CN108061517B - Surface structure photolysis method based on Moire sequence grating - Google Patents

Surface structure photolysis method based on Moire sequence grating Download PDF

Info

Publication number
CN108061517B
CN108061517B CN201711397481.4A CN201711397481A CN108061517B CN 108061517 B CN108061517 B CN 108061517B CN 201711397481 A CN201711397481 A CN 201711397481A CN 108061517 B CN108061517 B CN 108061517B
Authority
CN
China
Prior art keywords
grating
image
phase
moire
pitches
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201711397481.4A
Other languages
Chinese (zh)
Other versions
CN108061517A (en
Inventor
刘飞
赖俊霖
李佳鑫
何春桥
张圣明
吴明雄
谢志江
皮阳军
宋代平
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chongqing University
Original Assignee
Chongqing University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chongqing University filed Critical Chongqing University
Priority to CN201711397481.4A priority Critical patent/CN108061517B/en
Publication of CN108061517A publication Critical patent/CN108061517A/en
Application granted granted Critical
Publication of CN108061517B publication Critical patent/CN108061517B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The invention discloses a surface structure light phase-splitting method based on moire sequence grating, which compares the traditional fringe grating with the surface structure light direct projection pitches of P1, P2 and P3 by directly projecting moire grating fringes with the pitches of P12 and P123, jump errors caused by integer and decimal orders of the fringe gratings for calculating the virtual pitches P12 and P123 due to error transfer and amplification are avoided in the process of calculating the decimal part of the phase order, the method greatly restrains and corrects the phase jump error by directly calculating the decimal and integer part of the phase order of the moire fringe grating acquisition image with the pitches of P12 and P123, under the condition of ensuring the precision and the advantages of the structured light three-dimensional measurement, more effective phase information is obtained, meanwhile, the method has better effects on over-brightness, over-darkness and noise resistance, and the algorithm has better robustness.

Description

Surface structure photolysis method based on Moire sequence grating
Technical Field
The invention relates to the field of surface structure photolysis, in particular to a surface structure photolysis method based on moire sequence grating.
Background
Along with the improvement of science and technology, the demand of high-precision three-dimensional measurement technology is more and more, and according to whether contact with the measured object during measurement, three-dimensional measurement is divided into contact type and non-contact type, and non-contact type three-dimensional measurement technology still possesses the advantage that traditional contact type measurement technology does not possess under the condition that possesses same high-precision: such as surface protection of measuring workpieces, measurement of large-sized workpieces, less time consumption, portability and the like. In recent years, non-contact three-dimensional measurement technology is increasingly applied to the fields of cultural relic protection, reverse engineering, virtual reality and the like.
In non-contact three-dimensional measurement, an active three-dimensional measurement method based on phase structured light is becoming popular for research in the field of three-dimensional measurement with the advantages of high precision, high speed, easy implementation and the like.
Three-dimensional measurement principle based on surface structured light: in a structured light measurement system consisting of a projector and a camera, planar structured light with known phase information is projected to the surface of a measured object through the projector, then a fringe grating image subjected to object surface height modulation is synchronously acquired through the camera, corresponding phase distribution is obtained through phase resolution of the acquired fringe grating image, and then the three-dimensional appearance of the object is reconstructed according to the relation between the phase and the three-dimensional coordinate obtained in system calibration.
The problems that exist are that: in the practical application of the surface structured light three-dimensional measurement, whether accurate phase information can be solved from the acquired fringe grating image directly influences the three-dimensional measurement and reconstruction precision. In a traditional four-step phase shift multi-frequency projection measurement mode, when a phase progression integer part is calculated, due to the influences of factors such as random noise, nonlinear errors, over-brightness and over-darkness, when the phase progression is solved, due to continuous transmission and amplification of errors, jump errors exist in the solved phase progression integer part, integral multiple jump errors of 2 pi appear in the finally solved phase, phase loss is caused, and in actual measurement, the jump errors are often more and are not easy to eliminate.
Disclosure of Invention
In view of the above, an object of the present invention is to overcome the defects in the prior art, and provide a surface structured light phase-splitting method based on moire sequence grating, which can suppress and correct jump errors of an integer part when a phase progression is obtained due to noise and over-bright and over-dark regions in a surface structured light three-dimensional measurement process, thereby avoiding phase loss and ensuring that correct phase information is obtained.
The invention relates to a surface structure photolysis method based on moire sequence grating, which comprises the following steps:
step 1: obtaining two virtual secondary moire grating fringes with the pitches of P12 and P23 according to three primary grating fringes with the pitches of P1, P2 and P3 respectively and in a mode of grouping two primary grating fringes with the pitches of P12 and P23 respectively, and obtaining a virtual tertiary moire grating fringe with the pitch of P123 according to the two secondary grating fringes, wherein the tertiary moire grating fringe is a full-field grating fringe;
step 2: generating four-step phase shift grating fringe images of a primary grating fringe, a secondary moire grating fringe and a tertiary moire grating fringe with pitches of P1, P12 and P123 respectively according to the pitch data obtained in the step 1, and recording the four-step phase shift grating fringe images as a projection image 1, a projection image 12 and a projection image 123 respectively;
and step 3: projecting the projected image 1, the projected image 12 and the projected image 123 to the surface of an object through a projector respectively, and acquiring images through a camera to obtain an acquired image 1, an acquired image 12 and an acquired image 123;
and 4, step 4: calculating the wrapping phase corresponding to the collected image according to the collected image 1, the collected image 12 and the collected image 123 obtained in the step 3
Figure BDA0001518803450000021
And 5: obtaining wrapped phase according to step 4
Figure BDA0001518803450000022
Calculating a phase progression fractional part Δ N1 and an integer part N1 of the acquired image 1, a phase progression fractional part Δ N12 and an integer part of the acquired image 12, and a phase progression fractional part Δ N123 and an integer part N123 of the acquired image 123;
step 6: the absolute phase Φ 1 of the captured image 1 is calculated from the phase progression fractional part Δ N1 and the integer part N1 of the captured image 1 obtained in step 5.
Further, in step 1, the pitches of the secondary moire grating fringes and the tertiary moire grating fringes are obtained by the following formulas (1) to (3):
Figure BDA0001518803450000031
Figure BDA0001518803450000032
Figure BDA0001518803450000033
further, in step 4, the wrapping phase of each acquired image is obtained by the following equations (4) to (6):
Figure BDA0001518803450000034
Figure BDA0001518803450000035
Figure BDA0001518803450000036
wherein I1d、I12d、I123d… are the luminance values of the corresponding pixels in the four images corresponding to the acquired image.
Further, in step 5, the phase progression fractional part Δ N1 and the integer part N1 of the acquired image 1 are obtained by the following equations (7) to (11):
Figure BDA0001518803450000037
Figure BDA0001518803450000038
Figure BDA0001518803450000039
Figure BDA00015188034500000310
Figure BDA00015188034500000311
where round denotes a rounding operation, and since pitch 123 is a full field grating, N123 is 0.
Further, in step 6, the absolute phase Φ 1 of the acquired image 1 can be directly calculated according to the formula (12):
Figure BDA00015188034500000312
the invention has the beneficial effects that: the invention discloses a surface structure light dephasing method based on moire sequence grating, which avoids jumping error introduced by integer and decimal fraction of fringe grating for calculating virtual pitches P12 and P123 due to error transmission and amplification in the process of calculating fractional part of phase progression by directly projecting moire grating fringes with pitches P12 and P123, compared with the traditional fringe grating with pitches P1, P2 and P3, the method acquires fractional and integer part of phase progression of image by directly calculating the moire fringe gratings with pitches P12 and P123, greatly inhibits and corrects the phase jumping error, acquires more effective phase information under the condition of ensuring the accuracy and advantages of the structure light three-dimensional measurement, and has better effect on over-brightness, over-darkness and noise immunity, and the algorithm has better robustness, the phase-splitting method is simple to operate, can greatly inhibit and correct phase jump errors in the traditional heterodyne phase-splitting method, and is suitable for large-scale popularization and application.
Drawings
The invention is further described below with reference to the following figures and examples:
FIG. 1 is a schematic view of a measurement system of the present invention.
Fig. 2 is a schematic flow chart of the surface structured light phase-splitting method based on the molar sequence grating of the present invention.
Fig. 3 is a schematic diagram of the mol-sequence grating generation of the surface structure photolysis method based on the mol-sequence grating of the present invention.
Fig. 4 is a schematic diagram of the implementation of the planar structured photolysis method based on molar sequence grating according to the present invention.
Detailed Description
As shown in fig. 1 to 3, a moire-sequence grating-based planar structured light phase resolving method according to the present invention is implemented by a structured light measuring system including a projector 1, an industrial camera 2 and a terminal 3, the projector 1 and the industrial camera 2 are disposed in front of a measured object 4, and the projector 1 and the industrial camera 2 are connected to the terminal 3. The terminal 3 can control the projector 1 to project a fringe grating with phase information to the measured object, and the industrial camera 2 can collect a fringe image modulated by the surface of the measured object in real time and send the fringe image to the terminal 3 for analysis and subsequent operations, such as the operation of the method.
Referring to fig. 1, the invention discloses a surface structure photolysis method based on a molar sequence grating, which comprises the following steps:
step 1: the surface structured light measuring system as shown in fig. 1 mainly comprises the projector 1, the industrial camera 2 and the terminal 3, wherein the projector 1 and the industrial camera 2 are arranged in front of a measured object 4, and the arrangement positions of the projectors are such that the shooting range of the industrial camera 2 covers the projection range of the projector 1. For example, in the example of fig. 1, the projector 1 and the industrial camera 2 are respectively located in front of the object to be measured, and the projector 1 and the industrial camera 2 are respectively located on both sides of the object to be measured, so that the projector 1 can project a modulated fringe image to the object to be measured from one side portion in front of the object to be measured, and the industrial camera 2 can capture the fringe image projected to the object to be measured from the other side portion in front of the object to be measured; presetting three primary grating stripes with pitches of P1, P2 and P3 and obtaining two virtual secondary moire grating stripes with pitches of P12 and P23 in a mode of grouping two by two, obtaining a virtual tertiary moire grating stripe with a pitch of P123 according to the two secondary grating stripes, wherein the tertiary moire grating stripe is a full-field grating stripe, and preferably, in the step 1, the pitches of the secondary moire grating stripe and the tertiary moire grating stripe are obtained through the following expressions (1) to (3):
Figure BDA0001518803450000051
Figure BDA0001518803450000052
Figure BDA0001518803450000053
wherein the pitches P1, P2, P3, P12 and P23 are required to satisfy the following requirements: the stripe grating with P1< P2< P3, P12< P23 and P123 pitch needs to cover the whole field;
step 2: generating four-step phase shift grating fringe images of a primary grating fringe, a secondary moire grating fringe and a tertiary moire grating fringe with pitches of P1, P12 and P123 respectively according to the pitch data obtained in the step 1, and recording the four-step phase shift grating fringe images as a projection image 1, a projection image 12 and a projection image 123 respectively;
and step 3: projecting the projected image 1, the projected image 12 and the projected image 123 to the surface of an object through a projector respectively, and acquiring images through a camera to obtain an acquired image 1, an acquired image 12 and an acquired image 123;
and 4, step 4: calculating the wrapping phase corresponding to the collected image according to the collected image 1, the collected image 12 and the collected image 123 obtained in the step 3
Figure BDA0001518803450000061
Preferably, in step 4, the wrapping phase of each acquired image is obtained by the following equations (4) to (6):
Figure BDA0001518803450000062
Figure BDA0001518803450000063
Figure BDA0001518803450000064
wherein I1d、I12d、I123d… are the luminance values of the corresponding pixels in the four images corresponding to the acquired image.
And 5: obtaining wrapped phase according to step 4
Figure BDA0001518803450000065
Calculating a phase progression fractional part Δ N1 and an integer part N1 of the acquired image 1, a phase progression fractional part Δ N12 and an integer part of the acquired image 12, and a phase progression fractional part Δ N123 and an integer part N123 of the acquired image 123; preferably, in step 5, the phase progression fractional part Δ N1 and the integer part N1 of the acquired image 1 are obtained by the following equations (7) to (11):
Figure BDA0001518803450000066
Figure BDA0001518803450000067
Figure BDA0001518803450000068
Figure BDA0001518803450000069
Figure BDA00015188034500000610
where round represents rounding and rounding, and since the pitch 123 is a full field grating, N123 is 0, N12 and N1 can be calculated from the above, and it is verified that the calculated integer number does not have a skip phenomenon.
Step 6: the absolute phase Φ 1 of the captured image 1 is calculated from the phase progression fractional part Δ N1 and the integer part N1 of the captured image 1 obtained in step 5, and preferably, in step 6, the absolute phase Φ 1 of the captured image 1 is directly calculated according to the expression (12):
Figure BDA0001518803450000071
in general, in the surface structured light three-dimensional measurement system, the technical idea of suppressing and correcting the jump phenomenon caused by integer series solving in the phase solution result is to directly generate a mole sequence stripe grating image, project the image by a projector and acquire the image by an industrial camera so as to obtain the wrapping limit of each acquired image
Figure BDA0001518803450000072
The method for directly solving the phase series 12 of the collected image and the decimal parts delta n12 and delta n123 of the collected image 123 further avoids the problem that in the traditional multi-frequency heterodyne dephasing process, due to error transmission and amplification, the delta n12 and the delta n123 greatly jump during solving, so that integer series jump is caused, and 2 pi jump error of integral multiple of absolute phase is introduced.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims (5)

1. A surface structure photolysis method based on Moire sequence grating is characterized in that: the method comprises the following steps:
step 1: obtaining two virtual secondary moire grating fringes with the pitches of P12 and P23 according to three primary grating fringes with the pitches of P1, P2 and P3 respectively and in a mode of grouping two primary grating fringes with the pitches of P12 and P23 respectively, and obtaining a virtual tertiary moire grating fringe with the pitch of P123 according to the two secondary grating fringes, wherein the tertiary moire grating fringe is a full-field grating fringe;
step 2: generating four-step phase shift grating fringe images of a primary grating fringe, a secondary moire grating fringe and a tertiary moire grating fringe with pitches of P1, P12 and P123 respectively according to the pitch data obtained in the step 1, and recording the four-step phase shift grating fringe images as a projection image 1, a projection image 12 and a projection image 123 respectively;
and step 3: projecting the projected image 1, the projected image 12 and the projected image 123 to the surface of an object through a projector respectively, and acquiring images through a camera to obtain an acquired image 1, an acquired image 12 and an acquired image 123;
and 4, step 4: calculating the wrapping phase corresponding to the collected image according to the collected image 1, the collected image 12 and the collected image 123 obtained in the step 3
Figure FDA0002507193340000011
And 5: obtaining wrapped phase according to step 4
Figure FDA0002507193340000012
Calculating a phase progression fractional part Δ N1 and an integer part N1 of the acquired image 1, a phase progression fractional part Δ N12 and an integer part of the acquired image 12, and a phase progression fractional part Δ N123 and an integer part N123 of the acquired image 123;
step 6: the absolute phase Φ 1 of the captured image 1 is calculated from the phase progression fractional part Δ N1 and the integer part N1 of the captured image 1 obtained in step 5.
2. The surface structure photolysis method based on moire sequence grating as claimed in claim 1, wherein: in step 1, the pitches of the secondary moire grating fringe and the tertiary moire grating fringe are obtained by the following formulas (1) to (3):
Figure FDA0002507193340000013
Figure FDA0002507193340000014
Figure FDA0002507193340000021
3. the surface structure photolysis method based on moire sequence grating as claimed in claim 1, wherein: in step 4, the wrapping phase of each acquired image is obtained by the following formulas (4) to (6):
Figure FDA0002507193340000022
Figure FDA0002507193340000023
Figure FDA0002507193340000024
wherein I1d、I12d、I123dIs the brightness value, I, of the corresponding pixel in the image d1a、I12a、I123aIs the brightness value, I, of the corresponding pixel in the image a1b、I12b、I123bIs the brightness value, I, of the corresponding pixel in image b1c、I12c、I123cIs the luminance value of the corresponding pixel in image c.
4. The method of claim 3, wherein the method comprises: in step 5, the phase progression fractional part Δ N1 and the integer part N1 of the acquired image 1 are obtained by the following equations (7) to (11):
Figure FDA0002507193340000025
Figure FDA0002507193340000026
Figure FDA0002507193340000027
Figure FDA0002507193340000028
Figure FDA0002507193340000029
where round denotes a rounding operation, and since the pitch P123 is a full-field grating, N123 is 0.
5. The surface structure photolysis method based on moire sequence grating as claimed in claim 1, wherein: in step 6, the absolute phase Φ 1 of the acquired image 1 can be directly calculated according to the formula (12):
Figure FDA00025071933400000210
CN201711397481.4A 2017-12-21 2017-12-21 Surface structure photolysis method based on Moire sequence grating Active CN108061517B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711397481.4A CN108061517B (en) 2017-12-21 2017-12-21 Surface structure photolysis method based on Moire sequence grating

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711397481.4A CN108061517B (en) 2017-12-21 2017-12-21 Surface structure photolysis method based on Moire sequence grating

Publications (2)

Publication Number Publication Date
CN108061517A CN108061517A (en) 2018-05-22
CN108061517B true CN108061517B (en) 2020-08-11

Family

ID=62139795

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711397481.4A Active CN108061517B (en) 2017-12-21 2017-12-21 Surface structure photolysis method based on Moire sequence grating

Country Status (1)

Country Link
CN (1) CN108061517B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109297435A (en) * 2018-10-24 2019-02-01 重庆大学 A kind of reversed colorful number grating encoding method for offsetting nonlinearity erron
CN110428459B (en) * 2019-06-04 2023-05-16 重庆大学 Digital sequential coding-based phase unwrapping method
CN110207620B (en) * 2019-06-04 2021-07-02 重庆大学 Three-dimensional reconstruction method for determining optical series of digital grating projection structure through different frequencies
CN110207621B (en) * 2019-06-04 2021-03-26 重庆大学 Four-step phase shift surface structure photolysis method based on variable phase shift

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000234920A (en) * 1999-02-15 2000-08-29 Hitachi Electronics Eng Co Ltd Wafer flatness measuring equipment
CN101109616A (en) * 2007-08-02 2008-01-23 华中科技大学 Tri-band heterodyne phase shift phase demodulation method
CN202074952U (en) * 2011-05-04 2011-12-14 李中伟 Three dimensional profiles and colored textures acquisition system based on single camera-single overhead projector
CN107063128A (en) * 2016-04-29 2017-08-18 华南师范大学 A kind of double frequency phase shift method for three-dimensional measurement and system

Also Published As

Publication number Publication date
CN108061517A (en) 2018-05-22

Similar Documents

Publication Publication Date Title
CN108061517B (en) Surface structure photolysis method based on Moire sequence grating
CN104330052B (en) Heterodyne system three frequency the most not wait walk transfer from one place to another under escort phase method mutually
CN107607060B (en) A kind of phase error compensation method applied in the measurement of grating tripleplane
US9816287B2 (en) Updating calibration of a three-dimensional measurement system
CN101881605B (en) Optical three-dimensional measuring method based on phase coding technology
CN109489585B (en) Three-dimensional measurement method based on improved multi-frequency stripe structured light
CN108955571B (en) The method for three-dimensional measurement that double frequency heterodyne is combined with phase-shift coding
CN109523627B (en) Three-dimensional reconstruction method of profile structured light based on Taylor index expression
TWI573984B (en) System and method of adjusting matching image
CN101236066B (en) Projection grating self-correction method
CN110230997B (en) Shadow region phase noise correction method based on improved monotony method
CN104299218A (en) Projector calibration method based on lens distortion rule
CN109297435A (en) A kind of reversed colorful number grating encoding method for offsetting nonlinearity erron
CN108195313A (en) A kind of high dynamic range method for three-dimensional measurement based on Intensity response function
JPH0739935B2 (en) Image sensor
CN105300317A (en) Three-dimensional measurement method on the basis of projection of sinusoidal stripes and triangular wave stripes
CN106840038B (en) A kind of double frequency phase shift and Gray&#39;s code character close method
CN112880589A (en) Optical three-dimensional measurement method based on double-frequency phase coding
CN110608687A (en) Color coding grating crosstalk compensation method based on projection plane
CN110160468B (en) Defocused grating projection three-dimensional measurement method for moving object
CN110428459B (en) Digital sequential coding-based phase unwrapping method
Yin et al. High-speed 3D profilometry employing HSI color model for color surface with discontinuities
CN113596423B (en) Brightness correction method and device, electronic equipment and readable storage medium
Ding et al. Recovering the absolute phase maps of three selected spatial-frequency fringes with multi-color channels
CN110207621B (en) Four-step phase shift surface structure photolysis method based on variable phase shift

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant