WO2015133907A1

WO2015133907A1 - Method for use of a camera for surveillance of a work area and a crane provided with a camera

Info

Publication number: WO2015133907A1
Application number: PCT/NO2015/050041
Authority: WO
Inventors: Sigbjørn ULLESTAD
Original assignee: Nmi Holding As
Priority date: 2014-03-04
Filing date: 2015-02-25
Publication date: 2015-09-11
Also published as: NO20140281A1

Abstract

A crane (2) provided with a crane boom (23), the crane boom (23) being attached in a mounting portion (239) to a crane-boom holder (210), and the crane boom (23) including a crane-boom tip (230), and : - the crane (2) including a camera with optics (1) and the camera being provided with an image sensor; - the crane (2) including a monitor (51) for displaying the image, transferred from the camera, to a crane operator; - the crane (2) including an interface for the crane operator's communication with a computer; and - the crane (2) including a computer for processing the camera picture to display an image section with a marker (41) determined by the crane operator. A method of displaying a loading area on a monitor is described as well.

Description

METHOD FOR USE OF A CAMERA FOR SURVEILLANCE OF A WORK AREA AND A CRANE PROVIDED WITH A CAMERA

The invention relates to a crane provided with a camera for the observation of a loading area from above. More particularly, the invention relates to a crane provided with a camera which communicates with a monitor for a crane operator. By means of an interface the crane operator can communicate with a computer processing the image of the camera so that a desired image section with an aiming point is displayed on the monitor.

It has gradually become common to place a camera in a crane boom to monitor a loading area from above. This is particularly practical when there is a question of lifting operations in areas where the crane operator is prevented from having direct visual contact with the loading area . During lifting operations the free end portion of a crane boom is raised and lowered almost continuously to change the radial distance of the load from the vertical axis of rotation of the crane. Thus, the angle of the crane boom relative to the horizontal plane is changed by the boom being rotated around its axis of suspension. For the camera to be pointed towards the loading area, the suspension of the camera in the crane boom must thus be arranged to enable an, in the main, continuous angular change relative to the boom. A camera of this kind is usually suspended in such a way that it orients itself towards the desired area by means of gravity. As the crane is rotating around its own vertical axis, the centrifugal force will make a camera which is rotatably suspended in the crane boom swing outwards from its equilibrium position even without the angle of the crane boom being changed. The camera thereby leaves its desired setting and does not fall back until the turning motion is ended.

The relative movement of the camera relative to the crane boom must be damped in order for undesired pendular movements of the camera not to occur. A damping mechanism may be a friction brake. Friction brakes have the drawback of a momentum being required before the friction is overcome. A camera in a crane boom will be dislodged from its desired position by a small movement of the crane boom, before the frictional force of the brake is overcome. Friction brakes have also turned out to transmit an undue amount of vibration from the crane boom to the camera. A damping mechanism may be fluid-based. An oil is conveyed through narrow passages. Oils may change their fluidities with temperature, so that by cold ambient temperatures the oil is too thick and by warm ambient temperatures the oil is too thin to provide damping. The material of the damper may also alter its dimension with a change in the temperature, which alters the cross-sectional area of the passage for the oil .

The use of gyro-stabilized camera systems is known. This is a reliable solution to keep a fixed direction of observation. Gyros have the drawback of being relatively expensive. They are also dependent on an energy source for the operation of the gyro. The energy source may be a battery or solar cells which may be placed in the instrument housing, or it may be an energy source that supplies the gyro with energy via a cable.

A camera which is attached to a platform in a horizontally rotatable manner may be held in position by means of a weight which will adjust the camera housing according to the local gravitation. The camera housing may be a weight in itself. A weight has the drawback of oscillating around its pivot point for a long time before coming to rest. In practice, aboard a vessel, it will not come to rest. If the instrument is subjected to wind, it will not come to rest either.

The applicant's own patent publication NO20014188 relates to a damper/brake which seeks to solve the problem of damping penduiar movements. At least one electrically conductive plate which forms a braking disc is movably arranged between at least one pair of permanent magnets. The poles of the pair of permanent magnets are arranged in such a way that the permanent magnets are mutually attractive. The pairs of magnets are arranged in a semicircle in holding plates. Holding plates and brake disc form an open structure. The applicant's own patent publication WO2011/133044 relates to a damper for limiting penduiar movements as well. The damper includes an electrically conductive anchor plate and a magnet which is provided with a backing plate made from a ferrite-containing material at one pole.

An eddy-current damper may be provided with permanent magnets or with electromagnets. Electromagnets have the drawback of requiring electrical energy from an energy source. In environments in which there is a risk of explosions, such equipment requires encasing in accordance with known standards. This makes such a damper more expensive. If the energy is to be provided from an external energy source, ca- bling is required between the damper and the energy source, which also makes the installation of such a damper more expensive.

The known solutions with a camera in a camera housing and with a system for damping the movements of the camera have in common that they are affected by wind and movements of the crane boom itself. If the crane is positioned on a vessel, the camera is also affected by waves. The movable parts of the camera housing require maintenance and possibly repairs. There may also be problems with the cable which follows the camera motion.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through features which are specified in the description below and in the claims that follow.

The invention is defined by the independent claims/claim. The dependent claims define advantageous embodiments of the crane-boom invention.

By a crane is meant, in what follows, a tower crane with a rotatable crane boom or jib. The crane boom may be provided with a movable carriage provided with a raisable block and hook. By a crane is also meant, in what follows, a crane which is rotatable on a crane base and in which a crane boom is hingedly connected to the crane with a horizontal pivot axis. The crane boom may include a telescopic beam. By a crane is also meant a crane with a tower which is displaced along rails, and in which a horizontal crane boom or jib projects laterally relative to the rails. The crane boom may be provided with a movable carriage provided with a raisable block and hook. The crane may be positioned on a vessel.

By a loading area is meant, in what follows, an area in which a crane picks up a load or puts down a load. The area along which the load moves from when the load is picked up by a crane until the load is put down by the crane is meant as well.

In a first aspect, the invention relates to a crane provided with a crane boom, the crane boom being attached in a mounting portion to a crane-boom holder and the crane boom including a crane-boom tip, and this in such a way that:

- the crane boom includes a camera with optics and the camera is provided with an image sensor;

- the crane includes a monitor for displaying the image, transferred from the camera, to a crane operator; - the crane includes an interface for the crane operator's communication with a computer; and

- the crane includes a computer for processing the camera image for displaying an image section with a marker determined by the crane operator.

The camera with optics may be attached to the crane boom in a portion between the crane-boom tip and the mounting portion. The camera may be attached to a carriage which is movable along the crane boom in a portion between the crane-boom tip and the mounting portion.

The optics may comprise a wide-angle lens. The optics may comprise a fisheye lens. The optics may comprise a parabolic mirror and a lens.

The computer may include a piece of software for coordinating the fixed ground coordinates of the marker with the coordinates of the marker created in the image sensor of the camera.

In a second aspect, the invention relates to a method of displaying the loading area of a crane on a monitor for a crane operator, the method including :

- providing a crane with a camera with optics and with an image sensor on a crane boom, a monitor for displaying the camera image of the loading area to the crane operator, an interface for the crane operator's communication with a computer and a computer for processing the camera image;

- the crane operator defining a desired image section by means of the interface, the desired image section including the loading area and a chosen marker in the loading area; and a desired magnification of the image section on the monitor; and

- providing the computer with a piece of software which coordinates the fixed ground coordinates of the marker with the coordinates of the marker created in the image sensor of the camera,

so that the desired image section and the desired magnification are kept on the monitor through the movement of the camera on the crane boom or the movement of the camera with the crane boom.

The camera may be provided with a wide-angle lens. The camera may be provided with a fisheye lens. The camera may be provided with a parabolic mirror and a lens.

The computer may further be provided with a piece of software which can warn the crane operator about an object approaching the loading area. The computer may further be provided with a piece of software which can stop the operation of the crane if an object is approaching the loading area. This may happen without the crane opera- tor's participation. The crane operator may then activate the operation when the object is no longer in the loading area or in a dangerous zone near the loading area.

In what follows, examples of preferred embodiments are described, which are visualized in the accompanying drawings in which :

Figure 1 shows schematically a crane with a crane boom in a first position, the crane being provided with a camera in such a way that the field of view of the camera includes a loading area with a marker;

Figure 2 shows schematically the crane of figure 1 with the crane boom in a second position;

Figure 3 shows the same as figure 1, but wherein a load in the loading area includes the marker; and

Figure 4 shows an alternative embodiment in which the camera is shown in an alternative position to the side of the crane and such that the field of view of the camera includes the loading area.

In the drawings, the reference numeral 1 indicates a camera with optics. The camera with optics 1 is attached to a crane 2. The crane 2 is shown schematically and includes a crane tower 21, a crane boom 23, a crane-boom actuator 25, a wire 27 and a wire sheave 29. A hook 22 is attached to the wire 27. The crane 2 rests on a crane base 24. In a mounting portion 239, the crane boom 23 is hinged to the crane tower 21 in the crane-boom holder 210 of the crane tower 21. The crane 2 may be rotatable around a vertical axis on the crane base 24.

The camera with optics 1 is attached to a portion at the crane-boom tip 230 of the crane boom 23.

The camera with optics 1 creates an image covering an area 3. The area 3 is determined by the position of the crane boom 23 as shown in figures 1 and 2. The area 3 includes a loading area 4. The hook 22 can be lowered down to the loading area 4. The loading area 4 may have a marker 41. A display image 5 is displayed to a crane operator (not shown) on a monitor 51. The display image 5 shows the loading area 4 and possibly the marker 41.

The optics of the camera may consist of a lens (not shown) of a type known per se. The lens may consist of a wide-angle lens. In an alternative embodiment, the lens may consist of a fisheye lens. In a further alternative embodiment, the optics of the camera may comprise a parabolic mirror and a lens. The camera is provided with an image sensor of a kind known per se. The image is transferred to a computer (not shown) in the manner known in the art.

The crane 2 is provided with an interface of a kind (not shown) known per se for the crane operator to be able to communicate with the computer. The crane operator may choose a section of the area 3 via the interface. This area may be the loading area 4. The loading area 4 may include a marker 41 which may be any structure in the loading area 4. The crane operator marks the marker 41 in the display image 5 via the interface. The computer is provided with a piece of software coordinating the fixed ground coordinates of the chosen marker 41 with the coordinates of the marker 41 created in the image sensor of the camera so that the desired image section with the loading area 4, the marker 41 and the desired magnification of the image section is kept on the monitor 51 through the movement of the camera with optics 1 with the crane boom 23, as is shown in figures 1 and 2.

Other types of cranes may include a horizontal crane boom with a carriage provided with a raisable block and hook (not shown) which is moved along the crane boom. In an alternative embodiment, the camera with optics 1 may be attached to such a carriage.

In an alternative embodiment, a load 6 may include the marker 41, as shown in figure 3. The load 6 may be moved with the crane 2. The marker 41 is kept on the monitor 51 while the load 6 is moved by the crane 2 with the crane hook 22. Thereby the crane operator will be able to follow the load 6 while the load 6 is being moved through the entire loading area 4 as defined in the general part of the description.

As shown in figure 3, the computer may also be provided with software which recognizes a person, a vehicle or some other movable object 9 approaching the loading area 4. The software may be arranged to warn the crane operator, for example by a light signal, an audio signal or by a warning symbol on the monitor 51, of the fact that the object 9 is approaching the loading area 4, which may constitute a hazard to the object 9. The crane operator may then take action as necessary to prevent the dangerous situation. The software may further be arranged to stop the operation of the crane 2 without the crane operator's participation if an object 9 is approaching the loading area 4. The crane operator may then activate the operation of the crane 2 when the object 9 is no longer in the loading area 4 or in a dangerous zone near the loading area 4. A further, alternative embodiment is shown in figure 4. In this embodiment, the camera with optics 1 is positioned on a camera holder 7 to the side of the crane 2. The camera with optics 1 creates an image covering an area 3' . The loading area 4 of the crane is included in the area 3'. The loading area 4 may be an area in which the crane 2 picks up a load or an area in which the crane 2 puts down a load. Both areas may be within the area 3'. If both areas are within the area 3', the camera with optics 1 may cover the whole loading area 4, including the area along which the load is moving from when the load is picked up until it is put down.

Claims

C l a i m s

1. A crane (2) provided with a crane boom (23), the crane boom (23) being attached in a mounting portion (239) to a crane-boom holder (210), and the crane boom (23) including a crane-boom tip (230), c h a r a c t e r i z e d i n that:

- the crane (2) includes a camera with optics (1) and the camera is provided with an image sensor;

- the crane (2) includes a monitor (51) for displaying the image, transferred from the camera, to a crane operator;

- the crane (2) includes an interface for the crane operator's communication with a computer; and

- the crane (2) includes a computer for processing the camera image to display an image section with a marker (41) determined by the crane operator.

2. The crane (2) according to claim 1, wherein the camera with optics (1) is attached to the crane boom (23) in a portion between the crane-boom tip (230) and the mounting portion (239).

3. The crane (2) according to claim 1, wherein the camera is attached to a carriage which is movable along the crane boom (23) in a portion between the crane-boom tip (230) and the mounting portion (239).

4. The crane (2) according to claim 1, wherein the optics comprise a wide- angle lens.

5. The crane (2) according to claim 1, wherein the optics comprise a fisheye lens.

6. The crane (2) according to claim 1, wherein the optics comprise a parabolic mirror and an objective.

7. The crane (2) according to claim 1, wherein the computer includes a piece of software for coordinating the coordinates of the chosen marker (41) with the coordinates of the marker (41) reproduced on the image sensor of the camera .

8. A method of displaying the loading area (4) of a crane (2) on a monitor (51) for a crane operator, c h a r a c t e r i z e d i n that:

- a camera with optics (1) and with an image sensor, a monitor (51) for dis- playing the camera image of the loading area (4) to the crane operator, an interface for the crane operator's communication with a computer, and a computer for processing the camera image are provided;

- the crane operator defines a desired image section by means of the interface, the desired image section including the loading area (4) and a chosen marker (41) in the loading area (4); and a desired magnification of the image section on the monitor (51); and

- the computer is provided with a piece of software which coordinates the coordinates of the chosen marker (41) with the coordinates of the marker (41) reproduced on the image sensor of the camera,

so that the desired image section and the desired magnification are kept on the monitor (51).

9. The method according to claim 8, wherein the method further includes

providing the crane (2) with the camera with optics (1).

10. The method according to claim 8 or 9, wherein the camera is provided with a wide-angle lens.

11. The method according to claim 8 or 9, wherein the camera is provided with a fisheye lens.

12. The method according to claim 8 or 9, wherein the camera is provided with a parabolic mirror and a lens.

13. The method according to claim 8, wherein the computer is further provided with a piece of software which can warn the crane operator about an object (9) which is approaching the loading area (4).

14. The method according to claim 8, wherein the computer is further provided with a piece of software which can stop the operation of the crane (2) if an object (9) is approaching the loading area (4).