阅读说明：本技术 基于条纹级数不准度的解包裹相位误差检测与校正方法 (Phase Unwrapping Algorithm error detection and correction method based on fringe order not accuracy ) 是由 张春伟 赵宏 张振洋 乔嘉成 于 2019-08-26 设计创作，主要内容包括：本发明公开了一种基于条纹级数不准度的解包裹相位误差检测与校正方法,该方法定义了一种新参量——条纹级数不准度,用于实现对相位图快速、准确的边缘检测,进而进行解包裹相位误差校正。所提方法的主要步骤包括：综合多频相位解包裹中的不同频率相位,计算得到条纹级数不准度,作为相位图边缘检测的媒介；基于条纹级数不准度的空间分布特征,制定相位图边缘判定准则,据此建立相位图边缘逐点检测方案,实现对解包裹相位图的边缘检测；对检测得到的相位图边缘及边缘所包围区域进行解包裹相位误差校正,得到正确的相位分布。本发明所公开方法将解包裹相位误差的检测与校正两个过程相分离,在保证解包裹相位误差校正鲁棒性的前提下,显著提高了对不连续表面相位进行误差校正的效率。(The invention discloses a kind of Phase Unwrapping Algorithm error detection and correction methods based on fringe order not accuracy, the method define a kind of new parameters --- fringe order not accuracy, for realizing to phase diagram fast and accurately edge detection, and then progress Phase Unwrapping Algorithm error correction.The key step of mentioned method includes: the different frequency phase in comprehensive multifrequency phase unpacking, and fringe order not accuracy, the medium as phase diagram edge detection is calculated；Based on the spatial distribution characteristic of fringe order not accuracy, phase diagram edge decision criteria is formulated, establishes the point-by-point detection scheme in phase diagram edge accordingly, realizes the edge detection to Phase Unwrapping Algorithm figure；The phase diagram edge and edge institute's enclosing region obtain to detection carries out Phase Unwrapping Algorithm error correction, obtains correct phase distribution.Presently disclosed method mutually separates the detection of Phase Unwrapping Algorithm error with two processes of correction, under the premise of guaranteeing Phase Unwrapping Algorithm error correction robustness, significantly improves the efficiency that error correction is carried out to noncontinuous surface phase.)

1. the Phase Unwrapping Algorithm error detection and correction method based on fringe order not accuracy, which is characterized in that including following step It is rapid:

Step 1: calculating multifrequency Phase Unwrapping Algorithm figure fringe order not accuracy, the fringe order of multifrequency Phase Unwrapping Algorithm figure all points Accuracy does not form fringe order not accuracy distribution map to number；

Step 2: setting is with the fringe order phase diagram edge detection criteria that accuracy does not characterize；

Step 3: selected starting point, to fringe order, accuracy distribution map is not detected point by point, is examined according to edge set by step 2 Criterion is surveyed to be identified phase diagram edge；

Step 4: repeat step 3 until detected it is all traverse a little, obtain phase diagram edge, phase diagram edge and its surrounded Region is that there may be the points of phase error in phase diagram；

Step 5: multifrequency Phase Unwrapping Algorithm figure line by line or scan by column, will test there may be phase error Point carries out error correction.

2. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 1 Method, which is characterized in that accuracy is not defined as follows the fringe order in the step 1:

In formula, (x, y) indicates that sampled images pixel coordinate, FOI (x, y) indicate that accuracy is not distributed fringe order, k_c(x, y) is item Line series；

And

Wherein, R=T₂/T₁, T₁For the code period of high frequency fringes figure, T₂For the code period of low frequency fringes figure；Φ_l(x, y) is Low frequency fringes true phase,For high frequency fringes wrapped phase, if its Phase Unwrapping Algorithm is Φ_h(x,y)。

3. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 2 Method, which is characterized in that in the step 2, setting is expressed with the fringe order phase diagram edge detection criteria that accuracy characterizes Formula is as follows:

Wherein, edge (x, y) indicates phase diagram Φ_hThe edge distribution figure of (x, y), 1 indicates that the point is phase diagram edge, it is possible to It indicates that the point is not phase diagram edge there are the point of Phase Unwrapping Algorithm error, 0, Phase Unwrapping Algorithm error is not present；(x_a,y_a) be The neighborhood point of point (x, y).

4. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 1 Method, which is characterized in that in the step 3, selected starting point is the point not influenced by Phase Unwrapping Algorithm error；To fringe order When accuracy distribution map is not detected point by point, search is gradually extended to the outside centered on starting point, realizes that phase diagram edge determines.

5. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 1 Method, which is characterized in that in the step 4, the error (x, y) of the point of there may be phase error is set as 1, Its point is set as non-1 number；Error (x, y) is size and Φ_h(x, y) consistent Phase Unwrapping Algorithm error flag(s) matrix, 1 table Show the point there may be Phase Unwrapping Algorithm error, other values indicate that Phase Unwrapping Algorithm error is not present in the point.

6. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 5 Method, which is characterized in that in the step 5, point by point scanning is carried out by one end to the other end to the phase of every a line or each column, when When scanning error (x, y)=1 and not carrying out the point of phase error correction, phase error correction is carried out.

7. a kind of Phase Unwrapping Algorithm error detection and correction side based on fringe order not accuracy according to claim 6 Method, which is characterized in that in the step 5, a little meet edge (x in the front consecutive points of the direction of search when being corrected_a,y_a)≠1 When, bearing calibration are as follows:

Wherein, (x_a,y_a) it is front consecutive points of the point (x, y) in the direction of search, round (*) indicates to be rounded *, For Φ_hPhase value after the correction of (x, y)；

A little meet error (x in the front consecutive points of the direction of search when being corrected_a,y_aWhen)=1, bearing calibration are as follows:

Technical field

The invention belongs to optical three-dimensional measurement technical fields, and in particular to the Phase Unwrapping Algorithm based on fringe order not accuracy Error detection and correction method.

Background technique

Fringe projection technology of profiling is a kind of method for three-dimensional measurement that demand is increasingly extensive, in product quality detection, reverse work There is broad prospect of application in the fields such as journey.Phase is the core parameter that fringe projection technology of profiling carries out three-dimensional reconstruction, and precision is straight It connects and determines three-dimensional measurement precision.Phase is obtained by sampling bar graph through two phase demodulating, Phase- un- wrapping processing steps, essence Degree is determined by demodulation phase precision and Phase Unwrapping Algorithm accuracy rate.Multifrequency method be typical phase unwrapping package method, have by The advantages that point is handled, speed is fast, robustness is good, is widely used.

Although multifrequency method has good robustness, during practical unpacking, due to the complexity of measuring condition, There is unpacking mistake in low signal-to-noise ratio region to be difficult to avoid that.Thus, error-detecting is carried out to multifrequency method Phase Unwrapping Algorithm It is imperative with correcting.Wherein Phase Unwrapping Algorithm error-detecting is the basis of error correction, the phase error obtained based on detection It is the home to return to for carrying out phase error detection that distribution, which carries out error correction, is the important act for ensureing fringe projection technology of profiling measurement accuracy It arranges.

In recent years, domestic and foreign scholars have carried out some fruitful grind in terms of Phase Unwrapping Algorithm error detection and correction Study carefully.More representational to have, Feng Shijie et al. is in article " Automatic identification and removal of A variety of Null Spot detections are illustrated in outliers for high-speed fringe projection profilometry " Method, one of which are to carry out Gaussian smoothing to Phase Unwrapping Algorithm, and it is poor then to make the phase of smooth front and back, and difference is beyond setting The point of threshold value is judged as the point there are unpacking error, and then these points are rejected；Yi Ding et al. is in article “Simplified fringe order correction for absolute phase maps recovered with It is proposed in multiple-spatialfrequency fringe projections ", passes through the phase in detection demodulation phase The mark to same fringe order phase range is realized in jump, and then real in the same fringe order region identified by counting The point of negligible amounts is determined to have the point of unpacking error, and then these fringe orders put is replaced by border fringe order numerical value It is changed to quantity in the region and accounts for leading fringe order numerical value；Dong-ukKam et al. is in article " Unwrapped phase It is proposed in correction for robust 3D scanning ", by calculating the Local standard deviation of intermediate phase, by standard Difference is set as the credible point of initial unpacking lower than the point of given threshold, and then calculates candidate point and the recently credible point of initial unpacking Between two norm distances, the candidate point fringe order less than 2 is just set to true value；Zhang Chunwei et al. is in article " Fringe order error in multi-frequency fringe projection phase unwrapping:reason and It is based on Phase Unwrapping Algorithm spatial distribution characteristic in correction ", proposes and is respectively suitable for continuum and discontinuity zone Fringe order error calibration method.

The above method, which can be realized, rejects or corrects to effective detection of phase error point and error, but there is also not Foot.The mentioned method of Feng Shijie et al. can not detect point of the large area there are Phase Unwrapping Algorithm error, and in addition there are may be to one It is judged by accident by accidentally smooth point, and the error dot detected is corrected a bit not.The mentioned method of Yi Ding et al. is same Sample can not detect point of the large area there are Phase Unwrapping Algorithm error, and when discontinuous in the presence of the larger surface across visual field When, it is possible that the erroneous judgement near zone phase.The mentioned method of Dong-ukKam et al. exists to be mentioned with Feng Shijie et al. The similar deficiency of method, and it is specifically used during need the parameters such as multiple node-by-node algorithm phase mean square deviation, two norms, it is difficult to Realize the quick correction to phase error.The mentioned method of Zhang Chunwei et al. is not by the detection of phase error and correction course point From, thus can not be to there are the phases of discontinuity zone to carry out quick error correction.

Summary of the invention

For deficiency existing for existing Phase Unwrapping Algorithm error detection and correction method, it is an object of the invention to propose one Kind of more robust, the more efficient Phase Unwrapping Algorithm error detection and correction method based on fringe order not accuracy, unpacking error Judgement realized in the form of phase diagram edge detection, be distributed and then realized to error based on the obtained unpacking error of detection Quickly, robust corrects.

In order to achieve the above objectives, the invention adopts the following technical scheme:

Phase Unwrapping Algorithm error detection and correction method based on fringe order not accuracy, comprising the following steps:

Step 1: calculating multifrequency Phase Unwrapping Algorithm figure fringe order not accuracy, the item of multifrequency Phase Unwrapping Algorithm figure all points Accuracy does not form fringe order not accuracy distribution map to line series；

Step 2: setting is with the fringe order phase diagram edge detection criteria that accuracy does not characterize；

Step 3: selected starting point, to fringe order, accuracy distribution map is not detected point by point, according to deckle set by step 2 Edge detection criteria is identified phase diagram edge；

Step 4: repeat step 3 until detected it is all traverse a little, obtain phase diagram edge, phase diagram edge and its institute Enclosing region is that there may be the points of phase error in phase diagram；

Step 5: multifrequency Phase Unwrapping Algorithm figure line by line or scan by column, will test there may be phase mistakes The point of difference carries out error correction.

Further, accuracy is not defined as follows the fringe order in step 1:

In formula, (x, y) indicates that sampled images pixel coordinate, FOI (x, y) indicate that accuracy is not distributed fringe order, k_c(x,y) For fringe order；

And

Wherein, R=T₂/T₁, T₁For the code period of high frequency fringes figure, T₂For the code period of low frequency fringes figure；Φ_l(x, It y) is low frequency fringes true phase,For high frequency fringes wrapped phase, if its Phase Unwrapping Algorithm is Φ_h(x,y)。

Further, in step 2, setting with fringe order not accuracy characterization phase diagram edge detection criteria expression formula It is as follows:

Wherein, edge (x, y) indicates phase diagram Φ_hThe edge distribution figure of (x, y), 1 indicates that the point is phase diagram edge, i.e., It indicates that the point is not phase diagram edge there may be the point of Phase Unwrapping Algorithm error, 0, Phase Unwrapping Algorithm error is not present；(x_a, y_a) be point (x, y) neighborhood point.

Further, in step 3, selected starting point is the point not influenced by Phase Unwrapping Algorithm error；To fringe order When accuracy distribution map is not detected point by point, search is gradually extended to the outside centered on starting point, realizes that phase diagram edge determines.

Further, in step 4, the error (x, y) of the point of there may be phase error is set as 1, it is other Point is set as non-1 number；Error (x, y) is size and Φ_h(x, y) consistent Phase Unwrapping Algorithm error flag(s) matrix, 1 indicates For the point there may be Phase Unwrapping Algorithm error, other values indicate that Phase Unwrapping Algorithm error is not present in the point.

Further, in step 5, point by point scanning is carried out by one end to the other end to the phase of every a line or each column, when When scanning error (x, y)=1 and not carrying out the point of phase error correction, phase error correction is carried out.

Further, in step 5, a little meet edge (x in the front consecutive points of the direction of search when being corrected_a,y_aWhen) ≠ 1, Correcting scheme are as follows:

Wherein, (x_a,y_a) it is front consecutive points of the point (x, y) in the direction of search, round (*) indicates to be rounded *, For Φ_hPhase value after the correction of (x, y)；

A little meet error (x in the front consecutive points of the direction of search when being corrected_a,y_aWhen)=1, bearing calibration are as follows:

Compared with prior art, the present invention at least has technical effect beneficial below: by fringe order, accuracy is not real Now to phase diagram fast and accurately edge detection, accuracy is not association parameter in multifrequency unpacking to fringe order, does not need to disappear Consume extra resource；Spatial distribution characteristic based on fringe order not accuracy, it is determined that phase diagram edge decision criteria, phase diagram side Edge decision criteria has unified edge criterion, avoids the deficiency that decision threshold in conventional method needs subjective setting； The value to fringe order not accuracy distribution map consecutive points is only needed to be compared in edge detection process, without carrying out partial statistics Analysis, it is easy to operate, it is high-efficient；The point that edge detection obtains be considered Phase Unwrapping Algorithm error there may be point, Er Feibi So there are points, have better tolerance, help to realize more accurate Phase- un- wrapping error correction subsequent；By unpacking The detection of phase error is mutually separated with correction, can be improved the efficiency of correction and be improved to discontinuity zone progress phase mistake The robustness of difference correction.

The present invention realizes the quick detection to Phase Unwrapping Algorithm error and corrects, not by data statistics in detection process Information will not theoretically generate the erroneous judgement to the Phase Unwrapping Algorithm error in addition to noncoherent boundary, can be realized to comprising discontinuous The quick of region phase, robust correction.

Detailed description of the invention

Fig. 1 is to set the period as 24 high frequency wrapped phase figure；

Fig. 2 is to set the period as 1536 low-frequency phase bitmap；

Fig. 3 is wrapped phase shown in Fig. 1 by low frequency phase shown in Fig. 2, the high-frequency solution obtained using multifrequency method unpacking Wrapped phase figure；

Fig. 4 is the not accuracy distribution map of fringe order obtained in unpacking process；

Fig. 5 is the edge distribution of fringe order Fig. 3 that accuracy distribution map does not detect as shown in Figure 4；

The point for the there may be phase error that Fig. 6 obtains for phase diagram edge distribution as shown in Figure 5；

Fig. 7 carries out the phase diagram obtained after error correction for the mentioned method of use to Phase Unwrapping Algorithm figure shown in Fig. 3.

Specific embodiment

The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments.

Phase Unwrapping Algorithm error detection and correction method based on fringe order not accuracy, comprising the following steps:

Step 1: fringe order not accuracy is calculated during multifrequency unpacking, the fringe order of phase diagram all points is not Accuracy forms fringe order not accuracy distribution map；

Fig. 1 is to set the period as the sampling sine streak figure of 24 pixels to use the high frequency wrapped phase that demodulates of phase shift method Figure, if high frequency wrapped phase isFig. 2 is to set the period as the true phase of the sampling sine streak figure of 1536 pixels Figure, is set as Φ_l(x,y)。

To high frequency wrapped phase figure as shown in Figure 1 by low-frequency phase bitmap as shown in Figure 2 carry out multifrequency unpacking, obtain as High frequency Phase Unwrapping Algorithm figure shown in Fig. 3, if it is Φ_h(x,y)。

Two groups of phases as shown in Fig. 1, Fig. 2 can be calculated inaccurate corresponding to the fringe order of Fig. 3 according to following formula Degree:

Wherein, R=T₂/T₁=1536/24=64, wherein T₁For high frequency fringes graph code period, T₂For low frequency fringes figure Code period.

Accuracy figure is not as shown in Figure 4 for the fringe order being actually calculated.

Step 2: setting is with the fringe order phase diagram edge detection criteria that accuracy does not characterize；

Specific phase diagram edge detection criteria is as follows:

Wherein, edge (x, y) indicates Φ_hThe edge distribution figure of (x, y), 1 indicates that the point is phase diagram edge, that is, can There can be the point of Phase Unwrapping Algorithm error, 0 indicates that the point is not phase diagram edge, and Phase Unwrapping Algorithm error is not present；(x_a,y_a) For the neighborhood point of point (x, y).

Step 3: selected starting point, to fringe order as shown in Figure 4, accuracy distribution map is not detected point by point, according to step The edge detection criteria of 2 settings is identified phase diagram edge；

To guarantee that selected starting point is the point not influenced by Phase Unwrapping Algorithm error, initial search point is selected in phase The high quality region of figure.The high quality region of phase diagram can be sentenced by a variety of various criterions such as bar graph contrast, phase gradient It is fixed.Starting point is chosen to be (600,250) in the present embodiment.Fig. 5 as detects phase diagram edge shown in obtained Fig. 3, these Edge and its institute's enclosing region are the points in phase diagram shown in Fig. 3 there may be phase error.Comparison diagram 5 and Fig. 3 can be obtained, this Invention disclosed method has been accurately detected edge present in phase diagram.

Step 4: repeat step 3 until detected it is all traverse a little, what is obtained meets the point of edge detection criteria Form phase diagram edge；Phase diagram edge and its institute's enclosing region are that there may be the points of phase error in phase diagram；To own There may be the error (x, y) of the point of phase error to be set as 1, and the error (x, y) of other points is set as 0, wherein error (x, y) is size and Φ_h(x, y) consistent Phase Unwrapping Algorithm error flag(s) matrix.It is finally obtained to there may be unpacking Wrap up in the point of phase error as shown in fig. 6, white area therein be phase error there may be regions.

Step 5: multifrequency Phase Unwrapping Algorithm figure line by line or scan by column, by step 4 detection obtain there may be The point of phase error carries out error correction.Detailed process is as follows:

When being corrected to multifrequency Phase Unwrapping Algorithm error, every a line or each column phase are carried out by one end to the other end Point by point scanning carries out phase error correction when scanning arrives error (x, y)=1 and do not carry out the point of phase error correction.

A little meet error (x in the front consecutive points of the direction of search when being corrected_a,y_aWhen)=0, bearing calibration is

Wherein, (x_a,y_a) it is front consecutive points of the point (x, y) in the direction of search, round (*) indicates to be rounded *,For Φ_hPhase value after the correction of (x, y)；

A little meet error (x in the front consecutive points of the direction of search when being corrected_a,y_aWhen)=1, bearing calibration is

The searching route of phase error correction can carry out a wheel by the right side after having carried out scanning correction from left to right again Scanning correction to the left can also carry out similar scanning correction in a column direction.

It is first here using mentioned method to shown in fig. 6 there may be the point of Phase Unwrapping Algorithm error progress phasing Phase Unwrapping Algorithm figure shown in Fig. 3 is scanned from left to right first, realizes first round phasing, obtains first round correction phase Position, and then first round phase calibration is scanned from right to left, final phase calibration is obtained, as shown in Figure 7.Comparison diagram 3 With Fig. 7 as it can be seen that mentioned method realizes the precise calibration to Phase Unwrapping Algorithm error.Whole process carries out automatically, time-consuming 0.25s shows higher efficiency.

Presently disclosed method be multifrequency Phase Unwrapping Algorithm error in fringe projection technology of profiling accurate judgement with it is quick Correction provides a kind of new method.The phase information of different frequency in comprehensive multifrequency phase unpacking, defines fringe order Not accuracy, the medium as phase diagram edge detection；Spatial distribution characteristic based on fringe order not accuracy, it is determined that phase diagram Edge decision criteria；And then the point-by-point detection scheme in phase diagram edge has been formulated, it the phase diagram edge that detects and its is surrounded Region be Phase Unwrapping Algorithm error there may be regions；Finally to detection obtain there are the points of error to carry out phase line by line Error correction.Presently disclosed method mutually separates the detection of Phase Unwrapping Algorithm error with correction, is obtained by detecting in advance Phase error point realizes the quick correction to phase error.Mentioned method be suitable for there are the phases of discontinuity zone, and Unpacking efficiency will not because of partial discontinuous presence and reduce.

The above content is merely illustrative of the invention's technical idea, and this does not limit the scope of protection of the present invention, all to press According to technical idea proposed by the present invention, any changes made on the basis of the technical scheme each falls within claims of the present invention Protection scope within.