CN111238382B - Ship height measuring method and ship height measuring device - Google Patents
Ship height measuring method and ship height measuring device Download PDFInfo
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- CN111238382B CN111238382B CN202010069924.2A CN202010069924A CN111238382B CN 111238382 B CN111238382 B CN 111238382B CN 202010069924 A CN202010069924 A CN 202010069924A CN 111238382 B CN111238382 B CN 111238382B
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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
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
- G01B11/0608—Height gauges
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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
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
- G01B11/0691—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of objects while moving
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Abstract
The application discloses a ship height measuring method and a ship height measuring device, wherein a first laser three-dimensional scanning device and a camera with known relative pose relation are used for respectively acquiring three-dimensional data and two-dimensional images of a ship body; finding the highest detection point of the ship body based on the three-dimensional data as an initial height value of the ship body; mapping part of the three-dimensional data to a two-dimensional image to obtain a corresponding two-dimensional coordinate and a corresponding height value; and correcting the initial height value of the ship body based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the part of the three-dimensional data. According to the invention, on one hand, the advantages of high single-point measurement precision and small environmental influence of the laser three-dimensional scanning device are utilized, and on the other hand, the result obtained by laser scanning measurement is corrected by utilizing the two-dimensional image, so that the measurement accuracy is further improved.
Description
Technical Field
The invention relates to a three-dimensional measurement technology, in particular to a ship measurement method and a ship measurement device based on a laser three-dimensional scanning technology.
Background
When a ship passes through a ship lock or a bridge, the height of the ship needs to be remotely measured to avoid collision accidents caused by overhigh ship body or loaded containers. Most of the existing ship height measurement adopts an image processing technology, a camera is used for shooting a ship, and then the ship height is obtained by processing the shot image. However, the shooting by the camera is greatly influenced by the environment, and the acquisition of three-dimensional information based on image processing requires a system having a large data calculation capability, thereby causing a certain limitation.
For this reason, a laser radar-based ship height measurement technology has been explored and developed. For example, chinese patent CN109178234A discloses a ship freeboard height measuring system, which utilizes a water level gauge and a laser radar installed under a bridge to measure the height of the ship to avoid collision. However, such techniques are also not without drawbacks.
For example, the technical solution disclosed in the above patent depends on a specific installation environment (below the bridge), and thus cannot meet the requirement of measuring the height of the ship when passing through a ship lock, for example, and is poor in universality. Furthermore, although the single-point measurement accuracy of the laser radar is high, there is a problem of relative data sparseness if the entire target scene is scanned. The problem of inaccurate measurement still exists by measuring the ship height based on the laser radar.
Moreover, the height of the ship body and the position of the water surface are respectively measured through the laser radar and the water level gauge, and the height of the laser radar relative to the water level gauge is difficult to accurately determine because the laser radar and the water level gauge are separately installed and far away from each other; when the measuring place is changed, the water level gauge needs to be reinstalled or the laser radar needs to be repositioned with respect to the water level gauge, which causes inconvenience in use.
In summary, there is a need for improvement in existing ship height measurement techniques.
Disclosure of Invention
It is an object of the present invention to provide a method and apparatus for measuring the height of a vessel which at least partially overcomes the deficiencies of the prior art techniques for measuring the height of a vessel.
According to an aspect of the present invention, there is provided a ship height measuring method, including: respectively acquiring three-dimensional data and a two-dimensional image of a ship body by using a first laser three-dimensional scanning device and a camera with known relative pose relation; finding a detection peak of the ship body based on the three-dimensional data, namely a three-dimensional detection peak, and taking the height value of the three-dimensional detection peak as an initial height value of the ship body; mapping part of the three-dimensional data to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and correcting the initial value of the height of the ship body based on the two-dimensional coordinate and the height value corresponding to the two-dimensional image and the part of the three-dimensional data to obtain the corrected height of the ship body.
Preferably, the partial three-dimensional data includes the three-dimensional detected highest point and a plurality of three-dimensional data points having substantially the same distance from the three-dimensional detected highest point relative to the first laser three-dimensional scanning device.
In some preferred embodiments, assuming that the distance from the three-dimensional highest point to the first laser three-dimensional scanning device is d, the three-dimensional data points are points in the three-dimensional data, which are within a range of d ± ξ from the first laser three-dimensional scanning device, where ξ is ≦ 0.5m, and preferably ξ is ≦ 0.1 m.
In some embodiments, the modifying the initial value of the hull height based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the part of the three-dimensional data to obtain a modified hull height includes: and establishing a fitting function to fit the relation between the two-dimensional coordinates corresponding to the part of the three-dimensional data and the corresponding height values. The fitting function may be a planar function. In such an embodiment, the correcting the initial value of the hull height based on the two-dimensional coordinates and the height values corresponding to the two-dimensional image and the part of the three-dimensional data to obtain the corrected hull height may further include: finding another detection highest point of the ship body based on the two-dimensional image, namely a two-dimensional detection highest point; calculating a compensation value of the height value of the three-dimensional detection highest point based on the difference value between the two-dimensional coordinate corresponding to the three-dimensional detection highest point and the two-dimensional coordinate of the two-dimensional detection highest point by using the fitting function; and correcting the initial value of the height of the ship body by using the compensation value to obtain the corrected height of the ship body. Preferably, the finding of the two-dimensional detected highest point based on the two-dimensional image includes finding the highest point of the ship in the two-dimensional image by an optical flow method.
In some embodiments, the vessel height measurement method may further include: scanning the water surface and obtaining three-dimensional data of the water surface by utilizing a second laser three-dimensional scanning device with a known pose relation with the first laser three-dimensional scanning device; fitting a water surface position based on the three-dimensional data of the water surface; and calculating the height of the ship relative to the water surface based on the known pose relationship of the first laser three-dimensional scanning device and the second laser three-dimensional scanning device and the fitted water surface position.
Preferably, the first laser three-dimensional scanning device comprises at least two laser radars which are symmetrically arranged by taking the camera as a center.
According to another aspect of the present invention, there is provided a ship height measuring apparatus including a first laser three-dimensional scanning device, a camera, and a calculation unit. The first laser three-dimensional scanning device is used for scanning the ship body to obtain three-dimensional data of the ship body. The camera has a known pose relationship relative to the laser three-dimensional scanning device and is used for acquiring a two-dimensional image of the ship body. The computing unit receives three-dimensional data from the first laser three-dimensional scanning device and a two-dimensional image from the camera, and is configured to: finding a detection peak of the ship body based on the three-dimensional data, namely a three-dimensional detection peak, and taking the height value of the three-dimensional detection peak as an initial height value of the ship body; mapping part of the three-dimensional data to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and correcting the initial value of the height of the ship body based on the two-dimensional coordinate and the height value corresponding to the two-dimensional image and the part of the three-dimensional data to obtain the corrected height of the ship body.
Preferably, the ship height measuring device can further comprise a second laser three-dimensional scanning device. The second laser three-dimensional scanning device and the first laser three-dimensional scanning device have a known pose relationship and are used for scanning the water surface and obtaining three-dimensional data of the water surface. And the computing unit is configured to further implement: fitting a water surface position based on the three-dimensional data of the water surface; and calculating the height of the ship relative to the water surface based on the known pose relationship of the first laser three-dimensional scanning device and the second laser three-dimensional scanning device.
Preferably, the first laser three-dimensional scanning device may include at least two laser radars symmetrically arranged with the camera as a center. More preferably, the first laser three-dimensional scanning device comprises four laser radars which are symmetrically arranged by taking the camera as a center, the camera is arranged at the center of the nine-grid array, the four laser radars are arranged in four opposite positions of the nine-grid array, which are located at the upper, lower, left and right sides of the camera, and the second laser three-dimensional scanning device is arranged at a vertex angle position of the nine-grid array.
According to the ship height measuring method and device provided by the embodiment of the invention, on one hand, the advantages of high single-point measurement precision and small environmental influence of the laser three-dimensional scanning device are utilized, on the other hand, the result obtained by laser scanning measurement is corrected by utilizing the two-dimensional image, and the measurement accuracy is further improved.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a schematic diagram of the operation of a vessel height measuring device according to an embodiment of the present invention;
FIG. 2 shows a schematic block diagram of a vessel height measuring device according to an embodiment of the invention;
FIG. 3 is a schematic diagram of an example of a vessel height measuring device according to an embodiment of the present invention;
FIG. 4 is a schematic structural view of an example of the ship height measuring device shown in FIG. 3;
FIG. 5 is a schematic flow chart of a vessel height measurement method according to an embodiment of the invention;
FIG. 6 is a schematic diagram showing one preferred way of selecting a portion of three-dimensional data to be mapped into a two-dimensional image;
fig. 7 shows a preferable example of the process of correcting the height of the hull in the ship height measuring method shown in fig. 5;
FIGS. 8 and 9 show perspective and side views, respectively, of a plane based on a plane fit function fit that may be used in the process shown in FIG. 7;
FIG. 10 illustrates another example of a vessel height measurement method according to an embodiment of the invention, in which a process of measuring the height of the vessel relative to the surface of the water is incorporated; and
fig. 11 shows a schematic flow diagram of a vessel height measurement method according to a variant of the invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
Fig. 1 is a schematic view showing the operation of a ship height measuring apparatus according to an embodiment of the present invention. As shown in fig. 1, the ship height measuring device 1 is installed, for example, on the shore, and when a ship 2 passes near the ship height measuring device 1, the ship height measuring device 1 operates to perform three-dimensional measurement of a hull region a and, at the same time, three-dimensional measurement of a water surface region B. The z direction shown in fig. 1 is the height direction. However, the invention is not limited thereto, and the ship debugging and measuring device can also be installed on a patrol ship to dynamically track passing ships for ship height measurement.
Referring to fig. 2, the ship height measuring apparatus 1 according to the embodiment of the present invention includes a first laser three-dimensional scanning device 10 for scanning a hull and obtaining three-dimensional data of the hull. The first laser three-dimensional scanning device 10 may include one or more laser radars 10a (see fig. 4) or any other device capable of laser three-dimensional scanning. The number of devices may be determined based on the range of the target field of view and the size of the field of view (scan range) of a single device, as the invention is not limited in this respect. The detected highest point (which may not be an actual highest point) of the ship body, namely the three-dimensional detected highest point, can be found based on the three-dimensional data acquired by the first laser three-dimensional scanning device 10. The height value of the three-dimensional detection highest point can be used as an initial height value of the ship body.
The vessel height measuring apparatus 1 may include a second laser three-dimensional scanning device 20 having a known pose (i.e., position and attitude) relationship with the first laser three-dimensional scanning device 10 for scanning the water surface and obtaining three-dimensional data of the water surface. Similar to the first laser three-dimensional scanning device 10, the second laser three-dimensional scanning device 20 may include one or more laser radars 20a or any other devices that can perform laser three-dimensional scanning. Based on the three-dimensional data acquired by the second laser three-dimensional scanning device 20, the water surface position can be fitted. The use of the first laser three-dimensional scanning device 10 in combination with the second laser three-dimensional scanning device 20 enables a new method or process of measuring the height of a vessel relative to the water surface (see fig. 10).
As shown in fig. 2, the ship height measuring device 1 may include a camera 30, the first laser three-dimensional scanning device 10 and the camera 30 have a known relative pose relationship, and the camera 30 is used for acquiring a two-dimensional image of the ship body. The use of the first laser three-dimensional scanning device 10 in combination with the camera 30 enables a vessel height measurement method according to an embodiment of the present invention, which will be described in detail below with reference to fig. 5 to 10.
The ship height measuring device 1 according to an embodiment of the present invention may also be integrated with the calculation unit 40. The calculation unit 40 may be connected to the first laser three-dimensional scanning device 10, the second laser three-dimensional scanning device 20, and the camera 30, and receives three-dimensional data of the hull to calculate the height of the hull, three-dimensional data of the water surface to calculate the height of the hull with respect to the water surface, and a two-dimensional image of the hull and corrects the height of the hull based on the two-dimensional image. Preferably, the computing unit 40 is configured for implementing the methods/processes illustrated in fig. 5-10.
It should be understood that the calculation unit may also be provided separately from the vessel height measuring device 1 according to an embodiment of the present invention, for example, the three-dimensional data and the two-dimensional image, etc. from the vessel height measuring device 1 may be transmitted by wire or wirelessly to, for example, a vessel height monitoring server, where the processing of the data and/or the image is performed by the server.
Next, an example of a ship height measuring device according to an embodiment of the present invention, i.e., a ship height measuring device 1A, will be described with reference to fig. 3 and 4. Fig. 3 shows a schematic view of the operation of the ship height measuring device 1A, and fig. 4 shows a schematic view of the structure thereof.
As shown in fig. 3, the ship height measuring device 1A includes a first laser three-dimensional scanning device 10, and a second laser three-dimensional scanning device 20 and a camera 30 each having a known pose relationship with the first laser three-dimensional scanning device 10; in operation, as shown in fig. 3, the first laser three-dimensional scanning device 10 and the camera 30 respectively acquire three-dimensional data and two-dimensional images of the hull 2, and the second laser three-dimensional scanning device 20 scans the water surface and acquires three-dimensional data of the water surface.
As schematically shown in fig. 3 and 4, the first laser three-dimensional scanning device 10, the second laser three-dimensional scanning device 20, and the camera 30 in the ship height measuring device 1A are arranged adjacent to each other in the same plane. Here, "adjacent" is not limited to a particular distance separation D1、D2But rather means that these devices are not arranged in a distributed manner but rather are reasonably close to each other, and preferably as close to each other as the technology allows.
The first laser three-dimensional scanning device 10 and the second laser three-dimensional scanning device 20 preferably have different pitch angles with respect to the horizontal plane.
In the preferred example shown in the figure, the first laser three-dimensional scanning device 10 comprises four laser radars 10a symmetrically arranged by taking the camera 30 as the center, the camera 30 is arranged at the center of the nine-grid array, and the four laser radars 10a are arranged in the nine-grid array at four opposite positions of the camera 30, namely, the upper position, the lower position, the left position and the right position; the second laser three-dimensional scanning device 20 includes a laser radar 20a and is disposed at a vertex angle position in the squared figure. The other position a in the grid may be a reserved position and may be used to adjust the position of the lidar 10a, 20a, for example, or to add a new lidar.
Although in the illustrated example the first laser three-dimensional scanning device 10 is shown as comprising four laser radars, it will be appreciated that the invention is not limited thereto. The first laser three-dimensional scanning apparatus 10 may include more or fewer or otherwise arranged lidar or like devices. In view of covering the field of view of the target, and in view of its use in cooperation with the camera, it is preferred that the first laser three-dimensional scanning device comprises at least two laser radars symmetrically distributed with respect to the camera.
Similarly, the second laser three-dimensional scanning device 20 may include more or fewer or otherwise arranged lidar or like devices. Preferably, the lidar 20a in the second laser three-dimensional scanning device 20 is arranged at the same height position as at least one of the lidar 10a in the first laser three-dimensional scanning device 10.
In addition, as shown in fig. 3, the first laser three-dimensional scanning device 10, the second laser three-dimensional scanning device 20, and the camera 30 are mounted on a carriage 40. Although not shown, it is preferable that the bracket 40 has a mechanism for height adjustment and a mechanism for pitch angle adjustment.
A ship height measuring method according to an embodiment of the present invention will be described below with reference to fig. 5 to 10.
Fig. 5 is a schematic flow chart of a ship height measuring method according to an embodiment of the present invention. As shown in fig. 5, a ship height measuring method 100 according to an embodiment of the present invention includes:
s10: respectively acquiring three-dimensional data and a two-dimensional image of a ship body by using a first laser three-dimensional scanning device and a camera with known relative pose relation;
s20: finding a detection peak of the ship body based on the three-dimensional data, namely a three-dimensional detection peak, and taking the height value of the three-dimensional detection peak as an initial height value of the ship body;
s30: mapping part of the three-dimensional data to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and
s40: and correcting the initial value of the height of the ship body based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the part of the three-dimensional data to obtain the corrected height of the ship body.
Here, "pose" refers to a spatial position and posture. Here, the "posture" may be expressed as, for example, a reference direction of the laser three-dimensional scanning and an orientation of an optical axis photographed by the camera for the laser three-dimensional scanning device and the camera.
The processing S10 and the processing S20 are easily understood and appreciated by those skilled in the art, and are not described herein.
In process S30, a portion of the three-dimensional data is selected for mapping into the two-dimensional image. Fig. 6 schematically shows a preferred way of selecting a part of the three-dimensional data to be mapped into a two-dimensional image, wherein,the part of the three-dimensional data comprises a three-dimensional detection peak P of the ship body0And with the three-dimensional detected highest point P0A plurality of three-dimensional data points P having substantially the same distance relative to the first laser three-dimensional scanning device1. As shown in fig. 6, the three-dimensional detection highest point P is assumed0If the distance from the first laser three-dimensional scanning device 10 is d, the three-dimensional data points are the distance d from the first laser three-dimensional scanning device 10 in the three-dimensional data1A point within d. + -. ξ, where ξ ≦ 0.5m is preferred, and ξ ≦ 0.1m is more preferred. And for the distance d from the first laser three-dimensional scanning device 102(|d-d2| ≧ ξ), the three-dimensional data point P2 may be discarded.
As an example, to realize the selection of the three-dimensional data points, the lidar may be used as a sphere center to detect the highest point P in three dimensions based on the acquired point cloud of the three-dimensional data points (X, Y, Z) of the lidar0The distance d is the radius, a sphere is constructed, and a three-dimensional data point set within the range of +/-xi from the sphere is found and is used as a point set to be mapped to the two-dimensional image.
This ensures that the points are located at substantially the same depth relative to the lidar and thus to the camera 30, thereby excluding the effect of depth on the height of the points, such that the height values of the points are related only to the coordinates at which the points are mapped in the two-dimensional image.
Since the first laser three-dimensional scanning device 10 and the camera 30 have known pose relationships, the three-dimensional data points and the points in the two-dimensional image can establish a mapping relationship through the rotation matrix R and the translation matrix T. The rotation matrix R and the translation matrix T may be expressed as follows:
T＝[Xcw，Ycw，Zcw]T (1)
the rotation matrix R and the translation matrix T of the three-dimensional data points and the points in the two-dimensional image can be obtained by resolving a mapping equation through a plurality of selected point groups consisting of the three-dimensional data points (X, Y, Z) and the corresponding points (U, V) in the two-dimensional image.
The process of selecting the point group and calculating to obtain the rotation matrix R and the translation matrix T may be referred to as a calibration process between the two-dimensional image and the three-dimensional image. This is known to the person skilled in the art and will not be described in further detail here.
The selected part of the three-dimensional data (X, Y, Z) is mapped into the two-dimensional image by, for example, the above-mentioned rotation matrix R and translation matrix T, to obtain the coordinates (U, V) of the corresponding point in the two-dimensional image, whose corresponding height value is H, at which time the three-dimensional data point can be expressed as (U, V, H) in the two-dimensional image, for example.
Next, in a process S40, the initial hull height value is corrected based on the two-dimensional image acquired by the camera 30 and the two-dimensional coordinates and the height value corresponding to the partial three-dimensional data (X, Y, Z), so as to obtain a corrected hull height.
Fig. 7 shows a preferred example of process S40, process 400. As shown in fig. 7, process 400 includes:
s41: establishing a fitting function to fit the relation between the two-dimensional coordinates corresponding to the part of the three-dimensional data and the corresponding height values;
s42: finding another detection highest point of the ship body based on the two-dimensional image, namely a two-dimensional detection highest point;
s43: calculating a compensation value of the height value of the three-dimensional detection highest point based on the difference value between the two-dimensional coordinate corresponding to the three-dimensional detection highest point and the two-dimensional coordinate of the two-dimensional detection highest point by using the fitting function; and
s44: and correcting the initial value of the height of the ship body by using the compensation value to obtain the corrected height of the ship body.
In the process S41, different fitting functions may be established according to a specific application scenario to fit the relationship between the two-dimensional coordinates corresponding to the three-dimensional data and the corresponding height values. Corresponding to the preferred way of selecting portions of three-dimensional data described above with reference to fig. 6, in a preferred example, the fitting function may be a planar function, as schematically illustrated in fig. 8 and 9. A three-dimensional space UVH of coordinates (U, V) of the two-dimensional image and corresponding height values H is shown in fig. 8 and 9, where the reference symbol "x" denotes a point (U, V, H) in the two-dimensional image acquired by the camera 30 that is selected from the three-dimensional data acquired by the first laser three-dimensional scanning device 10 and mapped thereto. Setting a target plane function aU + bV + c as H, wherein a, b and c are constant parameters; the numerical values of the three parameters a, b, and c are solved by, for example, the least square method using the relationship between the two-dimensional coordinates (U, V) of the mapped points and the corresponding height H, thereby obtaining a fitting plane function. Fig. 8 shows a perspective view of the fitted plane (gray portion), and fig. 9 shows a side view of the plane. However, it should be understood that fig. 8 and 9 are merely examples, and the present invention is not limited to a specific fitting function.
In the process S42, the two-dimensional detected highest point of the hull may be found based on the two-dimensional image acquired by the camera 30 using a technique of acquiring three-dimensional information based on image processing. Preferably, the two-dimensional highest point of detection of the hull is found based on the two-dimensional image by an optical flow method. Then, the process proceeds to S43 and S44. For example, a two-dimensional detected highest point (u1, v1) of a ship in a two-dimensional image can be obtained through an optical flow method; three-dimensional detection peak P0Coordinates of the points mapped on the two-dimensional image are (U0, V0), and coordinate differences of the two points on the two-dimensional image are U 'U0-U1, and V' V0-V1; substituting the plane fitting equation aU + bV + c as H to obtain a value of delta H as aU '+ bV' + c as a compensation value of the height value of the three-dimensional detection highest point of the ship body; if the height value of the three-dimensional detection highest point is recorded as H, the compensation value delta H is used for correction, and the corrected ship height H is obtainedShip with a detachable hull＝h+Δh。
In the example shown in fig. 7, it should be noted that although the process S42 is shown as being performed after the process S41, those skilled in the art will appreciate that the process S42 may be performed before the process S41, and even the process S42 may be performed after the camera 30 acquires the two-dimensional image (as in the process S10 shown in fig. 5); the invention is not limited in this respect.
Next, another example of a ship height measuring method according to an embodiment of the present invention will be described with reference to fig. 10, in which a process 500 of measuring the height of a ship with respect to the water surface is incorporated. The ship height measuring method shown in fig. 10 includes:
and (3) processing 100': measuring the height of the hull based at least in part on the first laser three-dimensional scanning device; and
the processing 500: the height of the vessel relative to the water surface is measured.
Here, the process 100' may be, for example, the process/method for measuring the height of the ship hull based on the combined use of the first laser three-dimensional scanning device and the camera as shown in fig. 5, or may be another alternative process/method for measuring the height of the ship hull based on the first laser three-dimensional scanning device, for example, may be the process/method for measuring the height of the ship hull based on the first laser three-dimensional scanning device alone.
As shown in fig. 10, process 500 may include:
s51: scanning the water surface and obtaining three-dimensional data of the water surface by utilizing a second laser three-dimensional scanning device with a known pose relation with the first laser three-dimensional scanning device;
s52: fitting a water surface position based on the three-dimensional data of the water surface; and
s53: and calculating the height of the ship relative to the water surface based on the known pose relationship between the first laser three-dimensional scanning device and the second laser three-dimensional scanning device and the fitted water surface position.
In processing S52, horizontal points scanned by the second laser three-dimensional scanning device are found, and a plane is fitted based on these points using, for example, RANSAC (random sample consensus) as the water surface position.
In the processing S53, since the first laser three-dimensional scanning device and the second laser three-dimensional scanning device have a known pose relationship, the height of the ship body measured by the first laser three-dimensional scanning device can be compared with the position of the water surface (water surface height) measured by the second laser three-dimensional scanning device, so as to obtain the phase of the ship bodyFor the height of the water surface. For example, if the height of the hull measured by the first laser three-dimensional scanning device relative to a fixed height reference is HShip with a detachable hullThe height of the water surface relative to the fixed height reference is measured to be H by the second laser three-dimensional scanning deviceWater (W)The height H of the hull relative to the water surfaceShip-water＝HShip with a detachable hull-HWater (W). For example, the fixed height reference may be a height position of the second laser three-dimensional scanning device.
Although process 500 is shown in fig. 10 as being performed after process 100', the invention is not so limited. Fig. 11 shows a schematic flow diagram of a vessel height measurement method according to a variant of the invention. As shown in fig. 11, a vessel height measurement method 100 "includes:
s10': respectively acquiring three-dimensional data of a ship body, three-dimensional data of a water surface and a two-dimensional image of the ship body by using a first laser three-dimensional scanning device, a second laser three-dimensional scanning device and a camera with known pose relations;
s20': finding a detection highest point of the ship body relative to the water surface based on the three-dimensional data of the ship body and the water surface, namely a three-dimensional detection highest point, and taking the height value of the three-dimensional detection highest point as an initial height value of the ship body;
s30: mapping part of data in the three-dimensional data of the ship body to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and
s40: and correcting the initial value of the height of the ship body based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the part of the three-dimensional data to obtain the corrected height of the ship body.
It can be seen that in the method 100 ", the process S10 'is combined with the process S51 in the process 500 shown in fig. 10, and the process S20' is combined with the processes S52 and S53 in the process 500; the processing S30 and the processing S40 may be the same as in the method 100 shown in fig. 5.
According to the embodiment of the invention, the height of the ship body relative to the water surface can be conveniently determined by combining the laser three-dimensional scanning device for respectively scanning the ship body and the water surface.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (14)
1. A method of measuring the height of a vessel, comprising:
respectively acquiring three-dimensional data and a two-dimensional image of a ship body by using a first laser three-dimensional scanning device and a camera with known relative pose relation;
finding a detection peak of the ship body based on the three-dimensional data, namely a three-dimensional detection peak, and taking the height value of the three-dimensional detection peak as an initial height value of the ship body;
mapping part of the three-dimensional data to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and
correcting the initial value of the height of the ship body based on the two-dimensional coordinate and the height value corresponding to the two-dimensional image and the part of three-dimensional data to obtain the corrected height of the ship body,
wherein the step of correcting the initial value of the height of the ship body based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the partial three-dimensional data to obtain the corrected height of the ship body comprises the following steps: and establishing a fitting function to fit the relation between the two-dimensional coordinates corresponding to the part of the three-dimensional data and the corresponding height values.
2. The vessel height measurement method of claim 1, wherein the partial three-dimensional data comprises the three-dimensional detected highest point and a number of three-dimensional data points having substantially the same distance from the three-dimensional detected highest point relative to the first laser three-dimensional scanning device.
3. The ship height measuring method of claim 2, wherein assuming that the distance from the three-dimensional highest point to the first laser three-dimensional scanning device is d, the three-dimensional data points are points in the three-dimensional data, which are within a range of d ± ξ from the first laser three-dimensional scanning device, and ξ is less than or equal to 0.5 m.
4. The ship height measuring method of claim 2, wherein assuming that the distance from the three-dimensional highest point to the first laser three-dimensional scanning device is d, the three-dimensional data points are points in the three-dimensional data, which are within a range of d ± ξ from the first laser three-dimensional scanning device, and ξ is less than or equal to 0.1 m.
5. The vessel height measurement method of claim 1, wherein the fitting function is a planar function.
6. The ship height measuring method according to any one of claims 1 to 5, wherein the step of correcting the initial value of the hull height based on the two-dimensional coordinates and the height values corresponding to the two-dimensional image and the partial three-dimensional data to obtain the corrected hull height further comprises:
finding another detection highest point of the ship body based on the two-dimensional image, namely a two-dimensional detection highest point;
calculating a compensation value of the height value of the three-dimensional detection highest point based on the difference value between the two-dimensional coordinate corresponding to the three-dimensional detection highest point and the two-dimensional coordinate of the two-dimensional detection highest point by using the fitting function; and
and correcting the initial value of the height of the ship body by using the compensation value to obtain the corrected height of the ship body.
7. The ship height measuring method according to claim 6, wherein the finding of the two-dimensional detected highest point based on the two-dimensional image includes finding the highest point of the ship in the two-dimensional image by an optical flow method.
8. The ship height measuring method of claim 1, further comprising:
scanning the water surface and obtaining three-dimensional data of the water surface by utilizing a second laser three-dimensional scanning device with a known pose relation with the first laser three-dimensional scanning device;
fitting a water surface position based on the three-dimensional data of the water surface; and
and calculating the height of the ship relative to the water surface based on the known pose relationship between the first laser three-dimensional scanning device and the second laser three-dimensional scanning device and the fitted water surface position.
9. The ship height measuring method according to any one of claims 1 to 5 and 8, wherein the first laser three-dimensional scanning device comprises at least two laser radars symmetrically arranged with the camera as a center.
10. A vessel height measuring device comprising:
the first laser three-dimensional scanning device is used for scanning the ship body to obtain three-dimensional data of the ship body;
the camera has a known pose relation relative to the laser three-dimensional scanning device and is used for acquiring a two-dimensional image of a ship body; and
a computing unit receiving three-dimensional data from the first laser three-dimensional scanning device and a two-dimensional image from the camera, and configured to:
finding a detection peak of the ship body based on the three-dimensional data, namely a three-dimensional detection peak, and taking the height value of the three-dimensional detection peak as an initial height value of the ship body;
mapping part of the three-dimensional data to the two-dimensional image to obtain two-dimensional coordinates and height values corresponding to the part of the three-dimensional data; and
correcting the initial value of the height of the ship body based on the two-dimensional coordinate and the height value corresponding to the two-dimensional image and the part of three-dimensional data to obtain the corrected height of the ship body,
wherein the step of correcting the initial value of the height of the ship body based on the two-dimensional image and the two-dimensional coordinates and the height values corresponding to the partial three-dimensional data to obtain the corrected height of the ship body comprises the following steps: and establishing a fitting function to fit the relation between the two-dimensional coordinates corresponding to the part of the three-dimensional data and the corresponding height values.
11. The vessel height measuring device of claim 10, further comprising a second laser three-dimensional scanning device having a known pose relationship with the first laser three-dimensional scanning device for scanning the water surface and obtaining three-dimensional data of the water surface; and is
The computing unit is configured to further implement:
fitting a water surface position based on the three-dimensional data of the water surface; and
and calculating the height of the ship relative to the water surface based on the known pose relationship of the first laser three-dimensional scanning device and the second laser three-dimensional scanning device.
12. The ship height measuring device of claim 10, wherein the first laser three-dimensional scanning device comprises at least two laser radars symmetrically arranged centering on the camera.
13. The ship height measuring device of claim 11, wherein the first laser three-dimensional scanning device comprises at least two laser radars symmetrically arranged centering on the camera.
14. The ship height measuring device of claim 13, wherein the first laser three-dimensional scanning device comprises four laser radars symmetrically arranged with the camera as the center, the camera is arranged at the center of the nine-grid array, the four laser radars are arranged at four opposite positions of the nine-grid array, which are located at the upper, lower, left and right positions of the camera, and the second laser three-dimensional scanning device is arranged at a vertex angle position of the nine-grid array.
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| CN111856492B (en) * | 2020-06-22 | 2021-04-23 | 北京驭光科技发展有限公司 | Dynamic ship height measuring method and device |
| CN111880209B (en) * | 2020-07-21 | 2022-09-06 | 山东省科学院海洋仪器仪表研究所 | Ship body attitude calculation method and application |
| CN112001962B (en) * | 2020-07-24 | 2021-03-05 | 北京驭光科技发展有限公司 | Ship height measuring and calculating method and system |
| CN112529958B (en) * | 2020-12-10 | 2022-08-26 | 神华天津煤炭码头有限责任公司 | Single laser radar bulk cargo ship hatch position identification method |
| CN112815898B (en) * | 2020-12-31 | 2024-03-15 | 上海外高桥造船海洋工程有限公司 | Method for converting ship three-dimensional data measurement into two-dimensional data measurement based on coordinate system |
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