CN109405735B - Three-dimensional scanning system and three-dimensional scanning method - Google Patents

Three-dimensional scanning system and three-dimensional scanning method Download PDF

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CN109405735B
CN109405735B CN201710714277.4A CN201710714277A CN109405735B CN 109405735 B CN109405735 B CN 109405735B CN 201710714277 A CN201710714277 A CN 201710714277A CN 109405735 B CN109405735 B CN 109405735B
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pixels
detected
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image
offset
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CN109405735A (en
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于景铭
冯晓端
王彬
潘攀
金榕
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Zhejiang Tmall Technology Co Ltd
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Alibaba Group Holding Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/002—Measuring arrangements characterised by the use of optical techniques for measuring two or more coordinates

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Abstract

The invention discloses a three-dimensional scanning system and a three-dimensional scanning method. The three-dimensional scanning system includes: the image acquisition module is used for shooting a first area of the object to be detected projected by the structured light coding pattern according to the image acquisition parameters to obtain an image of the object to be detected; the pixel screening module is used for removing the pixels which are larger than or equal to the amplitude threshold value from the object image to be detected based on the amplitude of the pixels in the object image to be detected; and the three-dimensional reconstruction module is used for taking the area of the object to be detected corresponding to the removed pixels as a reconstruction area based on the image acquisition parameters, and constructing the three-dimensional size of the reconstruction area of the object to be detected. According to the three-dimensional scanning system provided by the embodiment of the invention, the high-speed scanning of the three-dimensional size of the object can be realized by using lower time cost.

Description

Three-dimensional scanning system and three-dimensional scanning method
Technical Field
The invention relates to the field of three-dimensional reconstruction, in particular to a three-dimensional scanning system and a three-dimensional scanning method.
Background
With the development and maturity of digital image processing, digital projection display and computer processing technologies, the structured light three-dimensional scanning technology has been rapidly developed. The three-dimensional scanning system can project the structured light to the surface of the object, a single or a plurality of camera devices shoot images projected by the structured light, and three-dimensional size information of the surface of the object is obtained through reconstruction by a three-dimensional reconstruction algorithm according to the shapes of the shot images.
In order to scan the surface of an object with high contrast, when an image projected by structured light is shot, a dynamic exposure method can be generally used to perform multiple exposures on all pixels in a scanning area where the object to be measured is located to obtain an image, and then a three-dimensional reconstruction algorithm is used to reconstruct three-dimensional information of the surface of the object.
Disclosure of Invention
The embodiment of the invention provides a three-dimensional scanning system and a three-dimensional scanning method, which can realize high-speed scanning of three-dimensional sizes of objects by using lower time cost.
According to an aspect of an embodiment of the present invention, there is provided a three-dimensional scanning system including:
the image acquisition module is used for shooting a first area of the object to be detected projected by the structured light coding pattern according to the image acquisition parameters to obtain an image of the object to be detected;
the pixel screening module is used for removing the pixels which are larger than or equal to the amplitude threshold value from the object image to be detected based on the amplitude of the pixels in the object image to be detected;
and the three-dimensional reconstruction module is used for taking the area of the object to be detected corresponding to the removed pixels as a reconstruction area based on the image acquisition parameters, and constructing the three-dimensional size of the reconstruction area of the object to be detected.
According to another aspect of the embodiments of the present invention, there is provided a three-dimensional scanning method, including:
shooting a first area of the object to be detected projected by the structured light coding pattern according to the image acquisition parameters to obtain an image of the object to be detected;
removing pixels which are larger than or equal to an amplitude threshold value from the object image to be detected based on the amplitude of the pixels in the object image to be detected;
and based on the image acquisition parameters, taking the area of the object to be detected corresponding to the removed pixels as a reconstruction area, and constructing the three-dimensional size of the reconstruction area of the object to be detected.
According to the three-dimensional scanning system and the scanning method in the embodiment of the invention, the first area of the object to be detected projected by the structured light coding pattern is shot according to the image acquisition parameters to obtain the image of the object to be detected, the amplitude of the selected pixel in the pixels of the image of the object to be detected is used for carrying out three-dimensional reconstruction on the pixels which are larger than or equal to the preset amplitude threshold value.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram illustrating a three-dimensional scanning system according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram illustrating a three-dimensional scanning system according to another embodiment of the present invention;
FIG. 3 is a flow chart of a three-dimensional scanning method according to an embodiment of the invention;
FIG. 4 is a flow chart of a three-dimensional scanning method according to another embodiment of the invention;
fig. 5 is a block diagram illustrating an exemplary hardware architecture of a computing device that may implement a three-dimensional scanning method according to an embodiment of the present invention.
Detailed Description
Features and exemplary embodiments of various aspects of the present invention will be described in detail below, and in order to make objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. It will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
For a better understanding of the present invention, a three-dimensional scanning system and a scanning method according to embodiments of the present invention will be described in detail below with reference to fig. 1 and 2, and it should be noted that these embodiments are not intended to limit the scope of the present disclosure.
Fig. 1 is a schematic diagram of a three-dimensional scanning system 100 according to an embodiment of the invention. As shown in fig. 1, the three-dimensional scanning system 100 may include a projection device 112, an image capture device 114, and a processor 120.
In fig. 1, the projection device 112 may project structured light onto a surface of an object to be measured in a designated scanning area (not shown in the figure), the projected structured light is reflected by the surface of the object, and the imaging device 114 may capture the structured light reflected by the surface of the object to be measured, and obtain an image of the scanning area projected by the structured light code pattern under the set image capture parameters.
In one embodiment, the designated area of the object to be measured within the structured light projection range may be referred to as a first area of the object to be measured projected by the structured light code pattern, where the size of the first area is smaller than or equal to the overall size of the object to be measured.
As one example, the projection device 112 may be, for example, a scanner and the imaging device 114 may be, for example, a camera.
In an embodiment of the invention, the structured light represents a set of projected light rays of known spatial directions. As an example, the structured light code pattern projected by the projection device 112 onto the surface of the object to be measured is a sinusoidal fringe image, i.e., the intensity of the pixels in the fringe image varies according to a sinusoidal signal.
In an embodiment of the present invention, the image acquisition parameters of the three-dimensional scanning system include: exposure time of the image pickup apparatus, aperture diameter of the image pickup apparatus, projection brightness of the projection apparatus, intensity of the projected structured light, and the like.
For ease of understanding, the following describes in detail a process of scanning an object to be measured by using the three-dimensional scanning system 100 and performing three-dimensional reconstruction on the object to be measured by using a specific embodiment.
In the embodiment of the present invention, when the projection device 112 projects the structured light code pattern onto the surface of the object to be measured, the light stripes in the structured light code pattern may be coded, and different light stripes in the projected structured light may be positioned and matched by the coding of the structured light, so that after the image of the object to be measured projected by the structured light collected by the camera device 114 is decoded, a pixel position corresponding relationship between the projection device and the camera device may be obtained, and the pixel position corresponding relationship may be used for three-dimensional reconstruction of the image of the object to be measured.
The structured light may be encoded in a variety of forms, and in some embodiments, the light stripes on the projected structured light encoded pattern may be encoded, for example, based on a binary code or a plurality of color-associated symbols.
In some embodiments, the object to be measured may be scanned by a phase-shifting method, i.e., each projected structured light code pattern may have a certain phase.
As an example, the encoding form of the structured light encoding pattern can be represented by the following formula (1):
In(xp，yp)＝o+acos(ωxp+θn) (1)
in the above formula (1), (x)p，yp) Representing the pixel coordinates, I, on the projection device 112n(xp，yp) Representing the intensity of the pixels of the structured light code pattern, o representing the offset of the pixels of the structured light code pattern, a representing the amplitude of the pixels of the structured light code pattern, ω representing the period of the pixels of the structured light code pattern and ω ═ 2 π f, f representing the frequency of the pixels of the structured light code pattern, θnRepresents an offset phase of a pixel of the structured light encoding pattern, andn2N/N, where N represents the total number of phase shifts.
In this embodiment, the formula (1) can be applied as the coding form of the structured light coding patternThe shading device 112 may encode the structured light, for example, into a stripe-like image or a stripe grating, by the above equation (1), and output as the intensity I of the pixels in the structured light encoded patternn(xp，yp)。
In one embodiment, the offset distance of the pixels of the structured light code pattern projected by the projection device 112, the amplitude of the pixels of the structured light code pattern, and the phase of the pixel offset of the structured light code pattern in the above formula (1) can be used as the code information of the structured light code pattern.
In one example, the offset distance o of the pixels of the structured light code pattern can be expressed as an offset value of the position of the pixels of the object to be measured projected by the structured light code pattern, and the offset phase θ of the pixels of the structured light code patternnThere may be a corresponding relationship with the height of the corresponding pixel point on the object to be measured, and if the height information of the object surface is to be obtained, it is necessary to determine the phase change of the pixel in the image of the object to be measured projected by the structured light code pattern captured by the image capturing device 114.
Therefore, when the projection device 112 projects the N structured light code patterns with a certain phase difference onto the surface of the object to be measured, the structured light code patterns are deformed under the influence of the height of the object to be measured, the image pickup device 114 picks up the structured light reflected by the surface of the object to be measured according to the set image pickup parameters, and the image of the object to be measured projected by the picked-up structured light code patterns can be represented by the following formula:
Rn(x，y)＝oω+aωcos(ωxp+θn) (2)
in the above formula (2), the value of N is 1, 2, …, N, (x, y) denotes the pixel coordinates on the image pickup device 114, and RnRepresenting the intensity, o, of pixels in an image of the object to be measured taken by the imaging device 114ωRepresenting the offset of the pixels in the captured image of the object to be measured, aωRepresenting the amplitude, theta, of a pixel in a captured image of the object to be measurednAnd shooting the phase of the pixel in the image of the object to be measured.
In some embodiments, the above formula (2) may be used as a decoding form of the captured image of the object to be measured, and the processor 120 may decode the captured image of the object to be measured by using the above formula (2).
In this embodiment, the structured light code pattern to be projected can be shifted uniformly by N times in one period, each time by 2 pi/N phases, so as to obtain N structured light code patterns with a phase difference of 2 pi/N.
In this embodiment, each image of the object to be measured projected by the imaging device 114 can be expressed as an equation in the decoding form shown in the above formula (2), and the phase of the pixel in the captured image of the object to be measured can be obtained by combining the equations in the decoding form of the image of the object to be measured projected by each structured light.
As a specific example, the total number N of phase shifts may be greater than or equal to 3, that is, the projection device 112 needs to project at least 3 structured light code patterns with a certain phase difference to the object to be measured.
Specifically, the processor 120 may decode the object image to be detected by solving the above equation (2), and obtain a pixel position corresponding relationship between the position of the pixel in the structured light encoding image and the position of the pixel in the object image to be detected, that is, a pixel position corresponding relationship between the projection device and the imaging device.
In an embodiment of the present invention, the processor 120 may be configured to provide the structured light code pattern encoded in the above embodiment to the projection device 112, that is, the processor 120 may encode the structured light code pattern by using the above formula (1), and output the structured light code pattern containing the encoding information as the intensity of the pixel in the structured light code pattern.
In one embodiment, the processor 120 may combine the N structured-light code patterns with a certain phase difference into one structured-light code pattern, and the projection device 112 may project the combined structured-light code pattern to the surface of the object to be measured.
As an example, the processor 120 may encode N black-and-white grating images with a certain phase shift into a color grating image, such that projecting one color grating image may achieve the effect of projecting three black-and-white gratings, thereby increasing the speed and efficiency of scanning the three-dimensional size of the object in real time.
In one embodiment, the three-dimensional scanning system usually projects the structured light code pattern on the whole scanning area, in order to obtain an image of the object to be measured projected by the structured light code pattern with higher quality, a solid background image may be placed in the scanning area where the object to be measured is located, and the first area and the background area of the object to be measured projected by the structured light code pattern are distinguished by the contrast between the color of the object to be measured and the color of the solid background image.
As an example, the solid background image may be a single color such as white, black, green, blue, red, or the like, which has a large contrast with the main color of the object to be measured.
That is, when the scanning area includes the object area to be measured and the background area, the processor 120 may further include an object image determination unit (not shown in the figure) that may be used to acquire an image of the object to be measured in the scanning area image projected by the structured light.
In this embodiment, the region of the object under test projected by the structured light code pattern in the scan region can be identified as the first region of the object under test.
In one embodiment, if the whole scanning area needs to be scanned three-dimensionally, the step of distinguishing the object area to be measured from the background area in the above embodiment is not required, and the image area of the scanning area projected by the structured light code pattern can be marked as the object area to be measured.
With continued reference to fig. 1, in some embodiments, processor 120 may further include: a pixel screening module 122 and a three-dimensional reconstruction module 124.
In this embodiment, the processor 120 may decode the object image to be measured by solving the above equation (2), so as to obtain the amplitude of the pixel in the object image to be measured.
In order to increase the calculation speed, an approximation algorithm for solving the amplitude of the pixel may also be used, and the variance of the pixel intensity in the object image to be measured under the projection of the structured light collected by the image capturing device 114 is used as the amplitude of the pixel in the object image to be measured.
In the embodiment of the present invention, the pixel screening module 122 may screen the pixels in the object image to be detected according to the amplitude of the pixels in the object image to be detected.
Specifically, the pixel screening module 122 may select pixels with a pixel amplitude greater than a preset amplitude threshold from the pixels of the object image to be detected, and may use the pixels with the pixel amplitude greater than or equal to the preset amplitude threshold as the pixels removed from the object image to be detected.
In some embodiments, the three-dimensional reconstruction module 124 may construct a three-dimensional size of a reconstruction region of the object to be measured by using a region of the object to be measured corresponding to the removed pixels as the reconstruction region based on the image acquisition parameters.
Specifically, the three-dimensional reconstruction module 124 may utilize a triangulation method to restore the three-dimensional size of the object to be measured according to the phase of the pixel in the image of the object to be measured captured by the imaging device and the pixel position corresponding relationship between the projection device and the imaging device.
In the embodiment of the invention, the accuracy and the reliability of the three-dimensional size of the reconstruction area for constructing the object to be measured are determined by setting the pixel threshold, the larger the preset pixel threshold is, the fewer pixels which are larger than the pixel threshold are in the image of the object to be measured, and the more accurate the size data obtained by three-dimensional reconstruction of the reconstruction area is subsequently. As an example, the preset pixel threshold value in the embodiment of the present invention may be 5.
In the embodiment of the present invention, for pixels that are not removed from the object image to be measured in the object region to be measured, image acquisition may be performed again by adjusting the image acquisition parameters of the image pickup device 114.
Specifically, the processor 120 may further include: and a parameter adjusting module 126, configured to adjust the image acquisition parameter.
After the image acquisition parameters are adjusted, the image acquisition module can be further used for shooting a first area of the object to be measured projected by the structured light code pattern according to the adjusted image acquisition parameters to obtain an adjusted image of the object to be measured.
The pixel screening module can be further configured to remove the removed pixels from the adjusted object image to obtain an updated object image to be detected, and based on the amplitude of the pixels in the updated object image to be detected, take the pixels larger than or equal to the amplitude threshold value as the pixels to be removed, and remove the pixels to be removed from the updated object image to be detected.
In the embodiment of the present invention, the three-dimensional scanning system may further include a scanning stop control module, configured to send a parameter adjustment instruction to the parameter adjustment module, and stop sending the parameter adjustment instruction to the parameter adjustment module until a scanning stop condition is met.
In one embodiment, the offset distance of the pixels in the object image to be measured can be obtained by solving the above formula (2) to decode the object image to be measured.
In order to increase the calculation speed, an approximation algorithm for solving the offset distance of the pixel may also be used, and the average value of the pixel intensities in the object image to be measured projected by the structured light collected by the camera device 114 is used as the offset distance of the pixel in the object image to be measured.
For easy understanding, the mean offset distances of the pixels removed from the object image to be measured are calculated, the mean offset distances of the pixels removed are used as the first mean offset distances, the mean offset distances of the pixels not removed from the object image to be measured are calculated, and the mean offset distances of the pixels not removed are used as the second mean offset distances.
When the image acquisition parameter is exposure time, projection brightness, or projected structural light intensity, the parameter adjusting module may be specifically configured to:
and when the second offset average value is larger than or equal to the first offset average value, reducing the image acquisition parameters, and taking the reduced image acquisition parameters as the adjusted image acquisition parameters.
As an example, the image acquisition parameter is exposure time, and when the second offset average value is smaller than the first offset average value, the exposure time is increased, and the increased exposure time is taken as the adjusted exposure time; and when the second offset average value is larger than or equal to the first offset average value, reducing the exposure time, and taking the reduced exposure time as the adjusted exposure time.
As an example, the image acquisition parameter is projection brightness, and when the second offset average value is smaller than the first offset average value, the projection brightness is increased, and the increased projection brightness is taken as adjusted projection brightness; and when the second offset average value is larger than or equal to the first offset average value, reducing the projection brightness, and taking the reduced projection brightness as the adjusted projection brightness.
As an example, the image acquisition parameter is the intensity of the projected structured light, and when the second offset average value is smaller than the first offset average value, the intensity of the structured light code pattern is increased, and the increased intensity of the structured light code pattern is used as the intensity of the adjusted structured light code pattern; and when the second offset average value is larger than or equal to the first offset average value, reducing the intensity of the structured light code pattern, and taking the reduced intensity of the structured light code pattern as the adjusted intensity of the structured light code pattern.
When the image acquisition parameter is an aperture coefficient, the parameter adjusting module is specifically configured to: when the second offset average value is smaller than the first offset average value, reducing the aperture coefficient, and taking the reduced aperture coefficient as the adjusted aperture coefficient; and when the second offset average value is larger than or equal to the first offset average value, increasing the aperture coefficient, and taking the increased aperture coefficient as the adjusted aperture coefficient.
In the embodiment of the invention, when the object to be detected is scanned, the image of the object to be detected in the appointed area of the object to be detected projected by the structured light code pattern is acquired according to the set image acquisition parameters, the pixels in the acquired image of the object to be detected are screened, and the pixels larger than the preset amplitude threshold value are selected for three-dimensional reconstruction, so that the pixels in the image of the object to be detected selected after each exposure can have higher precision through three-dimensional reconstruction, and the scanning effect is good.
And comparing the offset distance of the pixel which is not selected for three-dimensional reconstruction in the object image to be detected with the offset distance of the pixel which is selected for three-dimensional reconstruction, and pertinently reducing and adjusting the image acquisition parameters so as to continuously screen the pixel which is larger than the preset amplitude threshold value for three-dimensional reconstruction.
According to the three-dimensional scanning system 100 of the embodiment of the invention, in the scanning process, only the area where the pixel in the image of the object to be detected, which is not subjected to three-dimensional reconstruction, is located in the designated area of the object to be detected is exposed, and a new area which can be reconstructed is screened out, so that compared with the situation that all pixels in the scanning range need to be exposed for multiple times to select proper pixels for reconstruction, the time cost is greatly saved.
In the embodiment of the invention, the optimal offset distance of the pixels in the image of the object to be detected can be obtained by adjusting the image acquisition parameters, so that more accurate three-dimensional size can be obtained through three-dimensional reconstruction.
In one embodiment, since the exposure time and aperture factor supported by the image capturing apparatus 114 are limited, in order to find the optimal exposure time as soon as possible, as an example, if the image capturing parameter is the exposure time, the initial value of the exposure time may be set to the upper limit of the exposure time or the lower limit of the exposure time within the selectable range of the exposure time; as one example, if the image pickup parameter is an aperture ratio, the initial value of the aperture ratio may be set to an upper limit or a lower limit of the aperture ratio within the aperture ratio selectable range.
As an example, if the selectable range of the exposure time of the image capturing apparatus 114 is not continuous, a fixed step length is provided between the selectable values of the adjacent exposure times within the selectable range of the exposure time, and if the exposure time needs to be increased, the current exposure time is added to the absolute value of one fixed step length to obtain a new exposure time, i.e., an increased exposure time; if the exposure time needs to be reduced, the current exposure time is subtracted from the absolute value of a fixed step length to obtain a new exposure time, namely the reduced exposure time.
If the selectable range of the exposure time of the image pickup apparatus 114 is a continuous space, if the exposure time needs to be increased, taking a median between the current exposure time and the maximum value of the continuous space as a new exposure time; if the exposure time needs to be reduced, the median between the current exposure time and the minimum value of the continuous space is taken as the new exposure time.
As an example, when the range of values of the exposure time of the image pickup apparatus 114 is an enumerated optional value, a fixed step size, for example, the range of values of the exposure time is selected as
Figure BDA0001383432230000101
When the current exposure time is
Figure BDA0001383432230000102
Setting new exposure time as
Figure BDA0001383432230000103
A unit of time.
As an example, when the value range of the exposure time of the image pickup apparatus 114 is a continuous space, for example, [0, 1], the current exposure time is 0.5 time units, and the exposure time needs to be increased, the new exposure time is set to a median between 0.5 and 1, that is, the new exposure time is 0.75 time units.
In the three-dimensional scanning system 100 according to the embodiment of the present invention, if a ratio of a size of a region corresponding to an unremoved pixel to a size of an assigned region projected by a structured light code pattern when the object to be detected is three-dimensionally scanned for the first time is smaller than a preset size ratio threshold, or an adjusted image acquisition parameter exceeds an allowable image acquisition parameter range, the adjustment of the image acquisition parameter may be stopped, that is, the object to be detected is stopped from being scanned.
As an example, when the ratio of the size of the region corresponding to the pixel that is not removed to the size of the first region in the embodiment of the present invention is less than 1%, the adjustment of the image acquisition parameter is stopped.
As an example, when the exposure time or aperture factor in the range of the exposure time of the apparatus is used up, and the exposure time is not faster or slower, and the aperture factor is not larger or smaller, the adjustment of the image acquisition parameters is stopped or the scanning of the region of the object to be measured is stopped, and the optimal offset distance of the image of the object to be measured is obtained in the range of the available exposure time or aperture factor, so as to ensure the precision of three-dimensional reconstruction of the image of the object to be measured.
In embodiments of the present invention, when the image acquisition parameter is the projection brightness or projected structure light intensity,
in this embodiment, the pixels in the image of the object to be measured can be acquired to the greatest extent by limiting the size ratio of the region corresponding to the pixel that is not removed in the scanning stop condition, and the image of the object to be measured is three-dimensionally reconstructed, so that the obtained three-dimensional size of the object to be measured has a higher degree of reduction.
In an actual application scene, when an object to be measured is scanned, if the three-dimensional reconstruction of the surface and the geometric information of the object to be measured is not high in requirement, or a test shows that when some specific types of objects to be measured are scanned, a good three-dimensional reconstruction effect can be achieved only by exposure for a limited number of times.
At this time, the three-dimensional scanning system of the embodiment of the present invention may have a more flexible setting, that is, when three-dimensional scanning is performed on an object to be measured, the maximum exposure times may be set according to the actual needs or experience of a user.
According to the three-dimensional scanning system disclosed by the embodiment of the invention, the scanning of the three-dimensional size of the object with low cost, high precision and high reduction degree can be realized by using lower time cost.
In one exemplary embodiment, the three-dimensional scanning system of embodiments of the present invention may be a three-dimensional scanner.
The three-dimensional scanner may include a projection device such as a projector, an image capture device such as a camera, and a processor as shown in fig. 1, which may be used to detect and analyze surface and geometric information of the object under test.
As an example, the object to be measured may be a commercial product having a high contrast surface.
When the object to be detected is a high-contrast surface with black and white colors, when overexposure occurs to white, that is, the second offset average value of the pixels of the image projected by the structured light in the white area shot by the camera equipment is greater than the first offset average value, the black area which is originally successfully exposed does not participate in the exposure after the exposure is carried out again by reducing the exposure time, increasing the aperture coefficient, and reducing the projection brightness or the intensity of the projected structured light, and the white which is subjected to the overexposure can be normally exposed by adjusting the image acquisition parameters, so that the pixels in the image which is normally exposed by the high-contrast object projected by the structured light can be reconstructed, the processing speed is high, and a relatively accurate reconstruction effect is obtained.
In some embodiments, the initial value of the image acquisition parameter, for example, the exposure time, may be an optimal value of the image acquisition parameter, and in the presence of a high-contrast surface, the image pickup device 114 may capture an image of the object to be detected through structured light transmission according to the initial image acquisition parameter, for example, the exposure time, and as long as the pixels in the image of the object to be detected meet the requirement of three-dimensional reconstruction, that is, the amplitude of the pixels in the image of the object to be detected is greater than a preset amplitude threshold, the three-dimensional scanning system may perform decoded three-dimensional reconstruction on most of the pixels in the image of the object to be detected; and for the pixels which do not meet the reconstruction requirements in the object image to be detected, exposure can be performed again after the corresponding image acquisition parameters are adjusted, so that the pixels which meet the three-dimensional reconstruction requirements in the object image to be detected are further screened.
Therefore, when the object to be detected has surfaces with different contrast ratios, most pixels on the surface of the object to be detected can be decoded for three-dimensional reconstruction through the primary decoding process of the formula (2), so that the calculation amount of decoding and three-dimensional reconstruction in the subsequent exposure process is reduced, and the processing efficiency is higher.
In one embodiment, the three-dimensional scanner can also be used for detecting an object with a non-high-contrast surface, and when the object with the non-high-contrast surface is detected, the exposure time does not need to be adjusted for many times, and after one exposure in the scanning process, pixels in an image of the object to be detected, which are acquired by the camera equipment, can basically complete reconstruction, so that the calculation complexity in the scanning process is reduced.
In some embodiments, when the object to be measured is scanned three-dimensionally, the initial value of the image capturing parameter when the image capturing apparatus 114 captures the object to be measured projected by the structured light may not be an optimal value without determining the optimal image capturing parameter. At this time, the three-dimensional scanning system of the embodiment of the present invention may adjust the image acquisition parameter according to a result of subsequent three-dimensional reconstruction, may obtain an optimal value of the corresponding image acquisition parameter after a limited number of adjustments, and may directly use or refer to the optimal value of the image acquisition parameter to set the initial image acquisition parameter when scanning the same and similar object to be measured subsequently, thereby implementing an automatic focusing capability of the three-dimensional scanning system for the exposure time.
In the embodiment of the invention, the proper image acquisition parameters can be selected according to the conditions of time cost, hardware support and the like of adjusting the image acquisition parameters.
Fig. 2 is a schematic structural diagram illustrating a three-dimensional scanning system according to another embodiment of the present invention. As shown in fig. 2, the three-dimensional scanning system 200 includes: an image acquisition module 110, a pixel screening module 122, and a three-dimensional reconstruction module 124.
In the three-dimensional scanning system 200, the image capturing module 110 may be configured to capture a first region of the object to be detected projected by the structured light code pattern according to the image capturing parameter, so as to obtain an image of the object to be detected.
In some embodiments, the image acquisition parameters include exposure time, aperture factor, projection brightness, or projected structured light intensity.
In some embodiments, the image acquisition module 110 further comprises:
projection device 112 may be configured to project the structured light code pattern onto a first region of the object under test using a phase shift method.
The camera device 114 may capture a first region of the object to be measured projected by the structured light code pattern according to the image capture parameters, so as to obtain an image of the object to be measured.
In the three-dimensional scanning system 200, the pixel screening module 122 may be configured to screen out, as pixels removed from the image of the object to be detected, pixels with an amplitude greater than or equal to a preset amplitude threshold value by using the amplitude of the pixels in the image of the object to be detected projected by the structured light code pattern, and update the area of the object to be detected to be an area where the pixels that are not removed are located.
In some embodiments, the image acquisition module 110 may further include:
and the parameter adjusting module is used for adjusting the image acquisition parameters.
The image acquisition module 110 is further configured to shoot a first region projected by the structured light coding pattern according to the adjusted image acquisition parameters, so as to obtain an adjusted image of the object to be detected;
the pixel screening module 122 is further configured to remove the removed pixels from the adjusted object image to obtain an updated object image to be detected, and based on the amplitude of the pixels in the updated object image to be detected, take the pixels greater than or equal to the amplitude threshold value as the pixels to be removed, and remove the pixels to be removed from the updated object image to be detected;
and the scanning stopping control module is used for sending a parameter adjusting instruction to the parameter adjusting module until a scanning stopping condition is met and determining to stop sending the parameter adjusting instruction.
In some embodiments, the scan stop condition is: the ratio of the size of the region corresponding to the pixel which is not removed to the size of the first region is smaller than a preset size ratio threshold, or the adjusted image acquisition parameter exceeds the allowable image acquisition parameter range.
In some embodiments, pixel screening module 122 may further include:
the amplitude calculation unit may be configured to calculate a variance of intensity values of pixels in the object image to be measured, and use the variance of the intensity values as the amplitude of the pixels in the object image to be measured.
In the three-dimensional scanning system 200, the three-dimensional reconstruction module 124 may use the region of the object to be measured corresponding to the removed pixels as a reconstruction region based on the image acquisition parameters, and construct a three-dimensional size of the reconstruction region of the object to be measured.
In some embodiments, the three-dimensional reconstruction module 124 may further include:
the decoding unit can be used for constructing an equation which accords with the coding form of the structured light coding pattern by utilizing the intensity of pixels in a reconstruction region of the object image to be detected shot under the projection of the N structured light coding patterns, solving the equation to obtain the phase of the pixels in the reconstruction region and the pixel position corresponding relation between the positions of the pixels in the structured light coding pattern and the positions of the pixels in the reconstruction region.
The three-dimensional size reduction unit can be used for reducing the three-dimensional size of the object to be measured in the reconstruction area according to the corresponding relation between the phase position and the pixel position of the pixel in the reconstruction area by using a triangulation method.
According to the three-dimensional scanning system disclosed by the embodiment of the invention, the object is scanned by using a phase shift method, and only the phase of the region of the object to be detected is calculated, so that the updated phase information of the pixels in the region of the object to be detected is obtained.
In some embodiments, when the image acquisition parameter includes an exposure time, a projection brightness, or a projected structural light intensity, the exposure time adjustment module may specifically include:
the offset distance calculation unit may be configured to calculate a mean value of intensity values of pixels to be removed and a mean value of pixels not to be removed in the object image to be detected, and obtain an offset distance of the pixels to be removed and an offset distance of the pixels not to be removed.
The offset mean calculation unit may be configured to calculate a mean of offsets of the pixels to be removed, take the mean of offsets of the pixels to be removed as a first offset mean, and calculate a mean of offsets of the pixels that are not to be removed, and take the mean of offsets of the pixels that are not to be removed as a second offset mean.
And the parameter updating unit can be used for increasing the image acquisition parameters when the second offset average value is smaller than the first offset average value, taking the increased image acquisition parameters as the adjusted image acquisition parameters, and reducing the image acquisition parameters when the second offset average value is larger than or equal to the first offset average value, and taking the reduced image acquisition parameters as the adjusted image acquisition parameters.
In some embodiments, when the image acquisition parameter includes an aperture coefficient, the exposure time adjustment module may specifically include:
the offset distance calculation unit is used for calculating the mean value of the intensity values of the pixels to be removed and the mean value of the pixels not to be removed in the object image to be detected to obtain the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed;
the offset mean value calculation unit is used for calculating the mean value of the offsets of the pixels to be removed, taking the mean value of the offsets of the pixels to be removed as a first offset mean value, calculating the mean value of the offsets of the pixels which are not removed, and taking the mean value of the offsets of the pixels which are not removed as a second offset mean value;
and the parameter updating unit is used for reducing the aperture coefficient when the second offset average value is smaller than the first offset average value, taking the reduced aperture coefficient as the adjusted aperture coefficient, increasing the aperture coefficient when the second offset average value is larger than or equal to the first offset average value, and taking the increased image acquisition parameter as the adjusted aperture coefficient.
In this embodiment, through adjustment of the image acquisition parameters, pixels in the object region to be measured, which can be reconstructed, are further screened through re-exposure during the scanning process.
In the embodiment of the invention, when the object to be detected is scanned in three dimensions, pixels in the current object region to be detected can be screened based on pixel amplitude, pixels which can be subjected to three-dimensional reconstruction in the object region to be detected are screened out, the object region to be detected is updated, and the pixels in the object region to be detected are continuously screened and subjected to corresponding three-dimensional reconstruction through adjustment of image acquisition parameters. The process of three-dimensional scanning of the object to be detected in the embodiment of the invention can be an iterative process, and compared with the process that all pixels in the scanning range need to be exposed for multiple times to select proper pixels for reconstruction in each scanning, the time cost is greatly saved.
In addition, in the embodiment of the present invention, the image acquisition parameters are adjusted according to the comparison and analysis of the offset distances of the pixels that are not screened out in the current scanning and the pixels that are screened out and can be reconstructed, so as to obtain the optimal offset distance of the pixels, where the offset distance of the pixels includes the height information of the pixel point. Therefore, the corresponding image acquisition parameters are increased or reduced in a targeted manner to obtain the optimal offset distance of the pixels in the region of the object to be measured, and the precision of three-dimensional reconstruction of the object to be measured can be improved.
Other details of the three-dimensional scanning system 200 according to the embodiment of the invention are similar to those of the three-dimensional scanning system 100 according to the embodiment of the invention described above with reference to fig. 1, and are not repeated herein.
Fig. 3 is a flowchart illustrating a three-dimensional scanning method according to an embodiment of the present invention. As shown in fig. 1, the three-dimensional scanning method 300 in the embodiment of the present invention includes the following steps:
step S110, shooting a first area of the object to be measured projected by the structured light code pattern according to the image acquisition parameters to obtain an image of the object to be measured.
In some embodiments, step S110 may include:
step S111, projecting a structured light code pattern to a first region of the object to be measured by using a phase shift method.
And step S112, shooting a first area of the object to be measured projected by the structured light code pattern according to the image acquisition parameters.
And step S120, removing the pixels which are larger than or equal to the amplitude threshold value from the object image to be detected based on the amplitude of the pixels in the object image to be detected.
Step S130, based on the image acquisition parameters, taking the area of the object to be measured corresponding to the removed pixels as a reconstruction area, and constructing the three-dimensional size of the reconstruction area of the object to be measured.
In some embodiments, the three-dimensional scanning method 300 further comprises:
step S140, adjusting image acquisition parameters.
And S150, shooting a first area projected by the structured light code pattern according to the adjusted image acquisition parameters to obtain an adjusted image of the object to be detected.
Step S160, removing the removed pixels from the adjusted object image to obtain an updated object image to be detected, and based on the amplitude of the pixels in the updated object image to be detected, taking the pixels greater than or equal to the amplitude threshold as the pixels to be removed, and removing the pixels to be removed from the updated object image to be detected.
And step S170, when the scanning stop condition is met, determining to adjust the image acquisition parameters.
In some embodiments, the scan stop condition is: the ratio of the size of the region corresponding to the pixel which is not removed to the size of the first region is smaller than a preset size ratio threshold, or the adjusted image acquisition parameter exceeds the allowable image acquisition parameter range.
In some embodiments, the step of reconstructing the reconstruction region in three dimensions in step S130 may include:
step S131, an equation which is in accordance with the encoding form of the structured light encoding graph is constructed by using the intensities of the pixels in the reconstruction region of the N objects to be detected shot under the projection of the structured light encoding graph, and the equation is solved to obtain the phase of the pixels in the reconstruction region and the pixel position corresponding relation between the positions of the pixels in the structured light encoding graph and the positions of the pixels in the reconstruction region.
And S132, restoring the three-dimensional size of the object to be detected in the reconstruction region by using a triangulation method according to the corresponding relation between the phase position and the pixel position of the pixel in the reconstruction region.
In some embodiments, the step of adjusting the image acquisition parameters in step S140 may specifically include:
step S141, calculating a mean value of the intensity values of the pixels to be removed and a mean value of the pixels not to be removed in the object image to be measured, and obtaining the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed.
Step S142, calculating the mean of the offsets of the removed pixels, taking the mean of the offsets of the removed pixels as the first offset mean, and calculating the mean of the offsets of the non-removed pixels, taking the mean of the offsets of the non-removed pixels as the second offset mean.
Step S143-01, configured to, when the image acquisition parameter includes exposure time, projection brightness, or projected structural light intensity, increase the corresponding image acquisition parameter if the second offset average is smaller than the first offset average, and use the increased exposure time as the adjusted image acquisition parameter, and decrease the corresponding image acquisition parameter if the second offset average is greater than or equal to the first offset average, and use the decreased image acquisition parameter as the adjusted image acquisition parameter.
And S143-02, when the image acquisition parameters comprise the aperture coefficient, if the second offset average value is smaller than the first offset average value, reducing the aperture coefficient, and taking the reduced aperture coefficient as the adjusted aperture coefficient, and when the second offset average value is larger than or equal to the first offset average value, increasing the aperture coefficient, and taking the increased aperture coefficient as the adjusted aperture coefficient.
According to the three-dimensional scanning method provided by the embodiment of the invention, the scanning of the three-dimensional size of the object with low cost, high precision and high reduction degree can be realized by using lower time cost.
For better understanding, the following describes the three-dimensional scanning method according to an embodiment of the present invention in detail by taking an image acquisition parameter as an exposure time as an example.
Fig. 4 shows a flow chart of a three-dimensional scanning method according to another embodiment of the invention. As shown in FIG. 4, in some embodiments, three-dimensional scanning of an object with a three-dimensional scanning system may include the steps of:
in step S401, an initial value of the exposure time of the imaging apparatus in the three-dimensional scanning system is set.
In step S401, the initial value of the exposure time may be the maximum value or the minimum value of the selectable range of the exposure time of the image pickup apparatus package.
Step S402, shooting the image of the object to be measured of the object area to be measured projected by the structured light code pattern according to the set exposure time.
In one embodiment, the projected structured light may be represented in the encoded form shown in equation (1) above.
In one embodiment, the captured image of the object to be measured projected by the structured light code pattern can be represented in a decoding form as shown in the above formula (2).
In step S403, the amplitude of the pixel in the object image to be measured is calculated.
In one embodiment, the amplitude of the pixel in the object image to be measured can be calculated by using the above formula (1) to encode the structured light and the above formula (2) to decode the object image to be measured.
In order to increase the calculation speed, in another embodiment, an approximation algorithm for solving the amplitude of the pixel may also be used, and the variance of the pixel intensity in the object image to be measured under the projection of the structured light collected by the image capturing apparatus 114 is used as the amplitude of the pixel in the object image to be measured.
Step S404, judging whether the amplitude of the pixel in the object image to be detected is larger than a preset amplitude threshold value.
Step S405, removing the pixels which are larger than or equal to the amplitude threshold value from the image of the object to be detected, and performing three-dimensional reconstruction on the region corresponding to the removed pixels.
In step S406, pixels smaller than the preset amplitude threshold in the object image to be detected are regarded as pixels that are not removed.
In step S407, it is determined whether the size of the pixel corresponding region that is not removed satisfies the scan stop condition.
In one embodiment, the scan stop condition may be: the ratio of the size of the region corresponding to the pixel which is not removed to the size of the first region is smaller than a preset size ratio threshold, or the adjusted image acquisition parameter exceeds the allowable image acquisition parameter range.
In another embodiment, the scan stop condition may be: the set exposure time limit is reached.
In this step, if the updated object-to-be-measured area satisfies the scan stop condition, step S411 is executed to stop scanning the object-to-be-measured.
In step S408, if the scan stop condition is not satisfied, a mean value K1 of offsets of pixels removed in the present exposure and a mean value K2 of offsets of pixels not removed in the present exposure are calculated.
In one embodiment, the offset distance of the pixel in the object image to be measured can be calculated by using the above formula (1) to encode the structured light and the above formula (2) to decode the object image to be measured.
In order to increase the calculation speed, an approximation algorithm for solving the offset distance of the pixels may be adopted, and the average value of the pixel intensities in the object image to be measured, which is projected by the structured light collected by the camera device, is used as the offset distance of the pixels in the object image to be measured.
In this step, a mean value K1 of the offsets of the pixels removed from the object image to be measured and a mean value K2 of the offsets of the pixels not removed in the current exposure can be calculated according to the offsets of the pixels in the object image to be measured.
In step S409, when K2 is smaller than K1, the exposure time is increased, and when K2 is equal to or greater than K1, the exposure time is decreased.
Step S410, determining whether the adjusted exposure time satisfies the scan stop condition, if not, repeating the above steps S402 to S409. Namely, pixels which can be subjected to three-dimensional reconstruction in the object region to be detected are screened under the new exposure time.
Step S411, if the adjusted exposure time meets the scanning stop condition, the scanning of the object to be measured is stopped. Namely, the adjusted exposure time exceeds the allowable exposure time range, and the scanning of the object to be measured or the adjustment of the exposure time is stopped.
Other details of the three-dimensional scanning method according to the embodiment of the present invention are similar to those of the three-dimensional scanning system according to the embodiment of the present invention described above with reference to fig. 1, and are not repeated herein.
The three-dimensional scanning system and the three-dimensional scanning method according to the embodiment of the present invention described in conjunction with fig. 1 to 4 may be implemented by a computing device.
Fig. 5 is a block diagram illustrating an exemplary hardware architecture of a computing device capable of implementing a three-dimensional scanning system and a three-dimensional scanning method according to an embodiment of the present invention.
As shown in fig. 4, computing device 500 includes an input device 501, an input interface 502, a central processor 503, a memory 504, an output interface 505, and an output device 506. The input interface 502, the central processing unit 503, the memory 504, and the output interface 505 are connected to each other through a bus 510, and the input device 501 and the output device 506 are connected to the bus 510 through the input interface 502 and the output interface 505, respectively, and further connected to other components of the computing device 500.
Specifically, the input device 501 receives input information from the outside (for example, a camera mounted on a three-dimensional scanner) and transmits the input information to the central processor 503 through the input interface 502; the central processor 503 processes input information based on computer-executable instructions stored in the memory 504 to generate output information, temporarily or permanently stores the output information in the memory 504, and then transmits the output information to the output device 506 through the output interface 505; output device 506 outputs the output information outside of computing device 500 for use by a user.
That is, the computing device shown in fig. 5 may also be implemented to include: a memory storing computer-executable instructions; and a processor which, when executing computer executable instructions, may implement the three-dimensional scanning system and the three-dimensional scanning method described in connection with fig. 1 to 4.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product or computer-readable storage medium. The computer program product or computer-readable storage medium includes one or more computer instructions. The procedures or functions according to the embodiments of the invention are brought about in whole or in part when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wirelessly (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.
It is to be understood that the invention is not limited to the specific arrangements and instrumentality described above and shown in the drawings. A detailed description of known methods is omitted herein for the sake of brevity. In the above embodiments, several specific steps are described and shown as examples. However, the method processes of the present invention are not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications and additions or change the order between the steps after comprehending the spirit of the present invention.
As will be apparent to those skilled in the art, for convenience and brevity of description, the specific working processes of the systems, modules and units described above may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again. It should be understood that the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the present invention, and these modifications or substitutions should be covered within the scope of the present invention.

Claims (15)

1. A three-dimensional scanning system, comprising:
the image acquisition module is used for shooting a first area of the object to be detected projected by the structured light coding pattern according to the image acquisition parameters to obtain an image of the object to be detected;
the pixel screening module is used for removing pixels which are larger than or equal to an amplitude threshold value from the object image to be detected based on the amplitude of the pixels in the object image to be detected;
and the three-dimensional reconstruction module is used for taking the area of the object to be detected corresponding to the removed pixels as a reconstruction area based on the image acquisition parameters, and constructing the three-dimensional size of the reconstruction area of the object to be detected.
2. The three-dimensional scanning system of claim 1, wherein the three-dimensional scanning system further comprises:
the parameter adjusting module is used for adjusting the image acquisition parameters;
the image acquisition module is further used for shooting the first area projected by the structured light coding pattern according to the adjusted image acquisition parameters to obtain an adjusted image of the object to be detected;
the pixel screening module is further configured to remove the removed pixels from the adjusted object image to be detected to obtain an updated object image to be detected, and based on the amplitude of the pixels in the updated object image to be detected, take the pixels larger than or equal to the amplitude threshold value as pixels to be removed, and remove the pixels to be removed from the updated object image to be detected;
and the scanning stopping control module is used for sending a parameter adjusting instruction to the parameter adjusting module until a scanning stopping condition is met and determining to stop sending the parameter adjusting instruction.
3. The three-dimensional scanning system of claim 2, the scan stop condition being:
the ratio of the size of the region corresponding to the pixel which is not removed to the size of the first region is smaller than a preset size ratio threshold, or the adjusted image acquisition parameter exceeds an allowable image acquisition parameter range.
4. The three-dimensional scanning system of claim 1, wherein the image acquisition module comprises:
the projection equipment is used for projecting the structured light coding pattern to the first area of the object to be measured by utilizing a phase shift method;
and the camera equipment is used for shooting a first area of the object to be detected projected by the structured light code pattern according to the image acquisition parameters to obtain an image of the object to be detected.
5. The three-dimensional scanning system of claim 1, wherein the pixel screening module comprises:
and the amplitude calculation unit is used for calculating the variance of the intensity values of the pixels in the object image to be detected, and taking the variance of the intensity values as the amplitude of the pixels in the object image to be detected.
6. The three-dimensional scanning system of claim 1, wherein the number of the structured light code patterns is N, wherein N is equal to or greater than 3, and pixels in each structured light code pattern located at the same pixel coordinate position have different offset phases;
the three-dimensional reconstruction module comprises:
the decoding unit is used for constructing an equation which accords with the coding form of the structured light coding diagram by utilizing the intensities of the pixels in the reconstruction region of the object to be detected shot under the projection of the structured light coding diagram, solving the equation to obtain the phase of the pixels in the reconstruction region and the pixel position corresponding relation between the positions of the pixels in the structured light coding diagram and the positions of the pixels in the reconstruction region;
and the three-dimensional size reduction unit is used for reducing the three-dimensional size of the object to be measured in the reconstruction area according to the corresponding relation between the phase of the pixel in the reconstruction area and the pixel position by using a triangulation method.
7. The three-dimensional scanning system of claim 2, wherein the image acquisition parameters include exposure time, projection brightness, or projected structured light intensity;
the parameter adjustment module comprises:
the offset distance calculation unit is used for calculating the mean value of the intensity values of the pixels to be removed and the mean value of the pixels not to be removed in the object image to be detected to obtain the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed;
the offset mean calculation unit is used for calculating the mean of the offsets of the pixels to be removed, taking the mean of the offsets of the pixels to be removed as a first offset mean, calculating the mean of the offsets of the pixels not to be removed, and taking the mean of the offsets of the pixels not to be removed as a second offset mean;
and the parameter updating unit is used for increasing the image acquisition parameters and taking the increased image acquisition parameters as the adjusted image acquisition parameters when the second offset average value is smaller than the first offset average value, and reducing the image acquisition parameters and taking the reduced image acquisition parameters as the adjusted image acquisition parameters when the second offset average value is larger than or equal to the first offset average value.
8. The three-dimensional scanning system of claim 2, wherein the image acquisition parameters include an aperture factor;
the parameter adjustment module comprises:
the offset distance calculation unit is used for calculating the mean value of the intensity values of the pixels to be removed and the mean value of the pixels not to be removed in the object image to be detected to obtain the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed;
the offset mean calculation unit is used for calculating the mean of the offsets of the pixels to be removed, taking the mean of the offsets of the pixels to be removed as a first offset mean, calculating the mean of the offsets of the pixels not to be removed, and taking the mean of the offsets of the pixels not to be removed as a second offset mean;
and the parameter updating unit is used for reducing the aperture coefficient and taking the reduced aperture coefficient as the adjusted aperture coefficient when the second offset average value is smaller than the first offset average value, and increasing the aperture coefficient and taking the increased image acquisition parameter as the adjusted aperture coefficient when the second offset average value is larger than or equal to the first offset average value.
9. A three-dimensional scanning method, comprising:
shooting a first area of the object to be detected projected by the structured light coding pattern according to the image acquisition parameters to obtain an image of the object to be detected;
based on the amplitude of the pixels in the object image to be detected, removing the pixels which are larger than or equal to an amplitude threshold value from the object image to be detected;
and based on the image acquisition parameters, taking the area of the object to be detected corresponding to the removed pixels as a reconstruction area, and constructing the three-dimensional size of the reconstruction area of the object to be detected.
10. The three-dimensional scanning method of claim 9, further comprising:
adjusting the image acquisition parameters;
shooting the first area projected by the structured light coding pattern according to the adjusted image acquisition parameters to obtain an adjusted image of the object to be detected;
removing the removed pixels from the adjusted image of the object to be detected to obtain an updated image of the object to be detected, taking the pixels larger than or equal to the amplitude threshold value as the pixels to be removed based on the amplitude of the pixels in the updated image of the object to be detected, and removing the pixels to be removed from the updated image of the object to be detected;
and when the scanning stop condition is met, determining to adjust the image acquisition parameters.
11. The three-dimensional scanning method according to claim 9,
the scanning stop conditions are as follows: the ratio of the size of the region corresponding to the pixel which is not removed to the size of the first region is smaller than a preset size ratio threshold, or the adjusted image acquisition parameter exceeds the allowable image acquisition parameter range.
12. The three-dimensional scanning method according to claim 9, wherein the capturing the first region of the object under test projected by the structured light code pattern according to the image acquisition parameters comprises:
projecting a structured light coding pattern to a first area of the object to be measured by using a phase shift method;
and shooting a first area of the object to be detected projected by the structured light code pattern according to the image acquisition parameters.
13. The three-dimensional scanning method according to claim 9, wherein the number of the structured light code patterns is N, wherein N is equal to or greater than 3, and pixels located at the same pixel coordinate position in each structured light code pattern have different offset phases;
the three-dimensional size of the reconstruction region for constructing the object to be measured comprises the following steps:
constructing an equation which accords with the coding form of the structured light coding pattern by using the intensities of N pixels in a reconstruction region of the object to be detected shot under the projection of the structured light coding pattern, solving the equation to obtain the phase of the pixels in the reconstruction region and the pixel position corresponding relation between the positions of the pixels in the structured light coding pattern and the positions of the pixels in the reconstruction region;
and restoring the three-dimensional size of the object to be detected in the reconstruction region by utilizing a triangulation method according to the corresponding relation between the phase of the pixel in the reconstruction region and the position of the pixel.
14. The three-dimensional scanning method of claim 9, wherein the image acquisition parameters include exposure time, projection brightness, or projected structured light intensity;
the method further comprises the following steps: adjusting the image acquisition parameters; wherein,
the adjusting the image acquisition parameters comprises:
calculating the mean value of the intensity values of the pixels to be removed and the mean value of the pixels not to be removed in the object image to be detected to obtain the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed;
calculating a mean value of offsets of the removed pixels, taking the mean value of offsets of the removed pixels as a first offset mean value, and calculating a mean value of offsets of the non-removed pixels, taking the mean value of offsets of the non-removed pixels as a second offset mean value;
and the image acquisition parameter is increased when the second offset average value is smaller than the first offset average value, the increased image acquisition parameter is used as an adjusted image acquisition parameter, and the image acquisition parameter is decreased when the second offset average value is larger than or equal to the first offset average value, and the decreased image acquisition parameter is used as an adjusted image acquisition parameter.
15. The three-dimensional scanning method according to claim 9, wherein the image acquisition parameter includes an aperture factor;
the method further comprises the following steps: adjusting the image acquisition parameters; wherein,
the adjusting the image acquisition parameters comprises:
calculating the mean value of the intensity values of the pixels to be removed and the mean value of the pixels not to be removed in the object image to be detected to obtain the offset distance of the pixels to be removed and the offset distance of the pixels not to be removed;
calculating a mean value of offsets of the removed pixels, taking the mean value of offsets of the removed pixels as a first offset mean value, and calculating a mean value of offsets of the non-removed pixels, taking the mean value of offsets of the non-removed pixels as a second offset mean value;
and when the second offset average value is smaller than the first offset average value, reducing the aperture coefficient, and taking the reduced aperture coefficient as the adjusted aperture coefficient, and when the second offset average value is larger than or equal to the first offset average value, increasing the aperture coefficient, and taking the increased aperture coefficient as the adjusted aperture coefficient.
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