CN101865674A - Phase information reading method and three-dimensional topography measurement system thereof - Google Patents

Abstract

The invention relates to a phase information reading method and a three-dimensional topography measurement system thereof. The invention provides an intermediate-pass filter which is utilized to obtain spectrum information corresponding to phase information and can approach to the appearance of an effective signal spectrum area in a spectrum image in the process of reading the phase information in the spectrum image. In one embodiment, the spectrum range of the intermediate-pass filter can be optimized by utilizing the method, so that the topography of the reduced surface is more accurate. Furthermore, the invention further provides the three-dimensional topography measurement system by utilizing the method, which can read a stripe image about an object, and obtains the phase information to the stripe image by utilizing the phase information reading method so as to reduce the topography of the surface of the object.

Description

Phase information read method and three dimensional shape measurement system thereof

Technical field

The present invention relates to a kind of phase information acquisition of technology, refer in particular to a kind of utilization and can press close to have the middle bandpass filter of spectral regions profile of phase information with a kind of phase information read method and the three dimensional shape measurement system thereof of the required phase information of leaching reduction phase place.

Background technology

Along with making rapid progress and industrial development of science and technology, measurement to surface profile, physical dimension, roughness, free form surface is more and more important, the requirement of precision is also more and more higher, but problems of measurement on the at present important line, is subject to the influence of environmental perturbation and produces measuring error.So it is increasingly important to have the technology of measuring three-dimensional morphology and instant measurement capability.

For example at the open application case US.Pat.No.4 of the U.S., 768,881 disclosed a kind of fourier transform measuring three-dimensional morphology technology that are applied to, it is to utilize interference fringe to be projected on the determinand, read its image by the image reading unit again, described technology is to use square image Chooser with square outer space image information filtering, then forwards the part of pass filter in the frequency domain execution to, obtains the three-dimensional appearance of its phase information and then reconstruction object.In addition, people such as another prior art such as C é dric Br é luzeau propose " Automatedfringe-pattern extrapolation for patterned surface profiling byinterference microscopy with Fourier transform analysis; " Proceedingsof SPIE, vol.5858,2005, it is to utilize an adjustable middle bandpass filter, sets related threshold and reaches best filter effect, avoids introducing the measuring error of three-dimensional reconstruction.In described technology, though the difform wave filter of exposure is arranged, but the shape of described wave filter only contains the stronger contiguous spectral regions of phase frequency spectrum signal, be not to contain the spectral regions that all has phase information, therefore the result of the surface topography that is reduced probably has real topography to rebuild the problem appearance of distortion, especially for the object appearance with acute angle, described problem more is prone to, and then influences the result that 3-dimensional image is measured.

Though bandpass filter read in the frequency spectrum image about the zone of phase information in order to performing calculations during but aforementioned techniques was utilized in the frequency spectrum image, and then reduction determinand image.Yet, bandpass filter among the existing two-dimensional member of Imperial Academy (2-D Hanning filter) or circular (circular), the frequency spectrum image capturing range that it read also can't completely be contained the zone about the determinand phase information, therefore in the result of follow-up reduction computing with reconstruction determinand surface topography, promptly can with the shape characteristic (size or shape) of determinand reality difference to some extent, and then the result that detects of influence.Shown in Figure 1A to Fig. 1 G, described figure is existing each stage striograph that utilizes the circular filter device spherical determinand to be carried out the surface topography reduction.Wherein, Figure 1A is for having the image of striated structure spatial domain that light reads (spatial domain) to spherical determinand projection.Figure 1B carries out the frequency spectrum image that Fu Liye changes resultant frequency domain (frequency domain) for the image to Figure 1A.Then in the zone of corresponding positive single order of the image of Figure 1B or negative first order spectrum, utilize bandpass filter in the circle (shown in Fig. 1 C) filter a spectrum information.Then described spectrum information is carried out the Fourier inverse transform and can obtain corresponding phase place encapsulation figure, shown in Fig. 1 D.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize again and draw conversion calculus and phase place reduction technique (phaseunwrapping) especially, obtain continuous phase place image (shown in Fig. 1 E) with reduction, and then rebuild the surface topography of determinand.Shown in Fig. 1 F and Fig. 1 G, wherein Fig. 1 F is the 3 D stereo reduction image of determinand, and Fig. 1 G is the determinand cross-sectional images.Shown in Fig. 1 H to Fig. 1 L, wherein Fig. 1 H has the high slip gauge structure in rank.Obtain according to Fig. 1 H after the striped striograph 1I of spatial domain (spatial domain), utilize Fu Li leaf conversion and obtain the frequency spectrum image of frequency domain (frequency domain), shown in Fig. 1 J.Spectrum information according to bandpass filter gained in the circle of people such as aforesaid C é dric Br é luzeau proposition carries out the phase place encapsulation figure that the Fourier inverse transform can obtain correspondence, utilize again and draw conversion calculus and phase place reduction technique (phase unwrapping) especially, obtain continuous phase place image with reduction, and then rebuild the surface topography of determinand.Shown in Fig. 1 K and Fig. 1 L, wherein Fig. 1 K is the 3 D stereo reduction image of determinand, and Fig. 1 L determinand cross-sectional images.According to described section profile result, it is circular-arc to find to utilize the high structural edge in rank of circular filter device gained to present because of distortion, does not have the structure at right angle.

Comprehensively above-mentioned, therefore need a kind of phase information read method and three dimensional shape measurement system thereof badly, solve the problem that prior art produces.

Summary of the invention

A purpose of the present invention provides a kind of phase information read method, it is to utilize the middle bandpass filter of the profile that can be close to the spectral regions with phase information to read spectrum information in a frequency spectrum image, then described spectrum information is performed calculations obtaining the phase information about determinand, and then reduce the pattern of described determinand according to described phase information.By ellipse can with in the frequency spectrum image about the complete taking-up of image of phase information, the surface topography error that obtains when making image reduction is lower.

Another object of the present invention provides a kind of three dimensional shape measurement system, and it is a striped image that can read about determinand, and changes described striped image and form a frequency spectrum image, and then described frequency spectrum image is carried out phase information reads in the image.Wherein, in described system, utilize wave filter on described frequency spectrum image, to have in the spectral regions of phase information and read a spectrum information, the shape of described wave filter is the profile that is close to described spectral regions, and then utilizes the algorithm of image reduction to obtain the surface topography of described determinand.

Still a further object of the present invention provides a kind of three dimensional shape measurement system, it is can utilize the formed striped image of striated structure light or pass through to interfere formed interference fringe image, and change described striped image and form a frequency spectrum image, and then described frequency spectrum image is carried out image information read.Utilize the system of invention can utilize single striped image to get final product the object analysis surface topography, save to have now and utilize the multistep phase shift reduction needed time of object surface appearance, and avoid existing multistep phase shift in the detecting process, to cause the problem of restore information error because of ambient vibration.

In order to achieve the above object, the invention provides a kind of phase information read method, it includes the following step: obtain the striped image with an object surface appearance phase information; Obtain a frequency spectrum image of described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively; Read a spectrum information with a wave filter in described main spectrum signal district and less important spectrum signal district, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district; And described spectrum information performed calculations to obtain corresponding described phase information.

In order to achieve the above object, the invention provides a kind of three dimensional shape measurement system, comprising: a structural light stripes projecting unit, it is on projection one striated structure light to one object; One image fetch device, it is to read the striped image with described object surface appearance phase information; An and control module, it is to communicate to connect with described image fetch device, described control module is handled to obtain a corresponding frequency spectrum image described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively, in described main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district, more described spectrum information is performed calculations to obtain corresponding described phase information.

In order to achieve the above object, the present invention also provides a kind of three dimensional shape measurement system, comprising: a light source projects portion, and it provides a light field; One modulation of source portion, it is modulated into a reference light and a detected light with described light field, and described detected light is projected on the object with formation to be had an object test light of object surface appearance phase information and interferes to form an interference light with described reference light; One image fetch device, it is the described interference light of sensing and form a striped image (interferograms); An and control module, it is to communicate to connect with described image fetch device, described control module is handled to obtain a corresponding frequency spectrum image described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively, and in described main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district, more described spectrum information is performed calculations to obtain corresponding described phase information.

Beneficial effect of the present invention is: phase information read method provided by the invention and three dimensional shape measurement system thereof, it can accurately read the foundation of effective signal spectrum as follow-up image reconstruction, to obtain accurate image morphology.

Description of drawings

Figure 1A to Fig. 1 G is existing each stage striograph that utilizes the circular filter device spherical object to be carried out the surface topography reduction.

Fig. 1 H to Fig. 1 L is the surface topography schematic flow sheet that utilizes the local filter of prior art to reduce.

Fig. 2 is a phase information read method embodiment schematic flow sheet of the present invention.

Fig. 3 A and Fig. 3 B are that multi-form structured light is projected to the striped striograph that object reads.

Fig. 4 A and Fig. 4 B are the spectrogram with the deforming stripe image.

Fig. 4 C then is the stereographic map of frequency spectrum.

Fig. 4 D then has the 2-d spectrum value synoptic diagram of extremal region on the XZ plane for the frequency spectrum stereographic map of Fig. 4 C.

Fig. 4 E is the first rank spectral regions profile synoptic diagram.

Fig. 5 A and Fig. 5 B are bandpass filter synoptic diagram in the ellipse.

Fig. 6 A and Fig. 6 B are that bandpass filter reads the spectrum information synoptic diagram in the ellipse.

Fig. 7 A to Fig. 7 C is the multi-form middle bandpass filter embodiment synoptic diagram of the present invention.

Fig. 8 is bandpass filter schematic flow sheet in the optimization ellipse of the present invention.

Fig. 9 A is a three dimensional shape measurement system embodiment synoptic diagram of the present invention.

Fig. 9 B is another embodiment synoptic diagram of three dimensional shape measurement system of the present invention.

Fig. 9 C is that three dimensional shape measurement system of the present invention utilizes interference mode to produce the embodiment synoptic diagram of striped image.

Fig. 9 D is that three dimensional shape measurement system of the present invention utilizes interference mode to produce another embodiment synoptic diagram of striped image.

Figure 10 A to Figure 10 D utilizes in the rectangle of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a spherical object.

Figure 11 A to Figure 11 E utilizes in the ellipse of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a spherical object.

Figure 12 A to Figure 12 E utilizes rectangle of the present invention to coincide circular middle bandpass filter according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a spherical object.

Figure 13 A to Figure 13 D utilizes in the rhombus of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a spherical object.

Shown in Figure 14 A and Figure 14 B, described figure is the image synoptic diagram that utilizes region-wide middle bandpass filter of the present invention to reduce for the structure of Fig. 1 H.

Description of reference numerals: 1-phase information read method; 10～13-step; 2a, 2b-elliptic filters; The 20-center; The 21-major axis; The 22-minor axis; 30-zeroth order fundamental frequency spectral regions; The local maximum of 300-fundamental frequency; The 301-vertex position; 302-minor axis lower boundary; The zone of 31-first order spectrum; The local maximum extreme value of 310-; The 311-minor axis; The 312-major axis; The 313-summit; The 314-minimum point; The zone of 32-second order frequency spectrum; The local maximum extreme value of 320-; The 321-summit; 322-minor axis coboundary; The 323-minimum point; The 33-wave filter; 40-zeroth order fundamental frequency spectral regions; The local maximum of 400-fundamental frequency; The 401-vertex position; The 402-limit on the right-right-hand limit; 403-minor axis left margin; The zone of 41-first order spectrum; The local maximum extreme value of 410-; The 411-major axis; The 412-minor axis; 413, the 414-left and right sides limit; The 414-minimum point; The zone of 42-second order frequency spectrum; The local maximum extreme value of 420-; 421, the 423-left and right sides limit; 424-minor axis right margin; 43,44,45,46-wave filter; 47,48-first order spectrum zone; Bandpass filter method in the 5-optimization ellipse; 50～57-step; The 6-three dimensional shape measurement system; 60-structural light stripes projecting unit; 600-striated structure light; 61-collimating mirror group; The 62-image fetch device; The 63-control module; The 64-object; The 7-three dimensional shape measurement system; 70-light source projects portion; 700-optical fiber; 71-modulation of source portion; The 710-optical fiber coupler; The 711-collimation lens set; The 712-grating; The 713-lens combination; The 714-projector; The 72-image fetch device; The 73-control module; The 74-object; The 8-three dimensional shape measurement system; 80-light source projects portion; 81-mirror group; 82,87-modulation of source portion; The 83-image fetch device; The 84-control module; 85a, 85b-lens; The 86-spectroscope; The 89-object; 90,91,92-zone; The main spectrum region of 910-; 911, the less important spectrum region of 912-; 901,913,921-extreme value place.

Embodiment

For making your juror further cognitive and understanding be arranged to feature of the present invention, purpose and function, hereinafter the spy describes the relevant thin portion structure of device of the present invention and the theory reason of design, so that the juror can understand characteristics of the present invention, detailed description is presented below:

See also shown in Figure 2ly, this figure is a phase information read method embodiment schematic flow sheet of the present invention.In the present embodiment, described method its be to include the following step: at first read a striped image with an object surface appearance phase information with step 10.Described striped image is periodicity or acyclic deforming stripe image (deformed fringe images), is aperiodicity deforming stripe image at present embodiment.In step 10, described striped image is to get by single-frequency scanning or double frequency scanning.So-called single-frequency scanning is meant and utilizes the structured light with single cycle striped to be projected on the object, utilize image fetch device to read then about the deforming stripe image (deformed fringe patterns) of described object under the structured light in described single cycle, as shown in Figure 3A.In Fig. 3 A, the described structured light that is projected to object only is single cycle P0.The image of double frequency scanning can be with reference to shown in Fig. 3 B in addition, and it is to be projected to formed image with double frequency periodicity striped on the object to have the double frequency structured light.Wherein, in the image of Fig. 3 B, have two structured light cycle P ₁With P ₂The structured light that has a striped except aforementioned utilization is projected to object and obtains the deforming stripe image, in step 10, more can utilize existing interfere type system, for example: McKesson formula interference system or Mirau interference system are interfered reference light and the object test light with surface topography phase information to be measured mutually and are obtained the striped image of interference.

Return shown in Figure 2ly, then carry out step 11, obtain a frequency spectrum image about described striped image.In this step, mainly be that described striped image is carried out fourier transform, with the deforming stripe video conversion of time domain to the frequency domain space.With the formed deforming stripe image of single-frequency structured light is example (as shown in Figure 3A), when formed image after it converts frequency domain to is shown in Fig. 4 A to Fig. 4 D.Wherein Fig. 4 A and Fig. 4 B are the spectrogram with the deforming stripe image; Fig. 4 C then is the stereographic map of frequency spectrum; Fig. 4 D then has the 2-d spectrum value synoptic diagram of extremal region on the XZ plane for the frequency spectrum stereographic map of Fig. 4 C.Wherein the extreme value place 901,913 and 921 of Fig. 4 D is bright band zone 90,91 in Fig. 4 A intermediate frequency spectrum image and 92 center.With Fig. 4 A is example, and the zone 90 that wherein local gray-value is high is zeroth order frequency spectrums of the described deforming stripe of representative, and the zone 91 that the gray-scale value of regional 90 both sides is high and 92 frequency spectrums of representing the 1st rank are respectively analogized then in regular turn, do not give unnecessary details at this.And the position, signal area with object surface appearance phase information is the spectral regions 92 of positive single order 91 or negative single order.Spectral regions 91 with positive single order is an example, and described spectral regions is to have a main spectrum signal district 910, and its both sides have a less important spectrum signal district 911 and 912 that extends to described frequency spectrum image side respectively.

Return shown in Figure 2ly, then carry out step 12, read a spectrum information with a wave filter in described main spectrum signal district and less important spectrum signal district, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district.Before this step of explanation, first talk about this notion of Benq, in the prior art, be example with the deforming stripe image of single-frequency, described image is to represent by following formula (1):

i(x，y)＝a(x，y)+b(x，y)cos[φ(x，y)]+n(x，y)………………(1)

Wherein, (x y) is the image coordinate, and x and y are respectively the row of image coordinate and the numerical value of row; (x y) is light intensity to i; (x y) is image background average luminous intensity to a; (x y) is striped intensity variation amplitude to b; (x y) is phase information to be measured to φ; And n (x y) is noise intensity (noise intensity).

Then (x y) divides into carrier phase phi with φ _c(x, y) (carrier phase) and initial phase φ ₀(x, y), shown in (2).φ wherein _c(x y) can be defined as shown in the formula (3) f in formula (3) again _{C, x}With f _{C, y}Be respectively the spatial frequency of level and vertical aspect.

φ(x，y)＝φ _c(x，y)+φ ₀(x，y)………………(2)

φ _c(x，y)＝2π(f _c，xx+f _c，yy)………………(3)

Formula (2) and formula (3) brought in the formula (1) obtain suc as formula (4).Not only because the cos[alpha+beta] so=cos α cos β-sin α sin β formula (4) but also can deduce an accepted way of doing sth (5).

i(x，y)＝a(x，y)+b(x，y)cos[φ _c(x，y)+φ ₀(x，y)]+n(x，y)………………(4)

i(x，y)＝a(x，y)+b(x，y)cosφ _c(x，y)cosφ ₀(x，y)-b(x，y)sinφ _c(x，y)sinφ ₀(x，y)+n(x，y)

………………(5)

Again formula (5) is decomposed the result that can obtain suc as formula (6).

$i(x,y)=a(x,y)+\frac{1}{2}b(x,y)[{\cos \mathrm{\φ}}_c(x,y)+{j\sin \mathrm{\φ}}_c(x,y)][{\cos \mathrm{\φ}}_0(x,y)+{j\sin \mathrm{\φ}}_0(x,y)]$

$+\frac{1}{2}b(x,y)[{\cos \mathrm{\φ}}_c(x,y)-{j\sin \mathrm{\φ}}_c(x,y)][{\cos \mathrm{\φ}}_0(x,y)-{j\sin \mathrm{\φ}}_0(x,y)]+n(x,y)$

$...\left(6\right)$

Suppose

In the formula of bringing into (6), can further deduce the result of the formula of obtaining (7).

i(x，y)＝a(x，y)+c(x，y)exp[jφ _c(x，y)]+c ^*(x，y)exp[-jφ _c(x，y)]+n(x，y)…(7)

Wherein fourier transform is shown in the formula (8):

$C(f_x-f_{c,x},f_y-f_{c,y})={\&Integral;}_{-\&infin;}^{\&infin;}{\&Integral;}_{-\&infin;}^{\&infin;}c(x,y)\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H200910135212XE0000062.png,H200910135212XE0000071.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f_{c,x}x+f_{c,y}y)\right]\mathrm{dxdy}...\left(8\right)$

Formula (8) can be obtained as the formula (9) result through fourier transform.

I(f _x，f _y)＝A(f _x，f _y)+C(f _x-f _c，x，f _y-f _c，y)+C ^*(f _x+f _c，x，f _y+f _c，y)+N(f _x，f _y)…(9)

In like manner, also be that similar aforesaid deduction obtains as the formula (10) for the structured light of double frequency, C wherein _EqWith C _Eq ^*Spectrum information for equivalent period striped (Equivalent period fringes).As for the skill of deducing is to belong to existing technology, does not give unnecessary details at this.

I(f _x，f _y)＝A(f _x，f _y)+C ₁(f _x-f _1x，f _y-f _1y)+C ₁ ^*(f _x+f _1x，f _y+f _1y)

C ₂(f _x-f _2x，f _y-f _2y)+C ₂ ^*(f _x+f _2x，f _y+f _2y) …(10)

C _eq(f _x-f _3x，f _y-f _3y)+C _eq ^*(f _x+f _3x，f _y+f _3y)

Through resulting frequency spectrum after the above-mentioned conversion

C _I=1,2(f _x-f _{C, x}, f _y-f _{C, y}) or C ^* _I=1,2(f _x-f _{C, x}, f _y-f _{C, y}), the phase information that this information is changed to object appearance the time corresponding to structured light projection.Whether correct described phase information then be related to when in the future reducing object appearance key.And described phase information in the position of frequency spectrum image the position of first rank or other high-order frequency spectrums just, be example with the single-frequency structural light stripes, that is label 91 or 92 spectral regions among Fig. 4 A or Fig. 4 D.

For the spectrum information (the first rank frequency spectrum) that has phase information as described in frequency spectrum image (as Fig. 4 A), obtaining, in the prior art, normally utilize the two-dimentional member of Imperial Academy (2-D Hanning filter) or circular middle bandpass filter (band-pass filter), the spectrum information in described main spectrum signal district is read out, obtain phase information through follow-up calculation again, and then obtain the three-dimensional appearance of object.And step 12 in the present embodiment is not to utilize circular middle bandpass filter, and be to use contain spectrum distribution zone, first rank main in the wave filter in main spectrum signal district and less important spectrum signal district obtain spectrum information.See also shown in Fig. 4 A, zone 93 is the zone of containing first order spectrum, and described zone is amplified then as shown in Fig. 4 E, and described figure is the first rank spectral regions profile synoptic diagram.Hatched example areas is the spectrum information zone with phase information.The present invention then utilize difform in bandpass filter try one's best and press close to meet the profile in described zone.

And wave filter used in the present invention is in order to meet the distribution scenario of true three-dimension frequency spectrum, designs an elliptic filters 2a and 2b (shown in Fig. 5 A and Fig. 5 B two types), represented by following formula (11):

$\left\{\begin{array}{ccc}\frac{{(x-h)}^2}{a^2}+\frac{{(y-k)}^2}{b^2}=1& \mathrm{for}& -a\&le;x\&le;a,-b\&le;y\&le;b\\ \frac{{(x-h)}^2}{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="H200910135212XE0000062.png,H200910135212XE0000071.png"\; state="\{\{state\}\}">b</figure-callout>}}^2}+\frac{{(y-k)}^2}{a^2}=1& \mathrm{for}& -a\&le;y\&le;a,-b\&le;x\&le;b\end{array}\right....\left(11\right)$

Wherein, (h k) is the symcenter point, the position at the center 20 of Fig. 5 A and Fig. 5 B; A is the length of long axis of ellipse 21; B is the length of the minor axis 22 of ellipse.And the center 20 of elliptic filter 2 is promptly corresponding to the position that is positioned at zone 91 or zone 92 local maximum among Fig. 4 A, that is the position that has maximum gradation value in described zone.

Utilize this elliptic filter can correctly read out projected fringe than complete frequency spectrum information, and this wave filter can be divided into two kinds of embodiments.First kind of embodiment is, when the projecting structural optical angle less than 45 the degree, or between 135 the degree and 180 the degree between the time, the synoptic diagram of its filter applies is as shown in Figure 6A, its be when the angle of projecting structural optical less than 45 degree, or the frequency spectrum image synoptic diagram between 135 degree and 180 degree the time.Because structured light may have the angle of inclination, therefore in Fig. 6 A, the line of centres of the spectral regions on each rank will become to have now the distribution of angle.Wherein, label 30 is a zeroth order fundamental frequency spectral regions, and label 300 is the local maximum position of fundamental frequency.Zeroth order fundamental frequency spectral regions has vertex position 301.And zone 31 is the zone of first order spectrum that is the zone with phase information.Have local maximum extreme value 310 described regional 31,31 in zone has summit 313 and minimum point 314 respectively.And zone 32 is the zone of second order frequency spectrum, has local maximum extreme value 320 at described regional 32, and zone 32 has summit 321 and minimum point 323 more respectively.

At first go out the position of kurtosis, find out the true kurtosis 300,310 and 320 of the frequency spectrum of Fig. 6 A by known light projector computation of Period.Next determine the position of elliptic filter, in the present embodiment, the center of elliptic filter 33 is the local maximum extreme values 310 at the place of the kurtosis of the first rank spectral regions, and the maximum length of the major axis of elliptic filter be entire spectrum image frequency spectrum image in half of the image length of first direction (fx).With Fig. 4 A is example, and the maximum length L of its major axis is an image in half of the total length of fx direction.Return shown in Fig. 6 A, the length of its minor axis is the minimum perpendicular distance at the most close described spectral regions 31 centers on a second direction (fy) smaller or equal to local maximum 310 positions of described spectral regions and adjacent spectra zone 30 and 32 then.The deciding means of described vertical range is an end point 323 of seeking the summit 301 and the zone 32 in zone 30 respectively, extends to first direction fx direction then.Get the vertical range of described local maximum 310 and described extension line again.According to aforesaid principle, its condition of elliptic filter equation is as shown in the formula shown in (12):

$\frac{{(x-h)}^2}{{f_a}^2}+\frac{{(y-k)}^2}{{{\mathrm{<figure-callout\; id="2"\; label="f\; b"\; filenames="H200910135212XE0000062.png,H200910135212XE0000071.png"\; state="\{\{state\}\}">f</figure-callout>}}_b}^2}=1$ for $f_b<\stackrel{\&OverBar;}{\left(310\right)\left(302\right)}$ And $f_b<\stackrel{\&OverBar;}{\left(310\right)\left(322\right)}...\left(12\right)$

Wherein, (h, k) the first rank spectral regions local maximum 310; f _aLength for the major axis 312 of Fig. 6 A; f _bBe the length of the minor axis 311 of Fig. 6 A, wherein

Represent the distance of local maximum extreme value 310 and minor axis lower boundary 302, and

Represent the distance of local maximum extreme value 310 and minor axis coboundary 322.

In addition, second kind of situation be, when light projector angle is between 45 degree and 135 degree, and the synoptic diagram of its wave filter such as Fig. 6 B.The local maximum 400 that has zeroth order fundamental frequency spectral regions 40 and fundamental frequency in the synoptic diagram of Fig. 6 B.Fundamental frequency spectral regions 40 has summit 401.And zone 41 is the zone of first order spectrum that is the zone with phase information.Have local maximum extreme value 410 described regional 41, the left and right sides in zone 41 has limit 413 and 414 respectively.And zone 42 is the zone of second order frequency spectrum, has local maximum extreme value 420 described regional 42, and the left and right sides in zone 42 then has limit position 421 and 423 respectively.

At first go out the position of kurtosis, find out the true kurtosis 400,410 and 420 of frequency spectrum, and set the center of elliptic filter 43 by the kurtosis known to the first rank spectral regions 41 by known light projector computation of Period.The maximum length of its major axis be entire spectrum image frequency spectrum image in half of the image length of second direction (fy).The length of its minor axis is then between local maximum 410 positions of described spectral regions and adjacent spectra zone 40 and 42 minimum horizontal distance of close described spectral regions on a first direction (fx).The deciding means of described horizontal range is to seek the right limit 402 in zone 40 and the left limit 423 in zone 42 respectively, extends to second direction fy direction then.Get the horizontal range of described local maximum 410 and described extension line again.According to aforesaid principle, designed its condition of elliptic filter equation is as shown in the formula shown in (13):

$\frac{{(x-h)}^2}{{{\mathrm{<figure-callout\; id="2"\; label="f\; b"\; filenames="H200910135212XE0000062.png,H200910135212XE0000071.png"\; state="\{\{state\}\}">f</figure-callout>}}_b}^2}+\frac{{(y-k)}^2}{{f_a}^2}=1$ for $f_b<\stackrel{\&OverBar;}{\left(410\right)\left(403\right)}$ And $f_b<\stackrel{\&OverBar;}{\left(410\right)\left(424\right)}...\left(13\right)$

Wherein, (h, k) the first rank spectral regions local maximum 410; f _aLength for major axis 411 among Fig. 6 B; f _bBe the length of minor axis 412 among Fig. 6 B, wherein

Represent the distance of local maximum extreme value 410 and minor axis left margin 403, and Represent the distance of local maximum extreme value 410 and minor axis right margin 424.

After the filtering through bandpass filter in the above-mentioned ellipse, can obtain the information of the first rank spectral regions, described information also is C (x, information y) of formula (9).Return shown in Figure 2ly, resulting spectrum information performs calculations to obtain corresponding described phase information with step 13 pair described spectrum information again after having used elliptic filter in the spectral regions that has phase information in described frequency spectrum image.The mode of carrying out be to striped C (x, information y) carry out inverse-Fourier be converted to c (x, y), earlier right for spectrum information being converted to phase information

Expansion is to form the result as shown in the formula (14):

$c(x,y)=\frac{1}{2}b(x,y)\exp \left[\mathrm{j\&phi;}(x,y)\right]=\frac{1}{2}b(x,y)\exp [\cos \left(\mathrm{\&phi;}\right)+j\sin \left(\mathrm{\&phi;}\right)]...\left(14\right)$

The phase information that can obtain the single cycle according to formula (13) is as the formula (15):

$\mathrm{\&phi;}={\tan }^{-1}\left[\frac{\mathrm{Im}\left[c1\right]}{\mathrm{Re}\left[c1\right]}\right]...\left(15\right)$

Phase information as for double frequency reads, and can utilize elliptic filter to obtain double frequency structural light stripes c on the frequency spectrum image _n(x, y) (n=1,2) and equivalent period c _Eq(x y), utilizes the inverse-Fourier conversion this moment, and the single cycle is become phase information with the information translation of equivalent period, and the phase place of wherein corresponding single cycle and equivalent period also can be expressed as formula (14) and (15):

${\mathrm{\&phi;}}_1={\tan }^{-1}\left[\frac{\mathrm{Im}\left[c_1\right]}{\mathrm{Re}\left[c_1\right]}\right]$

${\mathrm{\&phi;}}_2={\tan }^{-1}\left[\frac{\mathrm{Im}\left[c_2\right]}{\mathrm{Re}\left[c_2\right]}\right]...\left(14\right)$

${\mathrm{\&phi;}}_{\mathrm{eq}}={\tan }^{-1}\left[\frac{\mathrm{Im}\left[c_{\mathrm{eq}}\right]}{\mathrm{Re}\left[c_{\mathrm{eq}}\right]}\right]...\left(15\right)$

Had after the phase information, can carry out Phase Build Out.Can obtain corresponding phase place encapsulation figure via the Fourier inverse transform.Because tan (tan ^-1) belong to discontinuous function, so the phase value of reduction is discontinuous state.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize again and draw conversion and phase place reduction technique (phase unwrapping) to obtain continuous phase place especially, and then rebuild the object surfaces pattern with reduction.Aforesaid inverse-Fourier conversion, the technology of drawing conversion and image reduction to rebuild especially are to belong to existing technology, do not give unnecessary details at this.

In aforementioned, employed middle bandpass filter is oval-shaped middle bandpass filter, but the middle bandpass filter that in fact can contain main spectrum signal district and less important spectrum signal district is not limited to ellipse.See also shown in Fig. 7 A and Fig. 7 C, described figure is that the multi-form spectral regions profile of pressing close to positive single order of frequency spectrum or negative single order of the present invention is to contain the middle bandpass filter synoptic diagram in main spectrum signal district and less important spectrum signal district.In Fig. 7 A, described middle bandpass filter is the middle bandpass filter of rhombus.The center of bandpass filter 44 is then in the center of the described first rank spectral regions 47 in the rhombus.The major axis b of bandpass filter 44 in the described rhombus, minor axis is a.In Fig. 7 B, described middle bandpass filter is a rectangular filter 46, and it is main spectrum signal district and the less important spectrum signal district of pressing close to the first rank spectral regions 48.In Fig. 7 C, described middle bandpass filter is that circular filter device 45 is pressed close to the profile of the first rank spectral regions 48 thus with coinciding of rectangular filter 46.According to the spirit of Fig. 7 C, can also utilize the spirit that coincides, have difform wave filter and coincide mutually (for example: circle coincide ellipse or the circle rhombus that coincides) a plurality of, with as in the mode implemented of bandpass filter.

Aforesaid elliptic filter is only mentioned the deciding means of position and major and minor axis, but how not to mention the profile of optimization spectral range that described wave filter is contained.Next, the present invention more with an embodiment process description how optimization of the present invention in bandpass filter.See also shown in Figure 8ly, described figure is that the present invention is embodiment with the elliptic filter, bandpass filter schematic flow sheet in the optimization ellipse.Described method 5 is to include the following step: at first read the striped image that has with reference to sphere about with step 50.This step step 20 with Fig. 2 basically is similar, difference be that (for example: the canonical reference spheroid) as object, wherein said known reference feature includes proper sphere degree or features such as radius, diameter with reference sphere with known reference feature with the object in the step 20.Then carry out step 51, described striped image is carried out fourier transform to form a frequency spectrum image.Then, with step 52, have on described frequency spectrum image with an elliptic filter of specific frequency spectrum scope in the spectral regions of phase information and read a spectrum information, described spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively.The meaning of so-called specific frequency spectrum scope is the elliptic filter (the major axis size of wave filter with the size of frequency spectrum image be what one turns to for guidance or support) of elder generation with any minor axis size, there is no the restriction of certain size.Then carry out step 53, described spectrum information is performed calculations to obtain corresponding described phase information.Step 50 to the flow process of step 53 is that as shown in Figure 2 flow process is the same, and its explanation is as previously mentioned, does not give unnecessary details at this.Then carry out step 54, reduce described phase information to obtain about described at least one eigenwert with reference to sphere.Eigenwert in this step is meant described radius-of-curvature and curvature with reference to sphere, because the reference sphere of present embodiment is a standard ball, therefore described eigenwert includes the radius and the proper sphere degree of described spheroid.

Then, carry out step 55, changes the spectral range of described elliptic filter, and repeat abovementioned steps 52 to step 54 many times to obtain many groups about described at least one eigenwert with reference to sphere.This step changes the scope of described elliptic filter, be meant under the motionless situation of major axis, change the size of minor axis, because can understand minor axis according to formula (12) or (13) can change in a particular range, therefore in step 55, change minor axis length, therefore can obtain the elliptic filter of a specific frequency spectrum scope again, and then repeat step 52 to more than 55 times with this elliptic filter, can obtain the eigenwert combination of many groups, that is the proper sphere degree of many groups and the information of radius of sphericity.And then carry out step 56, described many at least one eigenwerts of group and described fixed reference feature with reference to sphere are carried out error ratio.In this step, because the reference sphere of entity can utilize instrument directly to measure its radius-of-curvature and curvature,, promptly be to utilize accurate surveying instrument to measure the radius and the out of roundness of spheroid with spheroid.And then the out of roundness that each group is restored and radius and actual measurement to value compare.Carry out step 57 more at last, the spectral range of the described group of pairing elliptic filter of at least one eigenwert of Select Error minimum is a bandpass filter in.The spectrum signal that elliptic filter read that utilizes step 57 to determine out, compare the error that minimum is arranged with the value of object actual measurement via resulting eigenwert about object after the reduction, therefore the elliptic filter of described size can be as the filter size size of follow-up Measuring Object.

See also shown in Fig. 9 A, described figure is a three dimensional shape measurement system embodiment synoptic diagram of the present invention.Described three dimensional shape measurement system 6 has a structural light stripes projecting unit 60 1 collimating mirror groups 61, an image fetch device 62 and a control module 63.Described structural light stripes projecting unit 60, it is can throw a striated structure light 600 to object 64, described striated structure light 600 is object test lights of single-frequency or double frequency.Described structural light stripes projecting unit 60 be can by digital light (digital light processing, DLP) or liquid crystal wafer (liquid crystal on silicon LCOS) is main light projector light source.In the present embodiment, be to be digital light (DLP), it is via the output of computer control striped, but use modulation sinusoid structured light (its ultimate principle is the line method that changes), convenience and the diversity of measuring different objects are provided, avoid object because curved sections poor (step heights) causes phase place discontinuous, can utilize digital reflecting element (the digital micromirror device in the digital light, DMD) modulation becomes single (or two) periodic structure striped, measures the high scope in rank to improve it.Described collimation lens 61, it is that described striated structure light 600 is directed on the object 64.In the present embodiment, described modulation of source portion 61 is lens combination, and its thin portion combination is to belong to existing technology, does not give unnecessary details at this.Described image fetch device 62, it is arranged on a side of described object 64, to read the striped image about described object 64.Described control module 63, it is to communicate to connect with described image fetch device 62, described control module 63 is that the flow process that can carry out Fig. 2 and Fig. 8 is handled to obtain a corresponding frequency spectrum image described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively.And in described main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district, more described spectrum information is performed calculations to obtain corresponding described phase information.

See also shown in Fig. 9 B, described figure is another embodiment synoptic diagram of three dimensional shape measurement system of the present invention.Basically similar to Fig. 9 A in the present embodiment, difference be that to have light that a light source projects portion 70 throwed be to be directed in the described modulation of source portion 71 by optical fiber 700 to described structural light stripes projecting unit.Described modulation of source portion last 71 connects with an optical fiber coupler 710 and described optical fiber 700 idols, and described modulation of source portion 71 is made of a collimation lens combination 711, a grating 712, a lens combination 713 and a projector 714.Described collimation lens set 711 earlier collimation by the light that described light source projects portion 70 is sent, produce the striated structure light through grating 712 then after, be projected on the object 74 through the described lens combination 713 and the described projector 714 again.Image fetch device 72 reads the striped image of object 74.Control module 73, it is to communicate to connect with described image fetch device 72, described control module 73 is that the flow process that can carry out Fig. 2 and Fig. 8 is handled to obtain a corresponding frequency spectrum image described striped image, and have on described frequency spectrum image with an elliptic filter in the spectral regions of phase information and read a spectrum information, more described spectrum information is performed calculations to obtain corresponding described phase information.

See also shown in Fig. 9 C and Fig. 9 D, described figure is respectively three dimensional shape measurement system of the present invention to utilize interference mode to produce the embodiment synoptic diagram of striped image.In Fig. 9 C, described three dimensional shape measurement system 8 comprises: a light source projects portion 80, a mirror group 81, modulation of source portion 82, an image fetch device 83 and a control module 84 are arranged.Described light source projects portion 80, it provides a light field, through a mirror group 81 and lens 85a and be projected to described modulation of source portion 82.Described modulation of source portion 82, present embodiment is a Mirau formula interference optics, it is modulated into a reference light and a detected light with described light field, and described detected light is projected on the object 89 to be had an object test light of object surface appearance phase information and form a striped image with lens combination 85b by 83 sensings of described image fetch device through spectroscope 86 to form an interference figure with described reference light interference with formation.

The framework of described Mirau formula interference optics is that existing technology is not given unnecessary details at this.Described control module 84, it is to communicate to connect with described image fetch device 83, described control module 84 utilizes the flow process of Fig. 2 and Fig. 8, described striped image is handled to obtain a corresponding frequency spectrum image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions is to have a main spectrum signal district, its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively, read a spectrum information with a wave filter in described main spectrum signal district and less important spectrum signal district, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district.And then in described main spectrum signal district and less important spectrum signal district, reading a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district.Again described spectrum information is performed calculations obtaining corresponding described phase information, and then reduce the surface topography of described object 89.Shown in Fig. 9 D, described basically system and Fig. 9 C are similar, difference be that described modulation of source portion 87 is McKesson formula (Michelson) interference opticses.Certainly, according to the explanation of this case Fig. 9 C and Fig. 9 D, obtain the mode of striped image and also can utilize Linnik interference system optics framework.

In addition, shown in Figure 10 A to 10D, described figure utilizes in the rectangle of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a canonical reference spherical object.In the present embodiment, utilize a rectangle formed in bandpass filter (shown in Figure 10 A) filter spectrum information.Then described spectrum information is performed calculations to obtain corresponding described phase information.Had after the phase information, can carry out Phase Build Out.Can obtain corresponding phase place encapsulation figure via the Fourier inverse transform, shown in Figure 10 B.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize draws conversion calculus and phase place reduction technique (phaseunwrapping) to obtain continuous phase place image (shown in Figure 10 C) with reduction especially again, and then rebuild the object surfaces pattern, shown in Figure 10 D.

See also shown in Figure 11 A to 11E, described figure utilizes bandpass filter in the ellipse of the present invention, according to phase information read method and three dimensional shape measurement system thereof, and resultant surface topography reduction process and result schematic diagram about a canonical reference spherical object.Wherein, when obtain as Figure 1B about the frequency spectrum image of spherical object the time, in the zone of the corresponding first order spectrum of image of Figure 1B, utilize one oval-shaped in bandpass filter (shown in Figure 11 A) filter spectrum information.Then described spectrum information is performed calculations to obtain corresponding described phase information.Had after the phase information, can carry out Phase Build Out.Can obtain corresponding phase place encapsulation figure via the Fourier inverse transform, shown in Figure 11 B.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize again and draw conversion calculus and phase place reduction technique (phaseunwrapping) especially, obtain continuous phase place image (shown in Figure 11 C) with reduction, and then rebuild the object surfaces pattern, shown in Figure 11 D and Figure 11 E.

See also shown in Figure 12 A to 12E, described figure utilizes circle of the present invention to coincide the formed middle bandpass filter of rectangle according to phase information read method and three dimensional shape measurement system resultant surface topography reduction process and result schematic diagram about a canonical reference spherical object.In the present embodiment, utilize a circle coincide rectangle formed in bandpass filter (shown in Figure 12 A) filter spectrum information.Then described spectrum information is performed calculations to obtain corresponding described phase information.Had after the phase information, can carry out Phase Build Out.Can obtain corresponding phase place encapsulation figure via the Fourier inverse transform, shown in Figure 12 B.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize draws conversion calculus and phase place reduction technique (phase unwrapping) to obtain continuous phase place image (shown in Figure 12 C) with reduction especially again, and then rebuild the object surfaces pattern, shown in Figure 12 D and Figure 12 E.

In addition, shown in Figure 13 A to 13D, described figure utilizes in the rhombus of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system thereof, resultant surface topography reduction process and result schematic diagram about a canonical reference spherical object.In the present embodiment, utilize a rhombus formed in bandpass filter (as shown in FIG. 13A) filter spectrum information.Then described spectrum information is performed calculations to obtain corresponding described phase information.Had after the phase information, can carry out Phase Build Out.Can obtain corresponding phase place encapsulation figure via the Fourier inverse transform, shown in Figure 13 B.In order to allow the discrete state joint of reduction obtain continuous PHASE DISTRIBUTION, therefore must utilize again and draw conversion calculus and phase place reduction technique (phaseunwrapping) especially, obtain continuous phase place image (shown in Figure 13 C) with reduction, and then rebuild the object surfaces pattern, shown in Figure 13 D.

With aforesaid result arrangement as following table one with shown in the table two, described table be utilize of the present invention in the surface topography rebuild of bandpass filter and existing circular filter device to the measurement proper sphere degree error of normative reference ball and the measurement plane degree error result table of normative reference face.Represent according to the result, can find that the result that middle bandpass filter reduced that this case proposes comes well than the result that bandpass filter reduced in the existing circle really.

With aforesaid result arrangement shown in following table three, described table be for utilize of the present invention in the diameter and the surface area error result of the surface topography rebuild of bandpass filter and existing circular filter device.D wherein ₀For actual measurement diameter, the d of object is the diameter of object after reduction; And A ₀, A long-pending for the real surface of object is resulting surface area after reducing.Represent that according to the result surface area that middle bandpass filter reduced that can find this case comes well than the result that bandpass filter reduced in the existing circle with the result of diameter really.

Table one:

Table two:

Table three:

See also in addition shown in Figure 14 A and Figure 14 B, described figure is the image synoptic diagram that utilizes region-wide middle bandpass filter of the present invention to reduce for the structure of Fig. 1 H.Because bandpass filter can be contained the spectral range of positive single order or negative single order in of the present invention, and obtains enough spectrum informations.Therefore, utilize the squareness of its piece stage structure that is had of profile that described spectrum information rebuilds can be by complete reconstruction.Reconstruction cross section profile according to Figure 14 B is compared with the reconstruction cross section profile of Fig. 1 L, can find out obviously that for same structural drawing 1H the accuracy that shape is rebuild is that the accuracy that spectrum signal has that utilizes middle bandpass filter of the present invention to be read comes highly than prior art.

Comprehensively above-mentioned, phase information read method provided by the invention and three dimensional shape measurement system thereof, it can accurately read the foundation of effective signal spectrum as follow-up image reconstruction, to obtain accurate image morphology.Therefore can improve the competitive power of described industry and drive arround the development of industry, really met the required important document that possesses of patent of invention method defined application invention, propose the application of patent of invention in accordance with the law.

More than explanation is just illustrative for the purpose of the present invention, and nonrestrictive, those of ordinary skills understand; under the situation of the spirit and scope that do not break away from following claims and limited, can make many modifications, change; or equivalence, but all will fall within the scope of protection of the present invention.

Claims (20)

1. a phase information read method is characterized in that it comprises the following steps:

Obtain a striped image with an object surface appearance phase information;

Obtain a frequency spectrum image of described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively;

Read a spectrum information with a wave filter in described main spectrum signal district and less important spectrum signal district, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district; And

Described spectrum information is performed calculations to obtain corresponding described phase information.

2. phase information read method as claimed in claim 1 is characterized in that, described wave filter be select combination that rectangular filter, elliptic filter, rhombus wave filter or at least two kinds of difform wave filters coincide mutually one of them.

3. phase information read method as claimed in claim 1 is characterized in that, the center of described wave filter is the described local maximum that has on the phase information zone.

4. phase information read method as claimed in claim 2 is characterized in that, the long axis length that described elliptic filter had be described frequency spectrum image in half of the image length of first direction.

5. phase information read method as claimed in claim 2, it is characterized in that the minor axis length that described elliptic filter had is smaller or equal to the local maximum position of a described spectral regions and adjacent spectra zone minimum perpendicular distance of close described spectral regions on a first direction.

6. phase information read method as claimed in claim 2, it is characterized in that a minor axis length that is had of described elliptic filter is smaller or equal to the local maximum position of a described spectral regions and adjacent spectra zone minimum horizontal distance of close described spectral regions on a first direction.

7. phase information read method as claimed in claim 1 is characterized in that, described striped image is to be projected to described object by a striated structure light to form, and the angle of described striated structure light is more than or equal to 0 degree and smaller or equal to 180 degree.

8. phase information read method as claimed in claim 1 is characterized in that, described striped image is by an interfere type optical system one reference light and a object test light with described object surface appearance phase information to be interfered to form.

9. phase information read method as claimed in claim 1 is characterized in that, it more includes described wave filter is carried out optimized step, and described optimized step more includes the following step:

Have on a wave filter of specific size in the spectral regions of phase information and read a spectrum information about a frequency spectrum image with reference to sphere with at least one fixed reference feature, described spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively;

Described spectrum information is performed calculations to obtain corresponding described phase information;

Reduce described phase information to obtain about described at least one eigenwert with reference to sphere;

Change the spectral range of described wave filter, and repeat aforementioned three steps to obtain many groups about described at least one eigenwert with reference to sphere;

Described many at least one eigenwerts of group and described at least one fixed reference feature with reference to sphere are carried out error ratio; And

The described group of pairing wave filter of at least one eigenwert of Select Error minimum is bandpass filter in.

10. phase information read method as claimed in claim 9 is characterized in that, described eigenwert be proper sphere degree, radius and aforesaid combination one of them.

11. a three dimensional shape measurement system is characterized in that, comprising:

One structural light stripes projecting unit, it is on projection one striated structure light to one object;

One image fetch device, it is to read the striped image with described object surface appearance phase information; And

One control module, it is to communicate to connect with described image fetch device, described control module is handled to obtain a corresponding frequency spectrum image described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively, in described main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district, more described spectrum information is performed calculations to obtain corresponding described phase information.

12. three dimensional shape measurement system as claimed in claim 11 is characterized in that, described structural light stripes projecting unit has more:

One light source projects portion, it is to throw an object test light; And

One modulation of source portion, its be with described object test light be modulated into have striped object test light to be projected on the described object.

13. three dimensional shape measurement system as claimed in claim 12 is characterized in that, described modulation of source portion has an optical grating element.

14. three dimensional shape measurement system as claimed in claim 11 is characterized in that, described structural light stripes projecting unit is a DLP unit or LCOS unit.

15. three dimensional shape measurement system as claimed in claim 11 is characterized in that, described wave filter be select combination that rectangular filter, elliptic filter, rhombus wave filter or at least two kinds of difform wave filters coincide mutually one of them.

16. a three dimensional shape measurement system is characterized in that, comprising:

One light source projects portion, it provides a light field;

One modulation of source portion, it is modulated into a reference light and a detected light with described light field, and described detected light is projected on the object with formation to be had an object test light of object surface appearance phase information and interferes to form an interference light with described reference light;

One image fetch device, it is the described interference light of sensing and form a striped image; And

One control module, it is to communicate to connect with described image fetch device, described control module is handled to obtain a corresponding frequency spectrum image described striped image, described frequency spectrum image has the spectral regions about described object surface appearance phase information, described spectral regions has a main spectrum signal district, its both sides have a less important spectrum signal district that extends to described frequency spectrum image side respectively, and in described main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of described wave filter is to contain described main spectrum signal district and less important spectrum signal district, more described spectrum information is performed calculations to obtain corresponding described phase information.

17. three dimensional shape measurement system as claimed in claim 16 is characterized in that, described modulation of source portion is a McKesson formula interference optics.

18. three dimensional shape measurement system as claimed in claim 16 is characterized in that, described modulation of source portion is a Mirau formula interference optics.

19. three dimensional shape measurement system as claimed in claim 16 is characterized in that, described modulation of source portion is a Linnik formula interference optics.

20. three dimensional shape measurement system as claimed in claim 16 is characterized in that, described wave filter be select combination that rectangular filter, elliptic filter, rhombus wave filter or at least two kinds of difform wave filters coincide mutually one of them.

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