CN115086569A - Method for acquiring images of bottom of super-large bridge based on networking camera - Google Patents
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Abstract
The invention discloses a method for acquiring images of a bottom of a super-large bridge based on a networking camera, wherein the networking camera comprises N cameras, a parallel acquisition tail end is formed and fixedly arranged on an overhaul platform at the bottom of the super-large bridge, the optimal acquisition position and the optimal installation angle of the camera are planned along the bridge width direction according to the structures of the bottom of the super-large bridge and the overhaul platform, the acquisition station planning is further performed along the bridge length direction, the driving system of the overhaul platform controls the movement of the overhaul platform carrying the networking camera in the bridge length direction, the non-contact acquisition is performed on the apparent image data of the bottom of the super-large bridge, and the automatic full-coverage image acquisition of the bottom of the bridge is realized.
Description
Technical Field
The invention belongs to the field of bridge detection, and particularly provides a method for acquiring an image of a bottom of a super-large bridge based on a networking camera.
Background
The bridge inspection becomes a main technical means for safe maintenance and normal operation guarantee of a bridge structure, regular inspection is carried out through manual inspection and bridge inspection vehicles by a common detection method, but the speed of the manual inspection and the speed of the bridge inspection vehicle detection are low, the efficiency is low, the condition of missed inspection can occur, the timeliness is lacked, normal transportation can be affected, the accessibility of inspection of a plurality of bridges is poor, the safety risk of personnel is high, factors such as severe environment and the like are influenced, and the high-frequency inspection is difficult to maintain.
With the continuous update of bridge detection technology, various nondestructive detection methods such as acoustic emission detection, ultrasonic detection, laser detection and the like have appeared later, but instruments used in the detection are expensive, and the measurement range has certain limitations, and cannot meet the requirements of bridge detection. The CCD camera sensor has the characteristics of low price, visual image data, convenience in installation, non-contact type and the like, the CCD camera is adopted as a bridge apparent data acquisition sensor in the years, and an intelligent bridge detection mode based on vision becomes a research hotspot. However, the detection area of the bridge with large span is wide, and how to realize comprehensive coverage acquisition through the CCD camera while ensuring the detection precision is also one of the research difficulties in reducing the use amount of the CCD camera and simultaneously reducing the splicing difficulty of subsequent bridge bottom pictures. Especially on service installations. In addition, the single camera has a limited shooting visual field, and the high-precision camera is required to be used for expanding the detection visual field, so that the price is high. Therefore, an arrangement for combining low-cost cameras to detect the field of view instead of a high-precision camera is required. When the cameras are combined, the limitation of a perspective distortion threshold value is received, the larger the deflection angles of the cameras on two sides are, the larger the perspective distortion is, the perspective distortion threshold value cannot be met, and therefore the deflection angle of the cameras cannot be increased infinitely.
At present, bridge maintenance platforms are installed on large-span bridges for manual regular inspection, but many bridges are poor in inspection accessibility, high in personnel safety risk, and difficult to maintain high-frequency inspection due to the influence of factors such as severe environment.
The noun interpretation:
GSD represents the ground pel resolution, which describes the size of an image pixel, and a pixel point on the image represents the real world dimensions.
Disclosure of Invention
Based on the background technology, the invention provides a method for acquiring an image of the bottom of a super bridge based on a networking camera. According to the structure of the bridge bottom, the networking camera acquisition device is arranged on the bridge maintenance platform to realize comprehensive image data acquisition of the extra-large bridge bottom.
The networking camera is carried on a bridge maintenance platform, and the bridge maintenance platform is mainly used for maintaining the bottom of a super large bridge and consists of a truss system, a driving system, an electrical control system and a track system. The suspension crane is adopted to hang upside down at the bottom of the super large bridge along the bridge width direction, the driving mechanism is arranged upside down on the H-shaped steel rail through steel wheels, the truss girder and the driving mechanism are connected together through a portal frame, and the forward and backward movement of the bridge maintenance platform along the bridge length direction is realized under the driving of the motor.
A method for acquiring an image of a bottom of a super bridge based on a networking camera comprises the following steps:
the method comprises the following steps that firstly, a plurality of types of array cameras with different visual fields are preset, wherein each array camera consists of a plurality of identical cameras;
step two, dividing the bottom of the super-large bridge into a plurality of continuous acquisition sections along the bridge width direction of the super-large bridge; according to the size of each acquisition section, arranging an array camera which is enough to cover the corresponding section and contains the least number of cameras on an overhaul platform at the bottom of the extra-large bridge; and forming a networking camera by each array camera set network; in each group of array cameras, the overlapping length of adjacent camera shooting areas along the bridge width direction is the overlapping amount overlapYZ of the cross section of the bridge; adjusting the angle of the camera in each group of array cameras to obtain the least cameras which can clearly obtain the bridge bottom image;
and step three, planning a collection station along the bridge length direction, and moving an overhaul platform carrying the networking camera according to the set collection station to realize automatic full-coverage image collection of the bottom of the extra-large bridge.
In a further improvement, the method for setting the array camera group includes the following steps:
1) selecting a camera, and determining relevant parameters of the camera: the horizontal field angle of the camera is beta, the vertical field angle of the camera is alpha, and the resolution of the camera is w x h; w represents the resolution in the horizontal direction; h represents the resolution in the vertical direction;
2) designing an array camera:
2.1) array camera related parameters are as follows:
the array camera set is of a symmetrical structure, namely N cameras are arranged on a horizontal base, and the installation positions of the cameras are relative to the installation center O of the array camera G Symmetrical with O G Is the origin of coordinates and is X along the bridge width direction T Axis, Y in the direction of bridge length T The axis, perpendicular to the bridge floor and upwards, being Z T Axis-establishing array camera coordinate system O G -X T Y T Z T (ii) a N camera optical centers of the array camera are located on the same horizontal line, the distance between the two outermost camera optical centers in the array camera is called a baseline distance baseline, the included angle between the left and right outermost horizontal field rays of the array camera in the horizontal direction is set as an array camera horizontal field angle CombFOVHorz, the included angle between the array camera vertical field rays is called an array camera vertical field angle CombFOVVerert, the included angle is equal to a vertical field angle alpha of a single high-definition camera, and the left and right outermost horizontal field rays and the vertical field rays of the array camera in the horizontal direction are intersected at an array camera virtual optical center point O E ；O G ，O E Are all on the same straight line and vertical to the object space imaging area and intersect at the central point T of the view cone of the array camera 0 ；
Setting the coverage range of an object space horizontal area of the array camera as LHorz, the coverage range of an object space vertical area of the array camera as LVert, the real imaging distance of the array camera as H, and the virtual imaging distance of the array camera as H E The distance between the virtual optical center projection of the array camera and the base line is H P The lower limit value of the closest imaging distance of the array camera is H Mmin The horizontal GSD of the array camera is GSDHorz, and the vertical GSD of the array camera is GSDVert; the key points of the view cone of the array camera comprise：O E ,T 0 ,T 1 ,T 2 ,T 3 ,T 4 ,T 5 ,T 6 ,T 7 ,T 8 ；T 0 Representing the projection of a virtual optical center on the object plane, T 1 T 2 T 3 T 4 Four corner points, T, of the entire field of view 1 T 4 Vertical field line, T, for the leftmost shot 5 Is T 1 T 4 Central point of (1), T 2 T 3 Vertical field line, T, for the rightmost shot 6 Is T of 2 T 3 Center point, T 1 T 2 Horizontal field lines, T, for front-most shots 7 Is T 1 T 2 Central point of (1), T 3 T 4 Horizontal field lines, T, for front-most shots 8 Is T 3 T 4 A center point of (a);
array camera with respect to mounting center O G Symmetrical, the installation positions and angles of the left and right cameras are also related to O G The symmetry, the deflection angle of one side of the origin point is calculated, and the deflection angle of the other side which is symmetrical to the other side can be obtained; number of deflection angles found n:
let the deflection angle of the outermost camera be K 1 The deflection angle of the sub outer layer camera is K 2 ,.., the angle of deflection of camera n closest to the origin of the array camera coordinates is K n ；
The distance between the intersection point of the horizontal field rays of two adjacent cameras and the base line is called the closest imaging distance, wherein the distance H from the object plane to the base line of the array camera is greater than the closest imaging distance; closest imaging distance also with respect to O G Symmetrical with O G The left side camera is arranged as an example, and the horizontal view fields of the outermost camera and the second outermost camera are intersected at a point O 1,2 Point of, O 1，2 The distance to the base line is the closest imaging distance H M1 The horizontal field of view of the second outer camera and the second outer camera intersect at a point O 2，3 Point of contactO 2，3 The distance to the base line is the closest imaging distance H M2 ,.. the n camera and the n +1 camera horizontal field of view intersect at point O n,n+1 Point of, O n,n+1 The distance to the base line is the closest imaging distance H Mn ；
2.2) the arrangement of the deflection angle of the camera in the array camera and the nearest imaging distance between the adjacent cameras meets the following geometrical constraint relation:
a.
b.
c.K n ＜...＜K 2 ＜K 1 ；
d.H Mn ＜H；
e.H Mn ＞H Mmin ；
2.3) solving related parameters of the array camera:
the distance from an object space plane to the base line of the array camera, namely the real imaging distance of the array camera is H, the horizontal field angle beta of a single camera, the vertical field angle alpha of the single camera and the base line distance baseline can be obtained through the position information of the bridge bottom overhauling platform and the bridge detection surface;
wherein the base line distance
Lower limit value H of closest imaging distance of array camera Mmin The solving formula is as follows:
the solving formula of the horizontal field angle CombFOVHorz of the array camera is as follows:
CombFOVHorz＝2*K 1 +β；
the vertical field angle CombFOVvert of the array camera is solved by the following formula:
CombFOVVert＝α；
the distance from the virtual optical center projection of the array camera to the base line is H P The solving formula is as follows:
the virtual imaging distance of the array camera is H E The solving formula is as follows:
H E ＝H+H P ；
the solution formula of the coverage range LHorz of the object space horizontal area of the array camera is as follows:
the solving formula of the coverage area LVert of the object space vertical area of the array camera is as follows:
the horizontal GSD precision GSDHorz solving formula of the array camera is as follows:
the vertical GSD precision GSDVert solving formula of the array camera is as follows:
in the array camera coordinate system O G -X T Y T Z T In (2), the coordinates of the key points of the viewing cone of the array camera are expressed as:
OE:(0,0,-H P )；
T0:(0,0,H)；
T1:
T2:
T3:
T4:
T5:
T6:
T7:
T8:
deflection angle K in the above solving process n And the nearest imaging distance H between adjacent cameras Mn For the parameters to be solved, the deflection angles of the array cameras formed by different numbers of cameras and the nearest imaging distances of two adjacent cameras are solved differently.
Further, when the array cameras respectively comprise 2, 3 and 4 cameras, the solving method of the deflection angles of the cameras respectively comprises the following steps:
3.1) array camera composed of 2 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene M1 Using default values, solve forDeflection angle K 1 ：
3.2) array camera composed of 3 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene H M1 Solving the deflection angle K by adopting a default value 1 ：
3.3) array camera composed of 4 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.5*H；H M2 The default values are: h M2 ＝0.3*H；
Determination of the distance H of the object scene M1 ，H M2 Solving the deflection angle K by adopting a default value 1 ，K 2 ：
K 2 Solving:
K 1 solving:
the horizontal view fields of the outermost side camera and the second outer side camera are intersected at a point O 1,2 Projected to base line point O' 1,2 Optical center O of outermost camera 1 1 To O' 1,2 Distance tmp1, optical center O of outermost camera 2 2 To O' 1,2 Tmp 2;
if it is not
If it is not
Whether the currently configured camera is reasonable is evaluated through indexes:
4) the coverage range LHorz of the object space in the horizontal direction is larger than a target plane range threshold value objSectThre, namely LHorz is larger than objSectThre, and the objSectThre is a range of the acquisition section in the horizontal direction, so that the acquisition range is ensured to be omitted;
5) the ratio ProjRatio of the object space unit distance and the distance projected to each camera plane needs to be greater than a threshold ProjRatioThre, namely ProjRatio < ProjRatioThre, and the object space perspective distortion is ensured not to exceed a preset threshold;
ProjRatio＝tan(K 1 )
6) the object sampling distance GSDHorz needs to be smaller than a threshold value, namely GSDHorz is smaller than GSDHorzThre, and GSDHorzThre is a pixel precision value required by a client, so that pixel resolution is ensured;
4)H Mn ＞H Mmin nearest imaging distance H Mn Is required to be greater than or equal to the lower limit value H of the closest imaging distance Mmin ；
And the four conditions are simultaneously met, namely the current configuration is judged to be reasonable, and otherwise, the current configuration is unreasonable.
In a further improvement, the step mode of each camera in the step two is as follows:
step 2.1) setting the outer margin of the cross section of the bridge as outerYZ, and obtaining the overlapping amount of overlapYZ between adjacent networking cameras;
step 2.2) calculating the range of the section camera to be shot according to the position of the section ab and the margin outyz outside the cross section of the bridge, and naming the range as an a 'point and a b' point, wherein the a 'b' is the field range of the section ab to be collected;
step 2.3) taking the length of a 'b' as the length of the collected section, testing the configuration of the networking camera consisting of 2, 3 and 4 cameras one by one according to the parameters of outerYZ and overlapYZ, and calculating the installation point O of the array camera G And the mounting angle mount of the array camera, as an optimal camera configuration, a group camera that can cover the minimum total number of cameras of ab.
In a further improvement, in the step 2.3), when the acquisition section is parallel to the corresponding maintenance platform, the array camera is vertical to and covers the acquisition section; when the acquisition section is not parallel to the corresponding maintenance platform, the installation angle of the corresponding array camera is adjusted, and the method comprises the following steps:
when the section of the overhaul platform is not parallel to the YZ cross section of the bridge bottom, the mounting angle mount of the array camera needs to be calculated;
setting AB as the shortest straight line of the YZ cross section at the bottom of the bridge beam, and AB as the track of the array camera on the maintenance platform; ab i array camera requires full coverageThe coordinates of a, B and A, B are known quantities, and the coordinate of a is (a) y ,a z ) The coordinates of b are (b) y ,b z ) The coordinate of A is (A) y ,A z ) The coordinates of B are (B) y ,B z )；
Equation of a line l for ab ab Comprises the following steps:
linear equation l of AB AB Comprises the following steps:
calculate midpoint c of ab:
perpendicular to ab through point c
Intersects AB at a point
Simultaneously satisfy the linear equation l AB And
will be provided with
Respectively substituted into the linear equation l AB And
solving for O G Coordinate of (a), O G Point is the midpoint of the array camera mount; passing point O G Making a straight line parallel to the Y-axis of the world coordinate system
ab perpendicular to
And
the included angle is the mounting angle mount of the array camera; passing point O G Make perpendicular to
Perpendicular line of (2)
Intersect ab at a straight line
By the equation of a straight line
And l ab Solving O' G The coordinates of (a); by straight line
And a straight line
Angle alpha of 3 Solving the installation angle mount of the array camera;
straight line
And a straight line
Angle alpha of 3 ：
If it is not
α 3 ＝-α 3 ；
Array camera mounting angle mount: motangle ═ 90 ° + α 3
Calculating the installation angle mount of the special section:
the acquisition section vertical to the XY coordinate plane is called a special section, the special section is ij, the corresponding section of the maintenance platform is an installation track BC, and the midpoint of the BC is taken as a coordinate origin O spe X in the direction of the bridge length spe Axis, Y in the direction of bridge width spe The axis is perpendicular to the bridge bottom and upwards is Z spe Axis, establishing coordinate system O of special section corresponding to the special section spe -X spe Y spe Z spe To do so by
In order to start the special cross-section ij,
the end point of the special section ij; the outer margin of the special section is outrZ, and the shot area is i' Z j' Z ，
As a starting point, the method comprises the following steps of,
is the end point; j' Z Is the array camera view cone down line of sight reference point, in j' Z The point is taken as the center of a circle, H is taken as the radius, and the point is intersected with the mounting track BC of the array camera at the point
According to O G And a view-cone down-line-of-sight reference point j' Z Calculating the installation angle mount, and setting O G j' Z Included angle of the mounting rail BCFor AngleTmp1, array camera virtual optical center ray and O G j' Z The included angle of (a) is AngleTmp 2;
Installation angle mount: mount angle 90 ° -AngleTmp1-AngleTmp 2.
In a further improvement, in the second step, the method for planning the array camera for a single cross section includes the following steps:
let a single transverse plane YZ in the direction of a h As a starting point, b h As an end point, a length of h b h (ii) a The area to be shot is a YZ b YZ ，a YZ As a starting point, b YZ Is the end point; according to the set outerYZ and overlapYZ parameters, the length L of the area to be shot of the single cross section ab is obtained YZ ：L YZ ＝outerYZ+a h b h +outerYZ；
The field of view of the array camera for single shooting along the bridge width direction is as follows:
number of arrayed camerasn YZ ：
First array camera origin of coordinates O G Is Start position Y ：
The installation interval between the arrayed cameras is moveStep Y ：moveStep Y ＝LHorz-OverlaYZ；
After each array camera is adopted for calculation, the array camera with the least total number of cameras is adopted for installation;
bridge cross section Sec ab Is configured to Start Y For the origin of coordinates O of the first array camera G Then at moveStep Y The arrangement of the array cameras is performed for the installation intervals.
In a further improvement, the third step, the method for planning the acquisition sites along the bridge length direction, comprises the following steps:
the bridge longitudinal section XZ direction is a v As a starting point, b v As an end point, a length of v b v (ii) a Setting the area to be shot in the XZ direction of the bridge longitudinal section as a XZ b XZ ，a XZ As a starting point, b XZ Is the end point; the allowance outside the bridge longitudinal section is outerXZ, and the overlapping amount of the bridge longitudinal section is overlapXZ;
total length of bridge longitudinal section L XZ ：L XZ ＝outerXZ+a v b v +outerXZ；
The field of view that the network camera of group shot along the long direction of bridge is single:
number of sites n XZ ：
Bridge longitudinal sectionThe Start position of the surface acquisition is Start X ：
Moving step size moveStep X ：moveStep X ＝LVert-OverlaXZ；
The vertical section of the bridge is started X Collecting the initial position for the networking camera, moving along the X (bridge length) direction, and moving moveStep each time X Moving n XZ Secondly, realizing the full-coverage acquisition of the bridge bottom;
respectively regarding the beam bottom web plate, the ribbed slab and the bottom plate as sections to be collected; the beam bottom overhauling platform is an overhauling device carried along the bridge width direction, a networking camera is arranged on the overhauling platform, the beam bottom section acquisition covering the whole bridge width direction small section area is realized, the beam bottom overhauling platform is moved along the bridge length direction through planning acquisition points, and the image acquisition of the bridge bottom is realized.
Drawings
FIG. 1 illustrates a girder bottom maintenance platform of a super bridge;
FIG. 2 is an elevation view of a beam bottom inspection platform of a Trans-sea bridge in Quanzhou bay;
FIG. 3 is a bottom concave surface of a Trans-sea bridge in Quanzhou bay;
FIG. 4 is a schematic diagram of a common cross-section of a Trans-sea bridge in Quanzhou bay;
FIG. 5 is a schematic cross-sectional view of a bay Trans-sea bridge and coordinate settings of points;
FIG. 6 coordinate setting of inspection cross section points of a bridge of a Trans-sea bridge in Quanzhou Bay;
FIG. 7 is a general cross-section of a webcam configuration;
FIG. 8 is a schematic diagram of an array camera design with two cameras;
FIG. 9 is a schematic diagram of an array camera design with three cameras;
FIG. 10 is a schematic diagram of an array camera design with four cameras;
FIG. 11 is a schematic view of a camera array camera deflection angle calculation;
FIG. 12 is a schematic diagram of the ratio of the unit distance of the object space to the distance projected to each camera plane
FIG. 13 bridge cross section networking camera planning;
FIG. 14 is a schematic view of a principle of calculating a mounting angle of a network camera;
FIG. 15 is a model diagram of a special cross-section XZ of a Trans-sea bridge in Bay of Quanzhou;
FIG. 16 is a schematic diagram for solving the installation angle of the XZ special section;
FIG. 17 is a model diagram of a special section YZ of a Trans-sea bridge in Qunzhou bay;
FIG. 18 is a schematic view of a configuration of a YZ special section networking camera;
FIG. 19 shows webcam mounting locations and image view coverage areas for the web, the rib, the base, and the raised base;
FIG. 20 bridge profile acquisition point planning;
Detailed Description
The technical means of the present invention will be specifically described below by way of specific embodiments.
The invention designs a networking camera on the existing beam bottom overhaul platform at the bottom of a super bridge, so as to realize the full coverage image data acquisition of the bottom of the super bridge, and the beam bottom overhaul platform is shown as figure 1.
This embodiment is exemplified by a cross-sea bridge in the bay of quan. Fig. 2 shows an elevation view of a bridge bottom maintenance platform of a quanzhou bay sea-crossing bridge, wherein a bridge bottom is generally composed of a web plate and a bottom plate, but the middle of the quanzhou bay sea-crossing bridge is a concave surface, and a beam bottom structure is divided into the web plate, a rib plate, the bottom plate and a raised bottom plate. The intermediate concave surface is shown in fig. 3. The quanzhou bay sea crossing bridge is divided into 5 common cross sections along the YZ direction along the bridge width direction, as shown in fig. 4. ab is the cross section of the left web plate, bc is the cross section of the bottom plate 1, de is the cross section of the raised bottom plate, fg is the cross section of the bottom plate 2, and gh is the cross section of the right web plate; the sections ab, bc, de, fg and gh are all parallel to the bridge detection platform, and the sections ab, bc, de, fg and gh are called as common sections. The beam bottom inspection vehicle is divided into AB, BC and CD3 cross sections, coordinates of the starting point and the end point of each cross section of the beam bridge and the beam bottom inspection platform can be obtained according to drawings of the beam bridge and the beam bottom inspection platform, and the coordinates of each point are recorded, as shown in figures 5 and 6.
The configuration method of the networking camera with the common section is consistent: for example, ab cross-section, as shown in FIG. 7.
Step 1.1) setting the outer margin of the cross section of the bridge as outerYZ, and obtaining the overlapping amount of overlapYZ between adjacent networking cameras;
step 1.2) calculating the range of the section camera to be shot according to the position of the section ab and the margin outyz outside the cross section of the bridge, and naming the range as an a 'point and a b' point, wherein the a 'b' is the field range of the section ab to be collected;
step 1.3) taking the length of a 'b' as the length of the collected section, testing the configuration of a networking camera consisting of 2, 3 and 4 cameras one by one according to the parameters of outerYZ and overlapYZ, and calculating the installation point O of the array camera G And the installation angle mount of the group network camera, as the optimal camera configuration, the group network camera that can cover the minimum total number of cameras of ab.
The configuration of the networking camera in step 1.3 comprises the following steps:
step 1.3.1) designing an array camera;
step 1.3.2) planning of a single cross section array camera;
and step 1.3.3) calculating the installation angle of the networking camera.
The array camera is characterized in that a plurality of cameras are fixedly connected to form a camera system, so that the field of view can be effectively enlarged under the condition of keeping the precision of a single camera, and the installation space is saved. The networking array camera is used for combining a plurality of array cameras to realize the acquisition of a large scene.
Step 1.3.1 the array camera design comprises the following steps:
1) and selecting a proper high-definition camera according to the detection requirement (namely the detection precision, the distance from the installation position of the maintenance platform camera to the acquisition section, namely the real imaging distance of the array camera is H). Determining relevant parameters of the camera: the horizontal field angle of the camera is beta, the vertical field angle of the camera is alpha, and the resolution of the camera is w x h;
2) designing an array camera:
2.1) array camera related parameters are as follows:
as shown in figure 8,9. 10, the array camera is a symmetrical structure, N cameras are arranged on a horizontal base, and the installation positions of the cameras are related to the installation center O of the array camera G Symmetrical with O G Is the origin of coordinates and is X along the bridge width direction T Axis, Y in the direction of bridge length T The axis is perpendicular to the bridge bottom and upwards is Z T Axis-establishing array camera coordinate system O G -X T Y T Z T . N camera optical centers of the array camera are positioned on the same horizontal line, the distance between the two outermost camera optical centers is called a baseline distance baseline, the included angle between the rays of the left and right outermost horizontal field fields of the array camera in the horizontal direction is called an array camera horizontal field angle CombFOVHorz, the included angle between the rays of the vertical field of the array camera is called an array camera vertical field angle CombFOVView, the included angle is equal to the vertical field angle alpha of a single camera, and the rays of the left and right outermost horizontal fields of the array camera in the horizontal direction and the rays of the vertical field of the array camera intersect at an array camera virtual optical center point O E 。 O G ，O E All on the same straight line and vertical to the object space imaging area to intersect at the central point T of the view cone of the array camera 0 。
Setting the coverage range of an object space horizontal area of the array camera as LHorz, the coverage range of an object space vertical area of the array camera as LVert, the real imaging distance of the array camera as H, and the virtual imaging distance of the array camera as H E The distance between the virtual optical center projection of the array camera and the base line is H P Lower limit value H of closest imaging distance of array camera Mmin (the nearest imaging distance of the array camera must not be less than the value, otherwise redundancy of camera configuration resources is caused), the horizontal GSD of the array camera is GSDHorz, and the vertical GSD of the array camera is GSDVert. The array camera view cone key points comprise: o is E ,T 0 ,O 1 ,T 2 ,T 3 ,T 4 ,T 5 ,T 6 ,T 7 ,T 8 ；
Array camera with respect to mounting center O G Symmetrical, the installation positions and angles of the left and right cameras are also related to O G Symmetry, and calculating the deflection angle of one side of the originThe other side is a deflection angle symmetrical with the other side. Number of deflection angles found n:
taking the arrangement of the left camera at the origin of the array camera as an example, the deflection angle of the outermost camera 1 is set to K 1 The deflection angle of the sub outer layer camera 2 is K 2 ,., camera n deflection angle K near the origin of the array camera coordinates n 。
The distance between the intersection point of the horizontal field rays of the two adjacent cameras projected to the base line is called the minimum imaging distance, the distance below which the two cameras may have no overlapped area in the object plane, and the minimum imaging distance is also related to O G Symmetrical with O G The left side camera is arranged as an example, and the horizontal view fields of the outermost camera 1 and the second outermost camera 2 are intersected at a point O 1,2 Point of, O 1，2 The distance to the base line is the closest imaging distance H M1 The horizontal fields of view of camera 2 and camera 3 intersect at point O 2，3 Point of, O 2，3 The distance to the base line is the closest imaging distance H M2 ,.. camera n and camera n +1 horizontal field of view intersect at point O n,n+1 Point of, O n,n+1 The distance to the base line is the closest imaging distance H Mn 。
2.2) the arrangement of the deflection angle of the array camera and the nearest imaging distance between adjacent cameras meets the following geometrical constraint relation:
a.
b.
c.K n ＜...＜K 2 ＜K 1 ；
d.H Mn ＜H；
e.H Mn ＞H Mmin 。
2.3) solving related parameters of the array camera:
through the position information of the bridge bottom overhauling platform and the bridge detection surface, the selected high-definition camera can acquire the real imaging distance H of the array camera, the horizontal field angle beta of a single camera, the vertical field angle alpha of the single camera and the baseline distance baseline.
Lower limit value H of closest imaging distance of array camera Mmin The solving formula is as follows:
the solving formula of the horizontal field angle CombFOVHorz of the array camera is as follows:
CombFOVHorz＝2*K 1 +β；
the vertical field angle CombFOVvert of the array camera is solved by the following formula:
CombFOVVert＝α；
the distance from the virtual optical center projection of the array camera to the base line is H P The solving formula is as follows:
the virtual imaging distance of the array camera is H E The solving formula is as follows:
H E ＝H+H P ；
the solution formula of the coverage range LHorz of the object space horizontal area of the array camera is as follows:
the solving formula of the coverage area LVert of the object space vertical area of the array camera is as follows:
the horizontal GSD precision GSDHorz solving formula of the array camera is as follows:
the vertical GSD precision GSDVert solving formula of the array camera is as follows:
in the array camera coordinate system O G -X T Y T Z T In (2), the coordinates of the key points of the view frustum of the array camera can be expressed as:
OE:(0,0,-H P )；
T0:(0,0,H)；
T1:
T2:
T3:
T4:
T5:
T6:
T7:
T8:
in the solving process, the deflection angle is a parameter to be solved, and the solving of the array camera deflection angle formed by different camera numbers and the closest imaging distance of two adjacent cameras are different. The invention mainly aims at the array camera composed of 2 cameras, 3 cameras and 4 cameras by combining the actual situation to make the deflection angle of the array camera.
2.4) solving the deflection angle of an array camera consisting of 2, 3 and 4 cameras:
the schematic design of an array camera consisting of 2 cameras is shown in fig. 8. 2 array cameras composed of cameras are arranged at the nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene M1 Solving the deflection angle K by adopting a default value 1 ：
A schematic diagram of an array camera design composed of 3 cameras is shown in fig. 9. The array camera composed of 3 cameras sets the nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene M1 Solving the deflection angle K by adopting a default value 1 ：
A schematic diagram of an array camera design consisting of 4 cameras is shown in fig. 10. The array camera composed of 4 cameras sets the nearest imaging distance H between two adjacent cameras M1 The default values are: h M1 ＝0.5*H；H M1 The default values are: h M2 ＝0.3*H；
Object space sceneIs determined by the distance H M1 ，H M2 Solving the deflection angle K by adopting a default value 1 ，K 2 ：
K 2 Solving:
K 1 solving:
the horizontal visual fields of the outermost side camera 1 and the second outer side camera 2 are intersected at a point O 1,2 Projected to baseline as point O 1 ' ,2 As shown in fig. 11, the optical center O of the outermost camera 1 1 To O 1 ' ,2 Distance tmp1, outermost camera 2 optical center O 2 To O 1 ' ,2 Distance tmp 2;
if it is not
If it is not
Whether the currently configured camera is reasonable is evaluated through indexes:
7) the coverage range LHorz of the object space in the horizontal direction is larger than a target plane range threshold value objSectThre, namely LHorz is larger than objSectThre, and the objSectThre is a range of the acquisition section in the horizontal direction, so that the acquisition range is ensured to be omitted.
8) The ratio ProjRatio of the object space unit distance and the distance projected to each camera plane needs to be larger than a threshold value ProjRatioThre, namely ProjRatio < ProjRatioThre, and the object space perspective distortion is small. A representation of the ProjRatio is shown in fig. 12.
ProjRatio＝tan(K 1 )
9) The object sampling distance GSDHorz needs to be smaller than a threshold value, namely GSDHorz is smaller than GSDHorzThre, and GSDHorzThre is a pixel precision value required by a client to ensure pixel resolution.
4)H Mn ＞H Mmin Nearest imaging distance H Mn Is required to be greater than or equal to the lower limit value H of the closest imaging distance Mmin 。
And the four conditions are simultaneously met, namely the current configuration is judged to be reasonable, and otherwise, the current configuration is unreasonable.
The single cross-sectional array camera planning described in step 1.3.2 comprises the steps of:
as shown in fig. 13, AB is the cross section to be collected, and AB is the installation section of the bridge maintenance platform. Let a single transverse plane (YZ) direction be a h As a starting point, b h As an end point, a length of h b h . The area to be shot is a YZ b YZ ， a YZ As a starting point, b YZ Is the end point. According to the outerYZ and overlapYZ parameters set in the step 1.1, the length L of the area to be shot of the single cross section ab can be obtained YZ ：L YZ ＝outerYZ+a h b h +outerYZ；
The field of view of the array camera for single shooting along the bridge width direction is as follows:
number n of array cameras YZ ：
First array camera origin of coordinates O G Is Start position Y ：
The installation interval between the arrayed cameras is moveStep Y ：moveStep Y ＝LHorz-OverlaYZ；
The networking camera of the bridge cross section ab is configured to Start Y For the origin of coordinates O of the first array camera G Then at moveStep Y The arrangement of the group network cameras is performed for the installation interval.
Step 1.3.3 the calculation of the installation angle of the networking camera comprises the following steps:
when the cross section of the maintenance platform is not parallel to the cross section of the bridge bottom (YZ), the installation angle mount of the networking camera needs to be calculated, as shown in FIG. 14.
And AB is the shortest straight line of the cross section of the bridge beam bottom (YZ), and AB is the track of the networking camera on the maintenance platform. ab is the acquisition range that the networking camera needs to cover comprehensively, the coordinates of a, B and A, B are known quantities, and the coordinate of a is (a) y ,a z ) The coordinates of b are (b) y ,b z ) The coordinate of A is (A) y ,A z ) The coordinates of B are (B) y ,B z )。
ab equation of a line l ab Comprises the following steps:
linear equation l of AB AB Comprises the following steps:
calculate midpoint c of ab:
perpendicular to ab through point c
Intersects AB at a point
Simultaneously satisfy the linear equation l AB And
will be provided with
Respectively substituted into the linear equation l AB And
can solve for O G The coordinates of (a). Passing point O G Making a straight line parallel to the Y-axis of the world coordinate system
ab perpendicular to
And
the included angle of (1) is the installation angle mount of the networking camera. Passing point O G Make perpendicular to
Perpendicular line of
Intersect ab at a straight line
By the equation of a straight line
And l ab Can solve O' G The coordinates of (a). By straight line
And a straight line
Angle alpha of 3 The networking camera mounting angle mount may be solved.
Straight line
And a straight line
Angle alpha of 3 ：
If it is not
α 3 ＝-α 3 ；
Installation angle mount of the networking camera mount angle mount: motangle ═ 90 ° + α 3
And calculating an ab section, calculating the total number of cameras required by the array cameras consisting of 2, 3 and 4 cameras one by one, and configuring the networking camera capable of covering the minimum total number of cameras on the ab section as the optimal camera. And setting the common section networking camera according to the steps.
The bridge bottom of the cross-sea bridge in the bay of spring comprises a ribbed plate. The acquisition cross section perpendicular to the XY coordinate plane is referred to as a special cross section, and the maintenance platform is not parallel to the special cross section, and a model diagram thereof is shown in fig. 15.
The method for setting the array cameras with the special cross sections is consistent, and the installation angles mount are different in calculation. The concave surface area of the bottom of the bridge of the cross-sea bridge of the Quanzhou Bay is divided into an XZ special section and a YZ special section. XZ is shown in fig. 16, and the installation angle mount is calculated as:
setting a special section as ij, taking the corresponding section of the maintenance platform as an installation track BC, and taking the midpoint of BC as a coordinate origin O spe X in the direction of the bridge length spe Axis, Y in the direction of bridge width spe The axis, perpendicular to the bridge floor and upwards, being Z spe Axis, establishing coordinate system O of special section corresponding to the special section spe -X spe Y spe Z spe To do so by
In order to start the special cross-section ij,
the end point of the special section ij. As shown in FIG. 15, the outer margin of the XZ special cross-section is outrZ, and the imaged region is i' Z j' Z ，
As a starting point, the method comprises the following steps of,
is the end point. j' Z Is a sight line reference point under the view cone of the networking camera,and j' Z The point is taken as the circle center, the H is taken as the radius, and the point meets the mounting track BC of the networking camera at the point
According to O G And a view-cone down-line-of-sight reference point j' Z And calculating the installation angle mount. Is provided with and O G j' Z The included angle of the mounting track BC is AngleTmp1, and the virtual optical center ray of the networking camera and O G j' Z Is AngleTmp 2.
the equation by circle can be solved
Installation angle mount: mountain of 90 ° -AngleTmp1-AngleTmp2
The YZ special section is shown in fig. 17, the installation angle mount of the networking camera mount is 45 ° in the vertical viewing field direction, and the networking camera is arranged as the same as the common section, which is not repeated here, as shown in fig. 18.
The configuration of the network cameras on each section in the bridge width direction is planned through the method, and the schematic diagram of the installation point positions and the image view angle coverage area of the network cameras of the large bridge web, the rib plates, the bottom plates and the raised bottom plate group of the quanzhou bay cross-sea bridge is shown in fig. 19.
And (5) well arranging the configuration of the networking cameras along the bridge width direction, and further planning the acquisition stations along the bridge length direction. A schematic diagram of the site plan collected by the quanzhou bay along the bridge length direction (XZ direction) is shown in fig. 20.
The longitudinal section of the bridge is expressed by a v As a starting point, b v As an end point, a length of v b v . Setting the area of the bridge vertical section to be shot as a XZ b XZ ，a XZ As a starting point, b XZ Is the end point. The allowance outside the bridge longitudinal section is outerXZ, and the overlapping amount of the bridge longitudinal section is overlapXZ.
Total length of bridge longitudinal section L XZ ：L XZ ＝outerXZ+a v b v +outerXZ；
The field of view that the network camera of group shot along the long direction of bridge is single:
number of sites n XZ ：
The initial position of the bridge longitudinal section acquisition is Start X ：
Moving step size moveStep X ：moveStep X ＝LVert-OverlaXZ；
The vertical section of the bridge is started X Collecting the initial position for the networking camera, moving along the X (bridge length) direction, and moving moveStep each time X Moving n XZ And secondly, full-coverage image data acquisition of the bottom of the cross-sea bridge in the bay of spring is realized.
The above description is only one specific guiding embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modification of the present invention using this concept shall fall within the scope of the invention.
Claims (7)
1. A method for acquiring an image of the bottom of a super bridge based on a networking camera is characterized by comprising the following steps:
the method comprises the following steps that firstly, a plurality of types of array cameras with different visual fields are preset, wherein each array camera consists of a plurality of identical cameras;
step two, dividing the bottom of the super-large bridge into a plurality of continuous acquisition sections along the bridge width direction of the super-large bridge; according to the size of each acquisition section, arranging an array camera which is enough to cover the corresponding section and contains the least number of cameras on an overhaul platform at the bottom of the extra-large bridge; and forming a networking camera by each array camera set network; in each group of array cameras, the overlapping length of the shooting areas of the adjacent cameras along the bridge width direction is the overlapping amount overlapYZ of the cross section of the bridge; adjusting the angle of the camera in each group of array cameras to obtain the least cameras which can clearly obtain the bridge bottom image;
and step three, planning a collection station along the bridge length direction, and moving an overhaul platform carrying the networking camera according to the set collection station to realize automatic full-coverage image collection of the bottom of the extra-large bridge.
2. The method for acquiring the images of the bottom of the grand bridge based on the networking camera as claimed in claim 1, wherein: the setting method of the array camera group comprises the following steps:
1) selecting a camera, and determining relevant parameters of the camera: the horizontal field angle of the camera is beta, the vertical field angle of the camera is alpha, and the resolution of the camera is w x h; w represents the resolution in the horizontal direction; h represents the resolution in the vertical direction;
2) designing an array camera:
2.1) array camera related parameters are as follows:
the array camera set is of a symmetrical structure, namely N cameras are arranged on a horizontal base, and the installation positions of the cameras are relative to the installation center O of the array camera G Symmetrical with O G Is the origin of coordinates and is X along the bridge width direction T Axis, Y in the direction of bridge length T Axle, vertical bridge bottomUpwards is Z T Axis-establishing array camera coordinate system O G -X T Y T Z T (ii) a N camera optical centers of the array camera are located on the same horizontal line, the distance between the two outermost camera optical centers in the array camera is called a baseline distance baseline, the included angle between the left and right outermost horizontal field rays of the array camera in the horizontal direction is set as an array camera horizontal field angle CombFOVHorz, the included angle between the array camera vertical field rays is called an array camera vertical field angle CombFOVVerert, the included angle is equal to a vertical field angle alpha of a single high-definition camera, and the left and right outermost horizontal field rays and the vertical field rays of the array camera in the horizontal direction are intersected at an array camera virtual optical center point O E ；O G ，O E Are all on the same straight line and vertical to the object space imaging area and intersect at the central point T of the view cone of the array camera 0 ；
Setting the coverage range of an object space horizontal area of the array camera as LHorz, the coverage range of an object space vertical area of the array camera as LVert, the real imaging distance of the array camera as H, and the virtual imaging distance of the array camera as H E The distance between the virtual optical center projection of the array camera and the base line is H P The lower limit value of the closest imaging distance of the array camera is H Mmin The horizontal GSD of the array camera is GSDHorz, and the vertical GSD of the array camera is GSDVert; the array camera view cone key points comprise: o is E ,T 0 ,T 1 ,T 2 ,T 3 ,T 4 ,T 5 ,T 6 ,T 7 ,T 8 ；T 0 Representing the projection of a virtual optical center on the object plane, T 1 T 2 T 3 T 4 Four corner points, T, of the entire field of view 1 T 4 Vertical field line for the leftmost shot, T 5 Is T 1 T 4 Central point of (1), T 2 T 3 Vertical field line, T, for the rightmost shot 6 Is T of 2 T 3 Center point, T 1 T 2 Horizontal field lines, T, for front-most shots 7 Is T 1 T 2 Central point of (1), T 3 T 4 Horizontal field of view line for front-most photography，T 8 Is T 3 T 4 A center point of (a);
array camera with respect to mounting center O G Symmetrical, the installation positions and angles of the left and right cameras are also related to O G The symmetry, the deflection angle of one side of the origin point is calculated, and the deflection angle of the other side which is symmetrical to the other side can be obtained; number of deflection angles found n:
let the deflection angle of the outermost camera be K 1 The deflection angle of the sub outer layer camera is K 2 ,.., the angle of deflection of camera n closest to the origin of the array camera coordinates is K n ；
The distance between the intersection point of the horizontal field rays of two adjacent cameras and the base line is called the closest imaging distance, wherein the distance H from the object plane to the base line of the array camera is greater than the closest imaging distance; closest imaging distance also with respect to O G Symmetrical with O G The left side camera is arranged as an example, and the horizontal view fields of the outermost camera and the second outermost camera are intersected at a point O 1,2 Point of, O 1，2 The distance to the base line is the closest imaging distance H M1 The horizontal field of view of the second outer camera and the second outer camera intersect at a point O 2，3 Point of, O 2，3 The distance to the base line is the closest imaging distance H M2 ,.. the n camera and the n +1 camera horizontal field of view intersect at point O n,n+1 Point of, O n,n+1 The distance to the base line is the closest imaging distance H Mn ；
2.2) the deflection angle of the camera in the array camera and the nearest imaging distance between the adjacent cameras satisfy the following geometrical constraint relation:
a.
b.
c.K n ＜...＜K 2 ＜K 1 ；
d.H Mn ＜H；
e.H Mn ＞H Mmin ；
2.3) solving related parameters of the array camera:
the distance from an object space plane to the base line of the array camera, namely the real imaging distance of the array camera is H, the horizontal field angle beta of a single camera, the vertical field angle alpha of the single camera and the base line distance baseline can be obtained through the position information of the bridge bottom overhauling platform and the bridge detection surface;
wherein the base line distance
Lower limit value H of closest imaging distance of array camera Mmin The solving formula is as follows:
the solving formula of the horizontal field angle CombFOVHorz of the array camera is as follows:
CombFOVHorz＝2*K 1 +β；
the vertical field angle CombFOVvert of the array camera is solved by the following formula:
CombFOVVert＝α；
the distance from the virtual optical center projection of the array camera to the base line is H P The solving formula is as follows:
the virtual imaging distance of the array camera is H E The solving formula is as follows:
H E ＝H+H P ；
the solution formula of the coverage range LHorz of the object space horizontal area of the array camera is as follows:
the solving formula of the coverage area LVert of the object space vertical area of the array camera is as follows:
the horizontal GSD precision GSDHorz solving formula of the array camera is as follows:
the vertical GSD precision GSDVert solving formula of the array camera is as follows:
in the array camera coordinate system O G -X T Y T Z T In (2), the coordinates of the key points of the viewing cone of the array camera are expressed as:
OE:(0,0,-H P )；
T0:(0,0,H)；
deflection angle K in the above solving process n And the nearest imaging distance H between adjacent cameras Mn For the parameters to be solved, the deflection angles of the array cameras formed by different numbers of cameras and the nearest imaging distances of two adjacent cameras are solved differently.
3. The networking camera-based grand bridge bottom image acquisition method according to claim 2, wherein: when the array cameras respectively comprise 2 cameras, 3 cameras and 4 cameras, the solving method of the deflection angle of the cameras is respectively as follows:
3.1) array camera composed of 2 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene M1 Solving the deflection angle K by adopting a default value 1 ：
3.2) array camera composed of 3 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.8*H；
Determination of the distance H of the object scene M1 Solving the deflection angle K by adopting a default value 1 ：
3.3) array camera composed of 4 cameras setting nearest imaging distance H of two adjacent cameras M1 The default values are: h M1 ＝0.5*H；H M2 The default values are: h M2 ＝0.3*H；
Determination of the distance H of the object scene M1 ，H M2 Adopting default value to solve deflection angle K 1 ，K 2 ：
K 2 Solving:
K 1 solving:
the horizontal view fields of the outermost side camera and the second outer side camera are intersected at a point O 1,2 Projected to base line point O' 1,2 Optical center O of outermost camera 1 1 To O' 1,2 Distance tmp1, outermost camera 2 optical center O 2 To O' 1,2 Distance tmp 2;
if it is not
If it is not
Whether the currently configured camera is reasonable is evaluated through indexes:
1) the coverage range LHorz of the object space in the horizontal direction is larger than a target plane range threshold value objSectThre, namely LHorz is larger than objSectThre, and the objSectThre is a range of the acquisition section in the horizontal direction, so that the acquisition range is ensured to be omitted;
2) the ratio ProjRatio of the object space unit distance and the distance projected to each camera plane needs to be greater than a threshold ProjRatioThre, namely ProjRatio < ProjRatioThre, and the object space perspective distortion is ensured not to exceed a preset threshold;
ProjRatio＝tan(K 1 )
3) the sampling distance GSDHorz of the object space is required to be smaller than a threshold value, namely GSDHorz is smaller than GSDHorzThre, and GSDHorzThre is a pixel precision value required by a client, so that pixel resolution is ensured;
4)H Mn ＞H Mmin nearest imaging distance H Mn Is required to be greater than or equal to the lower limit value H of the closest imaging distance Mmin ；
And the four conditions are simultaneously met, namely the current configuration is judged to be reasonable, and otherwise, the current configuration is unreasonable.
4. The method for acquiring the images of the bottom of the grand bridge based on the networking cameras as claimed in claim 3, wherein the step mode of each camera in the second step is as follows:
step 2.1) setting the outer margin of the cross section of the bridge as outerYZ, and obtaining the overlapping amount of overlapYZ between adjacent networking cameras;
step 2.2) calculating the range of the section camera to be shot according to the position of the section ab and the margin outyz outside the cross section of the bridge, and naming the range as an a 'point and a b' point, wherein the a 'b' is the field range of the section ab to be collected;
step 2.3) taking the length of a 'b' as the length of the acquisition section, testing the configuration of a networking camera consisting of 2, 3 and 4 cameras one by one according to the parameters of outerYZ and overlapYZ, and calculating the installation point O of the array camera G And the mounting angle mount of the array camera, as an optimal camera configuration, a group camera that can cover the minimum total number of cameras of ab.
5. The method for acquiring the images of the bottom of the grand bridge based on the networking camera as claimed in claim 4, wherein in the step 2.3), when the acquisition section is parallel to the corresponding maintenance platform, the array camera is vertical and covers the acquisition section; when the acquisition section is not parallel to the corresponding maintenance platform, the installation angle of the corresponding array camera is adjusted, and the method comprises the following steps:
when the section of the overhaul platform is not parallel to the YZ cross section of the bridge bottom, the mounting angle mount of the array camera needs to be calculated;
setting AB as the shortest straight line of the YZ cross section at the bottom of the bridge beam, and AB as the track of the array camera on the maintenance platform; ab is the acquisition range that the array camera needs to cover, the coordinates of a, B and A, B are known quantities, and the coordinate of a is (a) y ,a z ) The coordinates of b are (b) y ,b z ) The coordinate of A is (A) y ,A z ) The coordinates of B are (B) y ,B z )；
ab equation of a line l ab Comprises the following steps:
equation of the straight line l of AB AB Comprises the following steps:
calculate midpoint c of ab:
perpendicular line l to ab via point c ab⊥ :
Intersect AB at a point
Simultaneously satisfy the linear equation l AB And l ab⊥ Will be
Respectively substituted into the linear equation l AB And l ab⊥ Solving for O G Coordinate of (a), O G Point is the midpoint of the array camera mount; passing point O G Making a straight line parallel to the Y-axis of the world coordinate system
ab perpendicular toThread
And with
The included angle is the mounting angle mount of the array camera; passing point O G Make perpendicular to
Perpendicular line of
Intersect ab at a straight line
By the equation of a straight line
And l ab Solving for O' G The coordinates of (a); by straight line
And a straight line
Angle alpha of 3 Solving the installation angle mount of the array camera;
straight line
And a straight line
Angle alpha of 3 ：
If it is not
α 3 ＝-α 3 ；
Array camera mounting angle mount: motangle ═ 90 ° + α 3
Calculating the installation angle mount of the special section:
an acquisition section vertical to the XY coordinate plane is called a special section, the special section is ij, the corresponding section of the maintenance platform is an installation track BC, and the midpoint of the BC is taken as a coordinate origin O spe X in the direction of the bridge length spe Axis, Y in the direction of bridge width spe The axis is perpendicular to the bridge bottom and upwards is Z spe Axis, establishing coordinate system O of special section corresponding to the special section spe -X spe Y spe Z spe To do so by
In order to start the special cross-section ij,
the end point of the special section ij; the outer margin of the special section is outrZ, and the shot area is i' Z j' Z ，
As a starting point, the method comprises the following steps of,
is the end point; j' Z Is the array camera view cone down line of sight reference point, in j' Z The point is taken as the circle center, the H is taken as the radius, and the point meets the mounting track BC of the array camera at the point
According to O G And a view-cone down-line-of-sight reference point j' Z Calculating the installation angle mount, and setting O G j' Z The included angle of the mounting track BC is AngleTmp1, and the virtual optical center ray of the array camera and O G j' Z Is at an included angle ofAngleTmp2；
Installation angle mount: mount angle 90 ° -AngleTmp1-AngleTmp 2.
6. The method for acquiring the images of the bottom of the grand bridge based on the networking camera as claimed in claim 4, wherein in the second step, the method for planning the array camera for a single cross section comprises the following steps:
let a single transverse plane YZ in the direction of a h As a starting point, b h As an end point, a length of h b h (ii) a The area to be shot is a YZ b YZ ，a YZ As a starting point, b YZ Is the end point; according to the set outerYZ and overlapYZ parameters, the length L of the area to be shot of the single cross section ab is obtained YZ ：L YZ ＝outerYZ+a h b h +outerYZ；
The field of view of the array camera for single shooting along the bridge width direction is as follows:
number n of array cameras YZ ：
First array camera origin of coordinates O G Is Start position Y ：
The installation interval between the arrayed cameras is moveStep Y ：moveStep Y ＝LHorz-OverlaYZ；
After each array camera is adopted for calculation, the array camera with the least total number of cameras is adopted for installation;
bridge cross section Sec ab Is configured to Start Y For the origin of coordinates O of the first array camera G Then in moveStep Y The arrangement of the array cameras is performed for the installation intervals.
7. The method for acquiring the images of the bottom of the grand bridge based on the networking camera as claimed in claim 1, wherein the third step is that the method for planning the acquisition stations along the bridge length direction comprises the following steps:
the bridge longitudinal section XZ direction is a v As a starting point, b v As an end point, a length of v b v (ii) a Setting the area to be shot in the XZ direction of the bridge longitudinal section as a XZ b XZ ，a XZ As a starting point, b XZ Is the end point; the allowance outside the bridge longitudinal section is outerXZ, and the overlapping amount of the bridge longitudinal section is overlapXZ;
total length of bridge longitudinal section L XZ ：L XZ ＝outerXZ+a v b v +outerXZ；
The field of view that the network camera of group shot along the long direction of bridge is single:
number of sites n XZ ：
The initial position of the bridge longitudinal section acquisition is Start X ：
Moving step size moveStep X ：moveStep X ＝LVert-OverlaXZ；
The vertical section of the bridge is started X Collecting the initial position for the networking camera, moving along the X (bridge length) direction, and moving moveStep each time X Moving n XZ Secondly, realizing the full-coverage acquisition of the bridge bottom;
respectively regarding the beam bottom web plate, the ribbed slab and the bottom plate as sections to be collected; the beam bottom overhauling platform is an overhauling device carried along the bridge width direction, a networking camera is arranged on the overhauling platform, the beam bottom section acquisition covering the whole bridge width direction small section area is realized, the beam bottom overhauling platform is moved along the bridge length direction through planning acquisition points, and the image acquisition of the bridge bottom is realized.
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