CN102914262B - Non-cooperative target abutting measurement method based on additional sighting distance - Google Patents

Abstract

The invention discloses a non-cooperative target abutting measurement method based on additional sighting distance. The non-cooperative target abutting measurement method is combined by two measurement modes of different principles, i.e. a binocular vision measurement mode and a laser ranging mode, wherein the binocular vision measurement mode is a main measurement means for a six-degree-of-freedom parameter of a target relative position and a relative gesture; the laser ranging mode is mainly characterized in that a laser distance meter provides a laser light beam hot spot emitted on a target surface; and then, a Z coordinate of the hot spot to a laser distance meter coordinate system is obtained. Because measurement precision of the laser distance meter on a relatively long distance is far higher than that of the binocular vision measurement, the Z coordinate measured by a tiny fault of the laser distance meter can be used for correcting the Z coordinate obtained by the binocular vision measurement. X and Y coordinate correction can be carried out by relevance among three position coordinates in the binocular vision measurement, so that the three position coordinates of any characteristic point obtained by vision measurement can be corrected so as to improve binocular vision measurement precision, and especially measurement precision of a long-distance target characteristic point is improved.

Description

A kind of noncooperative target based on additional sighting distance presses close to measuring method

Technical field

The present invention relates to and a kind ofly can carry out to the relative position of noncooperative target and relative attitude the method that 6DOF accurately measures.

Background technology

In spacecraft Autonomous rendezvous and docking task, in tens meters of distance ranges before docking, be all the measurement carrying out target relative position and attitude by means of optical imagery sensor at present in the world.Therefore Installation Mark lamp or reverberator on passive space vehicle is needed, on intersection spacecraft, the equipment that installs and measures is measured it, by setting up target-based coordinate system and surving coordinate system, relative position between them and attitude relation is established through demarcating, and the relation between monumented point position and each coordinate system, then calculate 6 the degree of freedom kinematic parameters of target relative to surving coordinate system via the extraction of monumented point picture with distribution.Tens meters of measurement ranges to sub-rice are covered in order to make measuring system, the measuring technique of current space industry is limited to the measurement to cooperative target, adopt active target generator or passive corner reflector as cooperative target, adopt monocular camera can complete the position measurement of relative 6 degree of freedom of target.But, for noncooperative target, without any the mark installed in advance on it, to complete aforesaid spacecrafts rendezvous, the known measuring object of the identification light or reverberator and so on of certain space distribution just can not be adopted as reference target.Carry out spacecrafts rendezvous measurement for noncooperative target, in order to make measuring system cover tens meters of measurement ranges to sub-rice, current space flight still among exploration, does not have very proven technique in this technical field.

The principle utilizing Binocular vision photogrammetry target signature point relative position is ripe, as in April, 2003 Xu Gang cutting edge of a knife or a sword at Vol.32, in the article " movement parameter measurement based on binocular vision model " delivered in No.2 " infrared and laser engineering ", mention binocular measurement point object module, to derive error analysis formula, the error of visible Binocular vision photogrammetry is the inherent error brought by model, along with the increase of distance is in square relation with increase, therefore when Binocular vision photogrammetry baseline is certain, measuring accuracy declines rapidly with distance, the EFFECTIVE RANGE of binocular vision is caused to be very limited, distant object can not be measured.How to reduce measuring error, break the restriction that binocular Measuring error model medial error increases with square distance, make the impact point measuring error of far and near distance be all the key issue of biocular systems expanded application in less level.At present substantial breakthrough be there is no both at home and abroad for this problem.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, provide a kind of binocular measuring method based on additional sighting distance, can on-line proving sighting distance, thus correct the position coordinates that stereoscopic vision calculates, improve the precision measured, the tracking stability of measurement point can be improved simultaneously.

Technical solution of the present invention is: a kind of noncooperative target based on additional sighting distance presses close to measuring method, and step is as follows:

(1) install on the same direction of the intersection spacecraft of distance noncooperative target certain distance at least a set of binocular vision camera to a laser range finder, wherein laser range finder is positioned at the right centre position of binocular vision camera, and the laser beam exits direction of laser range finder is in binocular vision camera on the Bisector of angle of two camera optical axises in optical axial plane;

(2) utilize target to demarcate with laser range finder binocular vision camera, obtain the transformational relation of laser range finder surving coordinate system and any one vision camera surving coordinate system of binocular vision camera centering;

(3) laser range finder gives off laser beam to noncooperative target, noncooperative target forms hot spot, obtain the distance between laser range finder and noncooperative target, utilize binocular vision camera to carrying out imaging to described hot spot simultaneously simultaneously, obtain the three-dimensional coordinate of hot spot in vision camera surving coordinate system;

(4) transformational relation utilizing the distance between the laser range finder obtained and noncooperative target and step (2) to obtain, first to binocular vision camera to the flare three-dimensional coordinate middle distance obtained to coordinate revise, then binocular vision camera is revised the coordinate of all the other both directions in the flare three-dimensional coordinate obtained;

(5) obtain the 6DOF measuring amount of noncooperative target, wherein three position coordinateses are the result that step (4) is revised, and three attitudes are based on the right Attitude Calculation result of the binocular vision camera of three position correction results.

In described step (4) to binocular vision camera to the method that the flare three-dimensional coordinate obtained is revised be: utilize binocular vision camera to measure the distance of the laser spots that laser range finder sends, and compare with the distance that laser range finder exports, obtain distance to correcting value, then utilize distance to correcting value all the other both directions are corrected, the further feature point position simultaneously obtained for binocular vision camera pair and laser facula also adopts laser facula distance to correct to correcting value; Or adopt the mode of matching, each distance of carrying out required scope on ground carries out first time curve to position for the measuring error of Binocular vision photogrammetry camera, then to first time curve residual error again carry out matching, complete the correction to three-dimensional coordinate; Or adopt the mode of matching, adjust the distance in the process that space draws near and carry out segmentation, progressively obtain the range data of each section, error fit is carried out in segmentation, completes the correction to three-dimensional coordinate.

The present invention's advantage is compared with prior art: the inventive method with accurate laser range finder distance to position measurements correction two CCD camera measure system for distance to measured value, breach the square distance increasing law of traditional binocular vision measurement system for aiming spot measuring error, and utilize distance to measured value and vertical range to the algebraic relation between measured value, make three coordinate direction errors in position measurement values of far and near distance in ranging balanced, and significantly reduced, improve omnidistance measuring accuracy.The inventive method does not need the cooperation measurement target of picture identification light and reverberator and so on as utility appliance, the condition of spacecrafts rendezvous can be reduced, be suitable for arresting with completely unknown target spacecrafts rendezvous, but the inventive method is still feasible when there is cooperation measurement target, the vision measurement system of a pair binocular camera composition can be adopted to carry out the identification of unknown object feature and three coordinates are determined at super close distance, and then the measurement carrying out three-dimensional relative attitude is determined.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the inventive method;

Fig. 2 is the process flow diagram of the inventive method;

Fig. 3 is the schematic diagram utilizing the error of laser range finder to two CCD camera measure system to correct in the inventive method;

Fig. 4 is binocular imaging error analysis schematic diagram;

Fig. 5 is the matched curve of binocular measuring error data in the embodiment of the present invention;

Fig. 6 is wide lubber line error comparison diagram in the embodiment of the present invention;

Fig. 7 is wide baseline correction result in the embodiment of the present invention.

Embodiment

As shown in Figure 1, for the schematic diagram of the inventive method, there is shown two groups of binocular vision cameras pair, when realizing method of the present invention, only need one group of binocular vision camera to, but in order to improve the precision of measurement, two groups of even many group binocular vision cameras can be selected (use according to concrete segmentation, measure), each group binocular vision camera to all independent as measuring sensor (i.e. each group binocular vision camera between there is no contact), following methods in describing also only for one group of binocular vision camera to being described.

Binocular vision camera is installed head for target, makes it to keep certain angle between optical axis, and corner dimension is determined mainly to require to determine from meeting binocular intersection visual field, measuring distance scope, target sizes etc.Laser range finder is positioned at binocular vision camera and installs centre position, and laser beam exits direction is in binocular vision camera on the Bisector of angle of two camera optical axises in optical axial plane, and error is not more than 1/10 of its angle.In addition, in order to increase the sharpness of camera imaging, can increase active illumination system, to provide the operating spectral the illumination meeting camera exposure amount that cover vision camera, the change that active illumination system can adapt to measuring distance is divided into many grades of luminous intensities to control.In addition, active illumination system can be 1 group, also can be many groups, and installation site in the middle of baseline, also near each vision camera, also can can adopt distributed mounting means.

During measurement, relate to following coordinate system:

Laser range finder surving coordinate system O ₀x ₀y ₀z ₀: initial point O ₀be positioned on generating laser outgoing beam axle, and on laser range finder range zero point (determining by demarcating).O ₀z ₀direction of principal axis is consistent with outgoing beam axle, towards exit direction.O ₀x ₀axle is perpendicular to O ₀z ₀, direction is in face of O ₀z ₀towards the right side.O ₀y ₀right-handed system is become with front diaxon.

The left camera image coordinates system u of binocular vision _lp _lv _l: initial point p _lbe positioned at image planes detector upper left angle point pixel center, transverse axis p _lu _loverlap with detector the first row center line and meet target to the right, longitudinal axis p _lv _loverlap with left several first row center line and meet target down.

The right camera image coordinates system u of binocular vision _rp _rv _r: initial point p _rbe positioned at image planes detector upper left angle point pixel center, transverse axis p _ru _roverlap with detector the first row center line and meet target to the right, longitudinal axis p _rv _roverlap with left several first row center line and meet target down.

The left camera surving coordinate system O of binocular vision _lx _ly _lz _l: initial point O _lbe positioned at the center of detector center pixel, O _lz _ltarget is pointed to, O perpendicular to detector sensitive area _lx _land O _ly _lrespectively with p _lu _land p _lv _lparallel and direction is consistent.

The right camera surving coordinate system O of binocular vision _rx _ry _rz _r: initial point O _rbe positioned at the center of detector center pixel, O _rz _rtarget is pointed to, O perpendicular to detector sensitive area _rx _rand O _ry _rrespectively with p _ru _rand p _rv _rparallel and direction is consistent.

World coordinate system O _wx _wy _wz _w: initial point O _wfor arrange in measurement field a bit, three change in coordinate axis direction and O _lx _ly _lz _lor O _rx _ry _rz _rthree change in coordinate axis direction consistent.

Generally, world coordinate system overlaps with binocular vision left camera surving coordinate system, binocular vision right camera surving coordinate system.

Measuring method reality of the present invention is combined by the metering system of two different principle, one is Binocular vision photogrammetry mode, this is the main measurement means of 6 degree of freedom parameters of target relative position and relative attitude, another is laser ranging mode, mainly provide a laser beam speck beaten on the target surface by laser range finder, then obtain the Z coordinate of speck to laser range finder coordinate system.Because the measuring accuracy at relatively distant location laser range finder is far away higher than Binocular vision photogrammetry, the Z coordinate that the Z coordinates correction that therefore slight error of available laser stadimeter is measured is obtained by Binocular vision photogrammetry.Again by the relevance in Binocular vision photogrammetry between three position coordinateses, carry out X, Y-coordinate corrects, three position coordinateses of the arbitrary characteristics point that vision measurement is obtained all are corrected, thus improve the precision of Binocular vision photogrammetry, especially improve the measuring accuracy of distant location target signature point, flow process as shown in Figure 2.

Therefore, before measuring, need the relative coordinate relation known between laser range finder and vision camera, namely need to demarcate laser range finder surving coordinate system.Here suppose that laser range finder only has a laser beam, and coordinate is positioned at the center of baseline.Timing signal can adopt gridiron pattern target to carry out, and its principle is at the z along laser range finder ₀direction of principal axis selects three distances, places gridiron pattern target successively, then calibrates the coordinate relation between vision camera surving coordinate system and gridiron pattern target, obtain the coordinate relation between vision camera surving coordinate system and laser range finder surving coordinate system thus again.

Target is at laser range finder surving coordinate system o ₀-x ₀y ₀z ₀under position relationship known, therefore directly can obtain the laser coordinate of each lattice angle point on gridiron pattern target.In addition, can extract from the image of vision camera and calculate the coordinate of each angle point of target under camera image coordinates system, be converted into the three-dimensional coordinate under camera surving coordinate system again, the transition matrix between laser range finder surving coordinate system and vision camera surving coordinate system can be calculated according to these coordinates.

Suppose that target has N number of demarcation angle point, at laser coordinate system o ₀-x ₀y ₀z ₀that descends N number of demarcation angle point can be expressed as matrix P,

$P=\left[\begin{array}{cccc}{x}_1& x_2& ...& x_N\\ y_1& y_2& & y_N\\ z_1& z_2& & z_N\\ 1& 1& ...& 1\end{array}\right]$

At the left camera surving coordinate system o of binocular vision _l-x _ly _lz _lthat descends N number of demarcation angle point can be expressed as matrix P ₁,

$P_l=\left[\begin{array}{cccc}{x}_{l1}& x_{l2}& ...& x_{\mathrm{lN}}\\ y_{l1}& y_{l2}& & y_{\mathrm{lN}}\\ z_{l1}& z_{l2}& & z_{\mathrm{lN}}\\ 1& 1& ...& 1\end{array}\right]$

Transformational relation during rectangular coordinate system conversion between unique point coordinate is as follows,

$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]=\left[\begin{array}{ccc}{r}_{11}& r_{12}& r_{13}\\ r_{21}& r_{22}& r_{23}\\ r_{31}& r_{32}& r_{33}\end{array}\right]\left[\begin{array}{c}{x}_l\\ y_l\\ z_l\end{array}\right]+\left[\begin{array}{c}{t}_1\\ t_2\\ t_3\end{array}\right]$

Wherein, r _ijthe element of transformation matrix, t _iit is the translational movement of three-dimensional coordinate.i＝1，2，3；j＝1，2，3。Above formula is written as homogeneous form, can obtains:

$\left[\begin{array}{c}x\\ y\\ z\\ 1\end{array}\right]=\left[\begin{array}{cccc}{r}_{11}& r_{12}& r_{13}& t_1\\ r_{21}& r_{22}& r_{23}& t_2\\ r_{31}& r_{32}& r_{33}& t_3\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_l\\ y_l\\ z_l\\ 1\end{array}\right]$

If the transformation matrix between binocular vision left camera surving coordinate system and laser range finder surving coordinate system is M, being written as matrix form is

P＝M·P _l

Use least square method, can M be obtained,

M·P _lP _l ^T＝PP _l ^T

In order to ensure P ₁p ₁ ^treversible, point set must not be coplanar.Therefore in actual tests process, target provides 48 angle points, and three different distance are measured, and obtains 144 not coplanar angle points altogether.From calibration principle, the degree of accuracy of the position that target is placed has impact to stated accuracy.Measure the M that obtains can be used for laser range finder measurement data be transformed into Binocular vision photogrammetry coordinate system under coordinate so that calibration measurements error.

Laser range finder not only can measurement target to the distance of laser range finder surving coordinate system, and the hot spot that the laser beam of laser range finder projects on the target surface can use as the artificial feature point that binocular vision camera is right, this hot spot is imaging on the camera focal plane, two, left and right that camera is right respectively, by the conversion of camera image coordinates system and camera surving coordinate system, and the binocular camera known is for the feature extraction of this hot spot and binocular locus point computation, can determine this hot spot in vision camera to the coordinate in surving coordinate system.

Utilize additional sighting distance (the measuring distance value that laser range finder obtains) to have two kinds of methods for the measuring error correction of Binocular vision photogrammetry, one is direct correction method, and one is error fit method.

Utilize additional sighting distance (the measuring distance value that laser range finder obtains) as follows for the direct correction principle of measuring error of Binocular vision photogrammetry:

For pure two CCD camera measure system, still there is larger systematic error to the measurement of unique point after demarcating in vision camera, its Changing Pattern and Measuring error model coincide, and the measuring error of Z-direction is quafric curve rule.Therefore after vision camera is demarcated, also need to correct the measuring error of Binocular vision photogrammetry, utilize the method for curve to calculate the Changing Pattern of error, correct in measurement result exports.By verification experimental verification, after error correction, measuring accuracy will improve greatly.But aircraft in-orbit when, the correction carrying out systematic error has difficulties, therefore the inventive method proposes to utilize laser ranging to carry out error on-line correction as additional sighting distance to system: the distance measuring the laser spots that laser range finder sends with binocular vision system, the distance exported with laser range finder compares, obtain correcting value, thus other unique point coordinate is corrected, flow process is as shown in Figure 3.

Suppose that the actual range of laser spots is Z _i, for laser facula distance, the result of Binocular vision photogrammetry is D _c(Z _i), the reading i.e. additional sighting distance of laser range finder is D _l(Z _i), then correcting value b ₀(Z _i) be

b ₀(Z _l)＝D _C(Z _i)-D _L(Z _i)

For the further feature point of catching with laser facula simultaneously, all b can be adopted ₀(Z _i) correct, the distance D of the jth unique point that binocular vision camera exports _cj(Z _i), the value D ' after its correction _cj(Z _i) be

D _Cj(Z _i)＝D′ _Cj(Z _i)-b ₀(Z _i)

Be more than by additional sighting distance correct each unique point in a Binocular vision photogrammetry at surving coordinate system O _lx _ly _lz _lunder the method for Z coordinate vision determination error, the X under this coordinate system, Y-coordinate corrects by imaging model formulae discovery out, and method is as follows.

As shown in Figure 4, for z in Binocular vision photogrammetry _wthe correction in direction is completed, as mentioned above, for x by the additional sighting distance of laser range finder _w, y _wdirection position coordinates measurement update is by itself and z _wrelation corrected.In figure symbology points to the direction vector in the page; Y in figure _waxle points in the page by right-handed system rule; Two vision camera horizontal positioned, in same level, i.e. photocentre O _land O _ry coordinate identical; World coordinate system initial point is the projection centre of left camera, X _land X _rfor horizontal axis in image planes, Y _land Y _rfor the vertical coordinate axle in image planes, and coordinate axis y _win the same way; The focal length of two cameras is f ₁and f ₂, the angle of optical axis and x-axis is α ₁and α ₂, ω ₁and ω ₂for the projected angle of object point P, B is the parallax range between two camera subpoints, and the three-dimensional coordinate that can be obtained spatial point P by geometric relationship is:

$\left\{\begin{array}{c}{x}_w=z_w\·\cot ({\mathrm{\ω}}_1+{\mathrm{\α}}_1)\\ y_w=Y_l\frac{z_w\·\cos {\mathrm{\ω}}_1}{f_1\sin ({\mathrm{\ω}}_1+{\mathrm{\α}}_1)}=Y_r\frac{z_w\·\cos {\mathrm{\ω}}_2}{f_2\sin ({\mathrm{\ω}}_2+{\mathrm{\α}}_2)}\\ z_w=\frac{B}{\cot ({\mathrm{\ω}}_1+{\mathrm{\α}}_1)+\cot ({\mathrm{\ω}}_2+{\mathrm{\α}}_2)}\end{array}\right.$

From computing formula, when the additional sighting distance of utilization makes z _wmeasuring error reduce time, x _w, y _wthe measuring error of position coordinates also decreases.Namely z is corrected _wmeasuring error, also just corrects x simultaneously _w, y _wmeasuring error.

Utilize additional sighting distance (the measuring distance value that laser range finder obtains) as follows for the measuring error fitting correction principle of Binocular vision photogrammetry:

The method that vision measurement system error relies on additional sighting distance to correct is realized by the matched curve of error measuring value, can carry out online fitting correction by two kinds of approach.

The online fitting of the first corrects approach principle and is: the Curve of the Measuring Error fitting correction of additional sighting distance for Binocular vision photogrammetry camera carrying out required separation distance scope in ground experiment room, be called that first time corrects, residual error after correction still has certain regularity, second time carries out residual error fitting correction, can reduce measurement residual error further, secondary correction can realize by on-line correction.

The online fitting of the second corrects approach principle and is: in the process drawn near, be progressively obtain each positional distance data, instead of carry out matching to total data after obtaining all measurement data in ground experiment.Therefore online fitting algorithm needs segmentation to carry out.Such as, in the scope of 15m-10m, obtain sighting distance and the binocular measurement result of laser spots, calculate the interior measuring error that goes beyond the scope, and matching is carried out to this part data, after obtaining fitting result, according to fitting parameter, error correction is carried out to further feature point; When continuing close to target from 10m, along with the increase of sampled data, its fitting result also will be more accurate.

Embodiment

As shown in Figure 1, the baseline of Long baselines binocular measuring system (the first binocular vision camera to) is longer, is positioned at both sides; The baseline of Short baseline binocular measuring system (the second binocular vision camera to) is shorter, is positioned at middle part.Two cover binocular measuring systems are installed on the platform of maneuverable spacecraft, space layout can adjust as required, as long as determine mutual alignment relation through strict demarcation between the surving coordinate system of often overlapping binocular measuring system, double-basis line binocular measuring system can by data handling system collection image stores processor separately, data handling system can adopt the flush bonding processor of DSP similar functions, and common computer also can be adopted to carry out work.The data processor mount message process software of double-basis line two CCD camera measure system, this software has measuring system demarcation, image procossing, target signature identification and extraction, the extraction of target relative position and attitude information, camera control, Lighting control, the function such as systems axiol-ogy and autonomous operation control.

Long baselines and Short baseline binocular measuring system are arranged on maneuvering satellite platform, overlapping region, two one camera visual fields should cover measured noncooperative target, optical axis has certain angle so that the expansion of overlapping region, visual field, this angle is conducive to more greatly the expansion of overlapped fov, but can measuring accuracy be reduced, therefore should compromise selected, generally within 15 °, in particular cases can more than 15 °.Its space layout's mode can be rearranged according to actual needs on this basis, baseline as right in Short baseline camera and Long baselines camera between baseline angle 0 ° to 180 ° angle can be become, also can before and after staggered layout, should ensure that in various layout camera visual field is not separately blocked, and calibrate the transformational relation between different baseline system surving coordinate system.Camera focus and field angle require to determine according to measuring accuracy, and relative aperture determines that being no more than 4 times of depths of focus according to the defocusing amount caused in distance measurement ranges is that criterion is carried out.

As an application example, choose measuring system technical indicator herein as follows:

(1) position measurement distance range: 20m ~ 0.5m

Closely one camera field angle range of choice: (40-70) °

Long distance one camera field angle range of choice: (20-40) °

(2) binocular base length range of choice

Low coverage (second) binocular: 0.3m ~ 1m

Long distance (first) binocular: 1.5m ~ 2m

(3) positional accuracy measurement: 0.01m ~ 0.5m

(4) Data Update frequency: 1 ~ 10Hz

(5) rotation angle measuring accuracy: 1 ° ~ 3 °

(6) target size: 2m × 2m × 2m

(7) spin angle velocity term of reference: 0.5 ~ 2 °/s

(8) roll rate measuring accuracy: 0.2 ~ 0.5 °/s

According to above technical requirement, the design parameter of wide baseline binocular camera is defined as:

Focal length: 45mm

Field angle: 30 ° × 30 °

Relative aperture: 1/2 ~ 1/8

Frame per second: 5Hz

Base length: 2m

Optical axis included angle: 8 °

According to above technical requirement, the design parameter of Short baseline binocular camera is defined as:

Focal length: 29mm

Field angle: 46 ° × 46 °

Order is to aperture: 1/2 ~ 1/8

Frame per second: 5Hz

Base length: 0.5m

Optical axis included angle: 8 °

According to above technical requirement, the design parameter of laser range finder is defined as:

(1) operating distance: 100m ~ 0.5m;

(2) repetition frequency: 10Hz;

(3) optical maser wavelength: 650nm;

(4) distance accuracy 1mm (σ);

Above data are the tradeoff design results according to all technical requirement optimization and demonstration gained such as accuracy requirement, field coverage, measuring distances.

The first on-line correction method is direct correction, does not need ground measurement data in advance, and the additional sighting distance directly adopting laser ranging to obtain directly corrects, as mentioned above.

The second on-line correction method is fitting correction, and the first approach is wherein based upon on the basis that the omnidistance multimetering in ground demarcates, and obtains surveying omnidistance multimetering graph of errors, through once or quadratic fit eliminate systematic error.Wherein the second approach is set up on the basis of On-line multi-point measurement matching, along with the increase fitting precision of measurement point improves thereupon, finally reaches the precision similar to the first matching approach.

According to above technical scheme, ground simulation demonstration test is carried out for the first approach of the second on-line correction method, from ground test result, not proven its error of measurement result is larger, and increase according to quafric curve, the distance error of 5m at about 50mm, 10m time then rise to about 250mm.When carrying out systematic error demarcation, additional sighting distance may be used for the calibration to measuring.

Adopt the inventive method, first treatment and analysis is carried out to wide baseline case.Can systematic error be calculated according to the raw data of vision system to the range observation of dummy satellite unique point, see form 1

The wide baseline system error of form 1

Centre distance (mm)	Systematic error e S(mm)
		3700	-10.8
4000	-3.1
		4300	6.1
4600	5.3
		4900	17.3
5100	21.5
		5400	30.5
5700	26.6

6000	42.1
		6300	46.0
6600	62.5
		6800	59.5
7100	65.2
		7400	91.3
7700	106.0
		8000	113.8
8500	134.4
		9000	163.6
9500	193.7
		10200	230.2

As shown in Figure 5, be the z-axis range observation error of binocular measuring system in figure, binocular camera parallax range is about 2m to the binocular measuring error that test obtains.

The measurement result of wide baseline system to laser spots sees the following form.

Under the wide baseline of form 2, laser spots is measured

Wherein correcting value b is calculated by the difference of figure survey error and photometric error.Its rule is consistent with systematic error, sees Fig. 6.As can be seen from the figure, systematic error, figure survey error, the Changing Pattern of correcting value three is consistent, and correcting value is surveyed error substantially overlap with figure, is at this moment far smaller than because of laser error the reason that figure surveys error.

The measurement data at distance 10200mm, 6800mm and 3700mm tri-place is taken out analysis separately below.

Form 3 corrects result (mm) apart from 10200mm place

Form 4 corrects result (mm) apart from 6800mm place

Form 5 corrects result (mm) apart from 3700mm place

As can be seen from data, at 10200mm place, figure surveys error 230mm, and after correcting, error is-20mm; At 3700mm place, figure surveys error-11mm, is about 2mm after correction.After correcting, error reduces greatly.Can find, under same distance, it is also discrepant that each unique point must be schemed to survey between error simultaneously.

Error (mm) after form 6 figure surveys error and corrects

Its curve distribution as shown in Figure 7, is found out from test findings, and as distance < 5m, additional sighting distance corrects substantially identical with the error of image measurement, within 20mm; When after distance > 5m, the result that additional sighting distance corrects maintains within 20mm substantially, and figure survey error increases rapidly, exceeds 200mm.Therefore, after the correction of additional sighting distance, measuring accuracy improves greatly.

The content be not described in detail in instructions of the present invention belongs to the known technology of those skilled in the art.

Claims (1)

1. the noncooperative target based on additional sighting distance presses close to a measuring method, it is characterized in that step is as follows:

(1) install on the same direction of the intersection spacecraft of distance noncooperative target certain distance at least a set of binocular vision camera to a laser range finder, wherein laser range finder is positioned at the right centre position of binocular vision camera, and the laser beam exits direction of laser range finder is in binocular vision camera on the Bisector of angle of two camera optical axises in optical axial plane;

(2) utilize target to demarcate with laser range finder binocular vision camera, obtain the transformational relation of laser range finder surving coordinate system and any one vision camera surving coordinate system of binocular vision camera centering;

(3) laser range finder gives off laser beam to noncooperative target, noncooperative target forms hot spot, obtain the distance between laser range finder and noncooperative target, utilize binocular vision camera to carrying out imaging to described hot spot simultaneously, obtain the three-dimensional coordinate of hot spot in vision camera surving coordinate system;

(4) transformational relation utilizing the distance between the laser range finder obtained and noncooperative target and step (2) to obtain, first to binocular vision camera to the flare three-dimensional coordinate middle distance obtained to coordinate revise, then binocular vision camera is revised the coordinate of all the other both directions in the flare three-dimensional coordinate obtained; To binocular vision camera to the method that the flare three-dimensional coordinate obtained is revised be: utilize binocular vision camera to measure the distance of the laser spots that laser range finder sends, and compare with the distance that laser range finder exports, obtain distance to correcting value, then utilize distance to correcting value all the other both directions are corrected, the further feature point position simultaneously obtained for binocular vision camera pair and laser facula also adopts laser facula distance to correct to correcting value; Or adopt the mode of matching, each distance of carrying out required scope on ground carries out first time curve to position for the measuring error of Binocular vision photogrammetry camera, then to first time curve residual error again carry out matching, complete the correction to three-dimensional coordinate; Or adopt the mode of matching, adjust the distance in the process that space draws near and carry out segmentation, progressively obtain the range data of each section, error fit is carried out in segmentation, completes the correction to three-dimensional coordinate;

(5) obtain the 6DOF measuring amount of noncooperative target, wherein three position coordinateses are the result that step (4) is revised, and three attitudes are based on the right Attitude Calculation result of the binocular vision camera of three position correction results.