CN101865674B - 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 the middle bandpass filter of spectral regions profile that a kind of utilization can press close to have 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 increasingly high, but problems of measurement on the at present important line, is subject to the influence of environmental perturbation and produces measuring error.So have the technological increasingly important 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 a kind of fourier transform measuring three-dimensional morphology technology of being applied to of being disclosed, it is to utilize interference fringe to be projected on the determinand; Read its image through the image reading unit again; Said 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; " Automatedfringe-pattern extrapolation for patterned surface profiling byinterference microscopy with Fourier transform analysis, " Proceedingsof SPIE that people such as another prior art such as C é dric Br é luzeau propose, 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 said technology; Though the difform wave filter of exposure is arranged, and the shape of said wave filter only contains the stronger contiguous spectral regions of phase frequency spectrum signal, is not to contain the spectral regions that all has phase information; The problem that the result of the surface topography that is therefore reduced probably has real topography to rebuild distortion occurs; Especially for the object appearance with acute angle, said 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 follow-up reduction computing to rebuild the result of determinand surface topography, promptly can with the actual shape characteristic (size or shape) of determinand difference to some extent, and then the result that detects of influence.Shown in Figure 1A to Fig. 1 G, said 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.In the corresponding positive single order of image of Figure 1B or the zone of negative first order spectrum, utilize bandpass filter in the circle (shown in Fig. 1 C) to filter a spectrum information then.Then said 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 let 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 said section profile result, it is circular-arc to find to utilize the high structural edge in rank of circular filter device gained to appear 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 in a frequency spectrum image, to utilize the middle bandpass filter of the profile that can be close to the spectral regions with phase information to read spectrum information; Then said spectrum information is performed calculations obtaining the phase information about determinand, and then reduce the pattern of said determinand according to said phase information.Through 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 said striped image and form a frequency spectrum image, and then said frequency spectrum image is carried out phase information reads in the image.Wherein, In said system; Utilize wave filter on said frequency spectrum image, to have in the spectral regions of phase information and read a spectrum information; The shape of said wave filter is the profile that is close to said spectral regions, and then utilizes the algorithm of image reduction to obtain the surface topography of said determinand.

Still a further object of the present invention provides a kind of three dimensional shape measurement system; It is the formed striped image of striated structure light capable of using or passes through to interfere formed interference fringe image; And change said striped image and form a frequency spectrum image, and then said 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 and existingly to 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 present invention provides a kind of phase information read method, and it includes the following step: obtain the striped image with an object surface appearance phase information; Obtain a frequency spectrum image of said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively; In said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district; And said spectrum information performed calculations to obtain corresponding said phase information.

In order to achieve the above object, the present invention provides a kind of three dimensional shape measurement system, comprising: a structural light stripes projecting unit, and it is on projection one striated structure light to one object; One image fetch device, it is to read the striped image with said object surface appearance phase information; An and control module; It is to communicate by letter with said image fetch device with being connected; Said control module is handled to obtain a corresponding frequency spectrum image said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively, in said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter; The shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district, more said spectrum information is performed calculations to obtain corresponding said 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 said light field, and said 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 said reference light; One image fetch device, it is the said interference light of sensing and form a striped image (interferograms); An and control module; It is to communicate by letter with said image fetch device with being connected; Said control module is handled to obtain a corresponding frequency spectrum image said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively, and in said main spectrum signal district and less important spectrum signal district, reads a spectrum information with a wave filter; The shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district, more said spectrum information is performed calculations to obtain corresponding said 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 resultant about the surface topography reduction process of a spherical object and synoptic diagram as a result according to phase information read method and three dimensional shape measurement system thereof.

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

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

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

Shown in Figure 14 A and Figure 14 B, said 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 cognition and understanding arranged to characteristic of the present invention, purpose and function; The hereinafter 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, specify statement as follows:

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, said method its be to include the following step: at first read a striped image with an object surface appearance phase information with step 10.Said striped image is periodicity or acyclic deforming stripe image (deformed fringe images), is aperiodicity deforming stripe image at present embodiment.In step 10, said striped image is to get through 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 said object under the structured light in said single cycle, shown in Fig. 3 A.In Fig. 3 A, the said structured light that is projected to object is merely 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 each other and are obtained the striped image of interference.

Return shown in Figure 2ly, then carry out step 11, obtain a frequency spectrum image about said striped image.In this step, mainly be that said 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 (shown in Fig. 3 A), 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 the center in the bright band zone 90,91 and 92 in Fig. 4 A intermediate frequency spectrum image.With Fig. 4 A is example, and the zone 90 that wherein local gray-value is high is zeroth order frequency spectrums of the said 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 said 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 said frequency spectrum image side respectively.

Return shown in Figure 2ly, then carry out step 12, in said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of said wave filter is to contain said 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, said 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 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 and to obtain result suc as formula (6).

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

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

..................(6)

Suppose $c(x,y)=\frac{1}{2}b(x,y)\mathrm{Exp}\left[j{\mathrm{\φ}}_0(x,y)\right]$ 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):

$C(f_x-f_{c,x},f_y-f_{c,y})={\&Integral;}_{-\&infin;}^{\&infin;}{\&Integral;}_{-\&infin;}^{\&infin;}c(x,y)\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H200910135212XE00061.png,H200910135212XE00071.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f_{c,x}x+f_{c,y}y)\right]\mathrm{dxdy}...\left(8\right)$

Formula (8) can be obtained suc as formula the result shown in (9) 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 suc as formula shown in (10) for the structured light of double frequency, C wherein _EqWith C _Eq ^*Spectrum information for equivalent period striped (Equivalent period fringes).Skill as for deducing is to belong to existing technology, does not give unnecessary details at this.

I(f _x，f _y)＝A(f _x，f _y)+C1(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 said phase information then be related to when in the future reducing object appearance key.And said 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.

In order in frequency spectrum image (like Fig. 4 A), to obtain said spectrum information (the first rank frequency spectrum) with phase information; 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 said 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 said zone is amplified then as shown in Fig. 4 E, and said 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 said 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):

$\left\{\begin{array}{cc}\frac{{(x-h)}^2}{a^2}+\frac{{(y-k)}^2}{b^2}=1& \mathrm{for}-a\&le;x\&le;a,-b\&le;y\&le;b\\ \frac{{(x-h)}^2}{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="H200910135212XE00061.png,H200910135212XE00071.png"\; state="\{\{state\}\}">b</figure-callout>}}^2}+\frac{{(y-k)}^2}{a^2}=1& \mathrm{for}-a\&le;y\&le;a,-b\&le;x\&le;b\end{array}\right.$

.........(11)

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 in said zone, has maximum gradation value.

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 does; When the projection structure angular 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 shown in Fig. 6 A; It is 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 possibly 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 said 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 said 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 is half the in the image length of first direction (fx) of entire spectrum image frequency spectrum image.With Fig. 4 A is example, and what the maximum length L of its major axis was an image in the total length of fx direction is half the.Return shown in Fig. 6 A, the length of its minor axis then smaller or equal to local maximum 310 positions of said spectral regions and adjacent spectra zone 30 and 32 on a second direction (fy) near the minimum perpendicular distance at said spectral regions 31 centers.The deciding means of said 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 said local maximum 310 and said extension line again.According to aforesaid principle, its condition of elliptic filter equation is as shown in the formula shown in (12):

$\frac{{(x-h)}^2}{{f_a}^2}+\frac{{(y-k)}^2}{{{\mathrm{<figure-callout\; id="2"\; label="f\; b"\; filenames="H200910135212XE00061.png,H200910135212XE00071.png"\; state="\{\{state\}\}">f</figure-callout>}}_b}^2}=1$ For f _b＜(310) (302) and f _b＜(310) (322) (12)

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, the distance of the local maximum extreme value 310 of (310) (320) representative and minor axis lower boundary 302 wherein, and the distance of the local maximum extreme value 310 of (310) (322) representative and minor axis coboundary 322.

In addition, second kind of situation do, 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 said 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 said 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 that the first rank spectral regions 41 is known by known light projector computation of Period.The maximum length of its major axis is half the in the image length of second direction (fy) of entire spectrum image frequency spectrum image.The length of its minor axis then between local maximum 410 positions of said spectral regions and adjacent spectra zone 40 and 42 on a first direction (fx) near a minimum horizontal distance of said spectral regions.The deciding means of said 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 said local maximum 410 and said extension line again.According to aforesaid principle, its condition of elliptic filter equation that is designed is as shown in the formula shown in (13):

$\frac{{(x-h)}^2}{{{\mathrm{<figure-callout\; id="2"\; label="f\; b"\; filenames="H200910135212XE00061.png,H200910135212XE00071.png"\; state="\{\{state\}\}">f</figure-callout>}}_b}^2}+\frac{{(y-k)}^2}{{f_a}^2}=1$ For f _b＜(410) (403) and f _b＜(410) (424) (13)

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 the distance of local maximum extreme value 410 and minor axis left margin 403 is represented in (410) (403), and the distance of local maximum extreme value 410 of (410) (424) representative 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, said information also is C (x, information y) of formula (9).Return shown in Figure 2ly, resulting spectrum information performs calculations to obtain corresponding said phase information with step 13 pair said spectrum information again after having used elliptic filter in the spectral regions that in said frequency spectrum image, has phase information.The mode of carrying out be to striped C (x, information y) carry out inverse-Fourier be converted to c (x, y), earlier right in order spectrum information to be converted to phase information $c(x,y)=\frac{1}{2}b(x,y)\mathrm{Exp}\left[\mathrm{J\&phi;}(x,y)\right]$ Expansion is to form the result as shown in the formula (14):

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

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

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

Phase information as for double frequency reads, and elliptic filter capable of using obtains the 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):

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

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

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

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 let 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, said 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, said middle bandpass filter is the middle bandpass filter of rhombus.The center of bandpass filter 44 is then in the center of the said first rank spectral regions 47 in the rhombus.The major axis b of bandpass filter 44 in the said rhombus, minor axis is a.In Fig. 7 B, said 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, said 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 said 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, said figure is that the present invention is embodiment with the elliptic filter, bandpass filter schematic flow sheet in the optimization ellipse.Said 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 characteristic includes proper sphere degree or characteristics such as radius, diameter with reference sphere with known reference characteristic with the object in the step 20.Then carry out step 51, said striped image is carried out fourier transform to form a frequency spectrum image.Then; With step 52; Have on said frequency spectrum image with an elliptic filter of specific frequency spectrum scope in the spectral regions of phase information and read a spectrum information; Said spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said 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, does not have the restriction of certain size.Then carry out step 53, said spectrum information is performed calculations to obtain corresponding said phase information.The flow process of step 50 to step 53 is that flow process as shown in Figure 2 is the same, and its explanation is as previously mentioned, does not give unnecessary details at this.Then carry out step 54, reduce said phase information to obtain about said at least one eigenwert with reference to sphere.Eigenwert in this step is meant said radius-of-curvature and curvature with reference to sphere, because the reference sphere of present embodiment is a standard ball, therefore said eigenwert includes the radius and the proper sphere degree of said spheroid.

Then, carry out step 55, change the spectral range of said elliptic filter, and repeat abovementioned steps 52 to step 54 many times to obtain many groups about said at least one eigenwert with reference to sphere.This step changes the scope of said elliptic filter; Be meant under the motionless situation of major axis, to change the size of minor axis, can in a particular range, change because can understand minor axis according to formula (12) or (13); 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, said many at least one eigenwerts of group and said fixed reference feature with reference to sphere are carried out error ratio.In this step,,, promptly be to utilize accurate surveying instrument to measure the radius and the out of roundness of spheroid with spheroid because the reference sphere of entity can utilize instrument directly to measure its radius-of-curvature and curvature.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 said group of pairing elliptic filter of at least one eigenwert that Select Error is minimum is a bandpass filter in.The spectrum signal that elliptic filter read that utilizes step 57 decision to come 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 said size can be as the filter size size of follow-up Measuring Object.

See also shown in Fig. 9 A, said figure is a three dimensional shape measurement system embodiment synoptic diagram of the present invention.Said 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.Said structural light stripes projecting unit 60, it is can throw on striated structure light 600 to the object 64, said striated structure light 600 is object test lights of single-frequency or double frequency.Said 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, have avoided object because curved sections poor (step heights) causes phase place discontinuous, (the digital micromirror device of the digital reflecting element in the digital light capable of using; DMD) modulation becomes single (or two) periodic structure striped, measures the high scope in rank to improve it.Said collimation lens 61, it is that said striated structure light 600 is directed on the object 64.In the present embodiment, said 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.Said image fetch device 62, it is arranged on a side of said object 64, to read the striped image about said object 64.Said control module 63; It is to be connected with said image fetch device 62 communications; Said 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 said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information, and said spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively.And in said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter; The shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district, more said spectrum information is performed calculations to obtain corresponding said phase information.

See also shown in Fig. 9 B, said figure is another embodiment synoptic diagram of three dimensional shape measurement system of the present invention.Basically similar with 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 said modulation of source portion 71 through optical fiber 700 to said structural light stripes projecting unit.Said modulation of source portion last 71 connects with an optical fiber coupler 710 and said optical fiber 700 idols, and said modulation of source portion 71 is made up of a collimation lens combination 711, a grating 712, a lens combination 713 and 714 of projectors.The light that said collimation lens set 711 first collimations are sent by said light source projects portion 70, produce the striated structure light through grating 712 then after, be projected on the object 74 through the said lens combination 713 and the said projector 714 again.Image fetch device 72 reads the striped image of object 74.Control module 73; It is to be connected with said image fetch device 72 communications; Said 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 said striped image; And have on said frequency spectrum image with an elliptic filter in the spectral regions of phase information and read a spectrum information, more said spectrum information is performed calculations to obtain corresponding said phase information.

See also shown in Fig. 9 C and Fig. 9 D, said 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, said 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.Said light source projects portion 80, it provides a light field, through a mirror group 81 and lens 85a and be projected to said modulation of source portion 82.Said 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 said light field, and said 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 said image fetch device through spectroscope 86 to form an interference figure with said reference light interference with formation.

The framework of said Mirau formula interference optics is that existing technology is not given unnecessary details at this.Said control module 84; It is to be connected with said image fetch device 83 communications; Said control module 84 utilizes the flow process of Fig. 2 and Fig. 8, and said striped image is handled to obtain a corresponding frequency spectrum image, and said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions is to have a main spectrum signal district; Its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively, in said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, and the shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district.And then in said main spectrum signal district and less important spectrum signal district, reading a spectrum information with a wave filter, the shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district.Again said spectrum information is performed calculations obtaining corresponding said phase information, and then reduce the surface topography of said object 89.Shown in Fig. 9 D, said basically system and Fig. 9 C are similar, difference be that said 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 Linnik interference system also capable of using optics framework of striped image.

In addition, shown in Figure 10 A to 10D, said figure utilizes in the rectangle of the present invention bandpass filter resultant about the surface topography reduction process of a canonical reference spherical object and synoptic diagram as a result according to phase information read method and three dimensional shape measurement system thereof.In the present embodiment, utilize the formed middle bandpass filter (shown in Figure 10 A) of a rectangle to filter spectrum information.Then said spectrum information is performed calculations to obtain corresponding said 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 let 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, said figure utilizes bandpass filter in the ellipse of the present invention, and is according to phase information read method and three dimensional shape measurement system thereof, resultant about the surface topography reduction process of a canonical reference spherical object and synoptic diagram as a result.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 said spectrum information is performed calculations to obtain corresponding said 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 let 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, said figure be utilize circle of the present invention coincide rectangle formed in bandpass filter resultant according to phase information read method and three dimensional shape measurement system thereof about the surface topography reduction process of a canonical reference spherical object and synoptic diagram as a result.In the present embodiment, utilize a circle coincide rectangle formed in bandpass filter (shown in Figure 12 A) filter spectrum information.Then said spectrum information is performed calculations to obtain corresponding said 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 let 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, said figure utilizes in the rhombus of the present invention bandpass filter according to phase information read method and three dimensional shape measurement system thereof, and is resultant about the surface topography reduction process of a canonical reference spherical object and synoptic diagram as a result.In the present embodiment, utilize the formed middle bandpass filter (shown in Figure 13 A) of a rhombus to filter spectrum information.Then said spectrum information is performed calculations to obtain corresponding said 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 let 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 like following table one with shown in the table two, said 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, said 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 reduction.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:

Middle bandpass filter kind	The measurement proper sphere degree error of normative reference ball (standard ball diameter=20mm ± 0.00025mm)
		Circular	0.324mm
Rectangle	0.192mm
		Rhombus	0.175mm
Oval	0.167mm
		The circle rectangle that coincides	0.123mm

Table two:

Middle bandpass filter kind	The measurement plane degree error (zero level precision gauge block) of normative reference face
		Circular	0.135mm
Rectangle	0.073mm
		Rhombus	0.072mm
Oval	0.061mm
		The circle rectangle that coincides	0.055mm

Table three:

See also in addition shown in Figure 14 A and Figure 14 B, said 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 said 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 said 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 spirit that does not break away from following accompanying claims and limited and scope, can make many modifications, change; Or equivalence, but all will fall in protection scope 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 said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively;

In said main spectrum signal district and less important spectrum signal district, read a spectrum information with a wave filter, the shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district; And

Said spectrum information is performed calculations to obtain corresponding said phase information.

2. phase information read method as claimed in claim 1 is characterized in that, said wave filter is to select rectangular filter, elliptic filter, rhombus wave filter one of them or wherein at least two kinds of combinations that difform wave filter coincides mutually.

3. phase information read method as claimed in claim 1 is characterized in that, the center of said wave filter is the said 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 said elliptic filter had is half the in the image length of first direction of said frequency spectrum image.

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

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

7. phase information read method as claimed in claim 1 is characterized in that, said striped image is to be projected to said object through a striated structure light to form, and the angle of said 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, said striped image is through an interfere type optical system one reference light and a object test light with said 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 said wave filter is carried out optimized step, and said 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; Said spectral regions is to have a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively;

Said spectrum information is performed calculations to obtain corresponding said phase information;

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

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

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

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

10. phase information read method as claimed in claim 9 is characterized in that, said 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 said object surface appearance phase information; And

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

12. three dimensional shape measurement system as claimed in claim 11 is characterized in that, said 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 said object test light be modulated into have striped object test light to be projected on the said object.

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

14. three dimensional shape measurement system as claimed in claim 11 is characterized in that, said 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, said wave filter is to select rectangular filter, elliptic filter, rhombus wave filter one of them or wherein at least two kinds of combinations that difform wave filter coincides mutually.

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 said light field, and said 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 said reference light;

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

One control module; It is to communicate by letter with said image fetch device with being connected; Said control module is handled to obtain a corresponding frequency spectrum image said striped image; Said frequency spectrum image has the spectral regions about said object surface appearance phase information; Said spectral regions has a main spectrum signal district, and its both sides have a less important spectrum signal district that extends to said frequency spectrum image side respectively, and in said main spectrum signal district and less important spectrum signal district, reads a spectrum information with a wave filter; The shape of said wave filter is to contain said main spectrum signal district and less important spectrum signal district, more said spectrum information is performed calculations to obtain corresponding said phase information.

17. three dimensional shape measurement system as claimed in claim 16 is characterized in that, said 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, said 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, said 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, said wave filter is to select rectangular filter, elliptic filter, rhombus wave filter one of them or wherein at least two kinds of combinations that difform wave filter coincides mutually.

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