CN105953746A - Three-dimensional contour real-time measurement method of dynamic objects - Google Patents

Abstract

The present invention discloses a three-dimensional contour real-time measurement method of dynamic objects. The method comprises the steps of projecting a phase shift color fringe image according to a height change synchronizing signal of the measured objects placed in a measurement space, determining a measurement phase according to the phase shift color fringe image, and carrying out the phase unwrapping on the measurement phase according to a phase unwrapping method, and finally carrying out the three-dimensional reconstruction according to the phase-height one-to-one correspondence and a height search table. The three-dimensional contour real-time measurement method of the dynamic objects of the present invention realizes the high-precision depth measurement and the measurement system high-speed data processing to thereby carry out the high-precision dynamic object three-dimensional contour real-time measurement, opens up a new path for the dynamic complicated object three-dimensional measurement, is expected to achieve the equipment state dynamic monitoring and real-time measurement, and enables the technical levels of the online industrial detection( the closed loop quality control), a robot technology(the accurate navigation) and the dynamic target three-dimensional measurement (the rotating blades and the facial expression) to be improved substantially.

Description

The 3-D profile real-time measuring method of dynamic object

Technical field

The present invention relates to technical field of optical precision measurement, be specifically related to the 3-D profile real-time measuring of a kind of dynamic object Method.

Background technology

In high precision, high speed dynamic object three-dimensional measurement technology can with the three-dimensional feature of quick obtaining parts, geomery, The important informations such as operating attitude, and can be by its measurement feedback to manufacture process, to improve crudy, machining accuracy, because of This its technology industrial occasions such as parts 3-d shape measurement, deformation or vibration analysis under quality testing, operating mode has in a large number Demand.As, the vitals such as blade of aviation engine, turbine blade, fan blade, can be deformed under operating mode, from And greatly affect plant equipment service behaviour, and can cause when deforming more than certain threshold value himself material failure, Fracture, and cause serious security incident.

If the parts instantaneous whole audience three-dimensional appearance under operating mode can be obtained, by transient state whole audience 3 D deformation is divided Analysis, real-time whole audience three dimensional strain, stress distribution and the Deformation Anomalies of monitoring workpiece, workpiece fault can be realized and detect in real time and in advance Alert, also contribute to the optimization design of product simultaneously and manufacture, but current most of business-like 3D profile measuring system due to Employ projector, bulky, expensive, gamma correction must be carried out, the three-dimensional survey that otherwise can greatly reduce simultaneously Accuracy of measurement, DLP projector is owing to have employed optical integration principle (several milliseconds of whole integral process), in kinetic measurement occasion Data acquisition is slower.Fringe projection technology of profiling based on LCD projector, by LCD projector maximum projection frame per second (120HZ) limit System, its measuring speed is difficult to improve further.Due to differ markedly from static three-dimensional measure, dynamic 3 D measurement data acquisition and Process and require harshness, be both needed to complete in the extremely short time, and require enough precision.Up to now, also do not have a kind of method and Measuring instrument can be competent at these demands completely.Therefore develop and a kind of there is high accuracy, characteristic at a high speed and measurement system simultaneously Compact conformation, low-cost dynamic object measuring three-dimensional profile system are still filled with huge challenge.

Summary of the invention

In view of this, present invention is primarily targeted at the 3-D profile real-time measuring method of a kind of dynamic object is provided.

For reaching above-mentioned purpose, the technical scheme is that and be achieved in that:

The embodiment of the present invention provides the 3-D profile real-time measuring method of a kind of dynamic object, and the method is: according to being placed in The Measuring Object height change synchronizing signal projection phase shift color fringe image of measurement space, true according to described phase shift color fringe image Location survey amount phase place, and according to de-packaging method, described measurement phase place is carried out phase unwrapping, finally according to phase height one by one Correspondence and phase height look-up table carry out three-dimensional reconstruction.

In such scheme, the method for building up of described phase height look-up table is: be opposite to measure sky by red, blue-light source Between the plane of reference be irradiated, and gather the bar graph of the plane of reference of movement in whole measurement altitude range；According to described Bar graph determines the reference phase after the most mobile plane of reference, and launches wrapped phase；Divide according to the height that the plane of reference moves Cloth and corresponding phase place set up phase height look-up table.

In such scheme, the foundation side of phase height look-up table described in the method for building up of described phase height look-up table Method, particularly as follows: first one piece of surface plate of processing, with ideal plane maximum error less than 20 microns, as scaling board, by described Scaling board is placed in the reference plane position of measurement space；It is irradiated by the plane of reference red, that blue-light source is opposite to measurement space, throws Penetrate sine streak figure, and use this sine streak figure of camera record；Then application precision displacement table drives scaling board measuring Space moves a series of position along z-axis with the method for unique step thin tail sheep, and moving range is the scope that fathoms of system, equally The bar graph of record relevant position, then the phase place of application random phase shift algorithm demodulation current location, applies typical phase shift to calculate Method launches its phase place, and applies linked list data form by phase place storage corresponding for each degree of depth of movement, i.e. sets up phase place high Degree look-up table.

In such scheme, the Measuring Object height change synchronizing signal projection phase shift that described basis is placed in measurement space is colored Bar graph, particularly as follows: absorb secondary color bar graph under the conditions of single shot, separates the secondary color striped of described picked-up and forms monochrome Bar graph, and carry out color cross-talk correction, it is thus achieved that for demodulating the phase shift color fringe image of object surface appearance.

In such scheme, the secondary color striped of described picked-up is separated and forms single color stripe figure, and carry out color cross-talk correction, Particularly as follows: use following color recovery model

$\left[\begin{array}{c}{f}_R^{\′}(x,y)\\ f_G^{\′}(x,y)\\ f_B^{\′}(x,y)\end{array}\right]=M_{ref}{M}_{bal}{M}_{cou}\left[\begin{array}{c}{f}_R^C(x,y)\\ f_G^C(x,y)\\ f_B^C(x,y)\end{array}\right]---\left(1\right)$

Wherein, f_i' (x, y), i=R, G, B are each Color Channel after color decoupling, color balance and reflectance normalization Bar graph, M_ref、M_bal、M_couRepresent each color light relative reflection rate matrix, color balance matrix and color coupling moment respectively Battle array, is obtained by typical scaling method, and has:

$\begin{array}{cc}{M}_{ref}=\left[\begin{array}{ccc}1& 0& 0\\ 0& P_{GR}(x,y)& 0\\ 0& 0& P_{BR}(x,y)\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(2\right)$

$\begin{array}{cc}{M}_{bal}=\left[\begin{array}{ccc}1& 0& 0\\ 0& Q_{GR}\left(f_G^C\right(x,y))& 0\\ 0& 0& Q_{BR}\left(f_B^C\right(x,y))\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(3\right)$

$\begin{array}{cc}{M}_{cou}=\left[\begin{array}{ccc}1& C_{RG}\left(f_R^C\right(x,y))& C_{RG}\left(f_R^C\right(x,y))\\ C_{GR}\left(f_G^C\right(x,y))& 1& C_{GB}\left(f_G^C\right(x,y))\\ C_{BR}\left(f_B^C\right(x,y))& C_{BG}\left(f_B^C\right(x,y))& 1\end{array}\right].& \backslash *MERGEFORMAT\end{array}---\left(4\right).$

Compared with prior art, beneficial effects of the present invention:

1, the present invention by configuring that two red, to irradiate real grid be that measurement space projects phase shift bar graph to blue-light source simultaneously, will The gatherer process of dephasing processes and high-speed cmos video camera Tong Bu gets up, quick sampling phase shift bar graph number under single shot According to, during phase-shifting technique thought is applied to phase demodulating, utilizes the one_to_one corresponding of phase height, searched by foundation Measurement result is corrected by table, it is achieved high accuracy depth is measured, it is achieved measures system high-speed data and processes, thus carries out high-precision The dynamic object 3-D profile real-time measuring of degree；New way will be opened up for DYNAMIC COMPLEX three-dimensional measurement of objects, and be expected to realize equipment State dynamically monitors and measures in real time, it is possible to be greatly improved on-line industry detection (closed loop quality control), robotics (accurately Navigation), the technical merit of dynamic object three-dimensional measurement (rotating vane, human face expression)；

2, the present invention is compared with digital stripe sciagraphy, owing to not using projector, saves structure space, its structure That can do is more compact, and dephasing processes is only completed by increase light source, and therefore the measurement apparatus simple in construction of the present invention, price are just Preferably；

3, testee is placed in measurement space by the present invention, by the virtual instrument of development, completes relevant Initialize installation After, once can be automatically performed measurement, it is possible to carry out telemeasurement.

4, the present invention need not the concordance of light source, low to environmental requirement, it is adaptable to the measurement of industrial occasions needs.

5, the present invention uses random phase shift technology to carry out phase demodulating, utilizes phase height one_to_one corresponding, directly leads to Cross look-up table and carry out phase height conversion, it is achieved measuring error correction therein, and reduce measurement apparatus required precision.

6, the acquisition speed of the present invention is fast, and picking rate is video camera frame per second, it is possible to by the method to dynamically Object surface appearance is measured in real time, it is possible to automatically, complete testee measuring surface form, for realizing under operating mode in high precision Plant equipment key components and parts deformation monitoring etc. lays the first stone.

Accompanying drawing explanation

Fig. 1 is the measurement apparatus schematic diagram of the application embodiment of the present invention；

Fig. 2 provides the flow chart of the 3-D profile real-time measuring method of a kind of dynamic object for the embodiment of the present invention.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, right The present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, and It is not used in the restriction present invention.

The embodiment of the present invention provides the 3-D profile real-time measuring method of a kind of dynamic object, and the method is: according to being placed in The Measuring Object height change synchronizing signal projection phase shift color fringe image of measurement space, true according to described phase shift color fringe image Location survey amount phase place, and according to de-packaging method, described measurement phase place is carried out phase unwrapping, finally according to phase height one by one Correspondence and phase height look-up table carry out three-dimensional reconstruction.

The method for building up of described phase height look-up table is: entered by the plane of reference red, that blue-light source is opposite to measurement space Row irradiates, and gathers the bar graph of the plane of reference of movement in whole measurement altitude range；Determine often according to described bar graph Reference phase after the secondary mobile plane of reference, and launch wrapped phase ()；The height distribution moved according to the plane of reference and correspondence Phase place sets up phase height look-up table.

Particularly as follows: first process one piece of surface plate, if its size is 50mmX50mm, do not surpass with ideal plane maximum error Cross 20 microns, as scaling board, described scaling board is placed in the reference plane position of measurement space；It is opposite to by red, blue-light source The plane of reference of measurement space is irradiated, and projects sine streak figure, and uses this sine streak figure of camera record；Then apply Precision displacement table drives scaling board to move a series of position along z-axis with the method for unique step thin tail sheep at measurement space, such as movement Step-length 1 micron, moving range is the scope that fathoms of system, and the same bar graph recording relevant position, then application is random The phase place of phase shift algorithm demodulation current location, applies typical phase shift algorithm to launch its phase place, and applies linked list data form to incite somebody to action The phase place that each degree of depth of movement is corresponding stores, and i.e. sets up phase height look-up table.

Described basis is placed in the Measuring Object height change synchronizing signal projection phase shift color fringe image of measurement space, specifically For: under the conditions of single shot, absorb secondary color bar graph, the secondary color striped of described picked-up is separated and forms single color stripe figure, go forward side by side Row color cross-talk corrects, it is thus achieved that for demodulating the phase shift color fringe image of object surface appearance.

Using MatlaB software that secondary color bar graph resolves into unmarried bar graph, the method for color cross-talk correction is: use Following color recovery model

$\left[\begin{array}{c}{f}_R^{\′}(x,y)\\ f_G^{\′}(x,y)\\ f_B^{\′}(x,y)\end{array}\right]=M_{ref}{M}_{bal}{M}_{cou}\left[\begin{array}{c}{f}_R^C(x,y)\\ f_G^C(x,y)\\ f_B^C(x,y)\end{array}\right]---\left(1\right)$

Wherein, f_i' (x, y), i=R, G, B are each Color Channel after color decoupling, color balance and reflectance normalization Bar graph, M_ref、M_bal、M_couRepresent each color light relative reflection rate matrix, color balance matrix and color coupling moment respectively Battle array, can be obtained by typical scaling method, and have:

$\begin{array}{cc}{M}_{ref}=\left[\begin{array}{ccc}1& 0& 0\\ 0& P_{GR}(x,y)& 0\\ 0& 0& P_{BR}(x,y)\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(2\right)$

$\begin{array}{cc}{M}_{bal}=\left[\begin{array}{ccc}1& 0& 0\\ 0& Q_{GR}\left(f_G^C\right(x,y))& 0\\ 0& 0& Q_{BR}\left(f_B^C\right(x,y))\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(3\right)$

$\begin{array}{cc}{M}_{cou}=\left[\begin{array}{ccc}1& C_{RG}\left(f_R^C\right(x,y))& C_{RG}\left(f_R^C\right(x,y))\\ C_{GR}\left(f_G^C\right(x,y))& 1& C_{GB}\left(f_G^C\right(x,y))\\ C_{BR}\left(f_B^C\right(x,y))& C_{BG}\left(f_B^C\right(x,y))& 1\end{array}\right].& \backslash *MERGEFORMAT\end{array}---\left(4\right).$

Specifically, it is assumed that A_k(x y) is background, B_k(x y) is modulation item, φ_k(x, y) is phase place, k=1, and 2 is time domain bar Stricture of vagina sequence number, then the bar graph light intensity absorbed can be expressed as respectively:

I_k(x, y)=A_k(x,y)+B_k(x,y)cos[φ_k(x,y)]

According to above formula, the phase demodulating method of the present invention is:

Bar graph is decomposed by first application Bidimensional Empirical Mode Decomposition method (BEMD), removes the high frequency mould of bar graph Formula component and trend term, rebuild bar graph:

$\stackrel{\‾}{I_k}=\left[\begin{array}{ccc}{B}_{1}cos\left({\mathrm{\φ}}_1\right)& ......B_{1}cos\left({\mathrm{\φ}}_m\right)& ......B_{1}cos\left({\mathrm{\φ}}_n\right)\\ B_{2}cos({\mathrm{\φ}}_1+{\mathrm{\δ}}_1)& ......B_{2}cos({\mathrm{\φ}}_m+{\mathrm{\δ}}_m)& ......B_{2}cos({\mathrm{\φ}}_n+{\mathrm{\δ}}_n)\end{array}\right]$

In formula, n is pixel number.

For the amplitude in standardization above formula

$I\stackrel{\&OverBar;}{n_k}=\stackrel{\&OverBar;}{I_k}/\sqrt{<\stackrel{\&OverBar;}{I_k},\stackrel{\&OverBar;}{I_k}>},k=1,2$

Point box indicating inner product operation in formula, finally applies two frame phase shift algorithm to the bar graph after correction above, just may be used Extract and measure phase place.

If therefore application randomized can measure phase place, to measuring phase unwrapping, then according to phase height one a pair Ying Xing, by look-up table phase mapping to measurement space.

The embodiment of the present invention provides the 3-D profile real-time measuring method of a kind of dynamic object, real especially by following steps Existing:

Step one: the plane of reference is placed in measurement space, opens light source, and uses the colored phase shift bar that camera record produces Stricture of vagina；

Step 2: use precision displacement table with subsection (such as 0.001mm) mobile reference in whole measurement altitude range The bar graph produced behind face, and record movement every time；

Step 3: calculate the reference phase after the most mobile plane of reference according to the bar graph of record, and launch to wrap up phase Position；

Step 4: be distributed according to the height of movement and corresponding phase place sets up phase height look-up table；

Step 5: Measuring Object is placed in measurement space, changes synchronizing signal according to object height, projects phase shift color-bar Stricture of vagina figure, and record；

Step 6: calculate phase place according to the bar graph of shooting, and use the de-packaging method measurement phase place to extracting above Carry out phase unwrapping；

Step 7: according to phase height one_to_one corresponding, uses look-up table to carry out three-dimensional reconstruction, completes this measurement and appoints Business, as continued to measure, repeats step 4 to step 7.

Embodiment:

The embodiment of the present invention is applied to device as shown in Figure 1, uses multithreads computing method to process in real time, By simple numerical computations and the operation to the identical operation that each pixel is carried out, transfer to and Computer Image Processing unit (GPU), utilize Floating-point Computation powerful for GPU and parallel processing capability to accelerate data handling procedure, finally operate with Labwidow Platform, modulates stop position, the module such as light source control, data acquisition and procession integrates, and forms virtual measurement instrument, real Existing measuring process control so that whole measured process automation.

The optical axis seeing Fig. 1, CCD is perpendicular to grating face, and two light sources are equally spaced, in CCD optical center and light source The heart is placed in the distance of distance grating plane L, and first light source is d with camera center distance.Comprise the concrete steps that:

One, object is placed in measurement space, opens light source, use the secondary color bar graph that camera record produces；

Two, at computer, secondary color striped is separated, carry out color cross-talk correction, form single color stripe figure；

Three, the method using striped regularization removes striped background and amplitude, eliminates light source and moves the impact measured；

Four, random phase shift method is used to carry out phase extraction.

Five, launch phase place, according to phase height one_to_one corresponding, completed the mapping of phase height by look-up table.

The above, only presently preferred embodiments of the present invention, it is not intended to limit protection scope of the present invention.

Claims (5)

1. the 3-D profile real-time measuring method of a dynamic object, it is characterised in that the method is: according to being placed in measurement space Measuring Object height change synchronizing signal projection phase shift color fringe image, determine measurement phase according to described phase shift color fringe image Position, and carries out phase unwrapping according to de-packaging method to described measurement phase place, finally according to phase height one_to_one corresponding with And phase height look-up table carries out three-dimensional reconstruction.

The 3-D profile real-time measuring method of dynamic object the most according to claim 1, it is characterised in that: described phase place- The highly method for building up of look-up table is: is irradiated by the plane of reference red, that blue-light source is opposite to measurement space, and gathers The bar graph of the plane of reference of movement in whole measurement altitude range；The ginseng after the most mobile plane of reference is determined according to described bar graph Examine face phase place, and launch wrapped phase；The height distribution moved according to the plane of reference and corresponding phase place are set up phase height and are searched Table.

The 3-D profile real-time measuring method of dynamic object the most according to claim 1, it is characterised in that described phase place- The highly method for building up of phase height look-up table described in the method for building up of look-up table, particularly as follows: first one piece of surface plate of processing, With ideal plane maximum error less than 20 microns, as scaling board, described scaling board is placed in the plane of reference position of measurement space Put；It is irradiated by the plane of reference red, that blue-light source is opposite to measurement space, projects sine streak figure, and use video camera to remember Record this sine streak figure；Then application precision displacement table drive scaling board at measurement space along z-axis with the side of unique step thin tail sheep Method moves a series of position, and moving range is the scope that fathoms of system, the same bar graph recording relevant position, then should By the phase place of random phase shift algorithm demodulation current location, apply typical phase shift algorithm to launch its phase place, and apply linked list data Form, by phase place storage corresponding for each degree of depth of movement, i.e. sets up phase height look-up table.

The 3-D profile real-time measuring method of dynamic object the most according to claim 1 and 2, it is characterised in that described Phase shift color fringe image is projected according to the Measuring Object height change synchronizing signal being placed in measurement space, particularly as follows: in single shot Under the conditions of absorb secondary color bar graph, the secondary color striped of described picked-up is separated and forms single color stripe figure, and carry out color cross-talk school Just, it is thus achieved that for demodulating the phase shift color fringe image of object surface appearance.

The 3-D profile real-time measuring method of dynamic object the most according to claim 4, it is characterised in that described picked-up Secondary color striped separate and form single color stripe figure, and carry out color cross-talk correction, particularly as follows: use following color recovery model

$\left[\begin{array}{c}{f}_R^{\&prime;}(x,y)\\ f_G^{\&prime;}(x,y)\\ f_B^{\&prime;}(x,y)\end{array}\right]=M_{ref}{M}_{bal}{M}_{cou}\left[\begin{array}{c}{f}_R^C(x,y)\\ f_G^C(x,y)\\ f_B^C(x,y)\end{array}\right]---\left(1\right)$

Wherein, f '_i(x, y), i=R, G, B are each Color Channel striped after color decoupling, color balance and reflectance normalization Figure, M_ref、M_bal、M_couRepresent each color light relative reflection rate matrix, color balance matrix and color coupling matrix respectively, logical Cross typical scaling method to obtain, and have:

$\begin{array}{cc}{M}_{ref}=\left[\begin{array}{ccc}1& 0& 0\\ 0& P_{GR}(x,y)& 0\\ 0& 0& P_{BR}(x,y)\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(2\right)$

$\begin{array}{cc}{M}_{bal}=\left[\begin{array}{ccc}1& 0& 0\\ 0& Q_{GR}\left(f_G^C\right(x,y\left)\right)& 0\\ 0& 0& Q_{BR}\left(f_B^C\right(x,y\left)\right)\end{array}\right],& \backslash *MERGEFORMAT\end{array}---\left(3\right)$

$\begin{array}{cc}{M}_{cou}=\left[\begin{array}{ccc}1& C_{RG}\left(f_R^C\right(x,y\left)\right)& C_{RG}\left(f_R^C\right(x,y\left)\right)\\ C_{GR}\left(f_G^C\right(x,y\left)\right)& 1& C_{GB}\left(f_G^C\right(x,y\left)\right)\\ C_{BR}\left(f_B^C\right(x,y\left)\right)& C_{BG}\left(f_B^C\right(x,y\left)\right)& 1\end{array}\right].& \backslash *MERGEFORMAT\end{array}---\left(4\right).$