CN102853783A - High-precision multi-wavelength three-dimensional measurement method - Google Patents

Abstract

The invention belongs to the field of three-dimensional machine vision, and relates to a high-precision multi-wavelength three-dimensional reconstruction method. In the method, light information of change of wavelengths of lambda 1, lambda 2,... and lambda nn according to a sine law or cosine law is projected, and each piece of information is subjected to phase-shifting by at least three steps, preferably 3-8 steps. If the projection direction of phase-shifting gratings is longitudinal for a light source projecting device with the resolution of LRXLC, the first wavelength lambda 1 in the selected wavelengths is used as the LR, if the projection direction of the phase-shifting gratings is transverse, the first wavelength lambda 1 in the selected wavelengths is used as the LC, the second wavelength is a half of the first wavelength, in other words, the lambda 2 is equal to a half of the lambda 1, the third wavelength is a half of the second wavelength, in other words, the lambda 3 is equal to a half of the lambda 2, and so on. By a phase demodulation method, the total phase phi k(x,y) of each wavelength can be obtained, wherein k=1-n, and high-precision three-dimensional coordinates of an object can be calculated by a final phi n(x,y). The three-dimensional reconstruction method is superior to the traditional three-dimensional reconstruction method by Gray codes and a heterodyne multi-frequency process, the problem that a complex scene and a measured object with inconsistent surface colors are measured difficultly in an existing three-dimensional measurement process can be effectively solved, developing agents are not required to be sprayed, and the high-precision multi-wavelength reconstruction method is environment-friendly.

Description

A kind of high precision multi-wavelength method for three-dimensional measurement

Technical field

The present invention relates to a kind of high precision multi-wavelength three-dimensional rebuilding method, in particular, three-dimensional rebuilding method provided by the present invention, can high-precision realization complex scene in the three-dimensional reconstruction of object.

Background technology

Three-dimensional rebuilding method has been widely used in a plurality of fields such as industrial detection, reverse-engineering, body scans, historical relic's protection, clothes, shoes and hats, and the detection of free form surface is had the advantage that speed is fast, precision is high.According to the difference of imaging lighting system, the optical three-dimensional measurement technology can be divided into passive three-dimensional measurement and active three-dimensional measurement two large classes.In active three-dimensional measurement technology, the structural light three-dimensional measuring technique is with the fastest developing speed, especially phase measuring profilometer (Phase Measuring Profilometry, PMP), be also referred to as phase-shift measurement technology of profiling (Phase Shifting Profilometry, PSP), be measuring method commonly used in the present three-dimensional measurement product.Method for Phase Difference Measurement is the luminance brightness image according to the variation of trigonometric function (sine or cosine) rule that throws the fixed cycle on testee, this luminance brightness image is through the even phase shift greater than 3 steps, be preferably 4-6 and go on foot even phase shift, to 4-6 luminance brightness image of object projection, finally finish the phase shifts of one-period.Each point above the object through after the projection of phase shifted images, can obtain respectively several different brightness values in image.This brightness value can obtain unique phase value through separating the phase computing.Because the breadth of the image that collects at present is larger, in order to improve phase accuracy, need to throw to testee the phase diagram in a plurality of cycles, therefore, in a sub-picture, the same phase value can occur repeatedly.In order to obtain unique phase value in image, the Gray code method is the auxiliary solution phase method of commonly using.The three-dimensional measurement product that occurs at present, generally adopt the optical projecting method of gray code, such as the COMMET series structure light three-dimension measuring system of the Atos-I type structured light three-dimensional measurement system of German GOM company, German Steinbichler company, the optoTOP series structure light three-dimension measuring system of German Breuckmann company, the OKIO-II type spatial digitizer of sky, Beijing three-dimensional Science and Technology Ltd. far away, the comprehensive spatial digitizer of 3DSS that the Shanghai number is made Science and Technology Ltd., CPOS spatial digitizer of Tianjin Century Power Photoelectric Science Instruments Co., Ltd. etc.Because the coding method of Gray code is mainly encoded by image binaryzation, therefore change more situation for the object in the complex scene and color of object surface, generally need the spraying developer could realize preferably measurement effect.

A kind of improved three-dimensional rebuilding method that heterodyne multifrequency method is and the Gray code method proposes afterwards can avoid Gray code only to carry out the situation of Threshold segmentation with binaryzation.The principle of heterodyne multifrequency is to utilize the phase-shifted grating of three kinds of different wave lengths, and the grating of a kind of more long-wave-shaped that superposes out in twos recycles the grating after two stacks, and the unique phase place of the whole audience finally superposes out.The method is owing to need to carry out superposition three times, if under the background complicated situation, there is very large error in the phase place of stack, greatly affects measurement effect.Therefore, although heterodyne multifrequency method has certain superiority than Gray code method, in the situation that surround lighting is weak, can produce a lot of measurement noises, the three-dimensional reconstruction effect is relatively poor, so the high-precision three-dimensional that heterodyne multifrequency method still can not solve in the complex scene situation is rebuild a difficult problem.

For a three-dimensional reconstruction difficult problem that solves complex scene and can't spray developer, the present invention has designed a kind of new three-dimensional rebuilding method, need not to spray developer, just can high-precision recovery complex environment and the three-dimensional appearance of the more object of change color.

Summary of the invention

The invention provides a kind of multi-wavelength three-dimensional rebuilding method based on phase-shifted grating, the method can be applied in the high precision three-dimensional measurement, can remedy the defective that Gray code and heterodyne multifrequency method exist in the three-dimensional reconstruction process.

The hardware system of described multi-wavelength three-dimensional reconstruction system comprises:

Be used for the light source projection device of projection optical signal, the resolution of light source projection device is L _R* L _C

Be used for the computing machine that precision control, image acquisition and data are processed;

Be used for gathering the colour TV camera of image, image resolution ratio is C _R* C _C, the camera number is 1-2;

Be used for placing the scanning platform of described light source projection device and described colour TV camera;

The three-dimensional rebuilding method that the present invention is designed, concrete operation step is as follows:

Step 1: be L for resolution _R* L _CLight source projection device, select n wavelength to carry out the projection of sine or cosine light signal, if the projecting direction of phase-shifted grating is vertically, the length lambda of first wavelength in the selected wavelength then ₁=L _RIf the projecting direction of phase-shifted grating is that laterally then the length of first wavelength in the selected wavelength is λ ₁=L _CThe length of second wavelength is 1/2 of first wavelength length, that is: λ ₂=λ ₁The length of the/2, three wavelength is 1/2 of second wavelength length, that is: λ ₃=λ ₂/ 2, the like, until the length lambda of n wavelength _nFall into best three-dimensional reconstruction wavelength coverage, i.e. 15≤λ _n≤ 30;

Step 2: for the sine wave of every kind of wavelength, projection surpasses the phase-shifted gratings (being preferably the 3-8 step) in 3 steps, is incident upon brightness value on the object by phase-shifted grating, calculates the Local Phase place value φ (x, y) of this point (x, y);

Step 3: calculate the corresponding overall phase place Φ of first wavelength light signal ₁(x, y), its value satisfies relational expression: Φ ₁(x, y) ≡ φ ₁(x, y) arranges counting variable k, and sets its initial value k=2;

Step 4: obtain its overall phase place Φ by following formula _k(x, y):

Φ _k(x，y)＝2πm _k(x，y)+φ _k(x，y) (1)

Wherein: $m_k(x,y)=\mathrm{Round}(\frac{{\mathrm{\Φ}}_{k-1}(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_k(x,y)}{2\mathrm{\π}})$

K carries out and to add 1 computing, if the k value less than n, then execution in step 4, otherwise execution in step 5;

Step 5: for the shortest sinusoidal signal λ of wavelength _n, utilize it to pass through the final overall phase place Φ that step 4 obtains _n(x, y) and the prior parameter well of demarcating, (x, y) puts corresponding three-dimensional coordinate (X, Y, Z) in the following formula acquisition of the utilization image:

$\left\{\begin{array}{c}X=x\×R_x\\ Y=y\×R_y\\ Z=\frac{{\mathrm{\Φ}}_n(x,y)\×L}{{\mathrm{\Φ}}_n(x,y)+2\mathrm{\π}{f}_{0}D}\end{array}\right.---\left(2\right)$

Wherein: D is the distance between projection light source and the video camera;

L is the distance of video camera and reference planes;

f ₀Sine or cosine signal wave frequency for the projection light source projection;

R _xImage is at the distance value of X-direction neighbor pixel;

R _yImage is at the distance value of Y direction neighbor pixel.

So far, the designed three-dimensional rebuilding method of the present invention finishes.

The invention has the beneficial effects as follows: the three-dimensional rebuilding method of introducing by the present invention, can solve the inconsistent difficult problem of background complexity and color of object surface, need not to spray developer, can realize the high precision three-dimensional measurement under the complex colors environment, can avoid existing Gray code and heterodyne multifrequency method, effective metrical information of existence is lost and is waited the measurement defective.

Description of drawings

Fig. 1: the photo of measuring scene;

Fig. 2: the picture that is used for reconstruction that collects in the Gray code three-dimensional measurement situation;

Fig. 3: the picture that is used for reconstruction that collects in the heterodyne multifrequency situation;

Fig. 4: the picture that being used for of collecting in the designed multi-wavelength situation of the present invention rebuilds;

Fig. 5: measurement effect comparison diagram

(a) three-dimensional measurement design sketch in the Gray code situation;

(b) three-dimensional measurement design sketch in the heterodyne multifrequency situation;

(c) three-dimensional measurement design sketch in the designed multi-frequency situation of the present invention;

Fig. 6: the process flow diagram of the three-dimensional rebuilding method that the present invention is designed.

Embodiment

Three-dimensional reconstruction mode provided by the present invention is to be based upon on the phase-shifted grating principle basis, but has very large difference with Gray's code method and heterodyne multifrequency method.The principle of phase-shifted grating is sine or the cosine function ripple that changes to the testee projection cycle, and the phase shift through 3 steps above (the preferably 4-8 step) by the phase-shifted grating information that collects, calculates this and puts corresponding phase information.From the sine-shaped Changing Pattern of light source projects shown in formula (1):

$I\left(x\right)=\sin (2\mathrm{\π}\×(\frac{j}{\mathrm{PW}}+\frac{i}{N}))$ Formula (1)

Wherein:

I (x) is projection light intensity;

J: be periodicity factor, its value is changed to: 0～PW

PW: be Cycle Length;

I: be step factor, its value is changed to: 0～N

N: be the step number of phase shift

If phase value

Phase-shift phase is:

Then formula (1) can be expressed as formula (2):

I (x)=sin (formula (2) of φ+δ)

In actual measurement, since the impact of bias light, the luminance brightness I that actual acquisition arrives _rFormula shown in formula (3):

I _r(x)=a+bsin (formula (3) of φ+δ)

Take three step phase shifts as example, for some pixel p, by four light projections, the gradation of image value I that collects _Rp1, I _Rp2, I _Rp3Shown in formula (4).

I _rp1＝a+bsin(φ-2π/3)

I _Rp2=a+bsin (φ) formula (4)

I _rp3＝a+bsin(φ+2π/3)

Therefore phase value φ can pass through formula (5) acquisition:

$\mathrm{\φ}=\arctan \left(\frac{\sqrt{3}(I_{\mathrm{rp}1}-I_{\mathrm{rp}3})}{2I_{\mathrm{rp}2}-I_{\mathrm{rp}1}-I_{\mathrm{rp}3}}\right)$ Formula (5)

In high precision three-dimensional measurement, the precision of 3 step phase shifts will be lower than 6 step phase shifts, for 6 step phase shifts, if the gradation of image value that collects is I _Rp1, I _Rp2, I _Rp3, I _Rp4, I _Rp5And I _Rp6, then this phase value can pass through formula (6) acquisition:

$\mathrm{\φ}={\tan }^{-1}\left(\frac{\underset{i=1}{\overset{6}{\mathrm{\Σ}}}{I}_{\mathrm{rp}1}\×\cos \left(\frac{2\mathrm{\π}\×5}{6}\right)}{\underset{i=1}{\overset{6}{\mathrm{\Σ}}}{I}_{\mathrm{rp}1}\×\sin \left(\frac{2\mathrm{\π}\×5}{6}\right)}\right)$ Formula (6)

In actual applications, if only throw the phase-shifted grating of 0-2 π to tested scene, need not in theory to carry out complicated solution phase computing, just can rebuild the three-dimensional appearance of object.But because the whole audience only throws in the situation of the phase-shifted grating that 0-2 π changes, because the brightness respective range of optical system and the Grey imaging scope of photographic system are and are 0-255, and the resolution of light source projection device is generally all more than 800 * 600, what therefore, will cause that monochrome information in the phase-shifted grating can't be correct expresses.Through verification experimental verification, find the Cycle Length PW of phase-shifted grating within the optic response scope, PW is less, and the precision of three-dimensional measurement is higher, certainly, if the value of PW surpasses the luminosity response scope that camera system can bear, is not the smaller the better so.Rule of thumb, be 800 * 600 optical system for resolution, in 1 meter measurement range, if the value of PW in the situation that between the 15-30, measurement effect is better, namely best three-dimensional reconstruction wavelength coverage is 15-30.

Phase-shifted grating iff a kind of wavelength of projection, in scene a plurality of phase cyclings will appear so, take the optical system of resolution as 800 * 600 as example, if phase cycling length PW=25, then the variation of 32 phase cyclings can appear in the whole audience, that is to say, any one value in the whole audience scope between the 0-2 π all can occur 32 times.Under the modulation of object height, phase value can change with the shape of object, be difficult to the affiliated phase cycling of definite each phase value, existing Gray code method all is in order to solve a difficult problem mutually with heterodyne multifrequency method, but still there are a lot of noise in the effect that solves, and perhaps effective information loses.

The present invention proposes a kind of new three-dimensional rebuilding method, be better than Gray code method and heterodyne multifrequency method.The present invention selects multi-wavelength's sinusoidal grating to carry out three-dimensional measurement.Be L for resolution _R* L _CLight source projection device, if the projecting direction of phase-shifted grating is vertically, the length lambda of first wavelength in the selected wavelength then ₁=L _RIf the projecting direction of phase-shifted grating is that laterally then the length of first wavelength in the selected wavelength is λ ₁=L _CThe length of second wavelength is 1/2 of first wavelength length, that is: λ ₂=λ ₁The length of the/2, three wavelength is 1/2 of second wavelength length, that is: λ ₃=λ ₂/ 2, the like, until the length lambda of n wavelength _nFall into best three-dimensional reconstruction wavelength coverage, i.e. 15≤λ _n≤ 30.

For the sine wave of every kind of wavelength, all need to throw the phase-shifted grating that surpassed for 3 steps.Be incident upon brightness value on the object by phase-shifted grating, can obtain the Local Phase place value φ (x, y) of this point (x, y).For the sinusoidal signal of first wavelength, because wavelength is identical with the length of the resolution of projector, that is to say that sine wave only has one-period, therefore, the phase value scope that obtains in whole measurement range is 0-2 π, does not need to separate the operation of phase place.Namely for the sinusoidal signal of first wavelength, its overall phase value Φ ₁(x, y) and Local Phase place value φ ₁(x, y) equate, that is:

Φ ₁(x，y)≡φ ₁(x，y) (7)

Be λ for wavelength ₂Sine wave, its overall phase place Φ ₂(x, y) can obtain by following formula:

Φ ₂(x，y)＝2πm ₂(x，y)+φ ₂(x，y) (8)

Wherein: m ₂(x, y) is the encoded radio in phase place place cycle.

Because λ ₁=2 λ ₂So, overall phase place Φ ₂(x, y) and overall phase place Φ ₁There is following relation in (x, y):

Φ ₂(x，y)＝2Φ ₁(x，y) (9)

Wherein: m ₂(x, y) can obtain by following formula:

$m_2(x,y)=\frac{{\mathrm{\Φ}}_1(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_2(x,y)}{2\mathrm{\π}}$ (10)

Because the signal of light source projection device projection is not simulating signal, but digital signal, so encoded radio m ₂(x, y) should be integer, so m ₂(x, y) can obtain by following formula:

$m_2(x,y)=\mathrm{Round}(\frac{{\mathrm{\Φ}}_1(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_2(x,y)}{2\mathrm{\π}})$ (11)

Wherein: Round () asks the computing of integer for rounding up.

Because λ ₃=λ ₂/ 2, so overall phase place Φ ₂(x, y) can be used for resolving overall phase place Φ ₃(x, y), the like, for employed each wavelength X _k, because λ _k=λ _K-1/ 2, so the coding m of this wavelength _k(x, y) can obtain by following formula:

$m_k(x,y)=\mathrm{Round}(\frac{{\mathrm{\Φ}}_{k-1}(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_k(x,y)}{2\mathrm{\π}})---\left(12\right)$

So overall phase place Φ _k(x, y) can obtain by following formula:

Φ _k(x，y)＝2πm _k(x，y)+φ _k(x，y) (13)

For the shortest sinusoidal signal λ of wavelength that throws _n, utilize the overall phase place Φ of its acquisition _n(x, y) can be by demarcating good parameter in advance, and (x, y) puts corresponding three-dimensional coordinate (X, Y, Z) in the acquisition image.

$\left\{\begin{array}{c}X=x\×R_x\\ Y=y\×R_y\\ Z=\frac{{\mathrm{\Φ}}_n(x,y)\×L}{{\mathrm{\Φ}}_n(x,y)+2\mathrm{\π}{f}_{0}D}\end{array}\right.---\left(14\right)$

Wherein: D is the distance between projection light source and the video camera;

L is the distance of video camera and reference planes;

f ₀Sine or cosine signal wave frequency for the projection light source projection;

R _xImage is at the distance value of X-direction neighbor pixel;

R _yImage is at the distance value of Y direction neighbor pixel.

In sum, the three-dimensional rebuilding method that the present invention is designed, concrete operation step is as follows:

Step 1: be L for resolution _R* L _CLight source projection device, select n wavelength to carry out the projection of sine or cosine light signal, if the projecting direction of phase-shifted grating is vertically, the length lambda of first wavelength in the selected wavelength then ₁=L _RIf the projecting direction of phase-shifted grating is that laterally then the length of first wavelength in the selected wavelength is λ ₁=L _CThe length of second wavelength is 1/2 of first wavelength length, that is: λ ₂=λ ₁The length of the/2, three wavelength is 1/2 of second wavelength length, that is: λ ₃=λ ₂/ 2, the like, until the length lambda of n wavelength _nFall into best three-dimensional reconstruction wavelength coverage, i.e. 15≤λ _n≤ 30;

Step 2: for the sine wave of every kind of wavelength, projection surpasses the phase-shifted gratings (being preferably the 3-8 step) in 3 steps, is incident upon brightness value on the object by phase-shifted grating, calculates the Local Phase place value φ (x, y) of this point (x, y);

Step 3: calculate the corresponding overall phase place Φ of first wavelength light signal ₁(x, y), its value satisfies relational expression: Φ ₁(x, y) ≡ φ ₁(x, y) arranges counting variable k, and sets its initial value k=2;

Step 4: obtain its overall phase place Φ by following formula _k(x, y):

Φ _k(x，y)＝2πm _k(x，y)+φ _k(x，y) (1)

Wherein: $m_k(x,y)=\mathrm{Round}(\frac{{\mathrm{\Φ}}_{k-1}(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_k(x,y)}{2\mathrm{\π}})$

K carries out and to add 1 computing, if the k value less than n, then execution in step 4, otherwise execution in step 5;

Step 5: for the shortest sinusoidal signal λ of wavelength _n, utilize it to pass through the final overall phase place Φ that step 4 obtains _n(x, y) and the prior parameter well of demarcating, (x, y) puts corresponding three-dimensional coordinate (X, Y, Z) in the following formula acquisition of the utilization image:

$\left\{\begin{array}{c}X=x\×R_x\\ Y=y\×R_y\\ Z=\frac{{\mathrm{\Φ}}_n(x,y)\×L}{{\mathrm{\Φ}}_n(x,y)+2\mathrm{\π}{f}_{0}D}\end{array}\right.---\left(2\right)$

Wherein: D is the distance between projection light source and the video camera;

L is the distance of video camera and reference planes;

f ₀Sine or cosine signal wave frequency for the projection light source projection;

R _xImage is at the distance value of X-direction neighbor pixel;

R _yImage is at the distance value of Y direction neighbor pixel.

So far, the designed three-dimensional rebuilding method of the present invention finishes.

In order to verify the validity of method proposed by the invention, to same scene, identical hardware collecting device adopts respectively the designed multi-wavelength method of Gray code method, heterodyne multifrequency method and the present invention to carry out three-dimensional measurement.Measure the photo of scene as shown in Figure 1.Utilize the picture of Gray code method and heterodyne multifrequency method collection respectively as shown in Figures 2 and 3.Utilize the designed method of the present invention, behind the phase-shifted grating of the different frequency of testee projection, a series of images that camera acquisition arrives as shown in Figure 4.Utilize three kinds of methods to carry out effect behind the three-dimensional reconstruction respectively such as Fig. 5 (a), shown in 5 (b) and 5 (c).As can be seen from Figure 5, the Gray code method can only be measured the bright three-dimensional information of object color, for the darker stool of color, do not measure, so the Gray code method can't realize the three-dimensional measurement difficult problem under the environment scene complicated situation; For heterodyne multifrequency method, can measure color than the three-dimensional data of dark-part, still from the three-dimensional measurement effect of stool, heterodyne multifrequency method measurement effect is bad, can have the content of a lot of disappearances; Utilize the method for three-dimensional measurement of the designed multi-wavelength of the present invention, can realize that the perfection in the bright and two kinds of situations of darker in color of object color is measured, measuring does not have noise substantially, and 3 d measurement data is very complete.Can find out that from the contrast of Fig. 5 the three-dimensional rebuilding method that the present invention is designed can solve complex scene and object color and change a three-dimensional measurement difficult problem in the large situation.

The designed three-dimensional rebuilding method process flow diagram of the present invention as shown in Figure 6.

The maximum difference of the present invention and existing solution phase method based on Gray code is: the Gray code method is that the image passing threshold that collects is cut apart, and is converted into 0 and 1 two kind of signal, can't solve color of object surface inconsistent and measure the background complicated situation; And the designed solution phase method of the present invention, be not only by 0 and 1 two kind of signal encode, but encode by the phase value of each point.Therefore the designed method of the present invention can solve the inconsistent measurement difficult problem of color of object surface, need not to spray developer, can realize high-precision measurement.

The difference of the present invention and existing heterodyne multifrequency method is: heterodyne multifrequency method need to be calculated the another kind of more equivalent phase information of long-wave-shaped according to the phase information of two kinds of wavelength, because in the actual acquisition process, there is certain error in the phase information that collects, behind this error process equivalent phase formula operation, error can be exaggerated.Heterodyne multifrequency method need to be carried out the calculating of three equivalent phase places, and each measurement all can bring larger measuring error, so that also can there be a lot of noises in final measurement data, causes the disappearance of normal useful signal.And the designed three-dimensional rebuilding method of the present invention, do not have the computing of Phase Stacking, avoided the noise that produces in the computing, so the designed method of the present invention has better adaptability, solved in the complex background situation three-dimensional reconstruction difficult problem of different colours object.

In sum, the advantage of three-dimensional rebuilding method of the present invention is:

(1) owing to not being to decide phase encoding by simple Threshold segmentation, therefore global solution phase of the present invention accuracy is higher than Gray code solution phase method.

(2) because the noise that produces when having avoided Phase Stacking, therefore, the designed three-dimensional rebuilding method of the present invention has more wide adaptability than heterodyne multifrequency method, and the three-dimensional reconstruction effect also is better than heterodyne multifrequency three-dimensional rebuilding method.

(3) really solve in the complex background situation and the inconsistent three-dimensional measurement difficult problem of color of object surface, need not to spray the painted materials such as developer, consumables cost in the measurement has also been saved in the measuring process environmental protection;

Below schematically the present invention and embodiment thereof are described, this description does not have limitation, and shown in the accompanying drawing also is one of embodiments of the present invention.So; if those of ordinary skill in the art is enlightened by it; in the situation that do not break away from the invention aim; adopt the same base part of other form or each component layouts mode of other form; without the creationary technical scheme similar to this technical scheme and the embodiment of designing, all should belong to protection scope of the present invention.

Claims (1)

1. high precision multi-wavelength three-dimensional rebuilding method, three-dimensional rebuilding method of the present invention may be used in the following hardware system:

Be used for the light source projection device of projection optical signal, the resolution of light source projection device is L _R* L _C

Be used for the computing machine that precision control, image acquisition and data are processed;

Be used for gathering the colour TV camera of image, image resolution ratio is C _R* C _C, the camera number is 1-2;

Be used for placing the scanning platform of described light source projection device and described colour TV camera;

Described high-precision three-dimensional method for reconstructing is characterized in that, its operation steps is as follows:

Step 1: be L for resolution _R* L _CLight source projection device, select n wavelength to carry out the projection of sine or cosine light signal, if the projecting direction of phase-shifted grating is vertically, the length lambda of first wavelength in the selected wavelength then ₁=L _RIf the projecting direction of phase-shifted grating is that laterally then the length of first wavelength in the selected wavelength is λ ₁=L _CThe length of second wavelength is 1/2 of first wavelength length, that is: λ ₂=λ ₁The length of the/2, three wavelength is 1/2 of second wavelength length, that is: λ ₃=λ ₂/ 2, the like, until the length lambda of n wavelength _nFall into best three-dimensional reconstruction wavelength coverage, i.e. 15≤λ _n≤ 30;

Step 2: for the sine wave of every kind of wavelength, projection surpasses the phase-shifted gratings (being preferably the 3-8 step) in 3 steps, is incident upon brightness value on the object by phase-shifted grating, calculates the Local Phase place value φ (x, y) of this point (x, y);

Step 3: calculate the corresponding overall phase place Φ of first wavelength light signal ₁(x, y), its value satisfies relational expression: Φ ₁(x, y) ≡ φ ₁(x, y) arranges counting variable k, and sets its initial value k=2;

Step 4: obtain its overall phase place Φ by following formula _k(x, y):

Φ _k(x，y)＝2πm _k(x，y)+φ _k(x，y) (1)

Wherein: $m_k(x,y)=\mathrm{Round}(\frac{{\mathrm{\Φ}}_{k-1}(x,y)}{\mathrm{\π}}-\frac{{\mathrm{\φ}}_k(x,y)}{2\mathrm{\π}})$

K carries out and to add 1 computing, if the k value less than n, then execution in step 4, otherwise execution in step 5;

Step 5: for the shortest sinusoidal signal λ of wavelength _n, utilize it to pass through the final overall phase place Φ that step 4 obtains _n(x, y) and the prior parameter well of demarcating, (x, y) puts corresponding three-dimensional coordinate (X, Y, Z) in the following formula acquisition of the utilization image:

$\left\{\begin{array}{c}X=x\×R_x\\ Y=y\×R_y\\ Z=\frac{{\mathrm{\Φ}}_n(x,y)\×L}{{\mathrm{\Φ}}_n(x,y)+2\mathrm{\π}{f}_{0}D}\end{array}\right.---\left(2\right)$

Wherein: D is the distance between projection light source and the video camera;

L is the distance of video camera and reference planes;

f ₀Sine or cosine signal wave frequency for the projection light source projection;

R _xImage is at the distance value of X-direction neighbor pixel;

R _yImage is at the distance value of Y direction neighbor pixel;

So far, the designed three-dimensional rebuilding method of the present invention finishes.

Images