CN1719194A - A kind of curved face measurement method - Google Patents
A kind of curved face measurement method Download PDFInfo
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- CN1719194A CN1719194A CN 200410069181 CN200410069181A CN1719194A CN 1719194 A CN1719194 A CN 1719194A CN 200410069181 CN200410069181 CN 200410069181 CN 200410069181 A CN200410069181 A CN 200410069181A CN 1719194 A CN1719194 A CN 1719194A
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Abstract
The invention discloses a kind of curved face measurement method, be used to gather the position data of a plurality of points on the curved surface, this method comprises: curved surface to be measured is divided into a plurality of Delta Regions, and wherein said Delta Region is three-dimensional plane triangle, and its three summits are positioned on the described curved surface; The characteristic distance of described Delta Region is less than or equal to a predetermined threshold values, and described characteristic distance is meant that the subpoint of a unique point on curved surface in the Delta Region arrives the distance of described Delta Region; The position data of this measurement point as measurement point, and is measured in the summit of described Delta Region.Curved face measurement method of the present invention focuses on choosing of measurement point on the curved surface, made full use of the geometrical property of curved surface to be measured, what make measurement point is distributed in big local close of curvature of curved surface, and dredge in little place, reduce redundant data, improved efficiency of measurement and measuring speed greatly.
Description
Technical field
The present invention relates to the reverse Engineering Technology in the CAD/CAM field, particularly measure the contact curved face measurement method on surface in kind.
Background technology
Reverse-engineering is different with traditional engineering, it is based on a mock-up that can obtain and constructs its design concept and cad model, and reach the approaching of mock-up, modification and perfect, and then these cad models are used for the analysis and the manufacturing of product by adjusting correlation parameter.It originates in the measurement to an existing mock-up, its research mainly to as if how discrete data point is transformed into sectionally smooth, continuous cad model, combining with traditional CAD/CAM system etc. constitutes a great system engineering.In fact, because the research of reverse-engineering concentrates on basically by the process of exemplar in kind to surface reconstruction, people are used as reverse-engineering to the first half of total system traditionally and treat.Therefore, reverse-engineering can be defined as simply: obtain data from the exemplar surface and it is converted to the process of cad model.This process can adopt different data processing and surface reconstruction method according to the difference (free form surface exemplar and ruled surface exemplar) of tested exemplar usually.
The process of reverse-engineering comprises following several stages: data acquisition, data pre-service, data are cut apart, the foundation of surface reconstruction, cad model.Certainly this is suitable generalities in proper order, and in fact, this several stages is often overlapping, and usually needs repeatedly to carry out repeatedly but not order is carried out.
Data acquisition is the key component of reverse-engineering.Have a lot of different collecting methods can obtain required body data, can be divided into basically contact, contactless, successively scan three major types.
The contact collecting method is that the sensor at joint of mechanical arm place is determined the relative coordinate position with the surface of mechanical probe contact measured amount.This method is stable, point promptly of poor quality less, precision height, repeatable accuracy height, but measuring speed is slow.Modal contact collecting method is coordinate measuring machine (CMM), normally three coordinate measuring machine.Coordinate measuring machine makes its contact sonde along the path pointwise catch surface data of measured surface through programming.During measurement, can record characteristic point data according to the feature selecting measuring position and the direction of material object.
When carrying out the contact data acquisition, measurement mechanism is arranged on the robot device usually.The robot device who is used for the contact data acquisition has a variety of, the application people for the ZL98101217 patent disclosure of Inst. of Mechanics, CAS so a kind of frame-type robot system with flexible transmission and five-axle linkage.
In the prior art, curved surface is carried out the contact data acquisition usually adopt equidistant scanning survey method, it is to get a little on the first-class step-length of horizontal vertical both direction of curved surface to be measured ground, and measurement one by one.Its shortcoming is to utilize the geometrical property of curved surface to be measured itself, and the measuring point number is more, and measuring speed is slow, and efficiency of measurement is lower.Simultaneously, because the measuring point data topological structure is not obvious, increase difficulty for the subsequent treatment of measuring point and surface reconstruction.
In the applicant's No. 03121461.4 patented claim, provide a kind of two-dimensional adaptive measuring method, it is earlier selected direction of measurement, on this direction of measurement, adopt adaptive step according to the curved transition of curved surface to be measured, with the vertical direction in plane, measuring route place on adopt the step-length that equates.This method has been utilized the geometrical property of curved surface itself to a certain extent, compares with equidistant scanning survey method, has reduced redundant data, and speed is accelerated to some extent.But it still in one direction step-length such as employing measure, therefore still have further minimizing redundant data, the space of improving measuring speed.
Summary of the invention
The objective of the invention is provides a kind of new curved face measurement method in order to overcome the shortcoming and defect that existing curved face measurement method redundant data is many, measuring speed is slow.
To achieve these goals, a kind of curved face measurement method provided by the invention, be used to gather the position data of a plurality of points on the curved surface, this method comprises: curved surface to be measured is divided into a plurality of Delta Regions, wherein said Delta Region is three-dimensional plane triangle, and its three summits are positioned on the described curved surface; The characteristic distance of described Delta Region is less than or equal to a predetermined threshold values, and described characteristic distance is meant that the subpoint of a unique point on curved surface in the Delta Region arrives the distance of described Delta Region; The position data of this measurement point as measurement point, and is measured in the summit of described Delta Region.
Described unique point is the center of gravity of described Delta Region.
Describedly curved surface to be measured is divided into a plurality of Delta Regions comprises: initial triangulation step is used for curved surface to be measured is divided into a plurality of initial Delta Regions; Thin subdivision step is used for characteristic distance is divided into a plurality of sub-Delta Regions again greater than the Delta Region of threshold values, and the characteristic distance until all Delta Regions all is less than or equal to a predetermined threshold values.
Described initial triangulation step comprises: choose a plurality of frontier points on the border of curved surface, choose one or more points on the curved surface of surface boundary inside, be divided into a plurality of Delta Regions according to the selected described curved surface to be measured of naming a person for a particular job.Delaunay triangulation method is adopted in described division.
Described thin subdivision step comprises: choose three mid points on three limits that lay respectively at described Delta Region, three mid points are projected on the described curved surface, obtain three subpoints; Three summits and pairing three subpoints of its three mid points with described Delta Region are divided into a plurality of sub-Delta Regions with described Delta Region.
Curved face measurement method of the present invention focuses on choosing of measurement point on the curved surface, made full use of the geometrical property of curved surface to be measured, what make measurement point is distributed in big local close of curvature of curved surface, and dredge in little place, reduce redundant data, improved efficiency of measurement and measuring speed greatly.The data topology structure of the measurement point of choosing in the curved face measurement method of the present invention is obvious, helps the subsequent treatment and the surface reconstruction of measuring point.Measuring method of the present invention is particularly suitable for the measurement of the little free form surface of large-area curved transition, has improved the efficient of the contact type measurement in the reverse-engineering greatly.
Description of drawings
Fig. 1 is a contact type measurement system architecture synoptic diagram;
Fig. 2 is curved face measurement method of the present invention carries out initial division to a curved surface to be measured synoptic diagram;
Fig. 3 is curved face measurement method of the present invention carries out thin subdivision to a Delta Region a synoptic diagram
Fig. 4 is the schematic flow sheet of an embodiment of curved face measurement method of the present invention.
Embodiment
Below in conjunction with the drawings and specific embodiments the present invention is described in further detail.
Curved face measurement method of the present invention can be realized with the contact type measurement system.The contact type measurement system can adopt frame-type robot system of the prior art, perhaps other measuring system well-known to those skilled in the art.Fig. 1 has exemplarily provided the structural representation of contact type measurement system, as shown in the figure, the contact type measurement system generally comprises frame 1, measuring staff 2 and gauge head 3, measuring system can drive a certain measurement point on the surface 5 that gauge head 3 moves to workpiece 4 according to programmed instruction, contact the position data that the trigger pip that produces records this measurement point by gauge head 3 with surface 5, and this measurement data is also stored by the computing machine that signal wire 6 turns back in the measuring system.The surface 5 of workpiece 4 is generally a curved surface, and in the above-mentioned measurement that curved surface is carried out, the selection of measurement point is a key issue.Suitable selection measurement point can reduce redundant data, improve measuring speed.
Fig. 4 shows the process flow diagram of a preferred embodiment of curved face measurement method of the present invention, and concrete steps are as described below:
In step 101, at first on the workpiece for measurement surface, choose curved surface to be measured.Among the embodiment as shown in Figure 2, the curved surface that thick lines 7 surround is a curved surface to be measured.Simultaneously, set a threshold values δ, the effect of threshold values δ will be described in more detail below.
In step 102, a plurality of frontier points of choosing curved surface to be measured are as measurement point, and measure its position data and record.In the embodiment of Fig. 2, the frontier point of the curved surface of choosing is P
0～P
5, set up three rectangular coordinate system X-Y-Z as shown in the figure, this frontier point P
0～P
5Position data its D coordinates value normally.Selected frontier point preferably includes some unique points on the surface boundary, as flex point etc.These frontier points P
0～P
5X, y coordinate when choosing curved surface to be measured, be known usually, therefore only need measure its z coordinate and get final product.In the system of Fig. 1, gauge head 3 is moved to x, the y coordinate place of a frontier point along X-Y plane, move down gauge head 3 to record the z coordinate figure of this frontier point.All selected frontier point P have been surveyed according to this process
0～P
5The z coordinate figure, so just obtained the D coordinates value of all selected frontier points.
In step 103, on the curved surface of inside, border, choose one or more equably as measurement point, measure the D coordinates value and the record of these points according to the mode of above-mentioned Measured Boundary point.For example in the embodiment of Fig. 2, the point of choosing in inside, border is P
6Although only chosen a bit on the curved surface in the border for illustrated convenience here, as can be known, when choosing multiple spot on the curved surface in the border, each step of the present invention also is readily appreciated that from following description.
In step 104, curved surface to be measured is carried out initial triangulation with the frontier point of choosing and the point of inside, border.In the embodiment of Fig. 2, the some P that chooses with step 102 and step 103
0～P
6Curved surface to be measured is carried out triangulation, with frontier point P
0～P
5Be linked in sequence, and will put P
6Respectively with frontier point P
0～P
5After the connection, can form a plurality of Delta Regions, as the Δ among the figure
0～Δ
5When choosing multiple spot on the curved surface in the border, adopt Delaunay triangulation method convenient, there is ready-made Delaunay triangulation program module available in the prior art.Delta Region Δ after cutting apart
0～Δ
5Be the plane triangle in three dimensions.
In step 105, get a Delta Region, determine a unique point in this Delta Region, this unique point is the center of gravity of this Delta Region preferably, this center of gravity is projected on the curved surface to be measured, obtain the subpoint of this center of gravity on curved surface to be measured, measure the position data of this subpoint.In the embodiment shown in Figure 2, choose Δ
0～Δ
5In a Delta Region Δ
1, calculate its center of gravity O
1Coordinate.Cross focus point and make a vertical line (as connecting O among Fig. 2 perpendicular to X-Y plane
1And O
2Dotted line), this vertical line and curved surface to be measured have an intersection point O
2, this intersection point O
2Promptly be the subpoint of focus point on curved surface to be measured.Because O
2X, y coordinate and focus point O
1Identical, gauge head 3 is moved to this coordinate place, move down with curved surface to be measured and contact, obtain subpoint O
2The z coordinate figure.So just measured subpoint O
2Three-dimensional coordinate.
In step 106, calculate the subpoint O in the step 105
2To the Delta Region Δ
1The distance on plane, place, this distance can be described as characteristic distance d.
In step 107, whether judging characteristic is less than or equal to predetermined threshold values δ apart from d, if be judged as not, then enters step 108; If be judged as is that then this Delta Region measurement finishes, and enters step 109.When practical application, the big I of this threshold values δ is provided with according to the actual curvature distribution of curved surface, in general this threshold values δ can be located at 0.3mm between the 1mm.
In step 108, characteristic distance d carefully is split into a plurality of new sub-Delta Regions again greater than the Delta Region of predetermined threshold values δ.In an embodiment shown in Figure 3, will be by summit P
i, P
jAnd P
kThe mode that thin subdivision is carried out in the Delta Region that is linked to be is: three mid point N that get three limits of this Delta Region
i, N
jAnd N
k, cross the vertical line of these three mid points works respectively perpendicular to X-Y plane, obtain three intersection point M with curved surface to be measured
i, M
jAnd M
k, these three intersection point M
i, M
jAnd M
kBe measurement point, measure the coordinate and the record of these three intersection points.Use intersection point M
i, M
jAnd M
kWith summit P
i, P
jAnd P
kAs vertex of a triangle triangulation is carried out in this Delta Region, form four sub-Delta Regions, as shown in Figure 3, these four sub-Delta Regions are respectively Δ M
iM
jM
k, Δ M
iM
jP
j, Δ M
jM
kP
kWith Δ M
kM
iP
iAfter step 108 is finished, come back to step 105, step 105 carry out～operation of step 107 in each sub-Delta Region.
In step 109, judge whether that all Delta Regions are all measured to finish.If be judged as not, then get back to step 105, measure next Delta Region; If be judged as be, then enter step 110, whole measuring process finishes.
Can find out that by above-mentioned step 101～step 109 measurement point of choosing in the measuring method of the present invention comprises in the frontier point, step 103 of the curved surface of choosing in the step 102 on measurement point of choosing on the curved surface of inside, border and the summit of forming sub-Delta Region in step 108 during to the thin subdivision in Delta Region.These measurement points have been split into a plurality of Delta Regions as vertex of a triangle with curved surface to be measured just, and make each Delta Region all satisfy the judgment criterion in the step 107, promptly the characteristic distance of each Delta Region all is less than or equal to a predetermined threshold values δ.In the present invention, make the Delta Region that is divided into approach curved surface to be measured, make the Delta Region after dividing to show the curved transition of curved surface to be measured basically by threshold values δ is set.
Claims (6)
1, a kind of curved face measurement method, the position data that is used to gather a plurality of points on the curved surface, this method comprises:
Curved surface to be measured is divided into a plurality of Delta Regions, and wherein said Delta Region is three-dimensional plane triangle, and its three summits are positioned on the described curved surface;
The characteristic distance of described Delta Region is less than or equal to a predetermined threshold values, and described characteristic distance is meant that the subpoint of a unique point on curved surface in the Delta Region arrives the distance of described Delta Region;
The position data of this measurement point as measurement point, and is measured in the summit of described Delta Region.
2, curved face measurement method according to claim 1 is characterized in that, described unique point is the center of gravity of described Delta Region.
3, curved face measurement method according to claim 1 and 2 is characterized in that, describedly curved surface to be measured is divided into a plurality of Delta Regions comprises:
Initial triangulation step is used for curved surface to be measured is divided into a plurality of initial Delta Regions;
Thin subdivision step is used for characteristic distance is divided into a plurality of sub-Delta Regions again greater than the Delta Region of threshold values, and the characteristic distance until all Delta Regions all is less than or equal to a predetermined threshold values.
4, curved face measurement method according to claim 3, it is characterized in that, described initial triangulation step comprises: choose a plurality of frontier points on the border of curved surface, on the curved surface of surface boundary inside, choose one or more points, be divided into a plurality of Delta Regions according to the selected described curved surface to be measured of naming a person for a particular job.
5, curved face measurement method according to claim 4 is characterized in that, Delaunay triangulation method is adopted in described division.
6, curved face measurement method according to claim 3 is characterized in that, described thin subdivision step comprises: choose three mid points on three limits that lay respectively at described Delta Region, three mid points are projected on the described curved surface, obtain three subpoints; Three summits and pairing three subpoints of its three mid points with described Delta Region are divided into a plurality of sub-Delta Regions with described Delta Region.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200410069181XA CN1306460C (en) | 2004-07-07 | 2004-07-07 | Measuring method of curved surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200410069181XA CN1306460C (en) | 2004-07-07 | 2004-07-07 | Measuring method of curved surface |
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| Publication Number | Publication Date |
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| CN1719194A true CN1719194A (en) | 2006-01-11 |
| CN1306460C CN1306460C (en) | 2007-03-21 |
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| CNB200410069181XA Expired - Fee Related CN1306460C (en) | 2004-07-07 | 2004-07-07 | Measuring method of curved surface |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101308523B (en) * | 2008-06-24 | 2010-06-09 | 中国科学院力学研究所 | Dummy laser processing procedure geometric simulation method |
| CN102062593A (en) * | 2010-11-12 | 2011-05-18 | 北京信息科技大学 | Method and device for acquiring measure points of helical curved surface |
| CN101713647B (en) * | 2008-09-30 | 2012-05-30 | 株式会社拓普康 | Lens shape measuring method and apparatus |
| CN108170896A (en) * | 2017-12-04 | 2018-06-15 | 武汉开目信息技术股份有限公司 | A kind of emulation mode and device that brush applied coating is applied in body surface |
| CN109870126A (en) * | 2017-12-05 | 2019-06-11 | 宁波盈芯信息科技有限公司 | A kind of area computation method and a kind of mobile phone for being able to carry out areal calculation |
| CN110579180A (en) * | 2019-08-07 | 2019-12-17 | 合肥学院 | Light vision and conoscopic polarization group sum-based reflective curved surface part measurement method |
| CN112509841A (en) * | 2020-11-18 | 2021-03-16 | 东莞市新美洋技术有限公司 | Manufacturing method of keyboard, keyboard and electronic equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB2161602B (en) * | 1984-07-12 | 1987-04-23 | Atomic Energy Authority Uk | Examination over a surface |
| CA1260638A (en) * | 1985-02-26 | 1989-09-26 | Tetsuzo Kuragano | Method of displaying image |
| CA1282142C (en) * | 1986-10-21 | 1991-03-26 | Sony Corporation | Method for generating offset surface data |
| US5319744A (en) * | 1991-04-03 | 1994-06-07 | General Electric Company | Polygon fragmentation method of distortion correction in computer image generating systems |
| JPH10254523A (en) * | 1997-03-12 | 1998-09-25 | Nkk Corp | Method for forming movement path of tool for machining |
| JPH11195139A (en) * | 1997-12-26 | 1999-07-21 | Sony Corp | Sculptured surface generating device, method therefor and providing medium |
| US6518964B1 (en) * | 2000-10-10 | 2003-02-11 | International Business Machines Corporation | Apparatus, system, and method for simplifying annotations on a geometric surface |
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2004
- 2004-07-07 CN CNB200410069181XA patent/CN1306460C/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101308523B (en) * | 2008-06-24 | 2010-06-09 | 中国科学院力学研究所 | Dummy laser processing procedure geometric simulation method |
| CN101713647B (en) * | 2008-09-30 | 2012-05-30 | 株式会社拓普康 | Lens shape measuring method and apparatus |
| CN102062593A (en) * | 2010-11-12 | 2011-05-18 | 北京信息科技大学 | Method and device for acquiring measure points of helical curved surface |
| CN102062593B (en) * | 2010-11-12 | 2012-11-07 | 北京信息科技大学 | Method for acquiring measure points of helical curved surface |
| CN108170896A (en) * | 2017-12-04 | 2018-06-15 | 武汉开目信息技术股份有限公司 | A kind of emulation mode and device that brush applied coating is applied in body surface |
| CN108170896B (en) * | 2017-12-04 | 2021-05-18 | 武汉开目信息技术股份有限公司 | Simulation method and device for coating on surface of object |
| CN109870126A (en) * | 2017-12-05 | 2019-06-11 | 宁波盈芯信息科技有限公司 | A kind of area computation method and a kind of mobile phone for being able to carry out areal calculation |
| CN110579180A (en) * | 2019-08-07 | 2019-12-17 | 合肥学院 | Light vision and conoscopic polarization group sum-based reflective curved surface part measurement method |
| CN112509841A (en) * | 2020-11-18 | 2021-03-16 | 东莞市新美洋技术有限公司 | Manufacturing method of keyboard, keyboard and electronic equipment |
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| CN1306460C (en) | 2007-03-21 |
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