A multi-layer multi-frequency radial stripe encoding and decoding method and device

Abstract

The application discloses a kind of multilayer multi-frequency radial stripe encoding and decoding method and device, to solve the technical problems that the existing stripe encoding and decoding mostly uses traditional single direction modulation stripe encoding and decoding technology to cause high projection cost.The method comprises obtaining stripe image basic parameters and preset frequency range, and generating multi-frequency stripe geometric parameters.After constructing stripe encoding pattern based on preset radius and angle conditions, signal encoding and phase shift zero point signal are extracted respectively, and the main pattern is calibrated to zero using zero point signal.The processed pattern is projected to the measured object, and after collecting multiple stripe images, the target absolute phase is obtained according to the frequency decoding of each frequency band stripe.Finally, three-dimensional information is output through depth phase mapping model.

Description

Technical Field

[0001] This invention relates to the field of structured light three-dimensional measurement technology, and in particular to a multi-layer multi-frequency radial stripe encoding and decoding method and apparatus. Background Technology

[0002] Fringe projection profilometry is widely used in surface structured light measurement devices, which are of great significance to optical three-dimensional measurement systems. They can provide accurate three-dimensional information for fields such as precision manufacturing, medical testing, and cultural relic protection.

[0003] Fringe projection profilometry, as a core method in surface structured light measurement, is closely related to the development of its encoding and decoding technology in response to the demands of optical 3D measurement. Fringe encoding and decoding technology originated in the 1970s and 80s, primarily based on unidirectional (horizontal or vertical) modulated periodic fringe patterns. Sinusoidal or rectangular wave fringes are projected through a projector, and after modulation by the surface morphology of the object being measured, a camera captures the deformed fringe image. Early methods employed time-phase demodulation algorithms (such as the four-step / three-step phase-shifting method), requiring the sequential projection of multiple phase-shifted fringes and the use of pixel-level phase calculations to achieve 3D reconstruction.

[0004] Most existing stripe coding and decoding methods use traditional unidirectional modulation stripe coding and decoding technology. This method uses a DLP (Digital Light Processing) projector to sequentially project a sequence of sinusoidal stripe patterns with a preset phase difference (such as π / 2 intervals). At the same time, a CCD (Charge-Coupled Device) camera synchronously acquires images of deformed stripes modulated by the object's surface. However, the stripe sequence output by this method relies on expensive micromirrors in a high-precision DLP (Digital Light Processing) projector, resulting in high projection costs. Summary of the Invention

[0005] This invention provides a multi-layer multi-frequency radial stripe encoding and decoding method and apparatus to solve the technical problem that most existing stripe encoding and decoding technologies use traditional unidirectional modulation stripe encoding and decoding techniques, resulting in high projection costs.

[0006] The first aspect of this invention provides a multi-layer, multi-frequency radial stripe encoding and decoding method, comprising:

[0007] Obtain the basic parameters of the stripe image, and generate multiple frequency components and stripe geometric parameters corresponding to each frequency component based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes;

[0008] Based on the preset coding region radius range and preset angle conditions, each frequency part and the stripe geometric parameters corresponding to each frequency part are used to generate a stripe coding pattern.

[0009] Signal extraction is performed on the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern to generate phase encoding region signal and zero-point signal. The zero-point signal is then used to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern.

[0010] Based on the effective number of phase-encoded region signals, the zero-return main stripe encoding pattern is projected onto the object under test to obtain multiple stripe images. The multiple stripe images are then decoded according to the stripe frequency in the stripe geometric parameters corresponding to each frequency part to generate the target absolute phase.

[0011] The absolute phase of the target is used as the input to a preset depth phase mapping model to output the three-dimensional information of the object being measured.

[0012] Optionally, the stripe geometric parameters further include the starting polar angle, radial distance, and polar angle; the preset highest and lowest stripe frequencies include the highest and lowest stripe frequencies; the step of generating multiple frequency components and corresponding stripe geometric parameters for each frequency component based on the stripe image basic parameters and the preset highest and lowest stripe frequencies includes:

[0013] Based on the basic parameters of the stripe image, generate the stripe image and the arc center point;

[0014] The stripe image is divided into multiple frequency components;

[0015] Calculate the image angle range corresponding to each frequency part based on the stripe frequency number corresponding to each frequency part.

[0016] Calculate the polar angle corresponding to each frequency component based on the image pixel coordinates corresponding to each frequency component;

[0017] Using the polar angle and image angle range corresponding to each frequency component, calculate the angle parameters corresponding to each frequency component;

[0018] Based on the angle parameters corresponding to each frequency component, determine the starting polar angle corresponding to each frequency component;

[0019] Calculate the stripe frequency corresponding to each frequency part based on the highest frequency of the stripe, the lowest frequency of the stripe, the number of stripe strokes corresponding to each frequency part, and the angle parameters.

[0020] Based on the center point of the arc and the image pixel coordinates corresponding to each frequency component, the radial distance corresponding to each frequency component is determined.

[0021] Optionally, the preset coding region radius range includes the main stripe coding region radius range, the signal coding region radius range, and the peripheral phase-shifted zero-point coding region radius range; the step of generating a stripe coding pattern based on the preset coding region radius range and preset angle conditions, each frequency component, and the stripe geometric parameters corresponding to each frequency component includes:

[0022] Determine whether the radial distance corresponding to each frequency portion is within the radius range of the main stripe coding region, the radius range of the signal coding region, or the radius range of the peripheral phase-shift zero-point coding region;

[0023] The frequency portion corresponding to the radial distance within the radius range of the main stripe coding region is taken as the target main stripe frequency portion, and the main stripe coding pattern is generated according to the stripe frequency, polar angle, and starting polar angle corresponding to each target main stripe frequency portion.

[0024] The frequency portion corresponding to the radial distance within the radius of the signal encoding region is taken as the initial signal frequency portion. Based on the preset angle condition, each initial signal frequency portion is filtered according to the stripe frequency, polar angle, starting polar angle, and phase shift step number corresponding to each initial signal frequency portion to determine multiple target signal frequency portions.

[0025] A signal encoding pattern is generated based on the starting polar angle corresponding to the frequency portion of each target signal.

[0026] The frequency portion corresponding to the radial distance within the radius range of the peripheral phase-shift zero-point encoding region is taken as the initial peripheral phase-shift zero-point frequency portion;

[0027] Based on the starting polar angle corresponding to each of the aforementioned frequency components, a polar angle range is set;

[0028] Determine whether the polar angle of each of the initial peripheral phase shift zero-point frequency portions is within the polar angle range;

[0029] The initial peripheral phase shift zero frequency portion corresponding to any polar angle within the polar angle range is taken as the target peripheral phase shift zero frequency portion, and a peripheral phase shift zero encoding pattern is generated according to the starting polar angle corresponding to each target peripheral phase shift zero frequency portion.

[0030] Optionally, generating the main stripe coding pattern based on the stripe frequency, polar angle, and starting polar angle corresponding to each of the target main stripe frequency portions includes:

[0031] The phase corresponding to each of the target main fringe frequency portions is calculated using the fringe frequency, polar angle, and starting polar angle corresponding to each of the target main fringe frequency portions.

[0032] Using the phase corresponding to the frequency portion of each of the target main fringe, calculate the gray value of the region corresponding to the frequency portion of each of the target main fringe;

[0033] Based on the starting polar angle corresponding to the frequency portion of each target main fringe, a main fringe code is generated;

[0034] A main stripe coding pattern is generated based on the main stripe coding and the grayscale values ​​of the regions corresponding to the frequency portions of each target main stripe.

[0035] Optionally, the step of filtering each initial signal frequency portion based on the preset angle condition according to the stripe frequency, polar angle, starting polar angle, and phase shift step number corresponding to each initial signal frequency portion to determine multiple target signal frequency portions includes:

[0036] Calculate the phase shift angle corresponding to each of the initial signal frequency portions based on the number of phase shift steps corresponding to each of the initial signal frequency portions;

[0037] The phase corresponding to each of the initial signal frequency components is calculated using the stripe frequency, polar angle, and starting polar angle corresponding to each of the initial signal frequency components.

[0038] Perform a modulo operation on the phase corresponding to each of the initial signal frequency components to determine the standard phase corresponding to each of the initial signal frequency components;

[0039] Calculate the absolute value of the difference between the standard phase and phase shift angle corresponding to each of the initial signal frequency portions, and compare it with the preset error limit;

[0040] The initial signal frequency portion corresponding to the absolute value of the difference between any standard phase and phase shift angle that is less than the preset error limit is taken as the intermediate signal frequency portion;

[0041] Based on the polar angle corresponding to each intermediate signal frequency portion, determine the start and end angles corresponding to each intermediate signal frequency portion.

[0042] Determine whether the start and end angles and polar angles corresponding to each intermediate signal frequency portion satisfy the preset angle conditions;

[0043] The intermediate signal frequency portion corresponding to any starting and ending angles and polar angles that satisfy the preset angle conditions is taken as the target signal frequency portion.

[0044] Optionally, generating a signal encoding pattern based on the starting polar angle corresponding to each of the target signal frequency portions includes:

[0045] Based on a preset constant, a region grayscale value is set for the frequency portion of each of the target signals;

[0046] Generate signal codes based on the starting polar angles corresponding to the frequency portions of each target signal;

[0047] A signal encoding pattern is generated based on the signal encoding and the grayscale values ​​of the regions corresponding to the frequency portions of each target signal.

[0048] Optionally, generating a peripheral phase-shift zero-point encoding pattern based on the starting polar angle corresponding to the frequency portion of each of the target peripheral phase-shift zero-points includes:

[0049] Based on a preset constant, a grayscale value is set for the peripheral phase-shift zero-point frequency portion of each target.

[0050] Based on the starting polar angle corresponding to the frequency portion of the peripheral phase shift zero point of each target, a peripheral phase shift zero point code is generated;

[0051] Based on the peripheral phase-shift zero-point encoding and the grayscale values ​​of the regions corresponding to the peripheral phase-shift zero-point frequency portions of each target, a peripheral phase-shift zero-point encoding pattern is generated.

[0052] Optionally, the step of decoding the multiple stripe images based on the stripe frequencies in the stripe geometric parameters corresponding to each of the frequency portions to generate the target absolute phase includes:

[0053] Group the multiple stripe images to determine multiple stripe image groups;

[0054] The wrapping phase of each stripe image group is calculated based on the light intensity of each stripe image in each stripe image group.

[0055] The zero-position wrapping phase and the lowest fringe frequency are selected from the wrapping phase of each of the stripe image groups and the fringe frequencies corresponding to each of the frequency portions, and the initial absolute phase is calculated based on the zero-position wrapping phase and the lowest fringe frequency.

[0056] Select the target wrapping phase and target stripe frequency from the wrapping phase of each stripe image group and the stripe frequency corresponding to each frequency part, and calculate the phase difference using the target stripe frequency, the target wrapping phase and the initial absolute phase;

[0057] Based on the lowest fringe frequency, determine the equivalent frequency;

[0058] The equivalent phase is calculated based on the equivalent frequency, the target fringe frequency, and the phase difference;

[0059] Calculate the number of integer cycles based on the equivalent phase and the target package phase;

[0060] The initial absolute phase is updated using the target fringe frequency, the target wrapping phase, and the number of integer cycles to determine the intermediate absolute phase, and the number of updates is counted in real time.

[0061] Determine whether the number of updates has reached the preset number of updates;

[0062] If so, the intermediate absolute phase is taken as the target absolute phase.

[0063] Optionally, it also includes:

[0064] If the number of updates does not reach the preset number of updates, the equivalent frequency is updated using the target stripe frequency to determine a new equivalent frequency;

[0065] New target wrapping phases and new target stripe frequencies are selected from the wrapping phases of each stripe image group and from the stripe frequencies corresponding to each frequency portion, respectively.

[0066] The intermediate absolute phase is used as the new initial absolute phase, and the new target wrapping phase and the new initial absolute phase are used to calculate the new phase difference;

[0067] Jump to execute the step of calculating the equivalent phase based on the equivalent frequency, the target fringe frequency, and the phase difference, until the number of updates reaches the preset number of updates;

[0068] The intermediate absolute phase determined when the number of updates reaches the above-mentioned preset number of updates is taken as the target absolute phase.

[0069] A second aspect of the present invention provides a multilayer multi-frequency radial stripe encoding and decoding device, comprising:

[0070] The acquisition module is used to acquire the basic parameters of the stripe image, and generate multiple frequency components and stripe geometric parameters corresponding to each frequency component based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes.

[0071] The stripe pattern generation module is used to generate a stripe coded pattern based on a preset coding region radius range and preset angle conditions, each frequency part and the stripe geometric parameters corresponding to each frequency part;

[0072] The zero-return module is used to extract signals from the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern, generate phase encoding region signals and zero-point signals, and use the zero-point signals to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern.

[0073] The phase output module is used to project the zero-return main stripe coding pattern onto the object under test based on the effective number of signals in the phase coding region, to obtain multiple stripe images, and to decode the multiple stripe images according to the stripe frequency in the stripe geometric parameters corresponding to each frequency part to generate the target absolute phase.

[0074] The three-dimensional information output module is used to take the absolute phase of the target as input to a preset depth phase mapping model and output the three-dimensional information of the measured object.

[0075] As can be seen from the above technical solutions, the present invention has the following advantages:

[0076] The above-mentioned technical solution of the present invention provides a multi-layer multi-frequency radial stripe encoding and decoding method. First, basic parameters of the stripe image are obtained, and multiple frequency components and corresponding stripe geometric parameters are generated based on the basic parameters and preset highest and lowest stripe frequencies. Next, based on a preset encoding region radius range and preset angle conditions, a stripe encoding pattern is generated for each frequency component and its corresponding stripe geometric parameters. Signal extraction is performed on the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern within the stripe encoding pattern to generate a phase encoding region signal and a zero-point signal. The zero-point signal is then used to perform a zero-return operation on the main stripe encoding pattern within the stripe encoding pattern to generate a zero-return main stripe encoding pattern. Given the effective number of phase-encoded region signals, the zero-return main fringe coding pattern is projected onto the object under test to obtain multiple fringe images. These images are then decoded based on the fringe frequencies in the fringe geometric parameters corresponding to each frequency component to generate the target absolute phase. Finally, the target absolute phase is used as input to a preset depth phase mapping model to output the three-dimensional information of the object under test. Based on this scheme, the present invention, using a preset coding region radius range and preset angle conditions, generates a fringe coding pattern whose coding style can be printed on a self-made grating code disk according to each frequency component and its corresponding fringe geometric parameters. This eliminates the need for expensive micromirrors in high-precision DLP projectors, effectively reducing projection costs. Attached Figure Description

[0077] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0078] Figure 1 This is a flowchart illustrating the steps of a multi-layer, multi-frequency radial stripe encoding and decoding method provided in Embodiment 1 of the present invention.

[0079] Figure 2 This is a schematic diagram of the striped coding pattern provided in Embodiment 1 of the present invention;

[0080] Figure 3 This is a flowchart illustrating a multi-layer, multi-frequency radial stripe encoding and decoding method provided in Embodiment 1 of the present invention;

[0081] Figure 4 This is a structural block diagram of a multi-layer multi-frequency radial stripe encoder / decoder device provided in Embodiment 2 of the present invention. Detailed Implementation

[0082] This invention provides a multi-layer multi-frequency radial stripe encoding and decoding method and apparatus to solve the technical problem that most existing stripe encoding and decoding technologies use traditional unidirectional modulation stripe encoding and decoding techniques, resulting in high projection costs.

[0083] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0084] Please see Figure 1 , Figure 1 The flowchart illustrates the steps of a multi-layer, multi-frequency radial stripe encoding and decoding method provided in Embodiment 1 of the present invention.

[0085] This invention provides a multi-layer, multi-frequency radial stripe encoding and decoding method, comprising:

[0086] Step 101: Obtain the basic parameters of the stripe image, and generate multiple frequency components and the corresponding stripe geometric parameters based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes.

[0087] The fringe geometry parameters include fringe frequency, starting polar angle, radial distance, and polar angle.

[0088] The preset highest and lowest frequency of the stripes includes the highest frequency and the lowest frequency of the stripes.

[0089] The basic parameters of a striped image include the pixel width and pixel height of the striped image.

[0090] Specifically, step 101 may include the following sub-steps S11-S18:

[0091] Step S11: Based on the basic parameters of the stripe image, generate the stripe image and the center point of the arc;

[0092] It should be noted that the center point of the arc is calculated using the pixel width and pixel height of the stripe image. for: Where W and H are the pixel width and pixel height of the stripe image, respectively. These are the x-coordinate and y-coordinate of the center point of the arc, respectively.

[0093] Step S12: Divide the stripe image to generate multiple frequency components;

[0094] Step S13: Calculate the image angle range corresponding to each frequency part based on the number of stripe frequencies corresponding to each frequency part.

[0095] It should be noted that the image angular range for each frequency region is calculated by dividing the stripes into frequency components. The stripe frequency is an integer not less than 1. The stripe frequency for each frequency region can be set as needed. The image angular range corresponding to each frequency region is as follows:

[0096] ;

[0097] in, denoted as the image angular range; n represents the stripe frequency.

[0098] Step S14: Calculate the polar angle corresponding to each frequency part based on the image pixel coordinates corresponding to each frequency part;

[0099] Step S15: Calculate the angle parameters corresponding to each frequency part using the polar angle and image angle range corresponding to each frequency part;

[0100] Step S16: Determine the starting polar angle for each frequency component based on the angle parameters corresponding to each frequency component;

[0101] Step S17: Calculate the stripe frequency corresponding to each frequency part based on the highest frequency of the stripe, the lowest frequency of the stripe, the number of stripe strokes corresponding to each frequency part, and the angle parameters.

[0102] Step S18: Based on the center point of the arc and the image pixel coordinates corresponding to each frequency part, determine the radial distance corresponding to each frequency part.

[0103] It should be noted that the lowest frequency f L (Lowest frequency of the stripes) and the highest frequency f H (Highest frequency of the stripes), and the fringe frequency f for each region (frequency component) is calculated based on the fringe division frequency. k Specifically, the lowest frequency f L With the highest frequency f H Both must strictly satisfy: f H >f L And fH Generally, f is taken. L Two to three times that, the fringe frequency f of each frequency section k Let f be the k-th frequency in a set of n fringe frequencies (fringe frequency set F), where F is: F = {f0, f1, f2, ..., fk}. f k , f k-1};n≥1.

[0104] Furthermore, f k The specific value is determined by the lowest frequency f. L With the highest frequency f H The frequency range formed [f L f H ] Determined, for [f L f H Perform linear interpolation to calculate:

[0105] ;

[0106] in, The fringe frequency corresponding to the kth frequency component; For angle parameters.

[0107] Furthermore, angle parameters It is an integer not less than 0, and its specific calculation method is as follows: ;in, Indicates to Round the value down to the nearest integer. pixel coordinates in the striped image (i.e., the image pixel coordinates corresponding to the frequency component) are mapped to the polar angle in the polar coordinate system (i.e., the polar angle corresponding to the frequency component): x and y are the x and y coordinates of the image pixels corresponding to the frequency component, respectively.

[0108] Furthermore, the pixel coordinates in the image To the center point of the arc radial distance That is, the radial distance corresponding to the frequency part. Determined as: ;

[0109] Step 102: Based on the preset coding region radius range and preset angle conditions, generate a stripe coding pattern for each frequency part and the corresponding stripe geometric parameters.

[0110] The preset coding area radius range includes the main stripe coding area radius range. Radius of the signal encoding region , radius range of peripheral phase-shifted zero-point coding region ,in, These are the lower and upper limits of the radius range of the main stripe coding area, respectively. These are the lower and upper limits of the radius of the signal encoding region, respectively. These are the lower and upper limits of the radius range of the peripheral phase-shifted zero-point encoding region, respectively.

[0111] It should be noted that, based on the preset radius range and angle conditions, and combined with each frequency component and its corresponding geometric parameters, the generated stripe coding pattern is as follows: Figure 2 As shown.

[0112] Specifically, step 102 may include the following sub-steps S21-S28:

[0113] Step S21: Determine whether the radial distance corresponding to each frequency part is within the radius range of the main stripe coding region, the radius range of the signal coding region, or the radius range of the peripheral phase-shifted zero-point coding region.

[0114] Step S22: Take any frequency part corresponding to the radial distance within the radius range of the main stripe coding area as the target main stripe frequency part, and generate the main stripe coding pattern according to the stripe frequency, polar angle and starting polar angle corresponding to each target main stripe frequency part.

[0115] Specifically, step S22 may include the following sub-steps S221-S224:

[0116] Step S221: Calculate the phase corresponding to the main fringe frequency of each target using the fringe frequency, polar angle, and starting polar angle corresponding to the main fringe frequency of each target.

[0117] Step S222: Calculate the gray value of the region corresponding to the frequency part of the main fringe of each target using the phase of the main fringe of each target.

[0118] Step S223: Generate the main fringe code based on the starting polar angle corresponding to the frequency portion of each target main fringe;

[0119] Step S224: Generate the main stripe coding pattern based on the main stripe coding and the grayscale values ​​of the regions corresponding to the frequency portions of each target main stripe.

[0120] It should be noted that when the radial distance corresponds to a certain frequency range... Within the radius of the main stripe coding area At that time, the pixel coordinates are located in the main stripe coding area, and its grayscale value is... (The grayscale value of the region corresponding to the frequency part of the target main fringe) is:

[0121] ;

[0122] in, Current pixel coordinates The corresponding phase (i.e., the phase corresponding to the frequency portion of the target main fringe) has the following specific value:

[0123] ;

[0124] in, The cumulative phase shift caused by multi-frequency coding , The fringe frequency corresponding to the target main fringe frequency portion; This is the starting polar angle corresponding to the current frequency (i.e., the starting polar angle corresponding to the frequency portion of the target main fringe). .

[0125] Step S23: Take any frequency part corresponding to the radial distance within the radius of the signal encoding area as the initial signal frequency part, and based on the preset angle conditions, filter each initial signal frequency part according to the stripe frequency, polar angle, starting polar angle and phase shift step number corresponding to each initial signal frequency part to determine multiple target signal frequency parts.

[0126] Specifically, step S23 may include the following sub-steps:

[0127] Step S231: Calculate the phase shift angle corresponding to each initial signal frequency part based on the phase shift step number corresponding to each initial signal frequency part;

[0128] Step S232: Calculate the phase corresponding to each initial signal frequency part using the fringe frequency, polar angle, and starting polar angle corresponding to each initial signal frequency part;

[0129] Step S233: Perform modulo operation on the phase corresponding to each initial signal frequency part to determine the standard phase corresponding to each initial signal frequency part;

[0130] Step S234: Calculate the absolute value of the difference between the standard phase and phase shift angle corresponding to each initial signal frequency part, and compare it with the preset error limit;

[0131] Step S235: Take the initial signal frequency part corresponding to the absolute value of the difference between any standard phase and phase shift angle that is less than the preset error limit as the intermediate signal frequency part;

[0132] Step S236: Determine the start and end angles corresponding to each intermediate signal frequency part based on the polar angles corresponding to each intermediate signal frequency part.

[0133] Step S237: Determine whether the start and end angles and polar angles corresponding to each intermediate signal frequency part meet the preset angle conditions.

[0134] Step S238: Take the intermediate signal frequency part corresponding to any start and end angle and polar angle that both satisfy the preset angle conditions as the target signal frequency part.

[0135] The starting and ending angles include the starting angle and the ending angle.

[0136] It should be noted that the number of phase shift steps required to identify the coding region by phase shift and its radius range are also important considerations. and minimum interval Calculate the set of phase shift angles The set of starting angles of the outer first-layer coding region of the main stripe at each frequency With the set of ending angles .

[0137] Furthermore, when pixel coordinates The radial distance r, i.e., the radial distance corresponding to the frequency part, is within the radius of the signal coding region. When the frequency part corresponding to the radial distance within the radius of the signal encoding region is used as the initial signal frequency part, the frequency part is taken as the frequency part of the signal.

[0138] Furthermore, the number of phase shift steps corresponding to each frequency segment (i.e., the number of phase shift steps required for the phase shift identification coding region) can be set as needed, and the phase shift angle set... for: For sets The i-th term in The specific calculation method is as follows: , Let i be the number of phase shift steps corresponding to the i-th initial signal frequency portion. It represents the phase shift angle corresponding to the i-th initial signal frequency portion.

[0139] Furthermore, to facilitate operations in the external phase-shift identification coding region, for Perform a modulo operation to map to the interval [0, ], calculate the standard phase :

[0140] ;

[0141] in, for right The modulo operation is performed as follows: , This refers to the phase corresponding to the frequency portion of the initial signal.

[0142] Furthermore, when pixel coordinates Corresponding standard phase satisfy: The initial signal frequency portion corresponding to the absolute value of the difference between any standard phase and phase shift angle less than a preset error limit is taken as the intermediate signal frequency portion. This is the absolute value of the difference between the standard phase and the phase shift angle corresponding to the initial signal frequency portion. To set the error limit, it is usually taken as... to .

[0143] Furthermore, the starting angle corresponding to the intermediate signal frequency portion The polar angle corresponding to the intermediate signal frequency portion The ending angle corresponding to the intermediate signal frequency portion for: Preset angle conditions include (Right now The starting angle of the secondary encoding Must meet: )and When the ending angle and polar angle corresponding to the intermediate signal frequency part both satisfy and If so, then the intermediate signal frequency part is taken as the target signal frequency part.

[0144] Step S24: Generate a signal encoding pattern based on the starting polar angle corresponding to the frequency portion of each target signal;

[0145] Specifically, step S24 may include the following sub-steps S241-S243:

[0146] Step S241: Set the regional grayscale value for the frequency portion of each target signal based on a preset constant;

[0147] Step S242: Generate signal codes based on the starting polar angles corresponding to the frequency components of each target signal;

[0148] Step S243: Generate a signal encoding pattern based on the signal encoding and the grayscale values ​​of the corresponding regions of each target signal frequency part.

[0149] It should be noted that the preset constant includes 1 and 0. The preset constant is used to set the grayscale value of the region corresponding to the frequency part of the target signal, that is, the grayscale value of the region corresponding to the frequency part of the target signal. Otherwise, the grayscale value of the region corresponding to the intermediate signal frequency portion that does not meet the preset angle condition. .

[0150] It is worth mentioning that the start and end angles corresponding to all the frequency components of the target signal can constitute the set of start angles for the phase shift identification coding region of the main frequency fringe. With the set of ending angles They are respectively:

[0151] ;

[0152] ;

[0153] Step S25: Take the frequency portion corresponding to the radial distance within the radius range of any peripheral phase-shift zero encoding region as the initial peripheral phase-shift zero frequency portion;

[0154] Step S26: Set the polar angle range based on the starting polar angle corresponding to each frequency section;

[0155] Step S27: Determine whether the polar angle of each initial peripheral phase shift zero-point frequency portion is within the polar angle range;

[0156] Step S28: Take the initial peripheral phase shift zero frequency part corresponding to any polar angle within the polar angle range as the target peripheral phase shift zero frequency part, and generate the peripheral phase shift zero encoding pattern according to the starting polar angle corresponding to each target peripheral phase shift zero frequency part.

[0157] It should be noted that the outer phase shift zero-point encoding and its radius range are determined by the number of fringe divisions, n. To determine the phase shift zero point of the main stripe coding region When n=1, this step can be ignored.

[0158] Specifically, step S28 may include the following sub-steps S281-S283:

[0159] Step S281: Set the regional grayscale value for the phase-shift zero-frequency part of the periphery of each target based on the preset constant;

[0160] Step S282: Generate peripheral phase shift zero-point codes based on the starting polar angles corresponding to the frequency portions of the peripheral phase shift zero-points of each target.

[0161] Step S283: Generate the peripheral phase-shift zero-point coding pattern based on the peripheral phase-shift zero-point coding and the grayscale values ​​of the corresponding regions of the peripheral phase-shift zero-point frequency parts of each target.

[0162] It should be noted that the radius range of the peripheral phase-shifted zero-point coding region... When pixel coordinates The radial distance, i.e., the radial distance corresponding to the frequency part, lies within the radius of the outer phase-shift zero-point coding region. At that time, this frequency part is taken as the initial peripheral phase shift zero-point frequency part, based on the starting polar angle corresponding to each frequency part. and Set polar angle range When the polar angle corresponding to the initial peripheral phase shift zero-point frequency part satisfy: Then, the initial peripheral phase shift zero-frequency portion is taken as the target peripheral phase shift zero-frequency portion; where and These are the values ​​corresponding to k=0 and k=1, respectively. At this time, the grayscale value of the region corresponding to the phase-shift zero-frequency part of the target's periphery is set to... The grayscale value of the region at the initial peripheral phase shift zero-point frequency that does not meet the polar angle range is set to... .

[0163] It is worth mentioning that this step can be ignored when the frequency of stripe division n=1.

[0164] Step 103: Extract signals from the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern to generate phase encoding region signals and zero-point signals. Then, use the zero-point signals to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern.

[0165] It should be noted that the zero-point signal is detected in the peripheral phase-shift zero-point encoding pattern using a photoelectric sensor. for:

[0166] ;

[0167] Where t is the time-dependent variable corresponding to the signal, and different t correspond to different... The value of f represents The frequency of this rectangular wave signal is specifically... , The period of this signal, specifically, depends on the maximum radius of the main stripe coding region. The two satisfy the following relationship: ; The phase shift of this signal represents the duty cycle. When the signal changes from high to low, it indicates that the grating disk has returned to the phase shift start point of the main fringe region. For each frequency's phase-encoded region, from the beginning to the end of the signal, the phase-encoded region signal... for:

[0168] ;

[0169] in, The period of the signal; its difference from the minimum interval The two conditions are related and satisfy the following: .

[0170] Step 104: Based on the effective number of phase-encoded region signals, project the zero-return main fringe coding pattern onto the object under test to obtain multiple fringe images. Then, decode the multiple fringe images according to the fringe frequencies in the fringe geometric parameters corresponding to each frequency part to generate the target absolute phase.

[0171] It should be noted that the stripe coding pattern generated by the above steps, as well as the zero-point code and zero-point signal (i.e., the photoelectric sensor signal), are all part of this process. The transformation performs a zero-return operation; the camera receives the signal detected by the photoelectric sensor. It captures the deformed fringes generated when the grating disk rotates at high speed and is projected onto the surface of the object under test by a light source, in order to solve for their corresponding phase and restore the three-dimensional information of the object under test.

[0172] Specifically, step 104 may include the following sub-steps:

[0173] Step S41: Group the multiple stripe images to determine multiple stripe image groups;

[0174] Step S42: Calculate the wrap phase of each stripe image group based on the light intensity of each stripe image in each stripe image group;

[0175] Step S43: Select the zero-position wrapping phase and the lowest fringe frequency from the wrapping phase and the fringe frequency corresponding to each frequency part of each fringe image group, and calculate the initial absolute phase based on the zero-position wrapping phase and the lowest fringe frequency.

[0176] Step S44: Select the target wrapping phase and target fringe frequency from the wrapping phase and fringe frequency corresponding to each frequency part of each fringe image group, and calculate the phase difference using the target fringe frequency, target wrapping phase and initial absolute phase;

[0177] Step S45: Determine the equivalent frequency based on the lowest fringe frequency;

[0178] Step S46: Calculate the equivalent phase based on the equivalent frequency, the target fringe frequency, and the phase difference;

[0179] Step S47: Calculate the number of integer cycles based on the equivalent phase and the target envelope phase;

[0180] Step S48: Update the initial absolute phase using the target fringe frequency, target wrap phase, and integer number of cycles to determine the intermediate absolute phase, and count the number of updates in real time.

[0181] Step S49: Determine whether the number of updates has reached the preset number of updates;

[0182] Step S410: If yes, then the intermediate absolute phase is taken as the target absolute phase.

[0183] It should be noted that the n×N stripe images captured by the camera (where n×N is the effective number of signals in the phase-coded region, n is the number of stripe frequencies, and N is the number of phase shift steps corresponding to each group of different frequency stripes) are used to determine the wrapping phase of each stripe image group based on the light intensity of each image. :

[0184] ;

[0185] in, The wrapping phase of the i-th stripe image group; For the j-th striped image in the i-th striped image group The light intensity corresponding to each pixel; N is the phase shift step number corresponding to each group of different frequency stripes, that is, the total number of image groups of different frequency stripes; n is the stripe frequency.

[0186] Furthermore, the lowest frequency f0, i.e., the lowest fringe frequency, is selected from the fringe frequency set F, and the zero-position wrapping phase is selected from the wrapping phases of all fringe image groups. Therefore, the initial absolute phase is calculated as follows: .

[0187] Furthermore, when i≥1, there exists a phase difference. That is, selecting the target wrapping phase from the wrapping phases of all striped image groups. And select the target fringe frequency from the fringe frequencies corresponding to all frequency components. Thus, the phase difference can be calculated: For example, if the current iteration is the first iteration (update count is 1), then the target package phase is... The target fringe frequency is The resulting phase difference is If the current iteration is the second iteration, then the target wrapping phase is... The target fringe frequency is The resulting phase difference is .

[0188] Furthermore, the equivalent phase can be calculated from this phase difference and the target fringe frequency. It is:

[0189] ;

[0190] in, Especially, Based on this, the number of integer cycles needs to be calculated. The specific calculation method is as follows:

[0191] ;

[0192] Then calculate the intermediate absolute phase :

[0193] ;

[0194] Furthermore, when the number of updates reaches the preset number of updates, the intermediate absolute phase is taken as the target absolute phase.

[0195] Optionally, it also includes:

[0196] If the number of updates does not reach the preset number of updates, the target stripe frequency is used to update the equivalent frequency to determine a new equivalent frequency.

[0197] Select new target wrapping phase and new target fringe frequency in the wrapping phase of each fringe image group and in the fringe frequency corresponding to each frequency part, respectively;

[0198] The intermediate absolute phase is used as the new initial absolute phase, and a new phase difference is calculated using the new target wrap phase and the new initial absolute phase.

[0199] Jump to the step of calculating the equivalent phase based on the equivalent frequency, target fringe frequency, and phase difference, until the number of updates reaches the above-mentioned preset number of updates;

[0200] The intermediate absolute phase determined when the number of updates reaches the above-mentioned preset number of updates is taken as the target absolute phase.

[0201] It should be noted that if the number of updates does not reach the preset number of updates, the equivalent frequency is updated using the target fringe frequency to determine the new equivalent frequency. This process can be represented as:

[0202] ;

[0203] in, This is the equivalent frequency when the number of updates is i-1; The equivalent frequency (i.e., the new equivalent frequency) is when the number of updates is i. Let i be the target fringe frequency when the number of updates is i.

[0204] Furthermore, new target wrapping phases and new target fringe frequencies are selected from the wrapping phases of each fringe image group and from the fringe frequencies corresponding to each frequency component. For example, if the target wrapping phase is... The new target package phase is Similarly, a new target fringe frequency can be obtained, the intermediate absolute phase is used as the new initial absolute phase, and a new phase difference is calculated using the new target wrapping phase and the new initial absolute phase; jump to step S46 until the number of updates reaches the above-mentioned preset number of updates; the intermediate absolute phase determined when the number of updates reaches the above-mentioned preset number of updates is used as the target absolute phase.

[0205] The absolute phase of the target can be obtained after n-1 iterations. : .

[0206] Step 105: Use the absolute phase of the target as the input of the preset depth phase mapping model, and output the three-dimensional information of the measured object.

[0207] It should be noted that the target's absolute phase is used as input to a preset depth phase mapping model, which outputs the 3D information of the measured object. From this, the 3D information of the measured object can be calculated using the absolute phase and the camera's intrinsic and extrinsic parameters. The preset depth phase mapping model is an existing depth phase mapping model.

[0208] For comparison of technical effects, existing technologies can be referenced. Fringe projection profilometry is widely used in surface structured light measurement devices, which are of great significance to optical 3D measurement systems, providing accurate 3D information for fields such as precision manufacturing, medical testing, and cultural relic preservation. The projectors required by classic surface structured light imaging systems have high-cost micromirror elements and limited projection speed, restricting the imaging speed and application of 3D structured light systems. Therefore, it is necessary to develop a flexibly coded grating disk that projects a fringe sequence that meets accuracy requirements during high-speed rotation.

[0209] To address the aforementioned problems, this invention provides a multi-layer, multi-frequency radial stripe encoding and decoding method. The stripe encoding is fabricated on a grating code disk, effectively reducing projection costs and enabling high-speed projection driven by a motor. For details, please refer to... Figure 3 In terms of encoding methods, after determining the basic parameters W and H of the stripe image, the required frequency n for stripe delineation and its corresponding lowest frequency f are determined. L (Lowest frequency of the stripes) and the highest frequency f H(Highest frequency of the stripes); using the radius as the identification parameter, the encoding region is divided into three layers: the main stripe encoding region, the phase shift identification encoding region, and the phase shift zero-point encoding region. The main stripe region is encoded by calculating its grayscale value from the stripe frequency and frequency value; the phase shift identification encoding region is encoded by the encoding angle of the main stripe encoding region and the phase shift step; the phase shift zero-point encoding region is encoded by the starting angle of the main stripe encoding region. In the decoding method, the camera receives the encoded signal and phase shift signal detected by the photoelectric sensor. The camera captures the stripe sequence projected onto the surface of the object being measured via a grating disk according to the signal type. The absolute phase of these stripe sequences is solved to reconstruct their three-dimensional information. This invention uses a polar coordinate system to convert traditional unidirectional modulation stripe encoding into radial stripe encoding. Furthermore, this invention can realize multi-layer, multi-frequency stripe encoding and decoding, providing a simple and effective solution for low-cost, high-speed projection of stripe sequence projection.

[0210] In summary, this invention allows for the calculation of the corresponding grayscale and phase in a polar coordinate system from the image width and height and the fringe frequency. The required number of phase shift steps allows for the calculation of the phase shift identification coding region and the angle value of the phase shift zero-point identification coding region. This invention achieves multi-layer, multi-frequency fringe encoding and decoding. The encoding pattern can be printed on a self-made grating code disk, significantly reducing costs compared to the expensive micromirrors used in traditional projectors for fringe sequence projection. The decoding method is flexible and reliable, and the grating disk using this invention's encoding pattern can rotate at high speed, resulting in a projected fringe sequence that meets the requirements of high-speed projection. Therefore, this invention provides a simple and effective solution for low-cost, high-speed fringe sequence projection.

[0211] In this embodiment of the invention, a multi-layer, multi-frequency radial stripe encoding and decoding method is provided. First, basic parameters of the stripe image are obtained. Based on the basic parameters and preset highest and lowest stripe frequencies, multiple frequency components and corresponding stripe geometric parameters are generated. Next, based on a preset encoding region radius range and preset angle conditions, a stripe encoding pattern is generated for each frequency component and its corresponding stripe geometric parameters. Signal extraction is performed on the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern within the stripe encoding pattern to generate a phase encoding region signal and a zero-point signal. The zero-point signal is then used to perform a zero-return operation on the main stripe encoding pattern within the stripe encoding pattern, generating a zero-return main stripe encoding pattern. Given the effective number of signals in the phase-encoded region, the zero-return main fringe coding pattern is projected onto the object under test to obtain multiple fringe images. These images are then decoded based on the fringe frequencies in the fringe geometric parameters corresponding to each frequency component to generate the target absolute phase. Finally, the target absolute phase is used as the input to a preset depth phase mapping model to output the three-dimensional information of the object under test. Based on this scheme, the present invention, using a preset coding region radius range and preset angle conditions, and based on each frequency component and its corresponding fringe geometric parameters, generates a fringe coding pattern whose coding style can be printed on a self-made grating code disk. This eliminates the need for expensive micromirrors in high-precision DLP projectors, effectively reducing projection costs.

[0212] Please see Figure 4 , Figure 4 This is a structural block diagram of a multi-layer multi-frequency radial stripe encoder / decoder device provided in Embodiment 2 of the present invention.

[0213] The present invention provides a multi-layer multi-frequency radial stripe encoding and decoding device, comprising:

[0214] The acquisition module 401 is used to acquire the basic parameters of the stripe image, and generate multiple frequency parts and stripe geometric parameters corresponding to each frequency part based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes.

[0215] The stripe pattern generation module 402 is used to generate a stripe coded pattern based on a preset coding region radius range and preset angle conditions, each frequency part and the stripe geometric parameters corresponding to each frequency part.

[0216] The zero-return module 403 is used to extract signals from the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern, generate phase encoding region signals and zero-point signals, and use the zero-point signals to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern.

[0217] The phase output module 404 is used to project the zero-return main stripe coding pattern onto the object under test based on the effective number of phase coding region signals, to obtain multiple stripe images, and to decode the multiple stripe images according to the stripe frequency in the stripe geometric parameters corresponding to each frequency part to generate the target absolute phase.

[0218] The three-dimensional information output module 405 is used to take the absolute phase of the target as input to a preset depth phase mapping model and output the three-dimensional information of the measured object.

[0219] Furthermore, module 401 is specifically used for:

[0220] Based on the basic parameters of the stripe image, generate the stripe image and the center point of the arc;

[0221] The stripe image is divided into multiple frequency components;

[0222] Calculate the image angle range corresponding to each frequency part based on the stripe frequency number corresponding to each frequency part.

[0223] Calculate the polar angle corresponding to each frequency component based on the image pixel coordinates corresponding to each frequency component;

[0224] Using the polar angle and image angle range corresponding to each frequency part, calculate the angle parameters corresponding to each frequency part;

[0225] Based on the angle parameters corresponding to each frequency segment, determine the starting polar angle corresponding to each frequency segment;

[0226] Calculate the fringe frequency corresponding to each frequency part based on the highest frequency of the fringe, the lowest frequency of the fringe, the number of fringe strokes corresponding to each frequency part, and the angle parameters.

[0227] Based on the center point of the arc and the image pixel coordinates corresponding to each frequency part, the radial distance corresponding to each frequency part is determined.

[0228] Furthermore, the preset coding region radius range includes the main stripe coding region radius range, the signal coding region radius range, and the peripheral phase-shifted zero-point coding region radius range; the stripe pattern generation module 402 includes:

[0229] The first submodule is used to determine whether the radial distance corresponding to each frequency part is within the radius range of the main stripe coding region, the radius range of the signal coding region, or the radius range of the peripheral phase-shift zero coding region.

[0230] The second submodule is used to take the frequency part corresponding to the radial distance within the radius range of the main stripe coding area as the target main stripe frequency part, and generate the main stripe coding pattern according to the stripe frequency, polar angle and starting polar angle corresponding to each target main stripe frequency part.

[0231] The third submodule is used to take any frequency part corresponding to the radial distance within the radius of the signal encoding area as the initial signal frequency part, and based on the preset angle conditions, to filter each initial signal frequency part according to the stripe frequency, polar angle, starting polar angle and phase shift step number corresponding to each initial signal frequency part, and determine multiple target signal frequency parts.

[0232] The fourth submodule is used to generate a signal encoding pattern based on the starting polar angle corresponding to the frequency portion of each target signal.

[0233] The fifth submodule is used to take the frequency portion corresponding to the radial distance within the radius range of any peripheral phase-shift zero coding region as the initial peripheral phase-shift zero frequency portion;

[0234] The sixth submodule is used to set the polar angle range based on the starting polar angle corresponding to each frequency section;

[0235] The seventh submodule is used to determine whether the polar angle of each initial peripheral phase shift zero-point frequency part is within the polar angle range;

[0236] The eighth submodule is used to take the initial peripheral phase shift zero frequency part corresponding to any polar angle within the polar angle range as the target peripheral phase shift zero frequency part, and generate the peripheral phase shift zero encoding pattern according to the starting polar angle corresponding to each target peripheral phase shift zero frequency part.

[0237] Furthermore, the second submodule is specifically used for:

[0238] The phase corresponding to the main fringe frequency of each target is calculated using the fringe frequency, polar angle, and initial polar angle of each target's main fringe frequency portion.

[0239] The grayscale value of the region corresponding to the frequency part of the main fringe of each target is calculated by using the phase corresponding to the frequency part of the main fringe of each target.

[0240] The main fringe code is generated based on the starting polar angle corresponding to the frequency portion of each target main fringe.

[0241] The main stripe coding pattern is generated based on the main stripe coding and the grayscale values ​​of the regions corresponding to the frequency portions of each target main stripe.

[0242] Furthermore, the third submodule is specifically used for:

[0243] Calculate the phase shift angle corresponding to each initial signal frequency part based on the number of phase shift steps corresponding to each initial signal frequency part;

[0244] The phase corresponding to each initial signal frequency part is calculated using the fringe frequency, polar angle, and initial polar angle corresponding to each initial signal frequency part.

[0245] Perform modulo operation on the phase corresponding to each initial signal frequency part to determine the standard phase corresponding to each initial signal frequency part;

[0246] Calculate the absolute value of the difference between the standard phase and phase shift angle corresponding to each initial signal frequency portion, and compare it with the preset error limit;

[0247] The initial signal frequency portion corresponding to the absolute value of the difference between any standard phase and phase shift angle that is less than the preset error limit is taken as the intermediate signal frequency portion;

[0248] Based on the polar angles corresponding to each intermediate signal frequency component, determine the start and end angles corresponding to each intermediate signal frequency component.

[0249] Determine whether the start and end angles and polar angles corresponding to each intermediate signal frequency segment meet the preset angle conditions.

[0250] The intermediate signal frequency portion corresponding to any starting and ending angles and polar angles that satisfy the preset angle conditions is taken as the target signal frequency portion.

[0251] Furthermore, the fourth submodule is specifically used for:

[0252] Set the grayscale value of the frequency portion of each target signal based on a preset constant;

[0253] Generate signal codes based on the starting polar angles corresponding to the frequency components of each target signal;

[0254] A signal encoding pattern is generated based on the signal encoding and the grayscale values ​​of the corresponding regions for each target signal frequency portion.

[0255] Furthermore, the eighth submodule is specifically used for:

[0256] The grayscale value of the area of ​​the phase-shift zero-point frequency part of the periphery of each target is set based on the preset constant;

[0257] Generate peripheral phase shift zero-point codes based on the starting polar angle corresponding to the frequency portion of the peripheral phase shift zero-points of each target.

[0258] The peripheral phase-shift zero-point coding pattern is generated based on the peripheral phase-shift zero-point coding and the grayscale values ​​of the corresponding regions of the peripheral phase-shift zero-point frequency parts of each target.

[0259] Furthermore, the phase output module 404 is specifically used for:

[0260] Group the multiple stripe images to determine multiple stripe image groups;

[0261] The wrap phase of each stripe image group is calculated based on the light intensity of each stripe image in each stripe image group.

[0262] The zero-position wrapping phase and the lowest fringe frequency are selected from the wrapping phase and the fringe frequency corresponding to each frequency part of each fringe image group, and the initial absolute phase is calculated based on the zero-position wrapping phase and the lowest fringe frequency.

[0263] Select the target wrapping phase and target fringe frequency from the wrapping phase and the fringe frequency corresponding to each frequency part of each fringe image group respectively, and calculate the phase difference using the target fringe frequency, target wrapping phase and initial absolute phase;

[0264] Determine the equivalent frequency based on the lowest fringe frequency;

[0265] Calculate the equivalent phase based on the equivalent frequency, the target fringe frequency, and the phase difference;

[0266] Calculate the number of integer cycles based on the equivalent phase and the target package phase;

[0267] The initial absolute phase is updated using the target fringe frequency, target wrap phase, and number of integer cycles to determine the intermediate absolute phase, and the number of updates is counted in real time.

[0268] Determine if the number of updates has reached the preset number of updates;

[0269] If so, then the intermediate absolute phase will be taken as the target absolute phase.

[0270] In one optional device embodiment, it further includes:

[0271] The first module is used to update the equivalent frequency using the target stripe frequency and determine a new equivalent frequency if the number of updates has not reached the preset number of updates.

[0272] The second module is used to select new target wrapping phase and new target fringe frequency from the wrapping phase of each fringe image group and from the fringe frequencies corresponding to each frequency part, respectively.

[0273] The third module is used to take the intermediate absolute phase as the new initial absolute phase, and to calculate the new phase difference using the new target wrapping phase and the new initial absolute phase.

[0274] The fourth module is used to jump to the execution of the step of calculating the equivalent phase based on the equivalent frequency, the target fringe frequency, and the phase difference, until the number of updates reaches the above-mentioned preset number of updates;

[0275] The fifth module is used to take the intermediate absolute phase determined when the number of updates reaches the above-mentioned preset number of updates as the target absolute phase.

[0276] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, modules, and sub-modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0277] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0278] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0279] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-layer, multi-frequency radial stripe encoding and decoding method, characterized in that, include: Obtain the basic parameters of the stripe image, and generate multiple frequency components and stripe geometric parameters corresponding to each frequency component based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes; The stripe geometry parameters also include the initial polar angle, radial distance, and polar angle; Based on the preset coding region radius range and preset angle conditions, each frequency part and the stripe geometric parameters corresponding to each frequency part are used to generate a stripe coding pattern. Signal extraction is performed on the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern to generate phase encoding region signal and zero-point signal. The zero-point signal is then used to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern. Based on the effective number of phase-encoded region signals, the zero-return main stripe encoding pattern is projected onto the object under test to obtain multiple stripe images. The multiple stripe images are then decoded according to the stripe frequency in the stripe geometric parameters corresponding to each frequency part to generate the target absolute phase. The absolute phase of the target is used as the input of a preset depth phase mapping model to output the three-dimensional information of the object being measured. The preset coding region radius range includes the main stripe coding region radius range, the signal coding region radius range, and the peripheral phase-shift zero-point coding region radius range; the step of generating a stripe coding pattern based on the preset coding region radius range and preset angle conditions, each frequency component, and the stripe geometric parameters corresponding to each frequency component includes: Determine whether the radial distance corresponding to each frequency portion is within the radius range of the main stripe coding region, the radius range of the signal coding region, or the radius range of the peripheral phase-shift zero-point coding region; The frequency portion corresponding to the radial distance within the radius range of the main stripe coding region is taken as the target main stripe frequency portion, and the main stripe coding pattern is generated according to the stripe frequency, polar angle, and starting polar angle corresponding to each target main stripe frequency portion. The frequency portion corresponding to the radial distance within the radius of the signal encoding region is taken as the initial signal frequency portion. Based on the preset angle condition, each initial signal frequency portion is filtered according to the stripe frequency, polar angle, starting polar angle, and phase shift step number corresponding to each initial signal frequency portion to determine multiple target signal frequency portions. A signal encoding pattern is generated based on the starting polar angle corresponding to the frequency portion of each target signal. The frequency portion corresponding to the radial distance within the radius range of the peripheral phase-shift zero-point encoding region is taken as the initial peripheral phase-shift zero-point frequency portion; Based on the starting polar angle corresponding to each of the aforementioned frequency components, a polar angle range is set; Determine whether the polar angle of each of the initial peripheral phase shift zero-point frequency portions is within the polar angle range; The initial peripheral phase shift zero frequency portion corresponding to any polar angle within the polar angle range is taken as the target peripheral phase shift zero frequency portion, and a peripheral phase shift zero encoding pattern is generated according to the starting polar angle corresponding to each target peripheral phase shift zero frequency portion.

2. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, The preset highest and lowest frequency of the stripes includes the highest frequency and the lowest frequency of the stripes; the step of generating multiple frequency components and stripe geometric parameters corresponding to each frequency component based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes includes: Based on the basic parameters of the stripe image, generate the stripe image and the arc center point; The stripe image is divided into multiple frequency components; Calculate the image angle range corresponding to each frequency part based on the stripe frequency number corresponding to each frequency part. Calculate the polar angle corresponding to each frequency component based on the image pixel coordinates corresponding to each frequency component; Using the polar angle and image angle range corresponding to each frequency component, calculate the angle parameters corresponding to each frequency component; Based on the angle parameters corresponding to each frequency component, determine the starting polar angle corresponding to each frequency component; Calculate the stripe frequency corresponding to each frequency part based on the highest frequency of the stripe, the lowest frequency of the stripe, the number of stripe strokes corresponding to each frequency part, and the angle parameters. Based on the center point of the arc and the image pixel coordinates corresponding to each frequency component, the radial distance corresponding to each frequency component is determined.

3. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, The step of generating a main stripe coding pattern based on the stripe frequency, polar angle, and starting polar angle corresponding to each of the target main stripe frequency portions includes: The phase corresponding to each of the target main fringe frequency portions is calculated using the fringe frequency, polar angle, and starting polar angle corresponding to each of the target main fringe frequency portions. Using the phase corresponding to the frequency portion of each of the target main fringe, calculate the gray value of the region corresponding to the frequency portion of each of the target main fringe; Based on the starting polar angle corresponding to the frequency portion of each target main fringe, a main fringe code is generated; A main stripe coding pattern is generated based on the main stripe coding and the grayscale values ​​of the regions corresponding to the frequency portions of each target main stripe.

4. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, Based on the preset angle conditions, the initial signal frequency portions are filtered according to their corresponding stripe frequency, polar angle, starting polar angle, and phase shift step number to determine multiple target signal frequency portions, including: Calculate the phase shift angle corresponding to each of the initial signal frequency portions based on the number of phase shift steps corresponding to each of the initial signal frequency portions; The phase corresponding to each of the initial signal frequency components is calculated using the stripe frequency, polar angle, and starting polar angle corresponding to each of the initial signal frequency components. Perform a modulo operation on the phase corresponding to each of the initial signal frequency components to determine the standard phase corresponding to each of the initial signal frequency components; Calculate the absolute value of the difference between the standard phase and phase shift angle corresponding to each of the initial signal frequency portions, and compare it with the preset error limit; The initial signal frequency portion corresponding to the absolute value of the difference between any standard phase and phase shift angle that is less than the preset error limit is taken as the intermediate signal frequency portion; Based on the polar angle corresponding to each intermediate signal frequency portion, determine the start and end angles corresponding to each intermediate signal frequency portion. Determine whether the start and end angles and polar angles corresponding to each intermediate signal frequency portion satisfy the preset angle conditions; The intermediate signal frequency portion corresponding to any starting and ending angles and polar angles that satisfy the preset angle conditions is taken as the target signal frequency portion.

5. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, The step of generating a signal encoding pattern based on the starting polar angle corresponding to each of the target signal frequency portions includes: Based on a preset constant, a region grayscale value is set for the frequency portion of each of the target signals; Generate signal codes based on the starting polar angles corresponding to the frequency portions of each target signal; A signal encoding pattern is generated based on the signal encoding and the grayscale values ​​of the regions corresponding to the frequency portions of each target signal.

6. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, The step of generating a peripheral phase-shift zero-point encoding pattern based on the starting polar angle corresponding to the frequency portion of the peripheral phase-shift zero-point of each target includes: Based on a preset constant, a grayscale value is set for the peripheral phase-shift zero-point frequency portion of each target. Based on the starting polar angle corresponding to the frequency portion of the peripheral phase shift zero point of each target, a peripheral phase shift zero point code is generated; Based on the peripheral phase-shift zero-point encoding and the grayscale values ​​of the regions corresponding to the peripheral phase-shift zero-point frequency portions of each target, a peripheral phase-shift zero-point encoding pattern is generated.

7. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 1, characterized in that, Decoding the multiple stripe images based on the stripe frequencies in the stripe geometric parameters corresponding to each of the frequency portions to generate the target absolute phase includes: Group the multiple stripe images to determine multiple stripe image groups; The wrapping phase of each stripe image group is calculated based on the light intensity of each stripe image in each stripe image group. The zero-position wrapping phase and the lowest fringe frequency are selected from the wrapping phase of each of the stripe image groups and the fringe frequencies corresponding to each of the frequency portions, and the initial absolute phase is calculated based on the zero-position wrapping phase and the lowest fringe frequency. Select the target wrapping phase and target stripe frequency from the wrapping phase of each stripe image group and the stripe frequency corresponding to each frequency part, and calculate the phase difference using the target stripe frequency, the target wrapping phase and the initial absolute phase; Based on the lowest fringe frequency, determine the equivalent frequency; The equivalent phase is calculated based on the equivalent frequency, the target fringe frequency, and the phase difference; Calculate the number of integer cycles based on the equivalent phase and the target package phase; The initial absolute phase is updated using the target fringe frequency, the target wrapping phase, and the number of integer cycles to determine the intermediate absolute phase, and the number of updates is counted in real time. Determine whether the number of updates has reached the preset number of updates; If so, the intermediate absolute phase is taken as the target absolute phase.

8. The multi-layer multi-frequency radial stripe encoding and decoding method according to claim 7, characterized in that, Also includes: If the number of updates does not reach the preset number of updates, the equivalent frequency is updated using the target stripe frequency to determine a new equivalent frequency; New target wrapping phases and new target stripe frequencies are selected from the wrapping phases of each stripe image group and from the stripe frequencies corresponding to each frequency portion, respectively. The intermediate absolute phase is used as the new initial absolute phase, and the new target wrapping phase and the new initial absolute phase are used to calculate the new phase difference; Jump to execute the step of calculating the equivalent phase based on the equivalent frequency, the target fringe frequency, and the phase difference, until the number of updates reaches the preset number of updates; The intermediate absolute phase determined when the number of updates reaches the above-mentioned preset number of updates is taken as the target absolute phase.

9. A multi-layer multi-frequency radial stripe encoding and decoding device, applied to the multi-layer multi-frequency radial stripe encoding and decoding method of claim 1, characterized in that, include: The acquisition module is used to acquire the basic parameters of the stripe image, and generate multiple frequency components and stripe geometric parameters corresponding to each frequency component based on the basic parameters of the stripe image and the preset highest and lowest frequencies of the stripes. The stripe pattern generation module is used to generate a stripe coded pattern based on a preset coding region radius range and preset angle conditions, each frequency part and the stripe geometric parameters corresponding to each frequency part; The zero-return module is used to extract signals from the signal encoding pattern and the peripheral phase-shifted zero-point encoding pattern in the stripe encoding pattern, generate phase encoding region signals and zero-point signals, and use the zero-point signals to perform a zero-return operation on the main stripe encoding pattern in the stripe encoding pattern to generate a zero-return main stripe encoding pattern. The phase output module is used to project the zero-return main stripe coding pattern onto the object under test based on the effective number of signals in the phase coding region, to obtain multiple stripe images, and to decode the multiple stripe images according to the stripe frequency in the stripe geometric parameters corresponding to each frequency part to generate the target absolute phase. The three-dimensional information output module is used to take the absolute phase of the target as input to a preset depth phase mapping model and output the three-dimensional information of the measured object.

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