Laser radar-video camera combined calibrating target and combined calibrating methodTechnical field
The invention belongs to multisensor combined calibrating technical fields, and in particular to a kind of laser radar-video camera joint markTargeting further relates to a kind of method for carrying out combined calibrating to laser radar-video camera using the combined calibrating target.
Background technique
In the vision guided navigation of intelligent robot, using multisensor Data Fusion technology, it is available about environment moreAdd description reliable, uniformly, finely, so as to decision, planning and control.It is sense when carrying out the data fusion of pixel scale moreThe calibration of device is one of must to solve the problems, such as.Calibration is generally divided into 2 parts: the calibration of each sensor inherent parameters and moreThe combined calibrating of sensor.The calibration of each sensor inherent parameters is the accuracy in order to guarantee acquired data, and senses moreThe combined calibrating of device is the accurate match for multi-sensor data.Laser radar and video camera are the main sensings of robotDevice, the color information that the range information and video camera that laser radar provides provide has very strong complementarity, therefore merges the twoInformation become current research hotspot.Wherein, camera calibration problem is preferably solved, e.g., based on radial rowThe two-step method of column constraint, the standardization based on 3D chessboard target and plane template standardization.About laser radar problem of calibratingAlso there is research, such as using thin bar as calibration object plane, e.g., for video camera and 2D laser radar, using right angle trigonometryShape plate uses trapezoidal inclined plane scaling board as target, obtains calibration result as matching characteristic using lines.All be byThe range information figure of laser radar acquisition makes the apparent protrusion in scene nature edge, then extract edge lines and take the photograph by transformationThe edge that detected in the photo of camera shooting matches；In sensor platform for fixation along wild trajectory moving processTarget multi collect data are demarcated by the European distortion of scene point between the multiframe of minimum different perspectives shootingAs a result etc..However due to the particularity of scanning laser radar, its angular resolution is lower, is generally only 0.15 ° -3 °, Er QieshouThe marginal portion of the influence of mixed pixel, distance mutation often cannot get accurate distance value.
Summary of the invention
The embodiment of the present invention provides a kind of laser radar-video camera combined calibrating target, does not move in sensor and calibration targetThe combined calibrating that laser radar and video camera are completed in the case where dynamic, can overcome laser radar angular resolution is lower actually to makeAccurate distance value can be obtained with the marginal portion of limitation, distance mutation, has structure simple, the spy of low manufacture costPoint, and be suitable for batch and demarcate.
In order to solve the above-mentioned technical problems, the present invention provides a kind of laser radar-video camera combined calibrating targets, including chessDisk scaling board and " L " font scaling board；" L " the font scaling board includes the first plane vertical plate and the second plane vertical plate, describedSecond plane vertical plate after the first 90 ° of plane vertical plate corner relative to being fixed on the first plane vertical plate；The chessboard calibration plate is flatRow is located on front side of the sight of the first plane vertical plate and is fixed on the first plane vertical plate in the first plane vertical plate, the chessboard markBlack and white chessboard grid pattern is placed on fixed board.
It further comprise that the chessboard calibration plate is located at the on the first plane vertical plate in a preferred embodiment of the present inventionThe lower section of one plane vertical plate and the second plane vertical plate connecting part.
It further comprise the first plane vertical plate and the second plane vertical plate linking part in a preferred embodiment of the present inventionThe extended line of position is plumb line, the wherein extended line of a black and white separator bar of the black and white chessboard grid pattern and described first flatThe extension line overlap of face vertical plate and the second plane vertical plate connecting part.
In order to solve the above-mentioned technical problems, the present invention provides a kind of laser radar-video camera combined calibrating methods, useThe combined calibrating target of the above structure carries out combined calibrating to laser radar and video camera, includes the following steps,
(1) laser radar scanning " L " font scaling board obtains the opposite position between laser radar and " L " font scaling boardSet relationship [R1,T1]；
(2) camera shoots chessboard calibration plate, obtains the relative positional relationship [R between video camera and chessboard scaling board2,T2]；
(3) relative position between chessboard calibration plate and " L " font scaling board is obtained according to the structure of combined calibrating target to closeIt is [R3,T3]；
(4) according to the relative positional relationship [R between laser radar and " L " font scaling board1,T1], video camera and chessboard markRelative positional relationship [R between fixed board2,T2] and chessboard scaling board and " L " font scaling board between relative positional relationship [R3,T3], determine the relative positional relationship [R, T] between laser radar and video camera.
It further comprise obtaining laser radar in step (1) and " L " font being demarcated in a preferred embodiment of the present inventionRelative positional relationship [R between plate1,T1] process are as follows:
S1, laser radar continuous scanning the first plane vertical plate and the second plane vertical plate, acquisition beat the first plane vertical plate withAll radar points on second plane vertical plate；
S2, the radar points for filtering out the radar points for belonging to the first plane vertical plate and belonging to the second plane vertical plate；
S3 is belonged to all radar points of the first plane vertical plate based on the fitting of least squares line fitting method, obtains firstLinear equation L1；All radar points for belonging to the second plane vertical plate based on the fitting of least squares line fitting method, obtain Article 2Linear equation L2；
S4 calculates the intersection point P of straight line and Article 2 straight line；
S5 is determined according to the difference in height between laser radar and " L " font scaling board using intersection point P as " L " font of originScaling board coordinate system.
It in a preferred embodiment of the present invention, further comprise that the process for screening radar points is in step S2,
When laser radar is scanned from the second plane vertical plate to the first plane vertical plate, the length according to the second plane vertical plate is pre-Surveying the radar points beaten on the second plane vertical plate has N (N is greater than 7 integer) a, is fitted based on least squares line fitting methodFirst radar points, second radar points ..., the N-5 radar points obtain screening linear equation L3；
The boundary radar between the second plane vertical plate and the first plane vertical plate is determined based on the screening straight linePoint, positioned at it is described boundary radar points before all radar points be to belong to the radar points of the second plane vertical plate, boundary radar points andLater all radar points are to belong to the radar points of the first plane vertical plate.
In a preferred embodiment of the present invention, further comprise determining that the process of the boundary radar points is,
It calculates and judges whether the N-4 radar points meets the range accuracy of laser radar to the distance of screening straight line:
If the distance of the N-4 radar points to screening straight line L3 meet the range accuracy of laser radar, then the N-4 thunderBelong to the radar points on the second plane vertical plate up to point, continues to judge whether the N-3 radar points be full to the distance of screening straight line L3The range accuracy of sufficient laser radar；Otherwise, the N-4 radar points is boundary radar points；
If the distance of the N-3 radar points to screening straight line L3 meet the range accuracy of laser radar, then the N-3 thunderBelong to the radar points on the second plane vertical plate up to point, continues to judge whether the N-2 radar points be full to the distance of screening straight line L3The range accuracy of sufficient laser radar；Otherwise, the N-3 radar points is boundary radar points；
And so on, until filtering out the boundary radar points between the second plane vertical plate and the first plane vertical plate.
It further comprise that video camera draw in chess is obtained based on PNP algorithm in step (2) in a preferred embodiment of the present inventionRelative positional relationship [R between disk scaling board2,T2]。
Beneficial effects of the present invention:
Laser radar of the invention-video camera combined calibrating target, it is complete in the case where sensor and calibration target do not moveAt the combined calibrating of laser radar and video camera, the lower actual use limitation of laser radar angular resolution can be overcome, away fromAccurate distance value can be obtained from the marginal portion of mutation, has structure simple, the characteristics of low manufacture cost, and is suitable for batchAmount calibration.
Laser Lei Fa-video camera combined calibrating method of the invention, the combined calibrating target designed using specific structure is with fastSpeed carries out combined calibrating to laser thunder method and video camera, is applicable to batch and demarcates, saves calibration cost.Wherein, using quasi-Conjunction method Calibration of Laser radar, accuracy is higher, is more suitable for the combined calibrating of low resolution laser radar.The combined calibrating methodThe combined calibrating of single game scape multi-cam and laser radar can also be generalized to.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of combined calibrating target in the preferred embodiment of the present invention；
Fig. 2 is the distribution schematic diagram of radar points on " L " font scaling board；
Fig. 3 is position mark figure when carrying out laser radar video camera combined calibrating using calibration target shown in Fig. 1.
Figure label explanation: 2- chessboard calibration plate, 4- the first plane vertical plate, 6- the second plane vertical plate, 8- chessboard grid pattern.
Specific embodiment
The present invention will be further explained below with reference to the attached drawings and specific examples, so that those skilled in the art can be withIt more fully understands the present invention and can be practiced, but illustrated embodiment is not as a limitation of the invention.
Embodiment one
The present embodiment discloses a kind of laser radar-video camera combined calibrating target, shown referring to Fig.1, the combined calibrating target packetInclude chessboard calibration plate 2 and " L " font scaling board；Above-mentioned " L " font scaling board includes the first plane vertical plate 4 and the second plane vertical plate6, above-mentioned second plane vertical plate 6 after 90 ° of 4 corner of the first plane vertical plate relative to being fixed on the first plane vertical plate 4；Above-mentioned chessboardScaling board 2 is parallel to the first plane vertical plate 4, and is located on front side of the sight of the first plane vertical plate 4 and is fixed on the first plane vertical plate 4On, black and white chessboard grid pattern 8 is placed on above-mentioned chessboard calibration plate 2.
The combined calibrating target of the above structure, chessboard calibration plate 2 are planar panel structure, thereon regular array black and white chessboard trrellis diagramCase 8；In the prior art, video camera is demarcated by the chessboard calibration plate 2 with black and white chessboard grid pattern 8, for example, being based onPosture method of chessboard calibration method and PNP asking acquires the intrinsic parameter of video camera and the outer parameter for arriving chessboard calibration plate, outer parameter hereinFor camera coordinate system to the relative positional relationship (including translation relation and rotation relationship) between chessboard coordinate system.
The scaling board of " L " font of the present embodiment optimizing structure design has the first plane vertical plate 4 as principal mark fixed boardWith the second plane vertical plate 6 of auxiliary scaling board, the second plane vertical plate 6 is perpendicular to the first plane vertical plate 4, the extension of the two connecting partLine is plumb line.Chessboard calibration plate 2 is located at 6 linking part of the first plane vertical plate 4 and the second plane vertical plate on the first plane vertical plate 4The lower section of position.Wherein, the wherein extended line of a black and white separator bar of above-mentioned black and white chessboard grid pattern 8 and above-mentioned first plane are verticalThe extension line overlap of 6 connecting part of plate 4 and the second plane vertical plate.
Laser radar-video camera combined calibrating target of the above structure design, in the feelings that sensor and calibration target do not moveThe combined calibrating that laser radar and video camera are completed under condition can overcome the lower actual use limitation of laser radar angular resolutionProperty, the marginal portion of distance mutation can obtain accurate distance value, have structure simple, the characteristics of low manufacture cost, and fitFor demarcating in batches.
Embodiment two
The present embodiment discloses a kind of laser radar-video camera combined calibrating method, is marked using combining disclosed in embodiment oneTargeting carries out combined calibrating to laser radar-video camera, and calibration target is placed on the field range of two cameras of two video camerasIt is interior, and it is placed on the distance apart from 2 meters of laser radar or so (ranging range of laser radar is 4 meters).Herein, the internal reference of video cameraNumber is demarcated using method in the prior art.
The combined calibrating method comprising the following specific steps
(1) laser radar scanning " L " font scaling board obtains the opposite position between laser radar and " L " font scaling boardSet relationship [R1,T1]。
The specific implementation process of the step is as follows:
S1, the first plane of laser radar continuous scanning vertical plate 4 and the second plane vertical plate 6, can from the first plane vertical plate 4 toSecond plane vertical plate, 6 direction continuous scanning, or from the second plane vertical plate 6 to 4 direction continuous scanning of the first plane vertical plate.Such as figureShown in 2, laser radar from the second plane vertical plate 6 to 4 direction continuous scanning of the first plane vertical plate, the light data of laser radar according toSecondary to beat on the second plane vertical plate 6 and the first plane vertical plate 4, due to laser radar range error, point is beaten in scaling boardOn joint shape be not necessarily the shape of straight line, but at wavy in zonule.It is flat first after laser radar scanningThere are multiple discrete radar points on face vertical plate 4 and the second plane vertical plate 6, acquisition is beaten vertical in the first plane vertical plate 4 and the second planeAll radar points on plate 6.
The first plane of laser radar continuous scanning vertical plate 4 and the second plane vertical plate 6, and the second plane vertical plate 6 is vertically fixedOn the first plane vertical plate 4, discrete radar points are whole to be also presented 90 degree of distributions of turning round.The application is quasi- based on least-squares lineThe legal radar points to be fitted on the first plane vertical plate 4 and the second plane vertical plate 6, the structure design of combined calibrating target, make scoreStraight line of the cloth on the first plane vertical plate 4 and the second plane vertical plate 6 after offline radar points fitting intersects at the linking part of the two.Before fitting a straight line, the point for needing to treat fitting is pre-processed, and is asked conducive to " homing point " on two intersecting straight lines of threshold decisionTopic, i.e., which radar points belongs to the first plane vertical plate, which radar points belongs to the second plane vertical plate.When laser radar is flat from secondWhen face vertical plate 6 is scanned to the first plane vertical plate 4, because scanning only has " L " font scaling board, therefore since laser scanning direction,The place for having barrier for the first time must be the left side of scaling board.It is specifically based on following manner and filters out and belong to the first plane vertical plate 4Radar points and belong to the radar points of the second plane vertical plate 6:
Having N according to the radar points that the length prediction of the second plane vertical plate 6 is beaten on the second plane vertical plate 6, (N is greater than 7Integer) it is a, based on first radar points on least squares line fitting method the second plane vertical plate 6 of fitting, second radarThe N-5 radar points of point ... obtain screening linear equation L3；
The boundary radar between the second plane vertical plate and the first plane vertical plate is determined based on above-mentioned screening straight linePoint, wherein determine that the process for demarcating radar points is,
It calculates and judges whether the N-4 radar points meets the range accuracy of laser radar to the distance of screening straight line:
If the distance of the N-4 radar points to screening straight line L3 meet the range accuracy of laser radar, then the N-4 thunderBelong to the radar points on the second plane vertical plate up to point, continues to judge whether the N-3 radar points be full to the distance of screening straight line L3The range accuracy of sufficient laser radar；Otherwise, the N-4 radar points is boundary radar points；
If the distance of the N-3 radar points to screening straight line L3 meet the range accuracy of laser radar, then the N-3 thunderBelong to the radar points on the second plane vertical plate up to point, continues to judge whether the N-2 radar points be full to the distance of screening straight line L3The range accuracy of sufficient laser radar；Otherwise, the N-3 radar points is boundary radar points；
And so on, until filtering out the boundary radar points between the second plane vertical plate and the first plane vertical plate, positionAll radar points before the boundary radar points are to belong to the radar points of the second plane vertical plate, the radar points and later of demarcatingAll radar points are to belong to the radar points of the first plane vertical plate.
S3 is belonged to all radar points of the first plane vertical plate based on the fitting of least squares line fitting method, obtains firstLinear equation L1；All radar points for belonging to the second plane vertical plate based on the fitting of least squares line fitting method, obtain Article 2Linear equation L2.Being fitted based on least squares line fitting method to multiple discrete points and obtaining fitting a straight line equation is existing skillArt, details are not described herein again.
S4 calculates the intersection point P of straight line and Article 2 straight line.After the equation for obtaining two straight lines, by solving equationIt is the prior art that the mode of group, which obtains two straight-line intersection coordinates, and details are not described herein again.
S5, as shown in figure 3, being determined according to the difference in height between laser radar and " L " font scaling board using intersection point P as origin" L " font scaling board coordinate system.Herein, " L " font scaling board is relative to the height and laser radar on ground relative to groundThe height in face it is known that difference in height i.e. between the two it is known that intersection point P coordinate it is known that the intrinsic parameter coordinate system of laser radarKnow, is based on three above known quantity, " L " font scaling board can be uniquely determined using intersection point P as the coordinate system of origin, it can be with thisUniquely determine the relative positional relationship [R between laser radar and " L " font scaling board1,T1]。
(2) camera shoots chessboard calibration plate, obtains the relative positional relationship [R between video camera and chessboard scaling board2,T2].Herein, the relative positional relationship [R between video camera and chessboard scaling board is obtained based on PNP algorithm in the prior art2,T2]。
(3) the opposite position obtained between chessboard calibration plate and " L " font scaling board is designed according to the structure of combined calibrating targetSet relationship [R3,T3].Herein, based on combined calibrating target structure design, the origin O of chessboard calibration plate be located at intersection point P just underSide, difference in height Δ H between the two2It uniquely determines；Relative positional relationship i.e. between chessboard calibration plate and " L " font scaling board[R3,T3] uniquely determine.
(4) according to the relative positional relationship [R between laser radar determined above and " L " font scaling board1,T1], camera shootingRelative positional relationship [R between machine and chessboard scaling board2,T2] and chessboard scaling board and " L " font scaling board between opposite positionSet relationship [R3,T3], determine the relative positional relationship [R, T] between laser radar and video camera；With this, complete laser radar andThe combined calibrating of video camera.
Laser Lei Fa-video camera combined calibrating method of the invention, can using the combined calibrating target that specific structure designsCombined calibrating quickly is carried out to laser thunder method and video camera, batch is applicable to and demarcates, save calibration cost.Wherein, it usesApproximating method Calibration of Laser radar, accuracy is higher, is more suitable for the combined calibrating of low resolution laser radar.The combined calibrating sideMethod can also be generalized to the combined calibrating of single game scape multi-cam and laser radar.
Embodiment described above is only to absolutely prove preferred embodiment that is of the invention and being lifted, protection model of the inventionIt encloses without being limited thereto.Those skilled in the art's made equivalent substitute or transformation on the basis of the present invention, in the present inventionProtection scope within.Protection scope of the present invention is subject to claims.