CN104897086A - Structured light phase decoding method based on double-frequency cosine wave - Google Patents
Structured light phase decoding method based on double-frequency cosine wave Download PDFInfo
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Abstract
The invention discloses a structured light phase decoding method based on a double-frequency cosine wave and belongs to the technical field of structured light three-dimensional measurement. The method comprises: projecting a first cosine wave and a second cosine wave, wherein the first cosine wave has a waveform function of y1 = k1*cos (2[pi]x/a1)+b1 and the second cosine wave has a waveform function of y2 = k2* cos (2[pi]x/a2)+b2; according to a given spatial position X, solving the phase main value phi1 of the first cosine wave and the phase main value phi2 of the second cosine wave; reassigning the phase main value phi1 of the first cosine wave and the phase main value phi2 of the second cosine wave: phi1 = a1*phi1/(2[pi]), phi2 = a2*phi2/(2[pi]); solving the difference between the phi1 and the phi2: h = phi1-phi2; solving the period integer of the first cosine wave and the period integer of the second cosine wave contained in the spatial position X, wherein the period integer of the first cosine wave n1 = mod (h, a2)/abs (a1-a2) and the period integer of the second cosine wave n2 = mod (h, a1)/abs (a1-a2); and solving a phase extended value by using n1*a1+phi1 or n2*a2+phi2. The method retains all technical advantages of the methods in the previous inventions and is better in flexibility and specific in algorithm compared with the methods in the previous inventions.
Description
Technical field
Structured light phase decoding method based on double frequency cosine wave (CW) belongs to structural light three-dimensional field of measuring technique.
Background technology
Measuring three-dimensional morphology is all widely used in fields such as scientific research, medical diagnosis, engineering design, criminal investigations.And structured light is as the important component part of measuring three-dimensional morphology means, contactless with it, cost is low, resolution is high and fireballing advantage, obtains the extensive concern of scholars and engineering technical personnel.
Structured light is one group of system architecture be made up of projector and camera.With after projector projects specific optical information to body surface and after background, then gathered by camera, the change in optical signal caused according to object calculates position and the depth information of object, and then restores whole object dimensional pattern.
Encoding and decoding technique is one of key technical problem of structured light, and the most original decoding method projects on testee by the whole cycle of projected light, this mode due to the gray-scale value difference before adjacent two pixels very little, therefore poor anti jamming capability.For the problems referred to above, developed the decoding method combined by two bundle different frequency light, wherein just comprise the method combined by two analog encoding light, the method has high sampling density, high resolving power and high measurement accuracy.But the phase-unwrapping algorithm of these class methods is complicated, and in actual application, discovery can exist phase place main value measuring error and cause phase hit problem.
The problem of and phase hit complicated for phase-unwrapping algorithm, this seminar has applied for patent of invention " the fault-tolerant phase unwrapping engineering method of a kind of double frequency analog encoding light " on November 18th, 2014, hereinafter " phase unwrapping engineering method ", this patent have employed one very simple calculations rule, can phase unwrapping be realized, and overcome the problem of phase hit.
And deepening continuously along with work, find that " phase unwrapping engineering method " can be more perfect, first, this work can specific to the double frequency cosine wave (CW) adopting " phase unwrapping engineering method " not mention, then, breaking through the cosine wave (CW) cycle is the restriction of integer, and double frequency cosine wave (CW) cycle difference is the restriction of 1, finally, the computing method of cosine wave (CW) phase unwrapping are provided.
Summary of the invention
The object of the invention is to carry out further refinement and perfect to earlier application invention " a kind of double frequency analog encoding light fault-tolerant phase unwrapping engineering method ", realize decoding to double frequency cosine wave (CW).
To achieve these goals, the invention discloses a kind of structured light phase decoding method based on double frequency cosine wave (CW), the method continues on the basis of this seminar earlier application patent of invention, not only remain whole technical advantages of earlier application invention, and the first invention that coexists is compared, dirigibility is better, and algorithm more specifically.
The object of the present invention is achieved like this:
Based on the structured light phase decoding method of double frequency cosine wave (CW), comprise the following steps:
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
K1 determines the contrast of the first cosine wave (CW), and a1 is the wavelength of the first cosine wave (CW), and b1 determines the brightness of the first cosine wave (CW);
K2 determines the contrast of the second cosine wave (CW), and a2 is the wavelength of the second cosine wave (CW), and b2 determines the brightness of the second cosine wave (CW);
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number;
Step b, according to given locus X, X ∈ (0, a1 × a2/ (a2-a1)), ask the corresponding phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW) of described locus X;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝a1×phi1/(2π)；
phi2＝a2×phi2/(2π)；
Steps d, ask the difference of step c gained phi1 and phi2: h=phi1-phi2;
Step e, solution room position X comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(h,a2)/abs(a1-a2)；
n2＝mod(h,a1)/abs(a1-a2)；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value.
The above-mentioned structured light phase decoding method based on double frequency cosine wave (CW), described a1 and a2 is all integer, or is all non-integer, or one be integer one is non-integer.
The above-mentioned structured light phase decoding method based on double frequency cosine wave (CW), for simulation calculating, adopt phi1 and phi2 obtained with the following method in step b:
phi1＝arccos(2πX/a1)；
If:
Tan (2 π X/a1) >0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) >0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1)=0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=0;
Tan (2 π X/a1)=0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=π;
phi2＝arccos(2πX/a2)；
If:
Tan (2 π X/a2) >0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) >0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2)=0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=0;
Tan (2 π X/a2)=0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=π;
The above-mentioned structured light phase decoding method based on double frequency cosine wave (CW), between steps d and step e, also comprises steps d ':
If abs (h) is greater than threshold value, h=h;
If abs (h) is not more than threshold value, h=0.
Described threshold value is 10
-10.
A kind of projection acquisition system realizing the above-mentioned structured light phase decoding method based on double frequency cosine wave (CW), comprise projector, measured object and image capturing system, described projector is to measured object projecting structural optical, image capturing system collection projection has the measured object image of structured light, and the structured light of described projector projects is:
Second cosine wave (CW) of wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be y2=k2 × cos (2 π x/a2)+b2;
Wherein:
K1 determines the contrast of the first cosine wave (CW), and a1 is the wavelength of the first cosine wave (CW), and b1 determines the brightness of the first cosine wave (CW);
K2 determines the contrast of the second cosine wave (CW), and a2 is the wavelength of the second cosine wave (CW), and b2 determines the brightness of the second cosine wave (CW);
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number.
Beneficial effect:
The first, due to basic thought continuity " phase unwrapping engineering method " of the present invention, therefore, there is the technical advantage of measurement gross error equally that avoid image information to extract error bringing, and there is the technical advantage that n1 or n2 that avoid having gross error affect computer memory position X actual value.
The second, present invention employs the double frequency cosine wave (CW) that " phase unwrapping engineering method " is not mentioned, give the concrete decoding algorithm of double frequency cosine wave (CW), solve in two fundamental formulars provided at " phase unwrapping engineering method " simultaneously and there will not be, the unforeseeable two problems of those skilled in the art:
First, because the phase place main value of cosine curve is from 0 to 2 π, make each dependent variable can by two independent variable correspondences, therefore need to carry out judgement to phase place main value and assignment again, The present invention gives concrete algorithm, solve this problem;
Secondly, due to rounding up in calculating process, make the slight error of h cause the jumbo saltus step of cycle integer, and then cause the miscount of phase unwrapping value, the present invention, by carrying out threshold decision to h, gives assignment algorithm again, solves this problem.
Three, compare with " phase unwrapping engineering method ", because the definition of the present invention to cosine wave (CW) function comprises k1 and k2 determining cosine wave (CW) contrast, determine b1 and b2 of cosine wave (CW) brightness, and when calculating phase unwrapping value, again not by the impact of these parameters, therefore the inventive method can under the prerequisite not changing cosine wave (CW) wavelength, and arbitrarily adjust the waveform of cosine wave (CW) according to actual needs, dirigibility has more advantage.
Four, compare with " phase unwrapping engineering method ", because the present invention adopts a1/ (a2-a1) ∈ N to limit cosine wave period, therefore complementation string length period of wave is not necessary for positive integer, do not require that the difference in two cosine wave (CW) cycles is necessary for 1 yet, therefore expand the scope of application of waveform, add the dirigibility of waveform selection during practical application.
Five, compare with " phase unwrapping engineering method ", because the present invention adopts a1/ (a2-a1) ∈ N to limit cosine wave period, make when solving n1 and n2, without the need to adopting the round rounding operation adopted in " phase unwrapping engineering method ", because this simplify calculation step.
In sum, the structured light phase decoding method based on double frequency cosine wave (CW) of the present invention, not only remain whole technical advantages of this seminar earlier application invention, and the first invention that coexists is compared, dirigibility is better, and algorithm more specifically.
Accompanying drawing explanation
Fig. 1 is the oscillogram of two cosine wave (CW)s that specific embodiment one is drawn.
Fig. 2 is the oscillogram of two cosine wave (CW)s that specific embodiment two is drawn.
Fig. 3 is the oscillogram of two cosine wave (CW)s that specific embodiment three is drawn.
Embodiment
Below in conjunction with accompanying drawing, the specific embodiment of the invention is described in further detail.
Specific embodiment one
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, for checking with the validity under " phase unwrapping engineering method " parameter the same terms.
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, is characterized in that, comprise the following steps:
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
k1＝1，a1＝9，b1＝0；
k2＝1，a2＝10，b2＝0；
X is locus;
And:
Two cosine wave (CW) starting points are identical;
a1/(a2-a1)＝9；
The figure drawn according to step a parameter as shown in Figure 1;
Step b, according to given locus 38.75, ask the phase place main value phi1 of corresponding first cosine wave (CW) in described the locus 38.75 and phase place main value phi2 of the second cosine wave (CW);
Wherein:
phi1＝arccos(cos(2π×38.75/9))＝1.9199；
Due to tan (2 π × 38.75/9) <0, cos (2 π × 38.75/9) <0, therefore: phi1=phi1=1.9199
phi2＝arccos(cos(2π×38.75/10))＝0.7854；
Due to tan (2 π × 38.75/10) <0, cos (2 π × 38.75/10) >0, therefore: phi2=2 π-phi2=5.4978;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝9×1.9199/(2π)＝2.7501；
phi2＝10×5.4978/(2π)＝8.7500；
Steps d, ask the difference of step c gained phi1 and phi2: h=2.7501-8.7500=-5.9999; Because abs (h) is greater than threshold value 10
-10, therefore h=-5.9999 retains;
Step e, solution room position 38.75 comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(-5.9999,10)/abs(9-10)＝4.0001；
n2＝mod(-5.9999,9)/abs(9-10)＝3.0001；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value, are specially:
n1×a1+phi1＝4.0001×9+2.7501＝38.751；
n2×a2+phi2＝3.0001×10+8.7500＝38.751。
It should be noted that, there is the error of 0.001 in actual phase unwrapping value of trying to achieve and given locus, that computing of rounding off in matlab software calculating process causes, because this error is very little, negligible, therefore can illustrate that the result of calculation of phase unwrapping value is identical with given locus, demonstrate the method with the validity under " phase unwrapping engineering method " parameter the same terms.
Specific embodiment two
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, for verifying that a1 and a2 is not validity during integer entirely.
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, is characterized in that, comprise the following steps:
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
k1＝1，a1＝9，b1＝0；
k2＝1，a2＝10.5，b2＝0；
X is locus;
And:
Two cosine wave (CW) starting points are identical;
a1/(a2-a1)＝6；
The figure drawn according to step a parameter as shown in Figure 2;
Step b, according to given locus 38.75, ask the phase place main value phi1 of corresponding first cosine wave (CW) in described the locus 38.75 and phase place main value phi2 of the second cosine wave (CW);
Wherein:
phi1＝arccos(cos(2π×38.75/9))＝1.9199；
Due to tan (2 π × 38.75/9) <0, cos (2 π × 38.75/9) <0, therefore: phi1=phi1=1.9199
phi2＝arccos(cos(2π×38.75/10.5))＝1.9448；
Due to tan (2 π × 38.75/10.5) >0, cos (2 π × 38.75/10.5) <0, therefore: phi2=2 π-phi2=4.3384;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝9×1.9199/(2π)＝2.7501；
phi2＝10.5×4.3384/(2π)＝7.2500；
Steps d, ask the difference of step c gained phi1 and phi2: h=2.7501-7.2500=-4.4999; Because abs (h) is greater than threshold value 10
-10, therefore h=-4.4999 retains;
Step e, solution room position 38.75 comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(-4.4999,10.5)/abs(9-10.5)＝4.0001；
n2＝mod(-4.4999,9)/abs(9-10.5)＝3.0001；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value, are specially:
n1×a1+phi1＝4.0001×9+2.7501＝38.751；
n2×a2+phi2＝3.0001×10.5+7.2500＝38.751。
It should be noted that, there is the error of 0.001 in actual phase unwrapping value of trying to achieve and given locus, that computing of rounding off in matlab software calculating process causes, because this error is very little, negligible, therefore can illustrate that the result of calculation of phase unwrapping value is identical with given locus, demonstrating the method at a1 and a2 is not validity during integer entirely.
Specific embodiment three
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, for verifying that a1 and a2 is not validity during integer entirely.
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
k1＝1，a1＝8.8，b1＝0；
k2＝1，a2＝9.9，b2＝0；
X is locus;
And:
Two cosine wave (CW) starting points are identical;
a1/(a2-a1)＝8；
The figure drawn according to step a parameter as shown in Figure 3;
Step b, according to given locus 38.75, ask the phase place main value phi1 of corresponding first cosine wave (CW) in described the locus 38.75 and phase place main value phi2 of the second cosine wave (CW);
Wherein:
phi1＝arccos(cos(2π×38.75/8.8))＝2.5347；
Due to tan (2 π × 38.75/8.8) <0, cos (2 π × 38.75/8.8) <0, therefore: phi1=phi1=2.5347
phi2＝arccos(cos(2π×38.75/9.9))＝0.5395；
Due to tan (2 π × 38.75/9.9) <0, cos (2 π × 38.75/9.9) >0, therefore: phi2=2 π-phi2=5.7437;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝8.8×2.5347/(2π)＝3.5500；
phi2＝9.9×5.7437/(2π)＝9.0500；
Steps d, ask the difference of step c gained phi1 and phi2: h=3.5500-9.0500=-5.5000; Because abs (h) is greater than threshold value 10
-10, therefore h=-5.5000 retains;
Step e, solution room position 38.75 comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(-5.5000,9.9)/abs(8.8-9.9)＝4.0000；
n2＝mod(-5.5000,8.8)/abs(8.8-9.9)＝3.0000；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value, are specially:
n1×a1+phi1＝4.0000×8.8+3.5500＝38.75；
n2×a2+phi2＝3.0000×9.9+9.0500＝38.75。
Visible, the result of calculation of phase unwrapping value is identical with given locus, and demonstrating the method at a1 and a2 is not validity during integer entirely.
Specific embodiment four
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, during for verifying that k1 and k2 be not 1, b1 and b2 is not entirely 0 entirely, validity of the present invention.
The structured light phase decoding method based on double frequency cosine wave (CW) of the present embodiment, comprises the following steps:
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
k1＝k1，a1＝a1，b1＝b1；
k2＝k2，a2＝a2，b2＝b2；
Expression like this, illustrates k1, and the selection of a1, b1, k2, a2 and b2 has universality;
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number;
Step b, according to given locus X, ask the corresponding phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW) of described locus X; Be specially:
phi1＝arccos(2πX/a1)；
If:
Tan (2 π X/a1) >0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) >0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1)=0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=0;
Tan (2 π X/a1)=0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=π;
phi2＝arccos(2πX/a2)；
If:
Tan (2 π X/a2) >0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) >0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2)=0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=0;
Tan (2 π X/a2)=0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=π;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝a1×phi1/(2π)；
phi2＝a2×phi2/(2π)；
Steps d, ask the difference of step c gained phi1 and phi2: h=phi1-phi2; And have:
If abs (h) is greater than threshold value, h=h;
If abs (h) is not more than threshold value, h=0;
Described threshold value is 10
-10;
Step e, solution room position X comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(h,a2)/abs(a1-a2)；
n2＝mod(h,a1)/abs(a1-a2)；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
The strict derivation of this formula is described in detail in the patent of invention " phase unwrapping engineering method " of this seminar earlier application, therefore no longer repeats in the application;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value.
Due to the k1 that step a relates to, b1, k2 and b2 not step b, step c, steps d, step e and, occur in step f, therefore, these four parameters are described for net result without any impact, and then can arbitrarily arrange, realize the dirigibility that waveform parameter is selected.
And follow-up formula is with the strict basis that is derived as, therefore equally there is universality, illustrate no matter whether a1 and a2 is integer entirely, and be not integer entirely, or be not integer entirely, this result is all correct, therefore, demonstrates the validity of the inventive method.
Above embodiment all adopts following projection acquisition system, this system comprises projector, measured object and image capturing system, described projector is to measured object projecting structural optical, image capturing system collection projection has the measured object image of structured light, these technical characteristics are all completely the same with traditional structure photosystem, are not repeated.Difference is, the structured light of described projector projects is:
Second cosine wave (CW) of wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be y2=k2 × cos (2 π x/a2)+b2;
Wherein:
K1 determines the contrast of the first cosine wave (CW), and a1 is the wavelength of the first cosine wave (CW), and b1 determines the brightness of the first cosine wave (CW);
K2 determines the contrast of the second cosine wave (CW), and a2 is the wavelength of the second cosine wave (CW), and b2 determines the brightness of the second cosine wave (CW);
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number.
Claims (6)
1., based on the structured light phase decoding method of double frequency cosine wave (CW), it is characterized in that, comprise the following steps:
Step a, to project wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be second cosine wave (CW) of y2=k2 × cos (2 π x/a2)+b2 respectively;
Wherein:
K1 determines the contrast of the first cosine wave (CW), and a1 is the wavelength of the first cosine wave (CW), and b1 determines the brightness of the first cosine wave (CW);
K2 determines the contrast of the second cosine wave (CW), and a2 is the wavelength of the second cosine wave (CW), and b2 determines the brightness of the second cosine wave (CW);
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number;
Step b, according to given locus X, X ∈ (0, a1 × a2/ (a2-a1)), ask the corresponding phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW) of described locus X;
Step c, assignment is again carried out to the phase place main value phi1 of the first cosine wave (CW) and the phase place main value phi2 of the second cosine wave (CW):
phi1＝a1×phi1/(2π)；
phi2＝a2×phi2/(2π)；
Steps d, ask the difference of step c gained phi1 and phi2: h=phi1-phi2;
Step e, solution room position X comprise the first cosine Integer n wave period 1 and the second cosine Integer n wave period 2:
n1＝mod(h,a2)/abs(a1-a2)；
n2＝mod(h,a1)/abs(a1-a2)；
Wherein: mod () is for getting remainder operation, and abs is the computing that takes absolute value;
Step f, employing n1 × a1+phi1 or n2 × a2+phi2 solve phase unwrapping value.
2. the structured light phase decoding method based on double frequency cosine wave (CW) according to claim 1, it is characterized in that, described a1 and a2 is all integer, or is all non-integer, or one be integer one is non-integer.
3. the structured light phase decoding method based on double frequency cosine wave (CW) according to claim 1, is characterized in that, for simulation calculating, adopt phi1 and phi2 obtained with the following method in step b:
phi1＝arccos(2πX/a1)；
If:
Tan (2 π X/a1) >0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=phi1;
Tan (2 π X/a1) >0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1) <0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=2 π-phi1;
Tan (2 π X/a1)=0, and cos (2 π X/a1) >0, carry out assignment again to phi1, have: phi1=0;
Tan (2 π X/a1)=0, and cos (2 π X/a1) <0, carry out assignment again to phi1, have: phi1=π;
phi2＝arccos(2πX/a2)；
If:
Tan (2 π X/a2) >0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=phi2;
Tan (2 π X/a2) >0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2) <0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=2 π-phi2;
Tan (2 π X/a2)=0, and cos (2 π X/a2) >0, carry out assignment again to phi2, have: phi2=0;
Tan (2 π X/a2)=0, and cos (2 π X/a2) <0, carry out assignment again to phi2, have: phi2=π.
4. the structured light phase decoding method based on double frequency cosine wave (CW) according to claim 1, is characterized in that, between steps d and step e, also comprise steps d ':
If abs (h) is greater than threshold value, h=h;
If abs (h) is not more than threshold value, h=0.
5. the structured light phase decoding method based on double frequency cosine wave (CW) according to claim 4, it is characterized in that, described threshold value is 10
-10.
6. one kind realizes the projection acquisition system based on the structured light phase decoding method of double frequency cosine wave (CW) described in claim 1,2,3,4 and 5, comprise projector, measured object and image capturing system, described projector is to measured object projecting structural optical, image capturing system collection projection has the measured object image of structured light, it is characterized in that, the structured light of described projector projects is:
Second cosine wave (CW) of wave function to be first cosine wave (CW) of y1=k1 × cos (2 π x/a1)+b1 and wave function be y2=k2 × cos (2 π x/a2)+b2;
Wherein:
K1 determines the contrast of the first cosine wave (CW), and a1 is the wavelength of the first cosine wave (CW), and b1 determines the brightness of the first cosine wave (CW);
K2 determines the contrast of the second cosine wave (CW), and a2 is the wavelength of the second cosine wave (CW), and b2 determines the brightness of the second cosine wave (CW);
X is locus;
And:
Two cosine wave (CW) starting points are identical;
A1/ (a2-a1) ∈ N, N is natural number.
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