CN101916457B - Datum body for acquiring three-dimensional point cloud data and point cloud synthesis method - Google Patents

Abstract

The invention discloses a datum body used for acquiring three-dimensional point cloud data, which comprises a base, a support shaft perpendicular to the base is fixed in the center of the base, the support shaft is provided with at least two metal balls arranged up and down, and the two balls are fixed and welded together through a connecting shaft; the surfaces of the balls are provided with sand blasting layers. The invention also provides a method for synthesizing a complete three-dimensional point cloud image by using the datum body to determine a central rotating shaft of a rotating table and splicing local three-dimensional point clouds according to the calculated central rotating shaft. The three-dimensional point cloud data acquired through the datum body has high density and low loss, the method for synthesizing the three-dimensional point clouds has high speed and high synthesis accuracy, and the synthesized image is clear and complete and has no double image.

Description

Three dimensional point cloud obtains the benchmark body and the point cloud synthesis method of usefulness

Technical field

The present invention relates to Computerized 3 D visual scanner uni detection technique field, be specifically related to benchmark body and point cloud synthesis method that a kind of three dimensional point cloud obtains usefulness.

Background technology

Obtaining of three dimensional point cloud just is meant the morphosis that obtains object by the three-dimensional digital technology, high-precision cloud data can show the three-dimensional configuration feature of testee preferably, in mould and product developments such as automobile, five metals household electrical appliances, aviation, potteries, rapid prototypings such as antique, handicraft, sculpture, portrait goods are made, and mechanical configuration design, medical science lift face, body configuration make, body shape is measured and all there is important use in phytomorph field such as obtain.

Than routine in the acquisition methods of cloud data is to utilize three-dimensional laser scanner to obtain three dimensional point cloud.Though it is more flexible that this method is obtained data, can obtain final some cloud in the scan edge limit, but the defective of this technical scheme is when the object that obtains than complex appearance, acquisition speed is slow, obliterated data is many, the some cloud is sparse and cloud data that obtain does not have color, is unfavorable for the aftertreatment such as synthetic grade of three dimensional point cloud.Another kind of acquisition methods is the structured light method, being about to light that the projector sends forms forms such as point, line, coding pattern and invests scenery through optical system, on scenery, form pattern and absorb by video camera, then calculate, obtain the depth image on scenery surface according to trigonometry and sensor construction parameter, further calculate the D coordinates value of object plane by image.

Appoint that minister in ancient times, Diao Changyu, east in Shandong Province are bright, Liu Gang is in document " based on the historical relic three-dimensional reconstruction of structured light " (Dunhuang research, 2005,93 (5): disclose a kind of three-dimensional reconstruction system 102-106) based on the projection coded structured light, its principle is based on structured light and rebuilds, one group of structured light of projection changes the 3D shape of extracting object by analyzing the projection of different coding structured light on object in three-dimensional scenic; 3 D scanning system based on the structured light principle generally is made up of following several parts: numerical control rotating platform, high-precision three-dimensional texture information obtain terminal, three-dimensional data process computer, three-dimensional information acquisition terminal, three-dimensional information acquisition software.Method by the synthetic three-dimensional point cloud of this system is that object is placed on the numerical control rotating platform, obtains the cloud data of different angles, uses reference point method then, and the some cloud of different angles is spliced synthetic complete three-dimensional point cloud.Though the some cloud precision of certain angle that this method obtains each time is very high, the precision of numerical control rotating platform is also very high, but its defective part is, because last the employing synthesized a complete three-dimensional point cloud by hand, during objects such as therefore synthetic some complex object such as live plant, the precision of synthetic three-dimensional point cloud is lower.

The dragon imperial or royal seal, Zhong Yuexian, Li Renju, by the will good fortune at document " the three-dimensional splicing technology of structural light three-dimensional scanning survey " (Tsing-Hua University's journal (natural science edition), 2002,42 (4): 477-480) also disclose a kind of new three-dimensional splicing technology, promptly utilize a stepper motor driven rotary table that the point cloud data of different visual fields is carried out the data stitching, so that complete piece surface three-dimensional information to be provided, but this article does not provide concrete definite method of rotary table rotating shaft, and also only propose to use reference point method, and in its practice, depending merely on naked eyes and mouse seeks and definite reference point in a cloud, He Cheng three-dimensional point cloud precision is lower at last, often has tangible ghost image.

Summary of the invention

The invention provides the benchmark body that a kind of three dimensional point cloud obtains usefulness, be used for determining the central rotating shaft of rotary table, solved in the prior art with the synthetic lower and incomplete problem of three-dimensional point cloud precision of reference point method.

A kind of three dimensional point cloud obtains the benchmark body of usefulness, comprises base, and described base center fixation has the back shaft perpendicular to base, and back shaft is provided with up and down the spheroid of at least two metals placing, fixedlys connected by coupling shaft between spheroid and the spheroid; Described spherome surface has the sandblast layer.

The spherical profile degree of described spheroid is 0.05, and surfaceness is 3.2～6.3.

Described ball material is selected a kind of in bearing steel, ferroalloy, the cast iron for use.

Preferably, described spheroid quantity is more than two or three.

Benchmark body among the present invention does not require the inner structure of spheroid, the general solid sphere that adopts gets final product, but there is very high requirement on the surface to spheroid, mainly comprise these two parameters of spherical profile degree and surfaceness, wherein the spherical profile kilsyth basalt is levied the machining precision of spheroid, surfaceness characterizes the surface treatment effect of spheroid, and both all are the principal elements that influence the three-dimensional point cloud synthetic effect.Therefore, the present invention adopts blasting craft that blasting treatment is carried out in the metal surface of spheroid, make the spheroid after handling to keep original machining precision of metal ball body, can overcome again when the metal material processing precision is higher, spherome surface is too bright and clean, is unfavorable for obtaining in the mode of structured light the technological deficiency of spheroid outline point cloud.The spheroid of surface after blasting treatment among the present invention, its spherical profile degree is 0.05, and surfaceness is 3.2～6.3, and it is better to make that the three dimensional point cloud of spheroid profile obtains effect, helps the synthetic processing of three-dimensional point cloud.

Blasting craft adopts prior art, promptly adopting pressurized air is power, to form the high velocity jet bundle, the appearance of surface of the work or shape are changed with the surface of material spray (copper ore, silica sand, emery, iron sand, extra large sand) high velocity jet to pending workpiece; Because abrasive material is to the impact and the shear action of surface of the work, make the surface of workpiece obtain certain cleanliness and different roughness, the mechanical property of surface of the work improves, therefore improved the fatigue resistence of workpiece, increase the adhesion between workpiece and the coating, prolong the permanance of filming, also helped the levelling and the decoration of coating.

The present invention also provides a kind of central rotating shaft that utilizes the said reference body to determine turntable, carries out the synthetic method of three-dimensional point cloud, has solved that prior art mid point cloud aggregate velocity is slow, reference point is difficultly looked for, the synthetic low excessively problem of precision.

Owing to adopt different spheroids in the synthetic processing of later stage three-dimensional point cloud, the point cloud composition algorithm of two spheroids and three and three some cloud composition algorithms with upper sphere are had any different, so the main just two ball benchmark bodies of the some cloud composition algorithm among the present invention and two kinds of structures of three ball benchmark bodies are illustrated.

A kind of point cloud synthesis method mainly may further comprise the steps:

(1) the benchmark body is placed on accurately controls on the turntable of rotational angle, scan the benchmark body with the three-dimensional structure photoscanner;

(2) turntable whenever turn 90 degrees run-down, and the cloud of selecting that obtains an angle of sphere is a partial sphere millet cake cloud, and accumulative total scans and obtains laying respectively at up and down two groups of squares, four groups of partial sphere millet cake clouds on totally 8 summits for four times, and calculates the central rotating shaft of turntable;

(3) determinand is placed on precision controls on the turntable of rotational angle, with three-dimensional structure photoscanner scanning determinand, turntable revolution single pass once, the anglec of rotation of turntable can be adjusted according to different determinands, scanning obtains several three dimensional point clouds;

(4) utilize step (2) to calculate the turntable central rotating shaft of gained, the three dimensional point cloud that scanning in the step (3) is obtained splices, synthetic complete three-dimensional point cloud.

The central rotating shaft computing method of described step (2) intermediate station are as follows:

1) according to the partial sphere millet cake cloud of each scanning, calculate the centre of sphere of each spheroid, each scanning can obtain two centre ofs sphere up and down, and four scanning can obtain two groups of four centre ofs sphere that are positioned at 4 summits of a square up and down;

2) connect the centre of sphere of the upper sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

3) connect the centre of sphere of the lower sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

4) calculate the intersection of diagonal A (x of two pairs of intersections up and down _a, y _a, z _a) and B (x _b, y _b, z _b);

5) tie point A and some B obtain the central rotating shaft of turntable.

In like manner, when three ball benchmark bodies calculate according to the central rotating shaft computing method of above-mentioned turntable, can obtain a plurality of points on the central rotating shaft, this moment, a plurality of points were equivalent to the fitting a straight line calculating of limited three-dimensional space point to the calculating of rotating shaft, this algorithm can adopt attacks poplar at document " a kind of method of space line match " (Qiqihar University's journal, 2009,25 (2): the algorithm that proposes 64-67).

" the synthetic complete three-dimensional point cloud " of step in the point cloud synthesis method of the present invention (4) promptly gives directions the calculating of rotating around dead axle, algorithm can adopt Sun Jiaguang, long works " the computer graphics " (publishing house of Tsing-Hua University that is valued for of poplar, May nineteen ninety-five the 2nd edition, ISBN 7-302-01708-5/TP.746, P346-348) the middle algorithm that proposes.

Three dimensional point cloud provided by the invention obtains the benchmark body of usefulness, and the metal surface of machining precision height and spheroid is through blasting treatment, and the three dimensional point cloud that makes the structured light method obtain is intensive and lose fewly, is beneficial to synthetic processing of three-dimensional point cloud in later stage.

The present invention determines the central rotating shaft of rotary table by the benchmark body, splice partial 3 d point cloud according to the central rotating shaft that calculates, and synthesize complete image, adopt that this method is carried out a cloud fast, synthetic precision height of aggregate velocity when synthetic, synthetic clear picture is complete and do not have ghost image.

Description of drawings

Fig. 1 obtains the structural representation of the benchmark body of usefulness for three dimensional point cloud among the present invention.

Fig. 2 obtains the another kind of structural representation of the benchmark body of usefulness for three dimensional point cloud among the present invention.

Fig. 3 is the schematic flow sheet of point cloud synthesis method among the present invention.

Fig. 4 is not for adopting the synthetic rape point cloud chart of benchmark body.

Fig. 5 is for adopting the synthetic rape point cloud chart of benchmark body.

Embodiment

Embodiment 1

As shown in Figure 1, a kind of three dimensional point cloud obtains the benchmark body of usefulness, comprises base 1, and base 1 center fixation has the back shaft 2 perpendicular to base 1, and back shaft 2 is provided with between 3, two spheroids 3 of two solid sphere of placing up and down fixedly connected by coupling shaft 4;

There is the sandblast layer on the surface of spheroid 3, and the spherical profile degree of the spheroid 3 after the process blasting treatment is 0.05, and surfaceness is 3.2;

The material of spheroid 3 is necessary for metal, make the present invention can obtain higher spherical profile degree with lower processing cost, the material selection bearing steel of spheroid 3 in the present embodiment, also can select other metal such as ferroalloy, cast iron etc. according to actual needs, as long as can guarantee the machining precision of spheroid 3 profiles; Also directly high-precision steel bearing balls is bought in market, again sandblast and welding processing voluntarily;

The diameter of spheroid 3 is relevant with the direct size of determinand, because the diameter scope of determinand is at 1～60cm among the present invention, therefore the diameter of the spheroid 3 of benchmark body is 40～50mm, makes to scan in the three dimensional point cloud that obtains, and has abundant sphere to count and gets final product.

As shown in Figure 3, the two ball benchmark bodies of a kind of usefulness carry out the synthetic method of a cloud, mainly may further comprise the steps:

(1) two ball benchmark bodies are placed on can precision control on the turntable of rotational angle, the precision of turntable is 0.000125 degree, with three-dimensional structure photoscanner scanning benchmark body;

(2) turntable whenever turn 90 degrees run-down, and the cloud of selecting that obtains an angle of sphere is a partial sphere millet cake cloud, and accumulative total scans and obtains laying respectively at up and down two groups of squares, four groups of partial sphere millet cake clouds on totally 8 summits for four times, and calculates the central rotating shaft of turntable;

(3) determinand is placed on precision controls on the turntable of rotational angle, with three-dimensional structure photoscanner scanning determinand, turntable revolution single pass once, the anglec of rotation of turntable can be adjusted according to different determinands, scanning obtains several three dimensional point clouds;

(4) utilize step (2) to calculate the turntable central rotating shaft of gained, the three dimensional point cloud that scanning in the step (3) is obtained splices, synthetic complete three-dimensional point cloud;

Wherein, the central rotating shaft computing method of step (2) intermediate station are as follows:

1) according to the partial sphere millet cake cloud of each scanning, calculate the centre of sphere of each spheroid, each scanning can obtain two centre ofs sphere up and down, and four scanning can obtain two groups of four centre ofs sphere that are positioned at 4 summits of a square up and down;

2) connect the centre of sphere of the upper sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

3) connect the centre of sphere of the lower sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

4) calculate the intersection of diagonal A (x of two pairs of intersections up and down _a, y _a, z _a) and B (x _b, y _b, z _b);

5) tie point A and some B obtain the central rotating shaft of turntable.

Wherein, " the synthetic complete three-dimensional point cloud " of step (4) promptly gives directions the calculating of rotating around dead axle, algorithm can adopt Sun Jiaguang, long works " the computer graphics " (publishing house of Tsing-Hua University that is valued for of poplar, May nineteen ninety-five the 2nd edition, ISBN 7-302-01708-5/TP.746, P346-348) algorithm that proposes in, specific as follows:

If the rotating shaft coordinate is AB, A (x _a, y _a, z _a), B (x _b, y _b, z _b);

P is supposed in the synthetic calculating of promptly putting around the dead axle rotation of some cloud ₁Be the result who scans for the first time, P ₂Be the some cloud after having changeed θ °.If P ₂The some cloud be synthesized to P ₁The coordinate system at place, then being equivalent to will be to P ₂(x _p, y _p, z _p) AB rotation-θ ° to P around the shaft ₂ ^*(x _p ^*, y _p ^*, z _p ^*), promptly

[x _p ^*?y _p ^*?z _p ^*?1]＝[x _p?y _p?z _p?1]×R _ab

Difference according to any two point coordinate in space is the direction number that connects these 2 straight lines, and then the direction number of AB is: (a, b, c); A=x wherein _b-x _a, b=y _b-y _a, c=z _b-z _a

Order: $v=\sqrt{a^2+b^2},$

$T_A=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\\ 0& 0& 1& 0\\ -x_a& -y_a& -z_a& 1\end{array}\right];$ $T_A^{-1}=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\\ 0& 0& 1& 0\\ x_a& y_a& z_a& 1\end{array}\right]$

$R_x=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& c/v& b/v& 0\\ 0& -b/v& c/v& 0\\ 0& 0& 0& 1\end{array}\right];$ $R_x^{-1}=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& c/v& -b/v& 0\\ 0& b/v& c/v& 0\\ 0& 0& 0& 1\end{array}\right]$

$R_y=\left[\begin{array}{cccc}v& 0& a& 0\\ 0& 1& 0& 0\\ -a& 0& v& 0\\ 0& 0& 0& 1\end{array}\right];$ $R_y^{-1}=\left[\begin{array}{cccc}v& 0& -a& 0\\ 0& 1& 0& 0\\ a& 0& v& 0\\ 0& 0& 0& 1\end{array}\right];$

$R_z=\left[\begin{array}{cccc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}& 0& 0\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right];$

Then $R_{\mathrm{ab}}=T_A{R}_x{R}_y{R}_z{R}_y^{-1}{R}_x^{-1}{T}_A^{-1}.$

Embodiment 2

Three dimensional point cloud obtains the benchmark body of usefulness among the present invention, except that the structure of 1 described pair of ball benchmark of embodiment body, can also be another kind of constructional device.

As shown in Figure 2, a kind of three dimensional point cloud obtains the benchmark body of usefulness, comprises base 1, and base 1 center fixation has the back shaft 2 perpendicular to base 1, back shaft 2 is provided with up and down three solid sphere 3 of placing, and all fixedlys connected by coupling shaft 4 between spheroid 3 and the spheroid 3; According to actual needs, the quantity of spheroid 3 can be three, also can be for more than three;

Spherical profile degree, surfaceness, the diameter of spheroid 3 and the material of selecting for use thereof are all identical with embodiment 1.

As shown in Figure 3, carry out the synthetic method of a cloud with three ball benchmark bodies, step is identical with embodiment 1; The difference part is, the related algorithm of embodiment 2 and embodiment 1 is different:

1. carry out a cloud when synthetic with three ball benchmark bodies, calculate the central rotating shaft of turntable by step (2), can obtain a plurality of points on the central rotating shaft, this moment, a plurality of points were equivalent to the fitting a straight line calculating of limited three-dimensional space point to the calculating of rotating shaft, this algorithm can adopt attacks poplar at document " a kind of method of space line match " (Qiqihar University's journal, 2009,25 (2): the algorithm that proposes 64-67), specific algorithm is as follows:

For a series of spatial point: P _i(x _i, y _i, z _i), i=1 ..., m; Find the solution down and establish an equation:

FF′A＝FX，

FF′B＝FY，

Wherein:

$F=\begin{array}{cccc}{z}_1& z_2& ...& z_m\\ 1& 1& ...& 1\end{array};$

A＝[a?b]′；X＝[x ₁…x _m]′；

B＝[c?d]′；Y＝[y ₁…y _m]′

According to m group data point, solving an equation group just can be in the hope of a, b, c, the value of d.When obtaining this a, b, c during d, promptly gets the straight-line equation in space:

$\left\{\begin{array}{c}x=\mathrm{az}+b\\ y=\mathrm{cz}+d\end{array}\right.$

2. three ball benchmark bodies carry out the calculating of step (4) " synthetic complete three-dimensional point cloud ", and specific algorithm is as follows:

Get 2 A ' B ' on the straight line of from previous step, trying to achieve arbitrarily, wherein A ' (x ' _a, y ' _a, z ' _a), B ' (x ' _b, y ' _b, z ' _b);

P is supposed in the synthetic calculating of promptly putting around the dead axle rotation of some cloud ₁Be the result who scans for the first time, P ₂Be the some cloud after having changeed θ °.If P ₂The some cloud be synthesized to P ₁The coordinate system at place, then being equivalent to will be to P ₂(x _p, y _p, z _p) AB rotation-θ ° to P around the shaft ₂ ^*(x _p ^*, y _p ^*, z _p ^*), promptly

[x _p ^*?y _p ^*?z _p ^*?1]＝[x _p y _p z _p?1]×R _ab

Difference according to any two point coordinate in space is the direction number that connects these 2 straight lines, and then the direction number of AB is: (a ', b ', c '); A '=x ' wherein _b-x ' _a, b '=y ' _b-y ' _a, c '=z ' _b-z ' _a

Order: $v^{,}=\sqrt{a^{\′2}+b^{\′2}},$

$T_A=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\\ 0& 0& 1& 0\\ -x_a^{\′}& -y_a^{\′}& -z_a^{\′}& 1\end{array}\right];$ $T_A^{-1}=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\\ 0& 0& 1& 0\\ x_a^{\′}& y_a^{\′}& z_a^{\′}& 1\end{array}\right]$

$R_x=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& c^{\′}/v^{\′}& b^{\′}/v^{\′}& 0\\ 0& -b^{\′}/v^{\′}& c^{\′}/v^{\′}& 0\\ 0& 0& 0& 1\end{array}\right];$ $R_x^{-1}=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& c^{\′}/v^{\′}& -b^{\′}/v^{\′}& 0\\ 0& b^{\′}/v^{\′}& c^{\′}/v^{\′}& 0\\ 0& 0& 0& 1\end{array}\right]$

$R_y=\left[\begin{array}{cccc}{v}^{\′}& 0& a& 0\\ 0& 1& 0& 0\\ -a^{\′}& 0& v^{\′}& 0\\ 0& 0& 0& 1\end{array}\right];$ $R_y^{-1}=\left[\begin{array}{cccc}{v}^{\′}& 0& -a^{\′}& 0\\ 0& 1& 0& 0\\ a^{\′}& 0& v^{\′}& 0\\ 0& 0& 0& 1\end{array}\right];$

$R_z=\left[\begin{array}{cccc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}& 0& 0\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right];$

Then $R_{\mathrm{ab}}=T_A{R}_x{R}_y{R}_z{R}_y^{-1}{R}_x^{-1}{T}_A^{-1}.$

Comprehensive embodiment 1 and embodiment 2 below are to compare not adopting the benchmark body and adopting the benchmark body to carry out the synthetic image effect of a cloud:

As shown in Figure 4, when not adopting the benchmark body, only with the naked eye choose reference point with mouse action, the image that carries out rape point cloud then is synthetic; Can significantly see among the figure because some are because stitching error produces the petiole of interruption etc.

As shown in Figure 5, when adopting the benchmark body, and with data that the rape point cloud of Fig. 4 obtains be under the prerequisite of same group of data, the image that carries out synthetic oil main dishes and pastries cloud then synthesizes; The blade of rape still is all smoother, a unanimity, complete of petiole part at blade-section among the figure.

Conclusion: Fig. 4 adopts reference point method to carry out a cloud when synthetic, generated time near approximately half an hour, and the manual result who chooses reference point is very unstable, needs debug repeatedly according to synthesizing the result, is similar to method of trial and error; Fig. 5 adopts method of the present invention, utilizes that to carry out a cloud behind the benchmark body examination central rotating shaft synthetic, and aggregate velocity is fast only to need 2 minutes, and synthetic clear picture is complete and do not have a ghost image.

Claims (6)

1. a three dimensional point cloud obtains the benchmark body of usefulness, comprise base, it is characterized in that described base center fixation has the back shaft perpendicular to base, back shaft is provided with up and down the spheroid of at least two metals placing, fixedlys connected by coupling shaft between spheroid and the spheroid; Described spherome surface has the sandblast layer; The spherical profile degree of described spheroid is 0.05, and surfaceness is 3.2～6.3.

2. three dimensional point cloud according to claim 1 obtains the benchmark body of usefulness, it is characterized in that, described ball material is selected a kind of in bearing steel, ferroalloy, the cast iron for use.

3. three dimensional point cloud according to claim 1 obtains the benchmark body of usefulness, it is characterized in that, described spheroid quantity is two.

4. three dimensional point cloud according to claim 1 obtains the benchmark body of usefulness, it is characterized in that, described spheroid quantity is more than three or three.

5. a point cloud synthesis method is characterized in that, comprises the steps:

(1) will be placed on and accurately to control on the turntable of rotational angle as the described benchmark body of above-mentioned claim 3, scan the benchmark body with the three-dimensional structure photoscanner;

(2) turntable whenever turn 90 degrees run-down, and the cloud of selecting that obtains an angle of sphere is a partial sphere millet cake cloud, and accumulative total scans and obtains laying respectively at up and down two groups of squares, four groups of partial sphere millet cake clouds on totally 8 summits for four times, and calculates the central rotating shaft of turntable;

(3) determinand is placed on precision controls on the turntable of rotational angle, with three-dimensional structure photoscanner scanning determinand, turntable revolution single pass once, the anglec of rotation of turntable can be adjusted according to different determinands, scanning obtains several three dimensional point clouds;

(4) utilize step (2) to calculate the turntable central rotating shaft of gained, the three dimensional point cloud that scanning in the step (3) is obtained splices, synthetic complete three-dimensional point cloud.

6. point cloud synthesis method according to claim 5 is characterized in that, the central rotating shaft computing method of described step (2) intermediate station are as follows:

1) according to the partial sphere millet cake cloud of each scanning, calculate the centre of sphere of each spheroid, each scanning can obtain two centre ofs sphere up and down, and four scanning can obtain two groups of four centre ofs sphere that are positioned at 4 summits of a square up and down;

2) connect the centre of sphere of the upper sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

3) connect the centre of sphere of the lower sphere of the benchmark body be positioned at square diagonal angle, can obtain the diagonal line of two intersections;

4) calculate the intersection of diagonal A (x of two pairs of intersections up and down _a, y _a, z _a) and B (x _b, y _b, z _b);

5) tie point A and some B obtain the central rotating shaft of turntable.

Images