination.

  The installation of a wiper system is impossible.

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  The object of the invention is to remedy these drawbacks by proposing an original method. According to the invention, the half or 3/4 of the protective sphere, integral with the barrel, is eliminated and replaced by a protective cover provided with a viewing window which pivots with the camera. (Figure 4 and 5 - plate 2/3) The protective cover, named "warhead" (10) in the description below, is no longer secured to the barrel (11), but pivots with the camera (12)

  whose vision is ensured through an optical window (13).

  This warhead (10) can be made of any known material and does not have to be transparent. Only an optical window (13), cut in the warhead and located in front of the part

  scanned by the camera lens (12), allows vision.

  This viewing window can be produced economically using any transparent material of optical quality (Plexiglas, glass, etc.). Thus, with the method according to the invention, this optical window offers the advantage, always of

  economically, to allow the camera to see clearly above the horizontal.

  According to the invention, the viewing angle above the horizontal can be 30 or more

(figure 6-plate 3/3).

  This offers an undeniable advantage over conventional domes. It is often useful to be able to see above the horizontal, especially in the mountains, where it is necessary to see

  vertices located very clearly above the location of the camera.

  This advantage can also be recognized in many other surveillance cases where the camera cannot be placed at the highest point, but nevertheless having the need to see above the horizontal. The need to rotate the warhead at the same time as the camera, poses the problem of sealing in case of outdoor use. It is indeed necessary to seal the part

  internal dome vis-à-vis the outside.

  This sealing can be achieved, in a conventional manner, using a lip seal implanted on the periphery of the support plate of the mobile assembly supporting the camera and

allowing its rotation.

  This process has the following drawbacks: * the use of a lip seal requires compliance with strict machining tolerances in order to

  remove backlash and obtain a perfect bearing surface for the joint.

  40. The lip seal requires regular maintenance.

  À It does not control variations in pressure due to variations in

  temperature between the interior of the dome and the exterior.

  À The friction of the seal requires a greater motorization of the azimuth rotation system. Besides the cost of a more powerful engine and its higher consumption, the volume taken by this engine will significantly increase the volume.

general of the dome.

  À The camera must be able to rotate very quickly on itself (300 per second or more) or at any time allow the "Fast U-turn" function (200 per second). The

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  seal friction greatly slows down this pivoting movement of the camera

  or requires an oversizing of the corresponding motor.

  * The risk of the seal sticking to the plate during a period of inactivity, due to frost or heat, risks blocking the system and damaging the seal, in the same way as on windscreen wipers. car. According to the invention, the seal between the barrel and the mobile part supporting the camera is

made with liquid.

  As shown in Figure 7 - board 3/3, the fit is fully sealed in its upper part (14). The lower part consists of a groove (15) which will be filled with

liquid (16).

  A plate with folded edge (17), integral with the plate allowing the rotation of the camera,

  soak in liquid filled throat.

  The liquid used in the invention is automotive coolant. This kind of

  liquid allows very good resistance to temperature variations and evaporates little.

  This system offers the following advantages:

Fully sealed.

Little or no maintenance.

  low machining constraints: the clearances between the rotary plate and the groove filled with

  liquid, not requiring any specific rating.

  25. compensation for pressure variations due to temperature variations between the interior of the dome and the exterior, by the rise of the liquid on each side of the wall of the

rotary plate with folded edge.

  * Negligible friction in the liquid allowing to keep a motorization

  classic, without slowing down the rotation.

  e No risk of the seal sticking during periods of inactivity or following temperatures

extremes: frost, hot weather.

  * Only a system upgrade is required.

  Conventional domes do not allow the installation of a wiper system. Indeed, the very shape of the half or 3/4 of the sphere does not allow mounting allowing

wipe the optical surface.

  According to the invention, a simple wiper method can be installed to clean the

optical window.

  The flat profile of the window allows the creation of a simple system.

  This wiper can be operated by an independent motor or driven by the same motor which allows the camera to move in elevation. A jet of liquid can easily be associated with the

  wiper system for cleaning the optical window.

  According to a particular version of the invention, the optical window can be protected by an air barrier, under slight pressure. This air is pressurized in the dome and exits through small holes located around the periphery of the viewing window. It thus allows

  external stains to be removed before sticking to the glass.

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Claims (8)

  1) Dome camera or video surveillance camera device, characterized in that it comprises a protective cover, called "warhead" (10) which is not integral with the fit (11), but pivots with the camera (12 ) whose vision is ensured through an optical window (13) allowing a vision above the horizontal. The rotary lower part is sealed by a lip seal or by a folded edge plate (17) which dips in a groove (15) filled with liquid (16).   2) System according to claim 1, characterized in that the electronics constituting the   interior dome can be of any known type.   3) System according to claim 2, characterized in that the barrel (11), the groove (15) and the plate   with folded edge (17), can be made of all known materials.   4) System according to claim 3, characterized in that the vision window (13) of the camera   can be made of any known material.   ) System according to claim 4, characterized in that the seal between the parts   upper and lower can be achieved by any conventional method of jointing.   6) System according to claim 5, characterized in that, in the version of the invention o the seal is produced by liquid (16), this liquid is coolant   automotive but can be of any known type.   7) System according to claim 6, characterized in that the warhead (10) can be equipped   a wiper system for cleaning the viewing window (13).   8) System according to claim 7, characterized in that the wiper can be driven by   the vertical pivot motor of the camera and follow its movement.   9) System according to claim 8, characterized in that the window (13) can be protected against external dirt, spray, water drops or snowflakes, by a barrier of air blown from inside the warhead (10), through small holes located on around the window (13).