CN113654487B - Dynamic three-dimensional measurement method and system for single color fringe pattern - Google Patents

Dynamic three-dimensional measurement method and system for single color fringe pattern Download PDF

Info

Publication number
CN113654487B
CN113654487B CN202110945053.0A CN202110945053A CN113654487B CN 113654487 B CN113654487 B CN 113654487B CN 202110945053 A CN202110945053 A CN 202110945053A CN 113654487 B CN113654487 B CN 113654487B
Authority
CN
China
Prior art keywords
color
channel
uniform intensity
patterns
fringe
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
CN202110945053.0A
Other languages
Chinese (zh)
Other versions
CN113654487A (en
Inventor
赵宏
朱倩
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.)
Xian Jiaotong University
Original Assignee
Xian Jiaotong 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 Xian Jiaotong University filed Critical Xian Jiaotong University
Priority to CN202110945053.0A priority Critical patent/CN113654487B/en
Publication of CN113654487A publication Critical patent/CN113654487A/en
Application granted granted Critical
Publication of CN113654487B publication Critical patent/CN113654487B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
    • G01B11/2504—Calibration devices
    • 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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
    • 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
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
    • G01B11/2518—Projection by scanning of the object
    • G01B11/2527—Projection by scanning of the object with phase change by in-plane movement of the patern
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

The invention discloses a dynamic three-dimensional measurement method and a system for a single color fringe pattern, wherein the method comprises the following steps: s1, projecting three uniform intensity diagrams of red, green and blue with consistent intensity; shooting a projected uniform intensity graph, and collecting red, green and blue uniform intensity graphs; s2, calculating coupling strength coefficients among color channels; s3, projecting a color fringe pattern to the object to be detected and shooting the color fringe pattern; s4, decoupling gray level fringe patterns of three channels in the color fringe pattern; s5, decomposing the decoupled color fringe patterns to obtain three background-free fringe patterns and three background patterns; s6, solving a modulation degree ratio by using a background image to obtain a color normalized background-free fringe image; s7, demodulating the color normalized background-free fringe pattern, and obtaining a demodulation phase; s8, unwrapping the demodulation phase, solving the unwrapped phase, and reconstructing the three-dimensional morphology. The invention encodes three gray level fringe patterns on a color fringe pattern, and obtains the gray level phase shift fringe pattern meeting the demodulation requirement of a phase shift method through projection and decoupling.

Description

Dynamic three-dimensional measurement method and system for single color fringe pattern
Technical Field
The invention belongs to the technical field of optical three-dimensional measurement, and particularly relates to a dynamic three-dimensional measurement method and system for a single color fringe pattern.
Background
In recent decades, dynamic three-dimensional topography measurement techniques have been widely used in various fields, such as industrial inspection, machine vision, and intelligent monitoring. To achieve three-dimensional topography measurement of dynamic objects, multi-camera stereoscopic methods and fringe projection profilometry are commonly employed. Wherein stereo vision results in low measurement accuracy due to uncertainty in stereo matching, and multiple cameras increase measurement costs. The fringe projection profilometry has the advantages of non-contact, full-field, high precision and the like, so that the fringe projection profilometry has been widely developed and applied. Fringe projection profilometry involves mainly three flows, phase demodulation, phase unwrapping, and phase-to-height mapping. The accuracy of phase demodulation has decisive significance for three-dimensional morphology measurement results, so that a great deal of research is developed by students.
Among the phase demodulation methods, the two most commonly used methods are the spatial domain method and the phase shift method. The spatial domain method can extract the phase by only one gray fringe pattern, but when the object to be measured is an object with a complex surface, the method is easy to generate spectrum aliasing, so that the phase extraction is wrong; the phase shift method is insensitive to ambient light, can obtain pixel-level phase points, and has high demodulation accuracy because the phase is calculated by using a plurality of gray phase shift fringe patterns, but the method requires that the gray phase shift fringe patterns are acquired in a static state of an object to be detected, so that the accuracy of demodulation phase can be ensured.
With the development of various industries, the requirements on the speed and precision of dynamic three-dimensional morphology measurement are higher and higher, and the traditional three-dimensional morphology measurement technology cannot meet the requirements, so that a dynamic and high-precision three-dimensional morphology measurement technology needs to be researched, and in the technology, the key problem is how to extract the demodulation phase rapidly and with high precision. Considering that the spatial domain method in the existing phase demodulation method can extract the phase by only shooting one gray-scale fringe pattern, the demodulation phase precision is low, and the method is not suitable for measuring objects with complex surfaces; the phase shift method can extract the phase only by shooting more than three gray level fringe patterns, thereby limiting the speed and the accuracy of dynamic measurement. Therefore, for the dynamic three-dimensional topography measurement technology based on fringe projection profilometry, a method for combining measurement precision and efficiency is lacking at present.
Along with the development of a color camera, the gray-scale image acquisition device has the advantages that three channels are provided, and the traditional gray-scale camera only has one channel, so that students encode three gray-scale images in one color image, information of the three gray-scale images can be obtained by acquiring one color image through projection, and the measurement efficiency is improved. However, in the use of Color cameras, because the Color responses of the projector and the camera are inconsistent, the unavoidable problem is Color coupling and unbalance between the three channels, and the Peisen s.huang and Zhang Zonghua teams each project three red, green and blue fringe patterns to collect the coupling coefficients (literature: color-encoded digital fringe projection technique for high-speed fringe-dimensional surface contouring and Time efficient Color fringe projection system for3D shape and Color using optimum 3-frequency Selection), which method is very good for decoupling, but has the problem that three red, green and blue fringe patterns need to be projected at each measurement, which is time-consuming and not adaptive. For correcting Color unbalance, a scholars Pan et al projects and acquires more than three Color fringe patterns, a fringe pattern background item and a modulation degree of each channel are calculated by using a mathematical relation among the three patterns, and then Color normalization correction of the three channels is carried out (document Color-encoded digital fringe projection technique for high-speed 3-D shape measurement: color coupling and imbalance compensation).
Disclosure of Invention
Aiming at the problem that the measurement speed and precision of the existing dynamic three-dimensional morphology measurement technology are limited by a demodulation method, the invention aims to provide a demodulation phase method and a demodulation phase system which are compatible with the speed and the precision at the same time so as to meet the requirement of dynamic three-dimensional morphology measurement. The method can extract the phase by only collecting one color fringe pattern through projection, so that the robustness of a phase shift method is maintained, the measurement efficiency is improved, and the dynamic three-dimensional morphology measurement is realized.
In order to achieve the above purpose, the method for dynamically measuring the three-dimensional single color fringe pattern comprises the following steps:
s1, projecting three uniform red intensity patterns with consistent intensity to a calibration white boardGreen uniform intensity plot->And blue uniform intensity map->Shooting a projected uniform intensity map, and acquiring a red uniform intensity map +.>Green uniform intensity plot->And blue uniform intensity map->
S2, utilizing the red uniform intensity graph acquired by S1Green uniform intensity plot->And blue uniform intensity map->Calculating the coupling intensity coefficient of each main color channel in the other two channels;
s3, projecting a color fringe pattern to the object to be measured by using the measuring system same as that of S1Wherein (1)>Respectively color stripe patterns I p Gray stripe patterns on a middle red channel, a green channel and a blue channel; synchronously shooting color fringe images, and collecting a color fringe image +.>Wherein (1)>Respectively color stripe patterns I c Gray stripe patterns on a middle red channel, a green channel and a blue channel;
s4, utilizing the coupling strength coefficient to acquire a color fringe pattern I c Gray fringe pattern of three channelsDecoupling respectively;
s5, decomposing the decoupled color fringe patterns, and outputting three background-free fringe patterns RIMF, GIMF, BIMF and three background patterns RIMF1, GIMF1 and BIMF1;
s6, using three background images RIMF1, GIMF1 and BIMF1, taking one channel as a reference channel, and obtaining modulation degree ratios M of the other two channels to the reference channel respectively 1 ,M 2 The method comprises the steps of carrying out a first treatment on the surface of the By means of the modulation degree ratio M 1 ,M 2 Performing color normalization on the three background-free fringe patterns RIMF, GIMF, BIMF to obtain three gray fringe patterns RIMF 'GIMF' with consistent amplitude values;
s7, demodulating the gray fringe pattern RIMF (graphic arts Filter) and the BIMF (graphic arts filter) to obtain a demodulation phase phi;
and S8, unwrapping the demodulation phase phi, solving the unwrapped phase, and reconstructing the three-dimensional morphology.
Further, in S1, the intensity range of the projected uniform intensity map is 120 to 220.
Further, in S2, the coupling intensity coefficient of each main color channel in the other two channels is calculated by the intensity ratio between the different channels.
Further, in S4, the decoupling formula is:
wherein, the liquid crystal display device comprises a liquid crystal display device,respectively gray level fringe patterns of a red channel, a green channel and a blue channel in the decoupled color fringe patterns; k (K) rg ,K rb Respectively acquiring coupling intensity coefficients of a red main color channel to a green channel and a blue channel in a red uniform intensity graph; k (K) gr ,K gb Respectively the collected greenIn the color uniformity intensity diagram, the coupling intensity coefficient of the green main color channel to the red channel and the blue channel; k (K) br ,K bg And respectively acquiring coupling intensity coefficients of a blue main color channel to a red channel and a green channel in the blue uniform intensity graph.
Further, in S5, the decoupled color fringe pattern is decomposed using an EMD algorithm.
Further, in S6, the background-free fringe pattern is color normalized by the modulation ratio.
Further, in S7, three gray-scale fringe patterns RIMF ", GIMF", BIMF ", which have the same amplitude, are demodulated by using the three-step phase shift method.
Further, in S8, the demodulation phase Φ is unwrapped by using a quality-scheme wrapping method.
A dynamic three-dimensional morphology measurement system based on a single color fringe pattern comprises a color camera, a projector and an upper computer; the output end and the input end of the color camera and the projector are connected with the upper computer and are used for receiving and transmitting instructions of the upper computer; the projector is used for projecting a red uniform intensity image, a green uniform intensity image and a blue uniform intensity image to a calibration white board and is used for projecting a color fringe image to an object to be measured; the color camera is used for shooting a uniform intensity image of projection for calibration and a projection image of a color fringe pattern on a measured object, transmitting the shot image to the upper computer, and storing a calculation program which can run on the upper computer, wherein the upper computer carries out phase demodulation on the received image when executing the calculation program.
Compared with the prior art, the invention has at least the following beneficial technical effects:
1) The invention provides a new idea for dynamic three-dimensional morphology measurement. The traditional phase shift demodulation method can be realized by more than three gray phase shift fringe patterns, and during the acquisition of the phase shift fringe patterns, if an object moves, demodulation precision can be affected, and high-precision three-dimensional reconstruction can not be realized. The invention utilizes the advantages of three channels of the color camera to encode three gray level fringe patterns on one color fringe pattern, and can obtain three gray level phase shift fringe patterns meeting the demodulation requirement of a phase shift method through single projection acquisition and subsequent decoupling, thereby preserving the robustness of the phase shift method, ensuring that the measurement result is not influenced by the movement of an object and realizing dynamic measurement;
2) The present invention utilizes empirical mode decomposition (Empirical Mode Decomposition: EMD) algorithm extracts three background images from one color fringe image, performs modulation normalization, realizes color normalization of the three fringe images, reduces the number of the needed color fringe images from three to one compared with the traditional color normalization method, and better meets the dynamic measurement requirement;
3) Compared with the traditional color decoupling method, the method has the advantages that three red, green, blue and uniform intensity images are projected and collected on the white board, the coupling coefficient of the whole system is pre-calibrated, the color images collected in the formal measurement are directly decoupled, multiple calibration is not needed, and the measurement efficiency is improved.
Drawings
FIG. 1 is a schematic flow chart of a dynamic three-dimensional measurement method of a single color fringe pattern;
FIG. 2 is a graph of three red, green and blue uniformity patterns for use in pre-calibration. Wherein Red, green, blue is respectively three acquired red, green and blue uniformity diagrams, R1, R2, R3, B1, B2, B3, C1, C2 and C3 are single-channel uniformity diagrams obtained by decomposing the red, green and blue uniformity diagrams;
FIG. 3a is a red channel stripe diagram after decoupling;
FIG. 3b is a background-free fringe pattern obtained by EMD decomposition of the fringe pattern of FIG. 3 a;
FIG. 3c is a background image obtained by EMD decomposition of the fringe image of FIG. 3 a;
FIG. 3d is a cross-section corresponding to the solid white line in FIG. 3 a;
FIG. 3e is a cross-section corresponding to the solid white line in FIG. 3 b;
FIG. 3f is a cross-section corresponding to the solid white line in FIG. 3 c;
FIG. 4a is a cross-section of column 350 of a background-free fringe pattern without color normalization in three channels;
FIG. 4b is a column 350 cross-section of a color normalized background-free fringe pattern in three channels;
FIG. 5a is a single color stripe diagram phase modulation result;
FIG. 5b is a cross-section of the solid white line of FIG. 5 a;
FIG. 5c is a cross section of the demodulation phase obtained by the demodulation phase and 12-step gray scale phase shift method in FIG. 5 b;
fig. 5d shows the demodulation phase error obtained by the present invention.
Note that: the more the number of the gray stripe pattern phase shifts, the higher the demodulation phase precision, so the invention adopts the demodulation phase obtained by the 12-step phase shift pattern as a reference value to check the demodulation phase error of the method.
FIG. 6a is a face unwrapped phase diagram;
FIG. 6b is a three-dimensional representation of FIG. 6 a;
FIG. 6c is a cross-section of the outline corresponding to the solid line AB in FIG. 6a, with an enlarged view of a portion of the outline shown in the black box;
FIG. 6d is a cross-section of the outline corresponding to the solid line CD in FIG. 6a, with a magnified view of a portion of the outline in the black box;
note that: the reference method in fig. 6c and 6d is a cross section of an unwrapped phase diagram obtained by a multi-frequency unwrapped method and demodulated by a 12-step phase shift method, and the three-dimensional reconstruction results of the two methods are consistent by comparing the method of the invention with the reference method;
fig. 7 is a schematic diagram of a measurement system.
In the drawing, a 1-color camera, a 2-projector, a 3-upper computer and a 4-object to be measured.
Detailed Description
In order to make the purpose and technical scheme of the invention clearer and easier to understand. The present invention will now be described in further detail with reference to the drawings and examples, which are given for the purpose of illustration only and are not intended to limit the invention thereto.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more. In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Referring to fig. 1, a dynamic three-dimensional measurement method for a single color fringe pattern includes the steps of:
step one: three uniform intensity red maps with consistent intensity are respectively projected to a calibration whiteboard by using a projector 2Green uniform intensity plot->And blue uniform intensity map->The intensity range is 120-220 (according to the linear range of the intensities of different cameras), the uniform intensity map of the projection is shot by the color camera 1, and the uniform intensity map is acquiredTo red uniform intensity plot->Green uniform intensity plot->And blue uniform intensity map->Fig. 2 is a single-channel uniformity map of three acquired red, green, and blue uniformity intensity maps, respectively. For example, the intensity values of the individual channels of the red uniform intensity plot, the observed intensity values are available, R 1 Is the main color channel, and has the maximum intensity value; r is R 2 Is R 1 The coupling intensity value in the green channel is adjacent to the red channel, so that the coupling intensity value is larger; and R is 3 Is R 1 The coupling intensity value in the blue channel is not adjacent to the red channel, so the coupling intensity value is the smallest (almost 0); the measurement system used in the present invention is shown in fig. 7.
Note that: in the invention, the image acquired by projection has three channels of red, green and blue.
The formula of the projected red, green and blue uniform intensity maps is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,red uniformity diagram for projection->A uniform intensity pattern over the red, green, blue channels;
green uniformity diagram for projection->A uniform intensity pattern over the red, green, blue channels;
for projected blue homogeneity map->A uniform intensity pattern over the red, green, and blue channels.
The formulas of the actually collected red, green and blue uniform intensity diagrams are as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,for red homogeneity of acquisition->In red, green and blue channelsA uniform intensity pattern thereon;
for the collected green homogeneity map->A uniform intensity pattern over the red, green, blue channels of the array;
for the acquired blue homogeneity map->A uniform intensity pattern over the red, green, and blue channels of (c).
Step two: using the red uniform intensity map collected in the step oneGreen uniform intensity plot->And blue uniform intensity map->Calculating the coupling intensity coefficient of each main color channel in the other two channels through the intensity ratio between different channels:
wherein K is rg ,K rb Respectively acquiring coupling intensity coefficients of a red main color channel to a green channel and a blue channel in a red uniform intensity graph; k (K) gr ,K gb Respectively acquiring coupling intensity coefficients of a green main color channel to a red channel and a blue channel in the green uniform intensity graph; k (K) br ,K bg And respectively acquiring coupling intensity coefficients of a blue main color channel to a red channel and a green channel in the blue uniform intensity graph.
Step three: using the measuring system in the first step, a color fringe pattern is projected by the projector 2 to the object 4 to be measuredWherein (1)>Respectively color stripe patterns I p Gray stripe patterns on a middle red channel, a green channel and a blue channel; synchronously shooting color fringe images through the color camera 1, and acquiring a color fringe imageWherein (1)>Respectively color stripe patterns I c Gray scale fringe patterns on the red, green, and blue channels. The specific formula is as follows:
projected color fringe pattern I p The gray fringe patterns of the three channels are respectively:
collected color fringe pattern I c The gray fringe patterns of the three channels are respectively:
wherein, the liquid crystal display device comprises a liquid crystal display device,respectively->Background item of->Respectively->A modulation degree of (2);respectively->Background item of->Respectively->Phi is the wrapping phase.
Step four: using the coupling strength coefficient K obtained in the second step rg ,K rb ,K gr ,K gb ,K br ,K bg Gray level fringe patterns of three channels in the color fringe pattern acquired in the step three are comparedDecoupling respectively, wherein the calculation formula is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,gray scale fringe patterns of red channel, green channel and blue channel in the decoupled color fringe pattern respectively, < >>Is->Background item of->Is->Is a modulation degree of (a) in the above-mentioned system. First toPerforming decoupling correction to obtain->Then use the corrected intensity +.>For->Decoupling to obtain->Finally use corrected intensity->And->For->Decoupling to obtain->The decoupling correction idea of the step is to use the corrected channel intensity to carry out decoupling correction on other channels, and the decoupling effect is better.
Step five: the decoupled color fringe pattern is decomposed by using an EMD algorithm, and three background-free fringe patterns and three background patterns are output, wherein the three background patterns are expressed as follows:
wherein the RIMF corresponds to a high frequency termGIMF corresponds to the high-frequency term->BIMF corresponds to the high frequency term->RIMF1 corresponds to the low frequency term (i.e., the background term)/(L)>GIMF1 corresponds to the low frequency term (i.e., the background term)BIMF1 corresponds to the low frequency term (i.e., background term)/(L)>
FIGS. 3a to 3f show red channel images in decoupled color fringe patterns during three-dimensional measurement of face modelsAfter EMD decomposition, the color is divided into a fringe image RIMF (high-frequency item) and a background image RIMF1 (low-frequency item), and as can be seen from fig. 3e and 3f, the high-frequency item and the low-frequency item are completely separated after EMD decomposition, so that preparation is made for the next color normalization;
step six: using the three background images RIMF1, GIMF1 and BIMF1 obtained in the step five, and taking the blue channel as a reference to obtain the background image modulation degree ratio M of the red channel and the green channel to the blue channel respectively 1 ,M 2 The following formula is shown:
wherein, corr1, corr2, corr3 and corr4 are modulation factors, the value range is-5, which is used for ensuring that the normalization degree of three background-free fringe patterns is better. (x, y) is the pixel coordinates of the background image, RIMF1 (x, y) is the pixel intensity value at (x, y) for RIMF1, RIMF2 (x, y) is the pixel intensity value at (x, y) for RIMF2, and RIMF3 (x, y) is the pixel intensity value at (x, y) for RIMF3, M 1 (x, y) is M 1 Numerical value M when coordinates are (x, y) 2 (x, y) is M 2 The coordinates are (x, y).
After the modulation ratio is obtained, performing color normalization on the three background-free fringe patterns RIMF, GIMF, BIMF in the step five to obtain three gray fringe patterns RIMF (graphic arts of colors), GIMF (graphic arts of colors), BIMF (graphic arts of colors) with consistent amplitude values, wherein the color normalization formula is as follows:
RIMF”＝RIMF/M 1
GIMF”＝GIMF/M 2
RIMF”＝BIMF
similarly, the present step may perform color normalization with respect to the green channel and the red channel, respectively. For example, when the green channel is used as a reference, the background image modulation degree ratio M of the red channel and the blue channel to the red channel is obtained 1 ,M 2 The following formula is shown:
the color normalization formula becomes:
RIMF”＝RIMF/M 1
GIMF”＝GIMF
RIMF”＝BIMF/M 2
when the red channel is taken as a reference, the modulation degree ratio M of the background image of the green channel and the blue channel to the blue channel is obtained 1 ,M 2 The following formula is shown:
the color normalization formula becomes:
RIMF”＝RIMF
GIMF”＝GIMF/M 1
RIMF”＝BIMF/M 2
in the step, no matter which channel of red, green and blue is used as a reference for color normalization, three fringe patterns with consistent modulation degrees can be obtained, namely, the three fringe patterns are subjected to color normalization. Fig. 4a and fig. 4b show fringe patterns before and after color normalization, and it can be seen from the figures that the magnitudes of the three fringe patterns are consistent after the color normalization treatment, so as to meet the demodulation requirement of the subsequent phase shift method.
Step seven: demodulating the three gray fringe patterns RIMF 'GIMF' with consistent amplitude obtained in the step six by using a three-step phase shift method, wherein the obtained demodulation phase and phase errors thereof are shown in fig. 5a to 5d, and the solving formula of the demodulation phase phi is shown as follows:
fig. 5a is a demodulation phase diagram of the face model obtained by the method of the present invention, and fig. 5b is a demodulation phase corresponding to the white solid line in fig. 5a, so that the obtained phase amplitude is between (-pi, pi). Since the demodulation accuracy is higher as the number of phase steps is larger in the demodulation by the phase shift method, the demodulation phase error of the method of the invention is evaluated by using the 12-step phase shift demodulation method as a reference. Fig. 5c is a cross-sectional view of the demodulation phase obtained by demodulating the method and the 12-step phase shift method, and fig. 5d is a phase error obtained by differencing the demodulation phase obtained by the two methods in fig. 5c, so that the error of the method is within 0.06rad, and the requirements of high-precision measurement and subsequent unwrapping are met.
Step eight: and (3) unwrapping the demodulation phase phi obtained in the step seven by using a quality diagram wrapping method, solving the unwrapped phase, and reconstructing a three-dimensional morphology, as shown in fig. 6a and 6 b. In the stripe projection profile operation, the unwrapped phase obtained by the multi-frequency method is high in accuracy due to demodulation by the 12-step phase shift method, so that the unwrapped phase is used as a reference value to compare the accuracy of the method, and the experimental results of fig. 6c and 6d show that the unwrapped phase obtained by the method is consistent with the unwrapped phase obtained by the reference method, and the three-dimensional morphology can be well reconstructed.
Referring to fig. 7, a dynamic three-dimensional morphology measurement system based on a single color fringe pattern comprises a color camera 1, a projector 2 and an upper computer 3, wherein the output end and the input end of the color camera 1 and the projector 2 are connected with the upper computer and are used for receiving and transmitting instructions of the upper computer. The projector 2 is used for projecting a red uniform intensity map, a green uniform intensity map and a blue uniform intensity map to the calibration white board and is used for projecting a color fringe pattern to the object 4 to be measured; the color camera 1 is used for shooting a uniform intensity image of projection for calibration and a projection image of a color fringe pattern on a measured object, transmitting the shot image to an upper computer, storing a calculation program which can run on the upper computer, and when the upper computer executes the calculation program, realizing the steps of the phase demodulation method, calculating a demodulation phase phi according to the received image, unwrapping according to the demodulation phase phi, obtaining an unwrapped phase, and reconstructing a three-dimensional morphology.
The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to accomplish the present invention.
The upper computer can be a desktop computer, a notebook computer, a palm computer, a cloud server and other computing devices. The upper computer may include, but is not limited to, a processor, a memory.
The processor may be a central processing unit (CentralProcessingUnit, CPU), but may also be other general purpose processors, digital signal processors (DigitalSignalProcessor, DSP), application specific integrated circuits (ApplicationSpecificIntegratedCircuit, ASIC), off-the-shelf programmable gate arrays (Field-ProgrammableGateArray, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.
The method disclosed by the invention provides a new idea for measuring the dynamic three-dimensional morphology. The method mainly comprises two steps, wherein the first step is a pre-calibration step, and the color coupling is mainly caused by the optical characteristics and devices of a measurement system, so that the coupling strength coefficient can be obtained through the pre-calibration of the first step and the second step, and the preparation is made for image decoupling in formal measurement. The second step is the formal measurement link, adopt the identity measurement system, collect a color fringe pattern, use the coupling intensity coefficient that the precalibration link obtains to decouple and correct and get the color fringe pattern without coupling, then through EMD decomposition and color normalization, get three gray phase shift fringe patterns without background, modulation degree is unanimous, has met the requirement of the demodulation method of three-step phase shift, can get the demodulation phase of high accuracy through the demodulation method of three-step phase shift. The method has the advantages that the high-precision demodulation phase is extracted by projecting and collecting a color fringe pattern, and the motion speed of the object has no influence on the precision of the phase because the phase is extracted by using a single-frame collected picture, so the method can be applied to the three-dimensional shape measurement of the dynamic object.
The above is only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited by this, and any modification made on the basis of the technical scheme according to the technical idea of the present invention falls within the protection scope of the claims of the present invention.

Claims (7)

1. The dynamic three-dimensional measurement method for the single color fringe pattern is characterized by comprising the following steps of:
s1, projecting three uniform red intensity patterns with consistent intensity to a calibration white boardGreen uniform intensity plot->And blue uniform intensity map->Shooting a projected uniform intensity map, and acquiring a red uniform intensity map +.>Green uniform intensity plot->And blue uniform intensity map->
S2, utilizing the red uniform intensity graph acquired by S1Green uniform intensity plot->And blue uniform intensity map->Calculating the coupling intensity coefficient of each main color channel in the other two channels;
s3, projecting a color fringe pattern I to the object to be detected by using the same equipment as that of S1 p ,Wherein, the liquid crystal display device comprises a liquid crystal display device,respectively color stripe patterns I p Gray stripe patterns on a middle red channel, a green channel and a blue channel; synchronously shooting color stripe images, and collecting a color stripePattern I c ,/>Wherein (1)>Respectively color stripe patterns I c Gray stripe patterns on a middle red channel, a green channel and a blue channel;
s4, utilizing the coupling strength coefficient to acquire gray level fringe patterns of three channels in the color fringe patternDecoupling respectively;
s5, decomposing the decoupled color fringe patterns, and outputting three background-free fringe patterns RIMF, GIMF, BIMF and three background patterns RIMF1, GIMF1 and BIMF1;
s6, using three background images RIMF1, GIMF1 and BIMF1, taking one channel as a reference channel, and obtaining modulation degree ratios M of the other two channels to the reference channel respectively 1 ,M 2 The method comprises the steps of carrying out a first treatment on the surface of the By means of the modulation degree ratio M 1 ,M 2 Performing color normalization on the three background-free fringe patterns RIMF, GIMF, BIMF to obtain three gray fringe patterns RIMF 'GIMF' with consistent amplitude values;
s7, demodulating the gray fringe pattern RIMF (graphic arts Filter) and the BIMF (graphic arts filter) to obtain a demodulation phase phi;
s8, unwrapping the demodulation phase phi, solving the unwrapped phase, and reconstructing the three-dimensional morphology;
in S4, the decoupling formula is:
wherein, the liquid crystal display device comprises a liquid crystal display device,respectively gray level fringe patterns of a red channel, a green channel and a blue channel in the decoupled color fringe patterns; k (K) rg ,K rb Respectively acquiring coupling intensity coefficients of a red main color channel to a green channel and a blue channel in a red uniform intensity graph; k (K) gr ,K gb Respectively acquiring coupling intensity coefficients of a green main color channel to a red channel and a blue channel in the green uniform intensity graph; k (K) br ,K bg And respectively acquiring coupling intensity coefficients of a blue main color channel to a red channel and a green channel in the blue uniform intensity graph.
2. The method for dynamically measuring three dimensions of a single color fringe pattern of claim 1 wherein in S1, the projected uniform intensity pattern has an intensity range of 120-220.
3. The method for dynamically measuring a single color fringe pattern in three dimensions according to claim 1, wherein in S2, the coupling intensity coefficient of each main color channel in the other two channels is calculated through the intensity ratio between different channels.
4. The method according to claim 1, wherein in S5, the decoupled color fringe pattern is decomposed using an EMD algorithm.
5. The method for dynamically measuring a single color fringe pattern in three dimensions according to claim 1, wherein in S7, three gray fringe patterns RIMF ", GIMF", BIMF ", which have identical magnitudes, are demodulated by using a three-step phase shift method.
6. The method for dynamic three-dimensional measurement of single color fringe pattern of claim 1 wherein in S8, the demodulation phase Φ is unwrapped by a mass-schematic wrapping method.
7. The dynamic three-dimensional morphology measurement system based on the single color fringe pattern is characterized by comprising a color camera (1), a projector (2) and an upper computer; the output end and the input end of the color camera (1) and the projector (2) are connected with an upper computer and are used for receiving and transmitting instructions of the upper computer; the projector (2) is used for projecting a red uniform intensity image, a green uniform intensity image and a blue uniform intensity image to a calibration white board and is used for projecting a color fringe image to an object to be measured (4); the color camera (1) is used for shooting a uniform intensity map of projection for calibration and a projection image of a color fringe pattern on a measured object, transmitting the shot image to the upper computer, storing a calculation program which can be run on the upper computer, and carrying out phase demodulation on the received image according to the method of any one of claims 1-6 when the upper computer executes the calculation program, obtaining an unwrapped phase and reconstructing a three-dimensional morphology.
CN202110945053.0A 2021-08-17 2021-08-17 Dynamic three-dimensional measurement method and system for single color fringe pattern Active CN113654487B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110945053.0A CN113654487B (en) 2021-08-17 2021-08-17 Dynamic three-dimensional measurement method and system for single color fringe pattern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110945053.0A CN113654487B (en) 2021-08-17 2021-08-17 Dynamic three-dimensional measurement method and system for single color fringe pattern

Publications (2)

Publication Number Publication Date
CN113654487A CN113654487A (en) 2021-11-16
CN113654487B true CN113654487B (en) 2023-07-18

Family

ID=78480633

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110945053.0A Active CN113654487B (en) 2021-08-17 2021-08-17 Dynamic three-dimensional measurement method and system for single color fringe pattern

Country Status (1)

Country Link
CN (1) CN113654487B (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB458491A (en) * 1935-03-12 1935-09-13 Cmc Corp Improvements in or relating to the projection of coloured images
US6024449A (en) * 1998-07-13 2000-02-15 Smith; Robert F. High speed topography measurement of semi-diffuse objects
CA2373284A1 (en) * 1999-05-14 2000-11-23 3D Metrics, Incorporated Color structured light 3d-imaging system
CA2573157A1 (en) * 2004-07-08 2006-02-09 Imax Corporation Equipment and methods for the display of high resolution images using multiple projection displays
CN104284625A (en) * 2012-05-14 2015-01-14 皇家飞利浦有限公司 Apparatus and method for profiling a depth of a surface of a target object
CN110986828A (en) * 2019-12-13 2020-04-10 杨鑫鑫 Novel real scene three-dimensional color data acquisition and display method
CN111060028A (en) * 2019-12-23 2020-04-24 广东工业大学 Composite sinusoidal trapezoidal stripe structured light three-dimensional measurement method
WO2021078300A1 (en) * 2019-10-24 2021-04-29 先临三维科技股份有限公司 Three-dimensional scanner and three-dimensional scanning method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB458491A (en) * 1935-03-12 1935-09-13 Cmc Corp Improvements in or relating to the projection of coloured images
US6024449A (en) * 1998-07-13 2000-02-15 Smith; Robert F. High speed topography measurement of semi-diffuse objects
CA2373284A1 (en) * 1999-05-14 2000-11-23 3D Metrics, Incorporated Color structured light 3d-imaging system
CA2573157A1 (en) * 2004-07-08 2006-02-09 Imax Corporation Equipment and methods for the display of high resolution images using multiple projection displays
CN104284625A (en) * 2012-05-14 2015-01-14 皇家飞利浦有限公司 Apparatus and method for profiling a depth of a surface of a target object
WO2021078300A1 (en) * 2019-10-24 2021-04-29 先临三维科技股份有限公司 Three-dimensional scanner and three-dimensional scanning method
CN110986828A (en) * 2019-12-13 2020-04-10 杨鑫鑫 Novel real scene three-dimensional color data acquisition and display method
CN111060028A (en) * 2019-12-23 2020-04-24 广东工业大学 Composite sinusoidal trapezoidal stripe structured light three-dimensional measurement method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
基于自适应条纹投影的彩色物体三维形貌测量;陈超;高楠;王向军;张宗华;;光学学报(第08期);全文 *

Also Published As

Publication number Publication date
CN113654487A (en) 2021-11-16

Similar Documents

Publication Publication Date Title
CN106989695B (en) Projector calibration method
CN109489585B (en) Three-dimensional measurement method based on improved multi-frequency stripe structured light
CN103868524B (en) A kind of monocular system calibrating method and device based on speckle pattern
US8823775B2 (en) Body surface imaging
TW201432619A (en) Methods and apparatus for merging depth images generated using distinct depth imaging techniques
CN202074952U (en) Three dimensional profiles and colored textures acquisition system based on single camera-single overhead projector
Hernández et al. Overcoming shadows in 3-source photometric stereo
Yang et al. Flexible and accurate implementation of a binocular structured light system
CN110567398A (en) Binocular stereo vision three-dimensional measurement method and system, server and storage medium
CN111028295A (en) 3D imaging method based on coded structured light and dual purposes
CN108871197B (en) Displacement field measuring method, device, equipment and storage medium for material surface
CN111932632A (en) Phase correction method in three-dimensional reconstruction of mechanical part
CN110942506A (en) Object surface texture reconstruction method, terminal device and system
CN107014313A (en) The method and system of weighted least-squares phase unwrapping based on S-transformation ridge value
CN110006365A (en) Phase developing method, device and electronic equipment based on two-dimensional look-up table
CN104266606B (en) Calibration method for infrared/visible light target surface of 2CCD camera
CN116129037A (en) Visual touch sensor, three-dimensional reconstruction method, system, equipment and storage medium thereof
CN107871337B (en) Visualization method of supersonic two-dimensional flow field data
US20240054662A1 (en) Capsule endoscope image three-dimensional reconstruction method, electronic device, and readable storage medium
Ravikanth et al. Location Related Signals with Satellite Image Fusion Method Using Visual Image Integration Method.
CN113654487B (en) Dynamic three-dimensional measurement method and system for single color fringe pattern
CN112880563B (en) Single-dimensional pixel combination mode equivalent narrow-area-array camera spatial position measuring method
CN111462331B (en) Lookup table method for expanding epipolar geometry and calculating three-dimensional point cloud in real time
CN108507476A (en) Displacement field measurement method, device, equipment and storage medium for material surface
CN114136236A (en) Phase profile adaptive projection measurement method combined with epipolar line constraint

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