WO2014184748A1 - Method for determining the orientation of a submerged surface and apparatus that carries out this method - Google Patents
Method for determining the orientation of a submerged surface and apparatus that carries out this method Download PDFInfo
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- WO2014184748A1 WO2014184748A1 PCT/IB2014/061421 IB2014061421W WO2014184748A1 WO 2014184748 A1 WO2014184748 A1 WO 2014184748A1 IB 2014061421 W IB2014061421 W IB 2014061421W WO 2014184748 A1 WO2014184748 A1 WO 2014184748A1
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- underwater support
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- 238000000034 method Methods 0.000 title claims abstract description 41
- 238000012545 processing Methods 0.000 claims abstract description 29
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- 238000005259 measurement Methods 0.000 description 13
- 239000011435 rock Substances 0.000 description 4
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- 230000000694 effects Effects 0.000 description 2
- 239000013598 vector Substances 0.000 description 2
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- 238000007689 inspection Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
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- Length Measuring Devices With Unspecified Measuring Means (AREA)
Abstract
A method for determining the orientation of a submerged surface (210) comprises the steps of arranging an underwater support (10) in a position arranged at a predetermined distance from the submerged surface (210); of determining the spatial orientation and the depth of the underwater support (10) at the above described position; of constructing a virtual image of the submerged surface (210). In particular, the constructing step comprises the steps of: projecting at least three points (101a-101d) of a laser light on the submerged surface (210); of acquisition of the above described at least three projected points (101a-101d) by a optical sensor (25) mounted on the underwater support obtaining a virtual image (130) comprising at least three virtual points (131a-13ld) corresponding to said at least three projected points (101a-101d); processing the virtual image (130). In particular, the processing step comprises the steps of: identifying on said virtual image (130) of a geometric figure to which said at least three virtual points belong (131a-131d); detecting the shape of said geometric figure; and of computing the orientation of the submerged surface (210) on the basis of the detected shape of said geometric figure identified on said virtual image (130).
Description
TITLE
METHOD FOR DETERMINING THE ORIENTATION OF A SUBMERGED SURFACE AND APPARATUS THAT CARRIES OUT THIS METHOD
DESCRIPTION
The present invention relates to the field of procedures for underwater inspections and, in particular it relates to a method for determining the orientation of a submerged surface, such as the surface of a wreck, of harbour or off-shore structures, of sea floor, of rocks and rocky walls, of submerged archaeological objects, etc.
Furthermore, the invention relates to an apparatus that carries out this method.
Description of the prior art
As well known, the measurement of the orientation of submerged surfaces is an activity that, even though it presents many technical difficulties, is, however, necessary in many application fields, both scientific and industrial. In particular, the measurement of the orientation of surfaces is used in operations of salvage and of recovering of wrecked ships, in operations of monitoring and controlling of harbour or off-shore structures and, more in general, for all the exploratory activities of the sea floors.
The prior art provides to carry out the measurements with classic techniques of geometric determination such as magnetic compass and mechanical goniometers, and then through the intervention of qualified underwater technical operators. This causes high costs, long time in addition to a high risk to the safety workers.
Another known method provides the use of acoustic tools as "multi-beam echo-sounder" that can achieve high accuracy and cover large areas.
However the costs of this kind of tools are very high and the use of the same needs to provide a support in surface, in particular adequately equipped ships. Such kind of tools has a very high size and energy consumption and they are therefore inadequate to be housed in a small underwater vector, such as an underwater ROV.
Another possible application provides the computing of the orientation of sea floor and of submerged rocky walls for bathymetric and geo-mechanical surveys. In particular, "geo-mechanical survey" means an ordered set of measuring and observations to be carried out in order to detect the basic parameters and the discontinuity of the rocks.
In this case, the description must to provide a general picture of the features of the rocks with particular care to their mechanical behaviours displaying, as much as possible, quantitative data. However in order to define the orientation of the submerged surfaces with conventional methods it is not always possible because the underwater environment is not of easy accessibility to scientific workers.
In US2012/0038932 a device is described for surveying a surface in a real world coordinates system. The device provides a projecting unit for projecting a predefined pattern on a surface and an optical measurement system that determines positional and image data of a projected pattern on the surface. The positional and image data are indicative of the predefined pattern in a measuring coordinate system. Furthermore, the device provides a
processing unit for determining the transformation data on the basis of a predefined pattern and of the positional and image data of the projected pattern.
US4948258 describes a method for determining the profile of a submarine surface. The method provides to pass a laser beam through a holographic grating structured to emit a divergent laser beam defining a two dimensional array of dots in a predetermined pattern and projecting the beam on the surface to survey.
US20060017720 describes an apparatus for measuring and reconstructing a three-dimensional image of an object. The apparatus comprises a projector that projects a pattern onto a surface of an object and a processor that examines the distortions produced in the pattern by the surface. Summary of the invention
It is then a feature of the present invention to provide a method for determining the orientation of a submerged surface that has an extremely reduced cost and that allows to measure quickly the orientation of submerged surfaces and with simple technologies.
It is a particular feature of the present invention to provide such a method that is extremely effective and that involves the use of suitable devices in terms of size and weight in order to be put on small underwater vectors.
It is a particular feature of the present invention to provide a method for determining the orientation of a submerged surface that can provide, in particular in case of submerged surfaces of large size, both a value of the local orientation of the submerged surface, i.e. of an its portion, and a value of the average orientation of the
same surface.
It is another feature of the present invention to provide an apparatus that has the same advantages above described for the method.
These and other objects are achieved by a method for determining the orientation of a submerged surface arranged at a predetermined depth, said method comprising the steps of:
- moving an underwater support up to position the underwater support at a predetermined distance from said submerged surface;
- determining the absolute spatial orientation of said underwater support at said position obtaining absolute spatial orientation data;
- computing the depth of said underwater support at said position obtaining depth data;
- constructing a virtual image of said submerged surface, said constructing step comprising the steps of:
- projecting at least three laser light beams on said submerged surface, said three laser light beams having a measured absolute spatial orientation because it corresponds to the measured orientation of said underwater support measured in said determining step of the absolute spatial orientation;
- locating three corresponding points of a laser light on said submerged surface;
- acquisition of said at least three projected points by means of an optical sensor mounted on said underwater support obtaining a virtual image
comprising at least three virtual points corresponding to said at least three projected points ;
- processing said virtual image, said processing step comprising the steps of:
- identifying on said virtual image a geometric figure to which said at least three virtual points belong;
- detecting the shape of said geometric figure;
- determining the relative orientation of the submerged surface with respect to said underwater support, said relative orientation being measured on the basis of the detected shape of said geometric figure identified on said virtual image;
- determining the absolute spatial orientation of said submerged surface on the basis of said relative spatial orientation and of said absolute spatial orientation of said underwater support.
In particular, the absolute spatial orientation and the depth of said underwater support can be predetermined.
Alternatively, the absolute spatial orientation and the depth of said underwater support can be determined through the steps of:
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the orientation of said underwater support with respect to a fixed reference, obtaining an absolute orientation data.
Advantageously, the determining step of the orientation of the submerged surface provides a comparing step of said detected shape of said geometric figure
defined with a predetermined shape of a predetermined geometric figure.
In particular, the projection of at least three points it is necessary to ensure to determine the slope of the plane to which the submerged surface to be examined belongs .
Advantageously, the at least three projected points on the submerged surface are three discrete points.
In this case, the projecting step provides preferably to project at the same time said at least three points of a laser light on said submerged surface, each point of said plurality being a point projected on said submerged surface by means of a respective sender of a laser light beam.
Alternatively, the three projected points can belong to a predetermined geometric figure comprising a plurality of points, for example of square shape, which is projected on the submerged surface by a single projection device.
Advantageously, the determining step of the orientation of the submerged surface comprises an association step for associating said identified geometric figure with a predetermined orientation of a predetermined plurality of orientations.
In particular, the determining step provides a comparing step for comparing the detected shape of the identified geometric figure with a plurality of models loaded in a database, each model of said plurality being associated with a predetermined orientation.
Advantageously, the comparing step provides the steps of:
- attribution to each model of said plurality of a
corresponding similarity index is with the detected shape of said identified geometric figure;
- selection among said plurality of models of the model having the highest similarity index, or with the similarity index is higher than a predetermined threshold value is *.
In a possible exemplary embodiment, the determining step of the submerged surface provides the steps of:
- determining the coordinates (x,y), i.e. the position, of at least three points of said geometric figure identified on said virtual image;
- comparing said determined coordinates (x,y) with predetermined coordinates (x*,y*) of corresponding points of a geometric figure of a virtual reference image;
- computing the deviation of said determined coordinates (x,y) from said coordinates of reference (x*, y*) ;
- determining the orientation of said submerged surface on the basis of said deviation.
In particular, the virtual reference image, and then the corresponding geometric figure, can be the image that would be obtained if said submerged surface was orthogonal to the axis of the optical sensor.
Advantageously, a plurality of senders of laser beams is provided. In general, in fact, the more senders of laser beams are mounted on the underwater support the higher can be the precision of the measurement of the orientation obtained at the end of the above described procedure. In particular, in fact, if obstacles, such as rocks, seaweeds, corals, etc. are present between the
underwater support and the submerged surface to be examined it is ensured, in any case, that a sufficient number of laser beams reaches the surface to be surveyed.
In particular, in case of a submerged surface of large size the possibility is provided of surveying a plurality of determining steps of the orientation of a plurality of different portions of said submerged surface, each determining step of said plurality being arranged to determine the orientation of a respective portion of said submerged surface.
Advantageously, the steps are provided of:
- arranging said underwater support at a first position, in said first position said underwater support having a predetermined first orientation;
- determining said first orientation of said underwater support;
- projecting at least three points of laser light on a first portion of said submerged surface arranged at said first position;
- acquisition of said at least three points of laser light by means of said optical sensor obtaining a first virtual image comprising at least three virtual points corresponding to said at least three points projected on said first portion;
- processing said . first virtual image, said processing step comprising the steps of:
- identifying on said first virtual image a first geometric figure to which said at least three virtual points belong;
- determining the orientation of the first portion of the submerged surface on the basis of the
detected shape of said first geometric figure identified on said first virtual image;
- arranging said underwater support at least at a second position, in said second position said underwater support having a predetermined second orientation;
- determining said second orientation of said underwater support;
- projecting at least three points of laser light on a second portion of said submerged surface arranged at said second position;
- acquisition of said at least three points of laser light by said optical sensor obtaining a second virtual image comprising at least three virtual points corresponding to said at least three projected points on said second portion;
- processing said second virtual image, said processing step comprising the steps of:
- identifying on said second virtual image a second geometric figure to which said at least three virtual points belong;
- determining the orientation of the second portion of the submerged surface on the basis of the detected shape of said second geometric figure identified on said second virtual image.
In particular, since the direction of the underwater support and the respective depth are known, for each determining step it is possible to determine the local orientation of each portion of the investigated submerged surface.
According to an exemplary embodiment, each sender is
arranged to project on said submerged surface a matrix of discrete, or continuous, points of laser light comprising a plurality of points.
In case of surfaces of large size the steps above described allow to determine a local orientation of the submerged surface. In this case, a step can be provided of computing the average orientation of the surface to be surveyed, said computing step of the average orientation providing the steps of:
- arranging said underwater support in a first position arranged at a first measured distance from said submerged surface;
- . measuring said first distance of said underwater support from said submerged surface, obtaining a first distance data;
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the orientation of said underwater support with respect to a fixed reference, obtaining a direction data;
- arranging said underwater support in at least one second position arranged at a second measured distance from said submerged surface, in particular with said second measured distance different from said first measured distance;
- measuring said second distance of said underwater support from said submerged surface, obtaining a second distance data;
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the direction of said underwater support with respect to a reference fixed, obtaining a direction data;
- processing said first and said at least second distance data, said orientation data of said underwater support and of said depth data by means of a processing unit obtaining an average orientation data of said submerged surface.
This way, through a combination of the local orientation data, i.e. of predetermined portions of the submerged surface, and through the average orientation, related to the whole submerged surface, a picture is obtained of the orientation in the space of the examined surface even if the size of the surface is very high.
In particular, by the absolute orientation of the underwater support and by the relative orientation of the submerged surface, the absolute orientation of the submerged surface is determined, again through known geometric relations.
In particular, the measuring step of the depth of the underwater support can be carried out by means of at least one pressure sensor configured to measure the value of the underwater pressure at a predetermined depth. In fact, by value of the underwater pressure and taking into account the local density of the water it is possible to compute the depth through known relations.
Advantageously, the measurement of the distance of the underwater support from the submerged surface is made by means of at least one acoustic underwater sensor, i.e. a sonar.
In particular, the measurement of the orientation of
said underwater support with respect to said fixed reference value can be done using an inertial platform comprising at least one measuring device selected from the group consisting of:
- a triaxial gyroscope;
- a magnetometer;
- a combination thereof.
Advantageously, the inertial platform further comprises an inclinometer, in particular a triaxial accelerometer .
In particular, the triaxial accelerometer can be a MEMS triaxial accelerometer.
For each measure the instant (ti) is detected in which the measure same is done in such a way that the different measured values in particular of depth, of orientation of the underwater support, of distance of the underwater support from the submerged surface, of orientation of the support, and of orientation of the submerged surface are referred to a predetermined instant of detection.
According to another aspect of the invention, an apparatus for determining the orientation of a submerged surface arranged at a predetermined depth, said apparatus comprising :
- a movable underwater support arranged to be positioned, in use, near said submerged surface, on said underwater support being mounted:
- a unit for determining the absolute spatial orientation of the underwater support obtaining absolute spatial orientation data;
- a unit for computing the depth of said underwater support at said position obtaining depth
data;
- a projection device which is arranged to project at least three beams of a laser light on said submerged surface obtaining three corresponding points on said submerged surface, said three beams of laser light having a measured absolute spatial orientation because corresponding to the orientation of said underwater support measured in said computing step of the absolute spatial orientation;
- an optical sensor arranged to detect said at least three points obtaining a virtual image comprising at least three virtual points corresponding to said at least three projected points ;
- a processing unit configured to process said virtual image through the steps of:
- identifying on said virtual image a geometric figure to which said at least three virtual points belong;
determining the relative orientation of the submerged surface with respect to said underwater support, said relative orientation being measured on the basis of the detected shape of said geometric figure identified on said virtual image;
- determining the absolute spatial orientation of said submerged surface on the basis of said relative spatial orientation and of said absolute spatial orientation of said underwater support .
In particular, the projection device can provide a sender of laser light arranged to project on said surface a predetermined geometric figure to- which said at least three points belong.
Alternatively, the projection device can comprise at least three senders of laser light, each sender arranged to project on said surface a respective point of said at least three points of laser light.
Preferably, the underwater support is a movable support.
In particular, the movable underwater support can be a ROV (Remotely Operated Vehicle) of underwater type, or an autonomous underwater vehicle or AUV.
In a possible exemplary embodiment, the underwater remotely operated vehicle has a main body with substantially cylindrical shape moved by means of four propellers .
In particular, can be provided:
- a first propeller arranged to produce on said main body a first thrust along a substantially axial direction;
- a second propeller positioned opposite to the first propeller with respect to the main body, said second propeller arranged to produce on said main body a second thrust along a substantially axial direction;
- a third propeller arranged to produce on said main body a third thrust along a direction substantially transversal; and
- a fourth propeller arranged to produce on said main body a fourth thrust along a direction substantially transversal and parallel to the thrust direction
produced by the third propeller.
In particular, the first and the second propeller are used for producing a thrust of movement and a rotation of the vehicle about a substantially vertical rotation axis. The third and the fourth propellers are instead arranged to produce a substantially vertical thrust, in order to change the depth of the vehicle and a rotation to the vehicle same about the side axis of the vehicle.
Advantageously, the third and the fourth propellers are arranged along a substantially radial direction and pass through the longitudinal axis of the main body.
In particular, the outlet mouths of the third and of the fourth propellers are arranged along a same generatrix of the main body with substantially cylindrical shape.
The particular type of propelling system chosen by the present invention for moving the underwater remotely operated vehicle provides a high manoeuvrability of the vehicle same also in hostile surroundings as the inner room of a wreck.
Advantageously, a frame provides protection of said main body, said frame of protection comprising a plurality of portions elongated shaped and being configured to form a substantially reticular structure.
In particular, the projection unit and the optical sensor are housed in respective fluid-tight cases in such a way that it is possible to use them in underwater applications. Alternatively, it is provided the possibility of arranging the projection unit and the optical sensor in a same fluid-tight case.
According to another aspect of the invention, a method
for determining the orientation of a submerged surface comprises the steps of:
- moving an underwater support up to position the same to a first measured distance from said submerged surface;
- measuring said first distance of said underwater support from said submerged surface, obtaining a first distance data;
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the direction said underwater support with respect to a reference fixed, obtaining a direction data;
- arranging said underwater support in at least one second position arranged at a second measured distance from said submerged surface with said second measured distance different, from said first measured distance;
- measuring said according to Distance of said underwater support from said submerged surface, obtaining a second distance data;
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the direction said underwater support with respect to a reference fixed, obtaining a direction data;
- processing said first and said at least second distance data, said orientation data of said underwater support and of said depth data by a processing unit obtaining an average orientation data of said submerged surface.
Brief description of the drawings
The invention will be now shown with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:
— figures 1 and 2 diagrammatically show in respective perspective side views a possible exemplary embodiment of an apparatus, according to the present invention, for determining the orientation of two submerged surfaces having different orientation;
— figures 3 to 6 diagrammatically show the principle of base of the method for determining the orientation of the submerged surface according to the present invention;
- figure 7 diagrammatically shows a perspective side view of a possible application of the apparatus of Fig. 1 to a surface of large size;
— figures 8 and 9 diagrammatically show in respective block diagrams the main phases provided by the method according to the invention, for determining the orientation of the submerged surface;
— figure 10 diagrammatically shows a perspective side view of a possible exemplary embodiment of the apparatus of figure 1;
— figures 11 to 18 diagrammatically show from different angles and prospective, a possible exemplary embodiment of an underwater support used for carrying out the method according to the invention, for determining the orientation of the submerged surface.
Detailed description of some exemplary embodiments
In Fig. 1 is diagrammatically shown a possible exemplary embodiment of a apparatus 100 for determining the orientation of a submerged surface, for example the surface 210 of a side wall of a submerged ship 200, or a rocky wall, or of another object. The apparatus 100 can comprise an underwater support 10 arranged to be located, in use, in a predetermined position with respect to the submerged surface 210 whose has to be determined the orientation. The underwater support 10 can be, for example, an underwater remotely operated vehicle, i.e. a ROV.
In particular, the underwater support 10 has a projection unit comprising at least three senders of laser light, for example comprising 4 senders 61a-61d, in order to have a redundant measure (Fig. 12) . Each sender 61a-61d is adapted to project a respective ray, or beam, of laser light 161a-161d on the submerged surface 210. Each laser beam 161a-161d, once achieved the submerged surface 210, locate a respective projected point lOla-lOld.
In the exemplary embodiment of figure 2, instead, the projection device of laser light is adapted to emit on the surface 210' a light laser beam 161' arranged to project a predetermined geometric figure 165, for example square, of which at least three points are located, for example 4 projected points lOla-lOld.
The underwater support 10 is also provided with an optical sensor 25, for example the optical sensor of a underwater camera not shown in figure and arranged at a protection cap 16 of transparent material (see figure 12).
The optical sensor 25 is adapted to detect the points lOla-lOld projected on the surface 210 obtaining a virtual image 130 comprising a plurality of points 131, in the present case 4 points 131a-131d, each of which corresponds to a point 101 projected on the submerged surface 210.
In particular, the projection unit comprises a fluid- tight receptacle, in which the sources of laser beam are arranged. In other words, each laser light source is arranged in a fluid-tight body, in order to be used underwater. Analogously also the optical sensor is provided arranged in a fluid-tight body, i.e. housed within a fluid-tight receptacle that makes it possible to use the same in underwater applications provided by the present invention. The optical sensor and the projection device can be housed in a same case, or in respective cases .
The apparatus 100 also comprises a processing unit 30, for example a microprocessor, configured to process the virtual image 130 through the succession of operations diagrammatically shown in the block diagram 300 of figure 8 for determining the orientation of the submerged surface 210. In particular, once arranged the underwater support 10 in a predetermined position with respect to the submerged surface 210, for example at a distance d set between 30 cm and 50 m, block 301, a step is started of construction of a virtual image 130 of the surface 210, block 302. The distance d can be, in any case, chosen on the basis of the type of instrument used for determining the same.
There is then a step of processing the virtual image
130, block 303, through which the orientation of the
submerged surface 210 is measured, block 304. More in detail, as diagrammatically shown in the block diagram 400 of figure 9, the step of construction of the virtual image begins with a step of projection on the submerged surface 210 of at least three points 101 of a laser light projected by respective senders. A step follows of acquisition of the above described plurality of points 101 by the optical sensor 25, block 402 obtaining an virtual image 130 comprising a plurality of virtual points, for example 4 virtual points 131, block 403. The virtual image 130 is then processed by the processing unit 30 as described below. Starting from the identified geometric figure to which the virtual points belong, on the virtual image 130 is detected the shape of the geometric figure identified on the virtual image, block 405. Once detected the shape of the geometric figure the orientation of the submerged surface 210 is measured, block 406.
The step of determining the orientation of the surface 210 can be obtained comparing the shape detected of the geometric figure identified on the virtual image 130 with a predetermined shape of a predetermined reference geometric figure 135.
For example, the determining step of the submerged surface provides a step of determining of the coordinates (x,y), i.e. of the position of at least three virtual points 131a-131d of the geometric figure identified on the virtual image 130. The determined coordinates (x,y) are, then, compared with the coordinates, i.e. with the positions, (x*,y*) of the corresponding points 134a-134d of the geometric figure 140' on a reference virtual image 135, in particular the geometric figure 135 that would be
obtained if the submerged surface 210 was orthogonal to the axis of the sensor of images 25 that acquires the projected points 161a-161d. By the deviation of the coordinates (x,y) from the coordinates of reference (x*,y*) it is possible to compute the orientation of the submerged surface 210 through some geometric relations.
The determining step can provide also a comparing step for comparing the detected shape of geometric figure identified on the virtual image 130 with a plurality of shapes of models previously loaded in a database, and wherein each model is associated with a predetermined orientation. The comparing step can provide an attribution to each model of the above described plurality of a corresponding similarity index is with the detected shape of the identified geometric figure and a selection between the models of the plurality of the model with the highest similarity index, or with the similarity index is higher than a predetermined threshold value is *. Since the model has a known orientation, to the submerged surface 210 is assigned the same value of orientation of the model that is "similar" to the submerged surface.
As diagrammatically shown in figures 3 to 6 the comparison can be made with reference geometric figure 135 having a predetermined shape, for example square shape, and that corresponds to the situation where the axis of the optical sensor 25 is arranged orthogonal to the surface 210' . In this referenced situation, owing to the spatial arrangement of the senders with respect to the optical sensor 25, the four points 131a' -131d' projected on the surface 210 define a geometric figure having square shape .
Starting from this reference figure, the orientation of the submerged surface 210 can be measured measuring the deviation of the shape of the geometric figure that is obtained on the virtual image 130, i.e. the deformation, with respect to the square shape of the reference geometric figure 135.
Figure 5 diagrammatically show the situation where the submerged surface 210 to be examined form an angle β with the axis 120 of the optical sensor 25. In this case, the optical sensor 25 having an angle of view Θ acquires the points 101a- lOld projected on the surface 210. The virtual image 130 that is obtained is reproduced in figure 6. On the virtual image 130 are, then identified the points 131a-131d and a geometric figure 140 identified, as described above. Such has a different shape with respect to the shape of the geometric figure 140' of the virtual reference image 135 of figure 4. Therefore, as described above, it is possible to compute the orientation of the surface 210 analysing the deformation of the two figures, i.e. the deviation of the shape of the geometric figure 140' from the shape of the geometric figure 140.
Generally, it is possible to carry out a comparison between the detected shape of geometric figure 140 identified on the virtual image 130 and a plurality of shapes of models loaded on a database. More in detail, the comparison can be carried out through a step of attribution to each model of the above described plurality of a corresponding similarity index is with the identified geometric figure and of selection between the above described plurality of models of the model with the highest similarity index, or with the similarity index is
higher than a predetermined threshold value is * .
As diagrammatically shown in figure 7, in the case of a submerged surface 210 of large size it is provided the possibility of executing a plurality of determining steps of the orientation of a plurality of portions, for example at least one first portion 211a and at least one second portion 211b of the submerged surface 210 arranged in different points of the same.
The underwater support 10 can be located in a first predetermined position 10a at a predetermined depth in which it is kept fixed. Then the projection occurs of at least three points, for example 4 points lOla-lOld on the surface 210. The 4 points lOla-lOld are, then, detected by the optical sensor 25 obtaining a first virtual image 130a comprising four virtual points corresponding to the projected points lOla-lOld on the portion 211a. The virtual image 130a is, moreover, computed through the steps of identifying on the first virtual image 130a of a first geometric figure 140a to that the at least three virtual points 131a-131d belong. On the basis of the detected shape of the first geometric figure 140a identified on the first virtual image 130a is then measured the orientation of the first portion 211a of the submerged surface 210.
The underwater support 10 is then arranged at least at a second position 10b the orientation of which is known, or measured by means of the instruments of which the underwater support 10 is provided. Analogously to what described for the first position 10a, also at the portion 211b there is the projection of at least three points of laser light, for example of 4 points lOl'a-101'd, on the
surface 210. Also in this case the acquisition of the points lOl'a-101'd of laser light by means the optical sensor 25 follows, obtaining a second virtual image 130b comprising 4 virtual points 131'a-131'd corresponding to 4 projected points lOl'a-101'd on the second portion 211b. There is then as already described with reference to the portion 211a, a processing of the second virtual image 130b comprising the steps of defining on the second virtual image 130b of a second geometric figure 140b to which the 4 virtual points belong. Even in this case, then, orientation of the second portion 211b of the submerged surface 210 is measured on the basis of the detected shape of the second geometric figure 140b identified on the second virtual image 130b.
In particular, since the absolute orientation of the underwater support 10 is known for each determining step, it is possible to determine the relative orientation for each portion of the submerged surface. Even if it has been referred to the case in which a same underwater support 10 is located in the first and in the second position it is in any case also provided that the procedure above described, i.e. the computing of two different portions 211 of the surface 210, can be carried out also by means of at least two different support devices.
Still in the case of submerged surface 210 of large size in addition to the procedure above described through which it is possible to determine the local orientation of one, or more portions of the submerged surface 210, is advantageously, also provided the possibility of determining an average orientation of the surface 210 (Fig. 10). More in detail, the average orientation m of
the submerged surface 210 can be measured through a measurement of the distance of the underwater support 10 from the submerged surface 210 same and combining this information with the depth and orientation data of the underwater support 10. More in detail, the measurement step of the depth of the underwater support 10 can be carried out by means of at least one pressure sensor 70 configured to measure value of the pressure underwater at a predetermined depth.
In fact, as well known, by the value of the underwater pressure and taking into account the local density of the water it is possible to compute the measurement of the depth through known relations. The measurement of the distance of the underwater support 10 from the submerged surface 210 is carried out, instead, by means of at least one underwater acoustic sensor, in particular a sonar. The above described measurements, which can be referred to the instant ti when they are executed, can be recorded on a store device mounted on the underwater support 10, or in a remote position from which the support 10 is remotely operated through an interface device with a user, such as a jaypad, or a joystick, not shown in figure. Advantageously, this way, it is possible to know for any instant ti the operating conditions in terms of the orientation of the surface, orientation of the underwater support 10, depth of the underwater support 10, detected image, distance from the surface 210, etc. The measurement of the orientation of the underwater support 10, for example with respect to a fixed reference, can be carried out using at least one measuring device selected from the group consisting of: a gyroscope, a magnetometer, but
preferably using both of them and in combination with an accelerometer, in particular a MEMS triaxial accelerometer, and suitably combining the data from them obtained.
The underwater remotely operated vehicle 10, or ROV, has a main body 11 with substantially cylindrical shape moved by means of four propellers 31-34. More in detail, a first propeller 31 can be provided arranged to produce on said main body a first thrust along a substantially axial direction, a second propeller 32 located opposite to the first propeller 31 with respect to the main body 11 and arranged to produce on said main body a second thrust which is also along a substantially axial direction. Furthermore, a third propeller 33 can be provided arranged to produce on the main body a third thrust along a substantially transversal direction and a fourth propeller 34 arranged to produce on the main body a fourth thrust along a substantially transversal direction.
In particular, the first and the second propellers 31 and 32 are used for producing a thrust of movement on the vehicle and a rotation of the vehicle 10 about its substantially vertical rotation axis 110.
The third and the fourth propellers 33 and 34 are arranged along a substantially axial direction with respect to the main body 11 and are adapted to produce a substantially vertical thrust , in order to change the depth of the vehicle and a rotation of the vehicle 10 same about the side axis of the vehicle. As shown, for example in figure 17, the outlet mouths 43 and 44 of the third and of the fourth propeller 33 and 34 are arranged along a same generatrix of the main body 11 with substantially
cylindrical shape.
The particular type of propelling system chosen by the present invention for moving the underwater remotely operated vehicle provides a high manoeuvrability of the vehicle same also in hostile surroundings as the inner rooms of a wreck 200.
As shown in Figs. 11 to 18, a protection frame 50 is provided comprising a plurality of elongated shaped portions 51 and configured to form a substantially reticular structure (figure 17) .
The foregoing description of specific exemplary embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation .
Claims
1. Method for determining the orientation of a submerged surface (210) arranged at a predetermined depth, said method characterized in that it comprises the steps of:
- moving an underwater support (10) up to position the same at a predetermined distance from said submerged surface (210) ;
- determining the absolute spatial orientation of said underwater support at said position obtaining absolute spatial orientation data;
- determining the depth of said underwater support at said position obtaining depth data;
- constructing a virtual image of said submerged surface (210) , said constructing step comprising the steps of:
- projecting at least three laser light beams (161a-161d) on said submerged surface (210), said three laser light beams having a measured absolute spatial orientation because corresponding to the orientation of said underwater support measured in said determining step of the absolute spatial orientation;
- locating three projected points (lOla-lOld) on said submerged surface (210) corresponding to said three (161a-161d) laser light beams;
- acquisition of said at least three projected points (lOla-lOld) by means of an optical sensor (25) mounted on said underwater support obtaining a
virtual image (130) comprising at least three virtual points (131a-131d) corresponding to said at least three projected points (lOla-lOld);
- processing said virtual image (130), said processing step comprising the steps of:
- identifying on said virtual image (130) a geometric figure to which said at least three virtual points belong (131a-131d) ;
- detecting the shape of said geometric figure;
- determining the relative orientation of said submerged surface (210) with respect to said underwater support, said relative orientation being measured on the basis of said detected shape of said geometric figure identified on said virtual image (130) ;
- determining the absolute spatial orientation of said submerged surface on the basis of said relative spatial orientation and of said absolute spatial orientation of said underwater support.
2. Method, according to claim 1, wherein said determining step provides the steps of:
- determining the coordinates (x,y) of at least three points (131a-131d) of said geometric figure identified on said virtual image (130) ;
- comparing said determined coordinates (x,y) with predetermined coordinates (x*,y*) of corresponding points of geometric figure of a virtual reference image (135), said virtual reference image (135) being the image that would be obtained if said submerged surface (210) was orthogonal to the axis of said
optical sensor (25) ;
- computing the deviation of said coordinates (x,y) determined by said coordinates of reference (x*,y*);
- determining the orientation of said submerged surface (210) on the basis of said deviation.
Method, according to claim 1, wherein said determining step provides the steps of:
- comparing said detected shape of said identified geometric figure with the shape of a plurality of models loaded in a database, each model of said plurality being associated with a predetermined orientation;
- association to each model of said plurality of a corresponding similarity index with said identified geometric figure;
- selection among said plurality of models of the model with the highest similarity index, or with the similarity index higher than a predetermined threshold value is*.
Method, according to any of the previous claims, wherein a plurality of steps is provided of determining the orientation of a plurality of different portions (211a, 211b) of said submerged surface (210), each determining step of said plurality arranged to determine the orientation of a respective portion (211a, 211b) of said submerged surface (210), said plurality of steps comprising the steps of:
- arranging said underwater support (10) at a first position (10a), in said first position (10a) said underwater support (10) having a predetermined first
orientation;
- determining said first orientation of said underwater support (10) ;
- projecting at least three points of laser light (lOla-lOld) on a first portion (211a) of said submerged surface (210) arranged at said first position (10a) ;
- acquisition of said at least three points (101a- lOld) of laser light by said optical sensor (25) obtaining a first virtual image (130a) comprising at least three virtual points (131a-131d) corresponding to said at least three projected points (lOla-lOld) on said first portion (211a) ;
- processing said first virtual image (130a) , said processing step comprising the steps of:
- identifying on said first virtual image (130a) a first geometric figure (140a) to which said at least three virtual points (131a-131d) belong;
- determining the orientation of the first portion (211a) of said submerged surface (210) on the basis of the detected shape of said first geometric figure (140a) identified on said first virtual image ( 130a ) ;
- arranging said underwater support (10) at least at a second position (10b) , in said second position (10b) said underwater support (10) having a predetermined second orientation;
- determining said second orientation of said underwater support (10);
- projecting at least three points of laser light (101' a-101' d) on a second portion (211b) of said
submerged surface (210) arranged at said second position (10b) ;
- acquisition of said at least three points of laser light (lOl'a-101'd) by said optical sensor (25) obtaining a second virtual image (130b) comprising at least three virtual points (131' a-131' d) corresponding to said at least three projected points (101' a-101' d) on said second portion (211b) ;
- processing said second virtual image (130b) , said processing step comprising the steps of:
- identifying on said second virtual image (130b) a second geometric figure (140b) to which said at least three virtual points ( 131 ' a-131 ' d) belong;
- determining the orientation of said second portion (211b) of said submerged surface (210) on the basis of the detected shape of said second geometric figure (140b) identified on said second virtual image (130b) .
5. Method, according to any of the previous claims, wherein, in the case of a submerged surface of large size a step is also provided of computing an average orientation of said submerged surface (210) , said computing step of the average orientation providing the steps of:
- arranging an underwater support (10) in a first position (10a) arranged at a first measured distance from said submerged surface (210) ;
- measuring said first distance of said underwater support (10) from said submerged surface (210) , obtaining a first distance data;
- measuring the depth of said underwater support (10), obtaining a depth data;
- measuring the direction said underwater support (10) with respect to a reference fixed, obtaining a direction data;
- arranging said underwater support (10) in at least one second position arranged at a second measured distance from said submerged surface with said second measured distance different from said first measured distance ;
- measuring said second distance of said underwater support from said submerged surface, obtaining a second distance data;
- measuring the depth of said underwater support, obtaining a depth data;
- measuring the orientation of said underwater support with respect to a reference fixed, obtaining a direction data;
- processing said first and said at least second distance data, said orientation data of said underwater support and of said depth data by a processing unit obtaining an average orientation data of said submerged surface (210) .
Method, according to claim 1, or 4, wherein said determining step, or said measuring step, of said depth of said underwater support (10) is carried out by at least one pressure sensor configured to measure the value of the underwater pressure at a predetermined depth.
Method, according to claim 4, wherein said measuring
step of said distance of said underwater support (10) from said submerged surface (210) is carried out by at least one underwater acoustic sensor, in particular a sonar .
Method, according to claim 4, wherein said measuring step of said distance of said underwater support (10) from said submerged surface (210) is carried out by at least one sonar.
Method, according to claim 1, or 4, wherein said determining step , or said measuring step, of said orientation of said underwater support (10) with respect to said fixed reference value is done using an inertial platform comprising at least one measuring device selected from the group consisting of:
- a triaxial gyroscope;
- a magnetometer;
- a combination thereof.
Method, according to claim 9, wherein said inertial platform further . comprises an inclinometer, in particular a triaxial accelerometer.
Method, according to any of the previous claims, wherein said underwater support (10) is an underwater remotely operated vehicle, or ROV.
Apparatus for determining the orientation of a submerged surface arranged at a predetermined depth, said apparatus characterized in that it comprises:
- a movable underwater support (10) arranged to be positioned, in use, near said submerged surface (210) , on said underwater support (10) being mounted:
- a unit for determining the absolute spatial orientation of the underwater support obtaining data of absolute spatial orientation;
- a unit for determining the depth of said underwater support at said position obtaining depth data;
- a projection device which is arranged to project at least three laser light beams (161a-161don said submerged surface (210) obtaining three corresponding points (lOla-lOld) on said submerged surface (210), said three laser light beams (161a- 161d) having a measured absolute spatial orientation because corresponding to the orientation of said underwater support measured in said determining step of the absolute spatial orientation;
- an optical sensor (25) arranged to detect said at least three points (lOla-lOld) obtaining a virtual image (130) comprising at least three virtual points (131a-131d) corresponding to said at least three projected points (lOla-lOld) ;
- a processing unit configured to process said virtual image (130) through the steps of:
- identifying on said virtual image (130) a geometric figure (140) to which said at least three virtual points (131a-131d) belong;
- determining the relative orientation of said submerged surface (210) with respect to said underwater support, said relative orientation being measured on the basis of said detected shape of said geometric figure (140) identified
on said virtual image (130);
- determining the absolute spatial orientation of said submerged surface on the basis of said relative spatial orientation and of said absolute spatial orientation of said underwater support .
13. Apparatus, according to claim 12, wherein said projection unit and said optical sensor are arranged to be housed in respective fluid-tight cases, in such a way that it is possible to us them in underwater applications .
14. Apparatus, according to any of the previous claims, wherein said underwater support (10) is an underwater remotely operated vehicle, or ROV.
15. Method for determining an average orientation of a submerged surface characterized in that it comprises the steps of :
- moving an underwater support (10) up to position it to a first measured distance from said submerged surface (210);
- measuring said first distance of said underwater support (10) from said submerged surface (210) , obtaining a first distance data;
- measuring the depth of said underwater support (10), obtaining a depth data;
- measuring the orientation spatial of said underwater support (10) with respect to a reference fixed, obtaining a direction data;
- moving said underwater support (10) up to position the same to a second measured distance from said
submerged surface with said second measured distance different from said first measured distance;
- measuring said second distance of said underwater support (10) from said submerged surface, obtaining a second distance data;
- measuring the depth of said underwater support (10) , obtaining a depth data;
- measuring the direction said underwater support (10) with respect to a reference fixed, obtaining a direction data;
- processing said first and said at least second distance data, said orientation data, of said underwater support (10) and of said depth data by a processing unit obtaining an average orientation data of said submerged surface (210) .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP14733322.3A EP2997325A1 (en) | 2013-05-14 | 2014-05-14 | Method for determining the orientation of a submerged surface and apparatus that carries out this method |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT000041A ITPI20130041A1 (en) | 2013-05-14 | 2013-05-14 | METHOD OF DETERMINING THE ORIENTATION OF A SUBMERSIBLE SURFACE AND EQUIPMENT THAT ACTIVATE THIS METHOD |
| ITPI2013A000041 | 2013-05-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2014184748A1 true WO2014184748A1 (en) | 2014-11-20 |
Family
ID=48672695
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IB2014/061421 WO2014184748A1 (en) | 2013-05-14 | 2014-05-14 | Method for determining the orientation of a submerged surface and apparatus that carries out this method |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP2997325A1 (en) |
| IT (1) | ITPI20130041A1 (en) |
| WO (1) | WO2014184748A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102016221325A1 (en) | 2016-10-28 | 2018-05-03 | Zf Friedrichshafen Ag | Method and device for determining three-dimensional image data using an image sensor and a lighting device for generating a lighting pattern |
| CN114111589A (en) * | 2021-11-19 | 2022-03-01 | 南方海洋科学与工程广东省实验室(湛江) | Mesh-based underwater ranging method, ranging system and storage medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4948258A (en) | 1988-06-27 | 1990-08-14 | Harbor Branch Oceanographic Institute, Inc. | Structured illumination surface profiling and ranging systems and methods |
| US20060017720A1 (en) | 2004-07-15 | 2006-01-26 | Li You F | System and method for 3D measurement and surface reconstruction |
| US20120038932A1 (en) | 2009-02-20 | 2012-02-16 | 3G Software & Measurement Gmbh | Mobile Projection System For Scaling And Orientation Of Surfaces Surveyed By An Optical Measuring System |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2480688B (en) * | 2010-05-28 | 2012-11-14 | Subsea 7 Contracting Norway As | Subsea position control system for elongate articles |
-
2013
- 2013-05-14 IT IT000041A patent/ITPI20130041A1/en unknown
-
2014
- 2014-05-14 WO PCT/IB2014/061421 patent/WO2014184748A1/en active Application Filing
- 2014-05-14 EP EP14733322.3A patent/EP2997325A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4948258A (en) | 1988-06-27 | 1990-08-14 | Harbor Branch Oceanographic Institute, Inc. | Structured illumination surface profiling and ranging systems and methods |
| US20060017720A1 (en) | 2004-07-15 | 2006-01-26 | Li You F | System and method for 3D measurement and surface reconstruction |
| US20120038932A1 (en) | 2009-02-20 | 2012-02-16 | 3G Software & Measurement Gmbh | Mobile Projection System For Scaling And Orientation Of Surfaces Surveyed By An Optical Measuring System |
Non-Patent Citations (1)
| Title |
|---|
| See also references of EP2997325A1 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102016221325A1 (en) | 2016-10-28 | 2018-05-03 | Zf Friedrichshafen Ag | Method and device for determining three-dimensional image data using an image sensor and a lighting device for generating a lighting pattern |
| CN114111589A (en) * | 2021-11-19 | 2022-03-01 | 南方海洋科学与工程广东省实验室(湛江) | Mesh-based underwater ranging method, ranging system and storage medium |
Also Published As
| Publication number | Publication date |
|---|---|
| EP2997325A1 (en) | 2016-03-23 |
| ITPI20130041A1 (en) | 2014-11-15 |
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