EP2335229B1 - Adjustment securing means for monitoring cameras - Google Patents

Description

The present invention relates to what is claimed in the preamble and, accordingly, to the question how, with surveillance cameras, an unwanted change of a monitored area can be avoided.

Surveillance cameras are often used to monitor a fixed area, which should be set before the surveillance during the initial camera assembly and should not be changed afterwards if possible. This applies both to surveillance cameras, which are to remain absolutely fixed during surveillance, and to cameras which are to be swung back and forth during a surveillance in order to repeatedly monitor the swept-over field of view.

After an initial, correct alignment, changes may be made by deliberate sabotage or third party intervention, but also by accidental events such as strong wind, birds landing on and departing from the camera, and the like; Such random events prove to be particularly disturbing if the camera was not optimally fixed during its installation, for example because a user has not sufficiently tightened adjustment-fixing screws.

In principle, it is possible to capture an adjustment through image viewing or automated image analysis. However, this, for example, reaches its limits, if the changes are small, but the monitoring of the peripheral areas is of particular importance. This can for example be the case with platforms. Moreover, problems arise when image recognition is required under changing environmental conditions or in places where image recognition is difficult, for example because of little horizontal or vertical lines in the image, such as in large squares and / or because of relevant traffic patterns are often obscured.

It is already known to monitor the tilt of cameras by integrating tilt switches into camera housings. The known tilt switch are relatively insensitive and also prevent pivoting of the housing, so that manipulation can not be excluded.

From the US 6,011,925 For example, a camera is known in which image information from an optical system is converted into an electrical signal and the electrical signal is output, wherein a swivel head has a control mechanism for at least two axes, a sensor detects the orientation of the camera and the swivel head based on the orientation the camera is controlled.

From the DE 10 2005 037 534 A1 For example, there is known a surveillance camera system in which an image taken by a pan / tilt camera is displayed on a screen and inverted upside down and bilaterally when an inclination angle is equal to or greater than a predetermined reverse inclination angle relative to a reference position , where provided further to be an inclination angle detector detecting a tilt angle of the monitoring camera, a reversible inclination angle memory which stores data of a plurality of predetermined reversal inclination angles, a reversal inclination actuator which detects one of the reversals stored in the reverse inclination angle memory Tilt angle comparing unit that compares the tilt angle detected by the tilt angle detector with the reverse tilt angle set by the reverse tilt angle setting unit, and an image inversion processing unit that operates as a result of comparing the tilt angle Compare unit performs the process of reversing and bilaterally symmetrizing the image obtained by the surveillance camera when the inclination angle is equal to or larger than the reverse inclination angle.

It is desirable to be able to provide protection against misalignment, which contributes to an increase in the security of surveillance cameras.

The object of the present invention is to provide new products for commercial use.

The solution to this problem is claimed in an independent form. Preferred embodiments can be found in the subclaims.

The invention thus proposes a surveillance camera arrangement with at least one adjustment axis for setting a surveillance area and a tilt detector in order to detect and signal changes in the surveillance area. before, wherein the adjustment axis after assembly is not illegal for setting a generally horizontal line of sight axis and the tilt detector is adapted to be able to signal a change in the horizontal monitoring area in response to detected tilting changes.

It is therefore initially proposed to detect the tilt of the camera independently of a monitoring image in order to detect a pivoting. For this purpose, the camera assembly is formed so that the (generally horizontal) pivot axis is slightly inclined in conventional assembly. Each pivotal movement then leads to a - albeit small - tilt, which is easily detectable with tilt detectors. By merely detecting an inclination of the pivot axis, pivoting can thus be detected particularly easily. Although an adjustment about the pivot axis no longer leads to an adjustment of the viewing direction exactly along the horizon, the arrangement is particularly advantageous insofar as now an adjustment of the pivoting direction leads to a change in the inclination, which is well independent of the monitoring image Tilting detector can detect as tilting change.

This helps ensure that changes to an original setting can be detected quickly and reliably without complex image analysis. At the same time, the use of tilt detectors makes it possible to detect even gradual changes with certainty.

It is particularly preferred to use the invention in surveillance camera arrangements in which a setting in Two directions is possible, so a tilt and / or a pivoting movement are provided. The invention is by no means limited to camera movements in one direction of rotation.

If the camera is tiltable, the tilting joint between the pivot axis and the camera is preferably arranged; this has structural advantages. The pivot axis is understood to be that axis about which the camera is to be changed to set a viewing direction generally along the horizon; this setting will not be exactly horizontal because the corresponding axis is tilted.

The adjustment axis is a pivot axis that is inclined or skewed to the perpendicular in the assembled state, which can be achieved by the adjustment axis non-orthogonal projecting from the camera body and is arranged non-orthogonal to a mounting planes such as a wall.

In order to ensure that the adjustment axis is sufficiently strong against the perpendicular, that is, the plumb line inclined and / or sufficiently skewed to this, a mounting plate for mounting the camera can be provided, from which projects the pivot axis, the pivot axis deliberately obliquely against the back the mounting plate is arranged. In this way, it is ensured that the inventive design results as desired.

The use of a corresponding mounting plate is particularly preferred because in the simplest way, a preferred assembly is guaranteed. In a particularly preferred variant the inclination of the pivot axis against the vertical will be above 3 °, preferably above 5 °, but less than 15 °, preferably not more than 10 °, these indications referring to an inclined pivot axis and the angle of the pivot axis to the perpendicular in a plane specify that contains both the pivot axis and the perpendicular. The sizes given are preferred because, on the one hand, the inclination must not be too low, because otherwise, when the base area is not sufficiently precisely aligned, the inventively preferred inclination of the pivot axis despite the mounting plate can no longer be achieved. However, if the inclination of the pivot axis is too large, the setting is difficult, because then a change around the pivot axis at the same time has a strong Bildverkippung or tendency to result. As long as the swivel axis inclination is not too large, these effects also occur, but are tolerable. These considerations also reveal how great the inclination should be in the case of a skewed axis perpendicular to the vertical axis.

It is particularly preferred if the camera comprises a correction means for correcting for tilted images. In other words, if the skewed axis of the pivot axis indicated a skewed image on an even monitor, rotation of the image could be provided. This can be done electronically already in the camera so that regardless of an observatory always perpendicular images are output, which is much more pleasant for monitoring purposes.

It should be noted that where the camera repeatedly sweeps over a surveillance area by and swiveled or inclined, the tilt detector can be designed to determine a change in the tilt occurring at a given sweep angle, for example the center position. This can easily be done by a middle switch or by measuring the sweep time between two extremes and halving the value, so that a goniometer is not necessarily required. It should be noted that in the presence of a correction means for correcting for tilted recorded images, the correction means may be adapted to correct the tilting which changes during a sweeping movement.

The tilt detector can be designed as an electromechanical component. In particular, it can be designed as an electronically acting spirit level or dragonfly. In a preferred variant, two tilt detectors are provided which detect mutually non-parallel, preferably mutually orthogonal, tiltings. Particularly preferably, three tilt detectors are provided which are preferably non-parallel in pairs and preferably span a Cartesian coordinate system. This simplifies the detector signal evaluation.

It is possible to evaluate the course of a tilt detector signal. Thus, a slight but permanent tilting will be more critical than short-term vibrations due to wind or hail. It is otherwise possible to match the Kippdetektorsignalverlauf against the waveform of a detector which is fixed in place during camera attachment, so is not moved in a pan or tilt movement of the camera. This is special there advantageous where the camera as a whole is strongly moved and can be subject to inclinations by this movement, for example on ships where cargo holds are to be monitored. Here can be determined by adjusting the Kippdetektorsignale between the ship's hull and camera, whether the camera tends to tilt together with the hull due to the ship's movement or whether a slope relative to the ship. The same applies to motor vehicles, rail vehicles and aircraft.

It is possible to retrofit existing cameras according to the invention. For this purpose, mounting sets can be provided with a base plate causing a pivot axis inclination and tilt detectors. Tilt detectors suitable for retrofitting can, for example, feed their signals via suitable interfaces to the camera to be retrofitted or directly to a data line also addressed by the camera.

Fig. 1

eine Überwachungskameraanordnung gemäß der vorliegenden Erfindung,

Fig. 2

Veranschaulichungen der Einstellung eines Kamerasichtpunktes im Sichtfeld der Überwachungskameraanordnung von Fig. 1.

The invention will now be described by way of example only with reference to the drawings. In this is represented by:

Fig. 1

a surveillance camera arrangement according to the present invention,

Fig. 2

Illustrations of the setting of a camera point of view in the field of view of the surveillance camera arrangement of Fig. 1 ,

To Fig. 1 For example, a surveillance camera arrangement generally designated 1 comprises at least one adjustment axis 2 for setting a surveillance area 3 and detection means 4 in order to be able to detect and signal changes in the surveillance area, the detection means 4 at least one monitoring image-independent tilt detector 4a comprises in order to be able to signal a monitoring range change in response to detected tilting changes.

In the present exemplary embodiment, the surveillance camera arrangement 1 is a permanently installed surveillance camera, which is mounted on a generally horizontal building ceiling 5 with a mounting plate 6. The surveillance camera arrangement 1 is connected via a data line to a remote control center for the delivery of images in order to be able to ensure permanent monitoring of the surveillance area 3, which here is intentionally shown to be extremely miniaturized for reasons of clarity. The surveillance camera arrangement comprises suitable signal transmission means, for example a TCP / IP interface or the like, via which tilt detector signals, cf.

The pivot axis 2 serves to pivot the camera, that is approximately along the line AA of Fig. 2 to move. The pivot axis 2 has corresponding articulated connections 2a to the mounting plate. The pivot axis 2 is now inclined α against the perpendicular 7 by an angle. This is achieved in a simple manner in that the axis is non-soldering on the mounting plate 6. In a particularly preferred variant of the invention, a wedge-shaped mounting plate is used for this purpose, which may also be formed in two parts; it is then possible to use a wedge-shaped sub-piece which is mounted under a conventional mounting plate (with pivot axis projecting perpendicularly therefrom) to obtain a total of a non-orthogonal standing on a ceiling pivot axis.

When the camera rotates about the pivot axis 2 by an angle φ, as in Fig. 2 Accordingly, the camera's viewing area 3 does not move along the horizontal line AA, but along the curved line φ-φ.

Spaced from the mounting plate 6, a tilt joint 8 is disposed on the pivot axis, so that the camera 1b of the surveillance camera assembly 1 can be tilted not only along the line φ-φ but also inclined along the line ψ-ψ.

The tilt detectors 4a1 and 4a2 are arranged in the housing of the camera 1b and thus make any movement of the camera body 1b with. They are merely for illustrative purposes Fig. 1 out drawn. It is shown schematically that the tilt detectors are illustrated as spirit level arrangement, namely from two orthogonal standing spirit levels 4a1 and 4a2.

A practical realization of the tilt detectors shown as spirit levels can be achieved by acceleration sensors of conventional design. As a rule, these acceleration sensors not only respond when their movement state changes appreciably, but are sensitive enough to detect the differences in the action of the earth's gravitational field associated with changes in their inclination. Incidentally, the use of acceleration sensors is also preferred because short, hard impacts, impacts, etc. can be detected with them; this helps to not only prevent tampering while monitoring the camera function, but also to detect defects by - a shot that does not alter a setting - etc.

Each of the tilt detectors shown here as an electromechanically designed spirit level can be zeroed in a desired position in which the camera has once been set up, that is to say adjusted so that no tilt signal is generated, but instead the center position is detected. The electro-mechanical spirit levels or tilt detectors are so precise that disturbing deflections of the camera body can be detected. The tilt detectors 4a1 and 4a2 are assigned a signal conditioning 4c to condition the signals 4b1 and 4b2 of the tilt detectors and to output a warning signal 4d to a warning unit 4e in response to changes in the tilt degree detected by the tilt detectors, which is transmitted via a TCP / IP or a TCP / IP other interface can happen over which the camera transmits, for example, images. The actual warning then takes place in the evaluation center, but can alternatively be done in other ways, such as by notifying an administrator by SMS or the like.

In operation, a desired position 3 ', compare Fig. 2 , set the viewing range and both tilt detectors 4a1 and 4a2 are set so that they in the resulting tilting position (see in particular straight line BB in Fig. 2 for the illustration of the tilt of tilt detector 4a2) not respond, so "zeroed" are. This can be done, for example, mechanically or electronically. In acceleration sensors that are preferably used, for example, the current g-value component can be stored in the desired position.

As long as there is no change in the setting, the tilt detector 4a2 will not respond. However, if the camera is rotated about the axis 2, so also changes the inclination of the tilt detector 4a2, for example, from its set position to a position 3 "on line φ-φ of Fig. 2 is moved and thus has a slope c corresponding to line CC. This is readily detectable in the Kippdetektorsignalauswertestufe 4c, so that a tilt signal can be output via line 4d to the warning unit 4e.

In this way, an adjustment of the pivoting direction can be detected easily. Even with a slightly inclined or uneven ceiling surface 5 is thereby to be detected by the sufficiently large inclination α of the pivot axis 2 against the perpendiculars 7 always a sufficiently strong tilt signal with the detector 4a2.

It should also be noted that, although not described above, an electronic, that is software technical compensation of an initial image skew in position 3 'can be made. If this, which is preferred, is set during assembly, this presetting no longer changes due to the undesirable and possibly sabotage-induced pivoting of the camera housing 1b about the pivot axis 2 from the viewing area 3 'into the viewing area 3 " The unwanted tilt can also be optically captured particularly well, because a previously shown horizon now appears tilted.

It should be noted that the Kippsignalauswertestufe 4c short-term tilting, such as vibration-induced fluctuations ignore the central position or at most issue a warning that indicate problems in the attachment, which warns against future permanent changes in the field of vision early.

It should be mentioned, moreover, that the arrangement of the tilt detectors can also be used in order to be able to determine a current orientation in particular by electric motor pivoting and / or tilting cameras. This independence from angle encoders or the (step) motor of the camera adjustment is possible; this is considered to be advantageous and inventive, even if, for example, a corresponding pivot axis is arranged vertically.

Claims (11)

1. Monitoring camera arrangement (1)
   having at least one setting axis (2) for setting a monitoring region
   by pivoting
   about the setting axis (2),
   wherein the setting axis (2)
   can be non-vertical
   after mounting,
   and having a tilt detector (4A),
   in order to be able to detect and signal tilt-induced variations in the monitoring region,
   characterized in that
   the setting axis (2) is arranged such that, after mounting the monitoring camera on a level surface, it is not normal to the bearing plane thereof,
   and the tilt detector (4A) is designed to the effect that in response to detected tilt variations
   it is possible to signal a variation in the horizontal monitoring region as indicating manipulations.
2. Monitoring camera arrangement according to the preceding claim, characterized in that two setting axes (2,8) are provided to enable an inclined setting and a pivot setting.
3. Monitoring camera arrangement according to the preceding claim, characterized in that an inclination joint (8) is arranged between setting axis (2) and camera.
4. Monitoring camera arrangement according to one of the preceding claims, characterized in that in the mounted state the at least one setting axis (2) is skewed in relation to the vertical.
5. Monitoring camera arrangement according to one of the preceding claims, having a mounting plate (6) for fitting the camera on a level surface, wherein the setting axis (2), which is not vertical after mounting, is arranged in a fashion not normal to the bearing plane of the mounting plate (6).
6. Monitoring camera arrangement according to one of the preceding claims, wherein the setting axis (2) is inclined relative to the vertical or is skewed in relation thereto, in which the inclination is above 3°, but not more than 15°, preferably not more than 10°.
7. Monitoring camera arrangement according to one of the preceding claims, characterized in that it comprises a correction means for correcting images recorded at a tilt.
8. Monitoring camera arrangement according to one of the preceding claims, characterized in that it comprises a drive for repeatedly scanning a monitoring region, the tilt detector (4A) being designed to determine a variation in tilt for a given scanning angle.
9. Monitoring camera arrangement according to one of the preceding claims, characterized in that the tilt detector (4A) is formed as an electromechanical component.
10. Monitoring camera arrangement according to one of the preceding claims, characterized in that two tilt detectors (4A, 4B) detecting at least mutually nonparallel tilts are provided, preferably three tilt detectors detecting mutually nonparallel tilts in pairs.
11. Monitoring camera arrangement according to one of the preceding claims, having an evaluating means for evaluating a tilt detector signal characteristic.

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