CN114485433A

CN114485433A - Three-dimensional measurement system, method and device based on pseudo-random speckles

Info

Publication number: CN114485433A
Application number: CN202210085942.9A
Authority: CN
Inventors: 雷志辉; 陈状; 刘宇; 熊祥祥; 丁华轩; 傅丹
Original assignee: Shenzhen Eagle Eye Online Electronics Technology Co ltd
Current assignee: Shenzhen Eagle Eye Online Electronics Technology Co ltd
Priority date: 2022-01-25
Filing date: 2022-01-25
Publication date: 2022-05-13

Abstract

The invention relates to a three-dimensional measurement system based on pseudorandom speckles, which comprises an image acquisition device, an image preprocessing device, a system calibration device, a height calculation device and a three-dimensional data processing device, wherein the image acquisition device acquires speckle images of a reference datum plane and speckle images of the surface of a target to be measured; the image preprocessing device carries out image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured; the system calibration device obtains calibration parameters according to the speckle images of the reference datum plane; the height calculating device obtains corresponding mass center offset according to the processed speckle images of the reference datum plane and the processed speckle images of the surface of the target to be measured; and the three-dimensional data processing device obtains the three-dimensional profile information of the surface of the target to be measured according to the height values of the speckle points relative to the reference datum plane. The invention also discloses a three-dimensional measuring method based on the pseudo-random speckles and a three-dimensional measuring device based on the pseudo-random speckles.

Description

Three-dimensional measurement system, method and device based on pseudo-random speckles

Technical Field

The present disclosure relates to the field of optical measurement technologies, and in particular, to a three-dimensional (3-Dimension, 3D) measurement system based on pseudo-random speckles, a three-dimensional measurement method based on pseudo-random speckles, and a three-dimensional measurement device based on pseudo-random speckles.

Background

Compared with the traditional two-dimensional image information, the three-dimensional information can reflect objective objects more comprehensively and truly, and detection requirements which cannot be met by the traditional two-dimensional image information are met, such as: and measuring the conditions of height, depth, thickness, flatness, warping degree, abrasion, scratch and the like. With the continuous iteration of industrial development, many three-dimensional measurement techniques are mature. In particular, since the structured light three-dimensional measurement technology has the characteristics of non-contact, high precision, high efficiency, strong interference resistance and the like, structured light three-dimensional measurement plays an increasingly important role in industrial automation and intelligent manufacturing in recent years, and is widely applied to the fields of semiconductor industry (Printed Circuit Board (PCB) detection, chip detection, mobile phone industry, hardware industry and the like.

The structured light three-dimensional measurement technology can be generally roughly classified into: point structured light technology, line structured light technology, and coded structured light technology. The point structured light technology has the advantages of simple algorithm, small calculated amount and high measurement precision, but only can acquire the height information of a single contour point at a time, and the full-field measurement can be completed only by scanning in the X direction and the Y direction by means of a precision displacement table, so that the measurement efficiency is low. The linear structured light technology can acquire height information of a single contour line at one time, full-field measurement can be completed only by scanning in the Y direction with the aid of a precision displacement table, and compared with the point structured light technology, the linear structured light technology is more complex in algorithm, larger in calculated amount and lower in measurement precision. The coded structured light technology can acquire height information of a full-field surface profile at one time through a phase shift phase-solving method, and compared with the point structured light technology, the coded structured light technology does not need a compact displacement table, but needs to project a plurality of stripes at one time, so that the algorithm is complex, the calculated amount is large, the processing speed is low, and the measurement accuracy is not high.

Therefore, how to rapidly and efficiently acquire high-precision full-field surface profile height information at one time is a problem that needs to be solved by technical personnel in the current structured light three-dimensional measurement technology.

Disclosure of Invention

In view of the defects of the prior art, the application aims to provide a three-dimensional measurement system based on pseudo-random speckles, and aims to solve the problems of low measurement precision, low processing speed, low detection efficiency and the like in the existing structured light three-dimensional measurement technology for acquiring full-field surface profile height information.

A three-dimensional measurement system based on pseudo-random speckles comprises an image acquisition device, an image preprocessing device, a system calibration device, a height calculation device and a three-dimensional data processing device, wherein the image acquisition device is electrically connected with the image preprocessing device and used for acquiring a speckle image of a reference plane and a speckle image of the surface of a target to be measured and transmitting the speckle images of the reference plane and the surface of the target to be measured to the image preprocessing device; the image preprocessing device is electrically connected with the system calibration device and the height calculation device, and is used for carrying out image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured, transmitting the processed speckle images of the reference datum plane to the system calibration device and the height calculation device, and transmitting the processed speckle images of the surface of the target to be measured to the height calculation device; the system calibration device is electrically connected with the height calculation device and is used for obtaining corresponding calibration parameters according to the speckle images of the reference datum plane and transmitting the calibration parameters to the height calculation device; the height calculating device is electrically connected with the three-dimensional data processing device and is used for obtaining corresponding mass center offset according to the processed speckle image of the reference datum plane and the processed speckle image of the surface of the target to be detected, calculating the mass center offset by combining the mass center offset with calibration parameters of each scattered spot to obtain a height value of each scattered spot on the speckle image of the surface of the target to be detected relative to the reference datum plane, and transmitting the obtained height value to the three-dimensional data processing device; and the three-dimensional data processing device is used for obtaining the three-dimensional contour information of the surface of the target to be detected according to the height value of each scattered spot relative to the reference datum plane, and analyzing and detecting the three-dimensional contour information of the surface of the target to be detected.

Optionally, the image acquiring device includes a first image acquiring circuit and a second image acquiring circuit, wherein the first image acquiring circuit is electrically connected to the image preprocessing device, and the first image acquiring circuit is configured to acquire speckle images of the reference datum plane under different conditions and transmit the speckle images of the reference datum plane to the image preprocessing device; the second image acquisition circuit is electrically connected with the image preprocessing device and is used for acquiring the speckle images of the surface of the object to be detected under different conditions and transmitting the speckle images of the surface of the object to be detected to the image preprocessing device.

Optionally, the image preprocessing device includes a first image preprocessing circuit and a second image preprocessing circuit, wherein the first image preprocessing circuit is electrically connected to the first image acquiring circuit, the system calibration device and the height calculating device, and the first image preprocessing circuit is configured to preprocess the speckle image of the reference plane to obtain a centroid coordinate of the scattered spot, and transmit the preprocessed speckle image of the reference plane and the centroid coordinate of the scattered spot to the system calibration device and the height calculating device; the second image preprocessing circuit is electrically connected with the second image acquisition circuit and the height calculation device, and is used for preprocessing the speckle image of the surface of the target to be detected to obtain the centroid coordinate of the scattered spot, and transmitting the preprocessed speckle image of the surface of the target to be detected and the centroid coordinate of the scattered spot to the height calculation device.

Optionally, the height calculating device includes a speckle image matching circuit and a height information acquiring circuit, wherein the speckle image matching circuit is electrically connected to the first image preprocessing circuit, the second image preprocessing circuit and the height information acquiring circuit, and the speckle image matching circuit is configured to match the preprocessed speckle image of the reference plane with the preprocessed speckle image of the surface of the target to be detected, and transmit a matching result to the height information acquiring circuit; the height information acquisition circuit is electrically connected with the system calibration device, the speckle image matching circuit and the three-dimensional data processing device, and is used for calculating to obtain a mass center offset according to mass center coordinates of the scattered spots, calculating to obtain height values of the scattered spots relative to the reference datum plane according to calibration parameters of the scattered spots on the speckle image of the reference datum plane, and transmitting the obtained height values of the scattered spots relative to the reference datum plane to the three-dimensional data processing device.

Optionally, the image preprocessing device is further configured to separately locate each scattered spot on the speckle image of the reference plane and the speckle image of the surface of the object to be measured, and separately number each scattered spot according to the coordinate distribution of the speckle image of the reference plane and the speckle image of the surface of the object to be measured.

Optionally, the system calibration device is further configured to detect a repetitive pattern of speckle images of the reference plane transmitted by the image preprocessing device.

Optionally, the three-dimensional data processing device is further configured to perform three-dimensional reconstruction and data analysis on the height values of the speckle points on the speckle images of the surface of the object to be detected, which are transmitted by the height calculating device, relative to the reference plane, and perform combination splicing and local predetermined area mapping on the height values of the scattered speckles on the speckle images of all the surface of the object to be detected, so as to obtain three-dimensional profile information of the surface of the object to be detected.

Optionally, the centroid offset is a centroid offset of a speckle point in the speckle image of the surface of the object to be measured relative to the speckle image of the reference datum plane.

Optionally, the three-dimensional measurement system further comprises a personal computer, a camera, a speckle generator, a calibration block and a data cable, wherein the personal computer, the camera and the speckle generator are electrically connected through the data cable.

In summary, the image acquiring device acquires speckle images of a reference plane and a target surface under different conditions, the image preprocessing device processes images according to the acquired speckle images of the reference plane and the target surface, the system calibration device processes and calculates corresponding calibration parameters according to the speckle images of the reference plane, the height calculating device processes and calculates the processed speckle images of the reference plane and the processed speckle images of the target surface to obtain a centroid offset, and calculates a height value of each speckle point on the speckle image of the target surface to be measured relative to the reference plane by combining the centroid offset with the calibration parameters of each speckle point, and the three-dimensional data processing device calculates a height value of each speckle point on the speckle image of the target surface to be measured relative to the reference plane And processing the value to obtain the three-dimensional contour information of the surface of the target to be detected, thereby completing the analysis and detection of the three-dimensional contour information of the surface of the target to be detected. Therefore, the three-dimensional measurement system based on the pseudo-random speckles can rapidly and efficiently acquire high-precision full-field surface profile height information at one time on the basis of not using a precision displacement table, and therefore the problems that in the prior art, the measurement precision is low, the processing speed is low, the detection efficiency is not high and the like when the structured light three-dimensional measurement technology acquires the full-field surface profile height information are solved.

Based on the same inventive concept, the application also provides a three-dimensional measurement method based on pseudo-random speckle, which is executed by the three-dimensional measurement system, and the three-dimensional measurement method comprises the following steps: respectively collecting speckle images of a reference plane and a target surface to be detected; performing image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots; obtaining corresponding calibration parameters according to the speckle images of the reference datum plane; matching the preprocessed speckle image of the reference datum plane with the preprocessed speckle image of the surface of the target to be detected; calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the target to be measured; calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters of each scattered speckle point on the speckle image of the reference datum plane and the mass center offset; and obtaining the three-dimensional profile information of the surface of the target to be detected according to the height value of each speckle point on the speckle image of the surface of the target to be detected relative to the reference datum plane.

Optionally, the respectively acquiring the speckle image of the reference plane and the speckle image of the surface of the object to be measured includes: collecting speckle images of the reference datum plane under different conditions; and collecting speckle images of the surface of the target to be measured under different conditions.

Optionally, the image processing according to the speckle image of the reference datum plane and the speckle image of the surface of the object to be measured to obtain the centroid coordinates of the corresponding scattered spots includes: preprocessing the speckle image of the reference datum plane to obtain the centroid coordinates of the scattered spots and the preprocessed speckle image of the reference datum plane; and preprocessing the speckle image of the surface of the target to be detected to obtain the centroid coordinates of the scattered spots and the preprocessed speckle image of the surface of the target to be detected.

In summary, in the three-dimensional measurement method based on the pseudo-random speckles, the speckle images of the reference plane and the surface of the object to be measured are respectively collected; performing image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots; obtaining corresponding calibration parameters according to the speckle images of the reference datum plane; matching the preprocessed speckle image of the reference datum plane with the preprocessed speckle image of the surface of the target to be detected; calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the target to be measured; calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters of each scattered speckle point on the speckle image of the reference datum plane and the mass center offset; and obtaining the three-dimensional profile information of the surface of the target to be detected according to the height value of each speckle point on the speckle image of the surface of the target to be detected relative to the reference datum plane. Therefore, the three-dimensional measurement method based on the pseudo-random speckles can quickly and efficiently acquire the high-precision full-field surface profile height information at one time, and solves the problems of low measurement precision, low processing speed, low detection efficiency and the like in the prior art when the structured light three-dimensional measurement technology acquires the full-field surface profile height information.

Based on the same inventive concept, the application also provides a three-dimensional measuring device based on pseudo-random speckle, which comprises: at least one processor and a storage, at least one of the processors executing computer-executable instructions stored by the storage, at least one of the processors performing the above-described pseudo-random speckle-based three-dimensional measurement method.

In summary, in the three-dimensional measuring device based on the pseudo-random speckles, the speckle images of the reference plane and the surface of the object to be measured are respectively collected; performing image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots; obtaining corresponding calibration parameters according to the speckle images of the reference datum plane; matching the preprocessed speckle image of the reference datum plane with the preprocessed speckle image of the surface of the target to be detected; calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the target to be measured; calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters of each scattered speckle point on the speckle image of the reference datum plane and the mass center offset; and obtaining the three-dimensional profile information of the surface of the target to be detected according to the height value of each speckle point on the speckle image of the surface of the target to be detected relative to the reference datum plane. Therefore, the three-dimensional measuring device based on the pseudo-random speckles can quickly and efficiently acquire high-precision full-field surface profile height information at one time, and solves the problems that the measurement precision is low, the processing speed is low, the detection efficiency is not high and the like when the structured light three-dimensional measuring technology acquires the full-field surface profile height information in the prior art.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic hardware composition diagram of a three-dimensional measurement system based on pseudo-random speckle disclosed in an embodiment of the present application;

fig. 2 is a schematic structural diagram of a three-dimensional measurement system based on pseudo-random speckle according to an embodiment of the present disclosure;

FIG. 3 is a schematic optical path diagram of the pseudo-random speckle based three-dimensional measurement system shown in FIG. 2;

FIG. 4(a) is a schematic diagram of a surface fitting result of the target surface to be measured;

FIG. 4(b) is a schematic diagram of a local area mapping supplement result of the target surface to be measured;

FIG. 5 is a schematic circuit diagram of the pseudo-random speckle based three-dimensional measurement system shown in FIG. 2;

FIG. 6 is a schematic diagram of a coarse matching process;

FIG. 7(a) is a schematic diagram showing the effect of the centroid offset of the reference base plane and the scattering spot on the surface of the target to be measured;

FIG. 7(b) is a schematic diagram illustrating the calculation of the height values of the reference plane and the scattering spots on the surface of the target;

fig. 8 is a schematic flowchart of a three-dimensional measurement method based on pseudo-random speckle disclosed in an embodiment of the present application;

fig. 9 is a schematic flowchart of step S10 in the three-dimensional measurement method based on pseudo-random speckle shown in fig. 8;

fig. 10 is a schematic flowchart of step S20 in the three-dimensional measurement method based on pseudo-random speckle shown in fig. 8;

fig. 11 is a schematic hardware structure diagram of a three-dimensional measurement device based on pseudo-random speckle disclosed in an embodiment of the present application.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The following description of the various embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments that can be implemented by the application. The ordinal numbers used herein for the components, such as "first," "second," etc., are used merely to distinguish between the objects described, and do not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). Directional phrases used in this application, such as "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "side," and the like, refer only to the direction of the appended figures and, therefore, are used in order to better and more clearly illustrate and understand the present application and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in the particular orientation, and, therefore, should not be taken to be limiting of the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. It should be noted that the terms "first", "second", and the like in the description and claims of the present application and in the drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprises," "comprising," "includes," "including," or "including," when used in this application, specify the presence of stated features, operations, elements, and/or the like, but do not limit one or more other features, operations, elements, and/or the like. Furthermore, the terms "comprises" or "comprising" indicate the presence of the respective features, numbers, steps, operations, elements, components or combinations thereof disclosed in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components or combinations thereof, and are intended to cover non-exclusive inclusions.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Compared with the traditional two-dimensional image information, the three-dimensional information can reflect objective objects more comprehensively and truly, and detection requirements which cannot be met by the traditional two-dimensional image information are met, such as: and measuring the conditions of height, depth, thickness, flatness, warping degree, abrasion, scratch and the like. With the advent of the industrial 4.0 era, a plurality of detection devices capable of acquiring and processing three-dimensional information are successfully developed, and a plurality of three-dimensional measurement technologies are mature day by day. The structured light three-dimensional measurement technology is generally roughly divided into a point structured light technology, a line structured light technology and a coded structured light technology according to the difference of a projector light source, wherein the point structured light technology has simple algorithm, small calculated amount and high measurement precision, but can only obtain the height information of a single contour point at one time, and can complete full-field measurement only by scanning in the X direction and the Y direction by a precise displacement table, so that the measurement efficiency is lower, the full-field measurement can be completed only by scanning in the Y direction by means of a precision displacement table, and compared with a point structured light technology, the line structured light technology has the advantages of more complex algorithm, larger calculated amount and lower measurement precision. The coded structured light technology can acquire height information of a full-field surface profile at one time through a phase shift phase-solving method, and compared with the point structured light technology, the coded structured light technology does not need a compact displacement table, but needs to project a plurality of stripes at one time, so that the algorithm is complex, the calculated amount is large, the processing speed is low, and the measurement accuracy is not high. Therefore, how to quickly and efficiently acquire high-precision full-field surface profile height information at one time without a precision displacement table is a problem to be solved by technical staff urgently.

Based on this, aiming at the defects of low measurement precision, low processing speed, low detection efficiency and the like existing in the existing structured light three-dimensional measurement technology for obtaining the height information of the full-field surface profile, the application hopes to provide a three-dimensional measurement scheme capable of solving the technical problems, and the high-precision full-field surface profile height information can be obtained quickly and efficiently, so that the measurement efficiency, the measurement precision and the measurement speed of a three-dimensional measurement system based on pseudo-random speckles are effectively improved, and the detailed contents of the three-dimensional measurement system are explained in the following embodiments.

Structured light (Structured light) is a system structure composed of a projector and a camera, and the projector projects specific light information to the surface of an object and the background, and the light information is collected by the camera, and information such as the position and depth of the object is calculated according to the change of a light signal caused by the object, so that the whole three-dimensional space is restored. The line structured light three-dimensional (3-Dimension, 3D) measurement technology has been widely applied to the semiconductor industry such as PCB board detection, Mini LED detection, chip wafer detection, etc., and the mobile phone industry such as screen thickness detection, etc. In the existing three-dimensional measurement system, under the condition of not needing to use a compact displacement table, a plurality of stripes need to be projected at one time, so that the algorithm is complex, the calculated amount is large, the processing speed is low, and the measurement accuracy is not high.

The three-dimensional measurement system based on the pseudo-random speckles disclosed by the embodiment of the application can be applied to the fields of the semiconductor industry (PCB detection and chip detection), the mobile phone industry (mobile phone cover plate curved surface detection and screen thickness detection), the hardware industry and the like.

Referring to fig. 1 and fig. 2, fig. 1 is a hardware composition schematic diagram of a three-dimensional measurement system based on pseudo-random speckles disclosed in the embodiment of the present application, and fig. 2 is a structural schematic diagram of the three-dimensional measurement system based on pseudo-random speckles disclosed in the embodiment of the present application. As shown in fig. 1, the hardware part of the three-dimensional measurement system 100 provided in the embodiment of the present application mainly includes a Personal Computer (PC), a camera, a speckle generator, a calibration block, a data cable, and other equipment, wherein the PC, the camera, and the speckle generator are electrically connected through the data cable. In the embodiment of the present application, the camera may be a Charge Coupled Device (CCD) camera or a Complementary Metal Oxide Semiconductor (CMOS) camera. The speckle generator may be a laser speckle transmitter.

As shown in fig. 2, the embodiment of the present application provides a three-dimensional measurement system 100 based on pseudo-random speckle, which at least includes an image acquisition device 110, an image preprocessing device 120, a system calibration device 130, a height calculation device 140, and a three-dimensional data processing device 150. The image acquiring device 110 is electrically connected to the image preprocessing device 120, the image preprocessing device 120 is electrically connected to the system calibrating device 130 and the height calculating device 140, the system calibrating device 130 is electrically connected to the height calculating device 140, and the height calculating device 140 is electrically connected to the three-dimensional data processing device 150.

The image acquiring device 110 is configured to acquire the speckle images of the reference plane and the surface of the object to be detected under different conditions, and transmit the speckle images of the reference plane and the surface of the object to be detected to the image preprocessing device 120. Specifically, referring to the schematic optical path diagram of the three-dimensional measurement system shown in fig. 3, the image acquisition device 110 can control the on or off of the speckle generator and the preset function of the camera unit through the control device on the basis of a preset control algorithm, and acquire the speckle images of the reference plane and the speckle images of the target surface to be measured under different conditions according to the measurement requirements. Wherein the control device may be the personal computer, and the image pickup unit may be a camera. In the embodiment of the present application, the image capturing apparatus 110 may include a plurality of camera units, and each of the camera units may be a three-dimensional (3D) camera.

The image preprocessing device 120 is configured to perform image processing according to the speckle images of the reference plane and the surface of the object to be measured, which are acquired by the image acquisition device 110, transmit the processed speckle images of the reference plane to the system calibration device 130 and the height calculation device 140, and transmit the processed speckle images of the surface of the object to be measured to the height calculation device 140.

Specifically, in this embodiment of the present application, the image preprocessing device 120 improves the image quality of the speckle image of the target surface to be measured acquired by the image acquisition device 110, so as to improve the accuracy of the height calculation device 140 in processing, and locates each scattered spot on the speckle image of the reference plane and the speckle image of the target surface to be measured, and numbers each speckle spot according to the coordinate distribution of the speckle image of the reference plane and the speckle image of the target surface to be measured. The image preprocessing device 120 may further obtain the speckle image of the reference plane and the centroid information of each scattered spot on the speckle image of the target surface to be measured, and eliminate or correct the unreasonable scattered spots, so as to increase the calculation speed of the height calculation device 140, thereby facilitating the subsequent height calculation of each scattered spot.

The system calibration device 130 is configured to process and calculate a corresponding calibration parameter according to the speckle image of the reference plane transmitted by the image preprocessing device 120, and transmit the processed and calculated calibration parameter to the height calculating device 140.

Specifically, in the embodiment of the present application, the system calibration device 130 performs detection according to the repetitive pattern of the speckle images of the reference plane transmitted by the image preprocessing device 120, so as to ensure that the speckle point distribution characteristic in each predetermined area on the speckle image of the reference plane is unique. Meanwhile, the system calibration device 130 may further calculate calibration parameters of each scattered spot on the speckle image of the reference plane according to the speckle image of the reference plane transmitted by the image preprocessing device 120, so as to be used for calculating the height of each scattered spot on the speckle image of the target surface to be measured in the following process.

The height calculating device 140 is configured to process and calculate the processed speckle image of the reference plane and the processed speckle image of the surface of the target to be measured, which are transmitted by the image preprocessing device 120, to obtain a centroid offset; the height calculating device 140 is further configured to calculate a height value of each speckle point on the speckle image of the target surface to be detected relative to the reference plane by combining the centroid offset with the calibration parameter of each scattered speckle transmitted by the system calibrating device 130, and transmit the obtained height value of each speckle point relative to the reference plane to the three-dimensional data processing device 150. And the centroid offset is the centroid offset of the speckle point in the speckle image of the surface of the target to be detected relative to the speckle image of the reference datum plane.

The three-dimensional data processing device 150 is configured to process the height value of each speckle point on the speckle image of the target surface to be detected, which is transmitted by the height calculating device 140, relative to the reference datum plane to obtain three-dimensional profile information of the target surface to be detected, and analyze and detect the three-dimensional profile information of the target surface to be detected.

In this embodiment, the three-dimensional data processing device 150 performs three-dimensional reconstruction and data analysis on the height value of each speckle point on the speckle image of the target surface to be detected, which is transmitted by the height calculating device 140, relative to a reference plane, to obtain three-dimensional profile information of the target surface to be detected, and analyzes and detects the three-dimensional profile information of the target surface to be detected, referring to a schematic diagram of a curved surface fitting result of the target surface to be detected shown in fig. 4 (a).

In this embodiment, the three-dimensional data processing device 150 further performs combination splicing and local predetermined area mapping on the height values of the scattered spots on the speckle images of all the surfaces of the objects to be measured to obtain the surface three-dimensional profile data information of the objects to be measured, please refer to the supplementary result diagram of the local area mapping of the surfaces of the objects to be measured shown in fig. 4 (b).

Specifically, in this embodiment of the present application, according to the coordinates of the mass centers of all scattered spots on the speckle image of the target surface to be measured, which are obtained by the image preprocessing device 120, the height values obtained by the height calculating device 140 are spliced to obtain a height point cloud image, then the height point cloud image is subjected to local small-area mapping operation, affine transformation between the speckle points in the speckle image of the target surface to be measured in the local small area and the speckle points in the speckle image of the reference base plane is established, so as to supplement the height values in the blank area on the height point cloud image, and then the supplemented height point cloud image is subjected to corresponding smoothing and denoising operations, so as to obtain the three-dimensional profile data information of the surface of the object to be measured.

In summary, the image acquiring device 110 acquires speckle images of a reference plane and a target surface under different conditions, the image preprocessing device 120 performs image processing according to the acquired speckle images of the reference plane and the target surface, the system calibration device 130 performs processing and calculation according to the speckle images of the reference plane to obtain corresponding calibration parameters, the height calculating device 140 performs processing and calculation on the processed speckle images of the reference plane and the processed speckle images of the target surface to obtain a centroid offset, the centroid offset is combined with the calibration parameters of each scattered spot to calculate a height value of each speckle point on the speckle image of the target surface to be measured relative to the reference plane, and the three-dimensional data processing device 150 calculates the height value of each scattered spot on the speckle image of the target surface to be measured relative to the reference plane And processing the height value of the quasi-plane to obtain the three-dimensional profile information of the surface of the target to be detected, thereby completing the analysis and detection of the three-dimensional profile information of the surface of the target to be detected. Therefore, the three-dimensional measurement system based on the pseudo-random speckles can rapidly and efficiently acquire high-precision full-field surface profile height information at one time on the basis of not using a precision displacement table, and therefore the problems that in the prior art, the measurement precision is low, the processing speed is low, the detection efficiency is not high and the like when the structured light three-dimensional measurement technology acquires the full-field surface profile height information are solved.

Please refer to fig. 5, which is a schematic circuit diagram of the three-dimensional measurement system based on pseudo-random speckle shown in fig. 2. As shown in fig. 5, the image capturing device 110 includes a first image capturing circuit 111 and a second image capturing circuit 112, wherein the first image capturing circuit 111 and the second image capturing circuit 112 are both electrically connected to the image preprocessing device 120.

In the embodiment of the present application, the first image obtaining circuit 111 is configured to collect speckle images of the reference plane under different conditions, and transmit the speckle images of the reference plane to the image preprocessing device 120.

Specifically, in the embodiment of the present application, the camera unit collects a pseudo speckle image projected onto the reference plane, and the pseudo speckle image is used as a pseudo random speckle reference map. The exposure time and the aperture of the camera unit can be adjusted according to the power of the speckle generator and the reflection characteristic of the reference datum plane. In the specific implementation process, the exposure time and the aperture of the camera are adjusted according to the power of the pseudo-random speckle projector and the reflection characteristic of the reference datum plane, and the light intensity of scattered spots on the collected pseudo-random speckle datum image is ensured to be proper.

The image capturing unit may be a Charge Coupled Device (CCD) camera or a Complementary Metal-Oxide-Semiconductor (CMOS) camera.

The second image acquiring circuit 112 is configured to acquire speckle images of the surface of the object to be detected under different conditions, and transmit the speckle images of the surface of the object to be detected to the image preprocessing device 120.

Specifically, in the embodiment of the application, the camera unit is used for collecting a pseudo speckle image projected onto the surface of an object to be measured, and the pseudo speckle image is used as a pseudo random speckle pattern. The exposure time and the aperture of the camera unit can be adjusted according to the power of the speckle generator and the reflection characteristic of the reference datum plane.

With reference to fig. 5, the image pre-processing apparatus 120 includes a first image pre-processing circuit 121 and a second image pre-processing circuit 122. The first image preprocessing circuit 121 is electrically connected to the first image acquiring circuit 111, the system calibrating device 130 and the height calculating device 140, respectively, and the second image preprocessing circuit 122 is electrically connected to the second image acquiring circuit 112 and the height calculating device 140, respectively.

In this embodiment, the first image preprocessing circuit 121 is configured to preprocess the speckle image of the reference plane transmitted by the first image acquiring circuit 111 to obtain the coordinates of the center of mass of the scattered spot, and transmit the preprocessed speckle image of the reference plane and the coordinates of the center of mass of the scattered spot to the system calibrating device 130 and the height calculating device 140.

Specifically, in this embodiment, the first image preprocessing circuit 121 performs image filtering processing on the speckle image of the reference plane by using a gaussian filtering method (for example, performs 5 × 5 gaussian filtering on the image), so as to eliminate background noise on the speckle image of the reference plane, and obtain the speckle image of the reference plane after the image filtering processing. Then, the gray level distribution condition of the speckle images of the reference plane after the image filtering processing is known through counting the gray level histogram of the speckle images of the reference plane after the image filtering processing of the filtered image, and the gray level enhancement operation is performed on the speckle images of the reference plane after the image filtering processing, so that the speckle points at the part darker area on the image can be normally identified, and a gray level enhanced image is obtained. And then, carrying out image sharpening on the speckle image of the reference datum plane by adopting a Sobel differential operator to enable the edge of each scattered spot on the speckle image of the reference datum plane to be better clear so as to obtain a sharpened image, and selecting a proper differential operator according to the shape of the pseudorandom scattered spots in the specific implementation process so as to ensure that the edge shape of the scattered spots cannot be changed. And finally, determining an optimal binarization segmentation threshold value of the sharpened image by adopting an Otsu principle adaptive threshold value calculation method, converting the sharpened image into a binarization image by using the segmentation threshold value, performing relevant morphological processing on the binarization image, removing partial disordered points in the binarization image to obtain a clean binarization image, performing contour extraction on the binarization image after the disordered points are removed, and evaluating geometric characteristics such as the area, the length-width ratio and the like of each contour region to segment and mark each scattered spot on the binarization image. And finally, calculating the centroid coordinate of each scattered spot on the reference image according to the marked area of each scattered spot to obtain a speckle point positioning image.

In the embodiment of the present application, since the scattered spots are different, the centroid coordinate may be other centers besides the gray scale center of gravity, such as: centroid, center of energy peak, center of gaussian, center of log, etc., which are not particularly limited in this application.

In this embodiment, the second image preprocessing circuit 122 is configured to preprocess the speckle image of the target surface to be detected transmitted by the second image acquiring circuit 112 to obtain the centroid coordinate of the scattered spot, and transmit the preprocessed speckle image of the target surface to be detected and the centroid coordinate of the scattered spot to the height calculating device 140.

Specifically, in this embodiment of the application, the second image preprocessing circuit 122 performs image filtering processing on the speckle image of the surface of the object to be detected by using a gaussian filtering method, so as to eliminate background noise on the speckle image of the surface of the object to be detected, and obtain the speckle image of the surface of the object to be detected after the image filtering processing. Then, the gray level histogram of the speckle image of the surface of the object to be detected after the image filtering processing is counted to know the gray level distribution condition of the speckle image of the surface of the object to be detected after the image filtering processing, and the gray level enhancement operation is performed on the speckle image of the surface of the object to be detected after the image filtering processing to ensure that the speckle points at the part of the darker area on the image can be normally identified, so that a gray level enhanced image is obtained. Then, the speckle image of the reference datum plane is sharpened by adopting a Sobel differential operator, so that the edge of each scattered spot on the speckle image of the reference datum plane becomes better clear, and a sharpened image is obtained. Then, an optimal binarization segmentation threshold value of the sharpened image is determined by adopting an Otsu principle adaptive threshold value calculation method, the sharpened image is converted into a binarization image by using the segmentation threshold value, then the binarization image is subjected to related morphological processing, partial disordered points in the binarization image are removed, a clean binarization image is obtained, then the binarization image after the disordered points are removed is subjected to contour extraction, and each scattered spot on the binarization image is segmented and marked according to geometric characteristics such as the area, the aspect ratio and the like of each contour region. And finally, calculating the centroid coordinate of each scattered spot on the reference image according to the marked area of each scattered spot to obtain a speckle point positioning image.

In the embodiment of the present application, the preprocessing includes operations such as image filtering, grayscale enhancement, image sharpening, image binarization, speckle point positioning, centroid extraction, and the like, which is not specifically limited herein.

With continued reference to fig. 5, the height calculating device 140 includes a speckle image matching circuit 141 and a height information acquiring circuit 142. The speckle image matching circuit 141 is electrically connected to the first image preprocessing circuit 121, the second image preprocessing circuit 122, and the height information acquiring circuit 142, respectively, and the height information acquiring circuit 142 is electrically connected to the system calibration device 130, the speckle image matching circuit 141, and the three-dimensional data processing device 150.

In this embodiment of the application, the speckle image matching circuit 141 is configured to match the preprocessed reference plane speckle images transmitted by the first image preprocessing circuit 121 with the preprocessed reference plane speckle images transmitted by the second image preprocessing circuit 122, and transmit the matching result to the height information obtaining circuit 142.

Specifically, in this embodiment of the application, the speckle image matching circuit 141 completes the preliminary matching between the preprocessed reference plane speckle image transmitted by the first image preprocessing circuit 121 and the preprocessed target surface speckle image transmitted by the second image preprocessing circuit 122 according to an image correlation algorithm, so as to realize the alignment of each effective scattered spot on the reference plane speckle image and the target surface speckle image. In the specific implementation process, according to the speckle distribution condition of the pseudo-random speckles, proper image windows are sequentially selected from the reference image and the image to be detected to perform image correlation calculation. Because the speckle distribution of the pseudo-random speckles can present sparse and dense situations, the size of an image window needs to be adjusted in a self-adaptive manner, for example, 20 × 100, at least more than 5 scattered speckles exist in the window area, and the accuracy of image correlation calculation is ensured.

As shown in fig. 6, in the rough matching process, a Region of Interest (ROI) (width n and height m) on the speckle image of the surface of the object to be measured and the relative movement of the speckle image of the reference base plane are selected, and the similarity C of the Region of the speckle image of the reference base plane is calculated by moving each time, where the formula is as follows:

and after the movement is finished, obtaining a similarity set { Ci }, finding a set with the maximum similarity in the set and a corresponding position (namely a coarse matching result), and obtaining the one-to-one corresponding number scattered spots in the region.

In this embodiment, the height information obtaining circuit 142 is configured to calculate a centroid offset according to the centroid coordinates of the scattered spots transmitted by the first image preprocessing circuit 121 and the second image preprocessing circuit 122, calculate a height value of each speckle point relative to the reference plane according to the calibration parameter of each scattered spot on the speckle image of the reference plane transmitted by the system calibration device 130, and transmit the obtained height value of each speckle point relative to the reference plane to the three-dimensional data processing device 150.

Specifically, in this embodiment of the present application, the centroid offset of the speckle point in the speckle image of the surface of the object to be measured with respect to the speckle image of the reference plane is calculated according to the centroid coordinates of the scattered speckles transmitted by the first image preprocessing circuit 121 and the second image preprocessing circuit 122, and the calculation process is as follows:

by using Otsu's method (the ohio method), the segmentation threshold of the ROI image is determined, and the principle is as follows:

calculating an accumulation average value M of the gray level K and an image global average value MG:

wherein, P_iFor the probability value of the current gray level, the final formula of this embodiment is:

the method comprises the following steps of calculating a segmentation threshold value k with a maximized formula, converting an ROI image into a binary image by using the segmentation threshold value, segmenting a hole target and a background plane, performing morphological open operation processing of a template 5 x 5 on the binary image, removing partial disordered points in the binary image, performing contour extraction on the binary image after removing the disordered points, evaluating geometric features such as the area and the length-width ratio of each contour region, segmenting and marking each scattered spot on the binary image, and finally calculating the centroid coordinate and the centroid formula of each scattered spot on a reference image according to the marked region of each scattered spot:

and finally, calculating to obtain the centroid offset between the speckle points with corresponding numbers. It should be noted that the relative centroid shift is calculated only when the screened outline positions of the image to be measured and the reference image exist.

Specifically, as shown in fig. 7(a), a schematic diagram of an effect of a centroid offset of the reference plane and the scattering spot on the target surface to be measured is shown, and a schematic diagram of a calculation of a height value of the scattering spot on the reference plane and the target surface to be measured is shown in fig. 7 (b). In this embodiment of the application, the height information obtaining circuit 142 is further configured to calculate, by using a calibration formula, a calibration parameter and a centroid offset of each speckle point transmitted by the system calibration device 130 to obtain a height value of each speckle point relative to a reference datum plane, where the calculation process is as follows:

according to the set of centroid offsets obtained in the formula (4), and the set of centroid offsets between the speckle points with corresponding numbers in each ROI; a linear relationship of the lateral offset dx of the corresponding number to the different height references is constructed. The abscissa is different reference heights, and the ordinate is a set of lateral offsets dx of corresponding numbers under different height references. The linear fitting principle is as follows:

fitting the obtained K value to construct delta x as Kz, wherein z is longitudinal displacement; this principle satisfies the triangulation principle. And obtaining the K value set of each numbered speckle point and different references in the same way.

And fitting a plane equation with independent variables of dx and dy and dependent variable of K according to the calibration data set (dx, dy, K), wherein the least square fitting plane equation is as follows:

wherein, the plane equation is constructed as follows: a is₀*x+a₁*y+a₂The linear matrix equation obtained by the least squares principle is as follows:

wherein, solving the matrix equation to obtain a₀，a₁，a₂The value of (c). From the above equation (6), K values at any dx and dy in the range of the calibration height can be obtained, and from the equation Δ x — Kz, the calibration relationship between the offset and the height in any speckle-related measurement can be obtained.

Referring to fig. 8, which is a schematic flow chart of a three-dimensional measurement method based on pseudo-random speckles disclosed in an embodiment of the present application, the three-dimensional measurement system based on pseudo-random speckles in the embodiments shown in fig. 1 to 7(b) measures an object to be measured by the following three-dimensional measurement method, so as to effectively improve the measurement efficiency, measurement accuracy, and measurement speed of the three-dimensional measurement system based on pseudo-random speckles. As shown in fig. 8, the pseudo-random speckle-based measurement method at least includes the following steps.

And S10, respectively acquiring the speckle images of the reference datum plane and the surface of the object to be measured.

In this embodiment, please refer to fig. 2, the image acquiring device 110 acquires the speckle images of the reference plane and the target surface under different conditions, and transmits the speckle images of the reference plane and the target surface to the image preprocessing device 120. Specifically, referring to the schematic optical path diagram of the three-dimensional measurement system shown in fig. 3, the image acquisition device 110 can control the on or off of the speckle generator and the preset function of the camera unit through the control device on the basis of a preset control algorithm, and acquire the speckle images of the reference plane and the speckle images of the target surface to be measured under different conditions according to the measurement requirements. Wherein the control device may be the personal computer, and the image pickup unit may be a camera. In the embodiment of the present application, the image capturing apparatus 110 may include a plurality of camera units, and each of the camera units may be a three-dimensional (3D) camera.

In the embodiment of the present application, referring to fig. 9 in combination with fig. 2 and fig. 5, the step S10 at least includes the following steps.

And S11, acquiring speckle images of the reference datum plane under different conditions.

In this embodiment, the first image obtaining circuit 111 collects speckle images of the reference plane under different conditions, and transmits the speckle images of the reference plane to the image preprocessing device 120.

And S12, collecting speckle images of the surface of the object to be measured under different conditions.

In this embodiment, the second image obtaining circuit 112 collects speckle images of the surface of the object to be measured under different conditions, and transmits the speckle images of the surface of the object to be measured to the image preprocessing device 120.

And S20, processing images according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots.

In this embodiment, referring to fig. 1 and fig. 2, the image preprocessing device 120 performs image processing according to the speckle image of the reference plane and the speckle image of the surface of the object to be measured, which are acquired by the image acquisition device 110, and transmits the processed speckle images of the reference plane to the system calibration device 130 and the height calculation device 140, and simultaneously transmits the processed speckle images of the surface of the object to be measured to the height calculation device 140.

In the embodiment of the present application, referring to fig. 10 in combination with fig. 2 and fig. 5, the step S20 at least includes the following steps.

And S21, preprocessing the speckle image of the reference datum plane to obtain the centroid coordinate of the scattered spots and the preprocessed speckle image of the reference datum plane.

Specifically, the first image preprocessing circuit 121 preprocesses the speckle image of the reference plane transmitted by the first image acquisition circuit 111 to obtain the centroid coordinate of the scattered spot, and transmits the preprocessed speckle image of the reference plane and the centroid coordinate of the scattered spot to the system calibration device 130 and the height calculation device 140.

In this embodiment of the application, the first image preprocessing circuit 121 performs image filtering processing on the speckle image of the reference plane by using a gaussian filtering method (for example, performs 5 × 5 gaussian filtering on the image), so as to eliminate background noise on the speckle image of the reference plane, and obtain the speckle image of the reference plane after the image filtering processing. Then, the gray level distribution condition of the speckle images of the reference plane after the image filtering processing is known through counting the gray level histogram of the speckle images of the reference plane after the image filtering processing of the filtered image, and the gray level enhancement operation is performed on the speckle images of the reference plane after the image filtering processing, so that the speckle points at the part darker area on the image can be normally identified, and a gray level enhanced image is obtained. And then, carrying out image sharpening on the speckle image of the reference datum plane by adopting a Sobel differential operator to enable the edge of each scattered spot on the speckle image of the reference datum plane to be better clear so as to obtain a sharpened image, and selecting a proper differential operator according to the shape of the pseudorandom scattered spots in the specific implementation process so as to ensure that the edge shape of the scattered spots cannot be changed. And finally, determining an optimal binarization segmentation threshold value of the sharpened image by adopting an Otsu principle adaptive threshold value calculation method, converting the sharpened image into a binarization image by using the segmentation threshold value, performing relevant morphological processing on the binarization image, removing partial disordered points in the binarization image to obtain a clean binarization image, performing contour extraction on the binarization image after the disordered points are removed, and evaluating geometric characteristics such as the area, the length-width ratio and the like of each contour region to segment and mark each scattered spot on the binarization image. And finally, calculating the centroid coordinate of each scattered spot on the reference image according to the marked area of each scattered spot to obtain a speckle point positioning image.

S22, preprocessing the speckle image of the surface of the target to be detected to obtain the centroid coordinates of the scattered spots and the preprocessed speckle image of the surface of the target to be detected.

Specifically, the second image preprocessing circuit 122 preprocesses the speckle image of the surface of the object to be detected transmitted by the second image acquiring circuit 112 to obtain the centroid coordinate of the scattered spot, and transmits the preprocessed speckle image of the surface of the object to be detected and the centroid coordinate of the scattered spot to the height calculating device 140.

And S30, obtaining corresponding calibration parameters according to the speckle image of the reference datum plane.

In this embodiment, referring to fig. 1 and fig. 2, the system calibration device 130 processes and calculates the speckle image of the reference plane transmitted by the image preprocessing device 120 to obtain corresponding calibration parameters, and transmits the processed and calculated calibration parameters to the height calculation device 140.

And S40, matching the preprocessed reference plane speckle image with the preprocessed target surface speckle image to be detected.

In this embodiment, referring to fig. 5, the speckle image matching circuit 141 matches the preprocessed reference plane speckle image transmitted by the first image preprocessing circuit 121 with the preprocessed reference plane speckle image transmitted by the second image preprocessing circuit 122, and transmits a matching result to the height information obtaining circuit 142.

Specifically, in this embodiment of the application, the speckle image matching circuit 141 completes the preliminary matching between the preprocessed reference plane speckle image transmitted by the first image preprocessing circuit 121 and the preprocessed target surface speckle image transmitted by the second image preprocessing circuit 122 according to an image correlation algorithm, so as to realize the alignment of each effective scattered spot on the reference plane speckle image and the target surface speckle image. In the specific implementation process, according to the speckle distribution condition of the pseudo-random speckles, proper image windows are sequentially selected on the reference image and the image to be detected to perform image correlation calculation. Because the speckle distribution of the pseudo-random speckles can present sparse and dense situations, the size of an image window needs to be adjusted in a self-adaptive manner, for example, 20 × 100, at least more than 5 scattered speckles exist in the window area, and the accuracy of image correlation calculation is ensured.

And S50, calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the target to be measured.

In the embodiment of the present application, referring to fig. 5, the height information obtaining circuit 142 calculates a centroid offset according to the centroid coordinates of the scattered spots transmitted by the first image preprocessing circuit 121 and the second image preprocessing circuit 122.

and finally, calculating to obtain the centroid offset between the speckle points with corresponding numbers. It should be noted that the relative centroid offset is calculated only when the screened outline positions of the image to be measured and the reference image exist.

And S60, calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters and the mass center offset of each scattered speckle point on the speckle image of the reference datum plane.

In this embodiment, the height information obtaining circuit 142 calculates a height value of each speckle point relative to the reference plane according to the calibration parameter of each scattered spot on the speckle image of the reference plane transmitted by the system calibration device 130, and transmits the obtained height value of each speckle point relative to the reference plane to the three-dimensional data processing device 150.

And S70, obtaining the three-dimensional profile information of the surface of the object to be detected according to the height value of each speckle point on the speckle image of the surface of the object to be detected relative to the reference datum plane.

In the embodiment of the present application, referring to fig. 1 and fig. 5, the three-dimensional data processing device 150 processes the height value of each speckle point on the speckle image of the target surface to be detected, which is transmitted by the height calculating device 140, relative to the reference datum plane to obtain the three-dimensional profile information of the target surface to be detected, and analyzes and detects the three-dimensional profile information of the target surface to be detected.

In summary, in the three-dimensional measurement method based on the pseudo-random speckles, the speckle images of the reference plane and the surface of the object to be measured are respectively collected; performing image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots; obtaining corresponding calibration parameters according to the speckle images of the reference datum plane; matching the preprocessed speckle image of the reference datum plane with the preprocessed speckle image of the surface of the target to be detected; calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the object to be detected; calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters of each scattered speckle point on the speckle image of the reference datum plane and the mass center offset; and obtaining the three-dimensional profile information of the surface of the target to be detected according to the height value of each speckle point on the speckle image of the surface of the target to be detected relative to the reference datum plane. Therefore, the three-dimensional measurement method based on the pseudo-random speckles can quickly and efficiently acquire the high-precision full-field surface profile height information at one time, and solves the problems of low measurement precision, low processing speed, low detection efficiency and the like in the prior art when the structured light three-dimensional measurement technology acquires the full-field surface profile height information.

Please refer to fig. 11, which is a schematic diagram of a hardware structure of a three-dimensional measurement apparatus based on pseudo-random speckle according to an embodiment of the present disclosure. As shown in fig. 11, the pseudo-random speckle-based three-dimensional measurement apparatus 200 provided by the embodiment of the present application includes at least one processor 201 and a memory 202. The pseudo-random speckle based three-dimensional measurement device 200 further comprises at least one bus 203. The processor 201 and the memory 202 are electrically connected by a bus 203. The pseudo-random speckle-based three-dimensional measurement device 200 may be a computer or a server, and the present application is not limited thereto.

The pseudo-random speckle based three-dimensional measurement device 200 may further include a pseudo-random speckle based three-dimensional measurement system as in the embodiments shown in fig. 1 to 7(b) above. In a specific implementation process, the at least one processor 201 executes the computer-executable instructions stored in the memory 202, so that the at least one processor 201 executes the three-dimensional measurement method of the pseudo-random speckle-based three-dimensional measurement system according to the embodiment shown in fig. 8 to 10 by using the pseudo-random speckle-based three-dimensional measurement system.

For a specific implementation process of the processor 201 provided in the embodiment of the present application, reference may be made to the embodiments of the three-dimensional measurement method of the three-dimensional measurement system based on pseudo-random speckle described in the embodiments of fig. 8 to 10, and the implementation principle and the technical effect are similar, which are not described herein again.

It is understood that the Processor 201 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method provided in connection with the present application may be embodied directly in a hardware processor, or in a combination of the hardware and software modules included in the processor.

The Memory 202 may be a Random Access Memory (RAM) or a Non-Volatile Memory (NVM).

The bus 203 may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (enhanced Industry Standard Architecture) bus, or the like. For ease of illustration, the bus 203 in the figures of the present application is not limited to only one bus or one type of bus.

It should be understood that the application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims.

Claims

1. A three-dimensional measuring system based on pseudo-random speckles is characterized by comprising an image acquisition device, an image preprocessing device, a system calibration device, a height calculation device and a three-dimensional data processing device,

the image acquisition device is electrically connected with the image preprocessing device and is used for acquiring a speckle image of a reference plane and a speckle image of the surface of the target to be detected and transmitting the speckle image of the reference plane and the speckle image of the surface of the target to be detected to the image preprocessing device;

the image preprocessing device is electrically connected with the system calibration device and the height calculation device, and is used for performing image processing according to the speckle images of the reference base plane and the surface of the object to be measured, transmitting the processed speckle images of the reference base plane to the system calibration device and the height calculation device, and transmitting the processed speckle images of the surface of the object to be measured to the height calculation device;

the system calibration device is electrically connected with the height calculation device and is used for obtaining corresponding calibration parameters according to the speckle images of the reference datum plane and transmitting the calibration parameters to the height calculation device;

the height calculating device is electrically connected with the three-dimensional data processing device and is used for obtaining corresponding mass center offset according to the processed speckle image of the reference datum plane and the processed speckle image of the surface of the target to be detected, calculating the mass center offset by combining the mass center offset with calibration parameters of each scattered spot to obtain a height value of each scattered spot on the speckle image of the surface of the target to be detected relative to the reference datum plane, and transmitting the obtained height value to the three-dimensional data processing device;

and the three-dimensional data processing device is used for obtaining the three-dimensional contour information of the surface of the target to be detected according to the height value of each scattered spot relative to the reference datum plane, and analyzing and detecting the three-dimensional contour information of the surface of the target to be detected.

2. The pseudo-random speckle based three-dimensional measurement system of claim 1, wherein the image acquisition device comprises a first image acquisition circuit and a second image acquisition circuit, wherein,

the first image acquisition circuit is electrically connected with the image preprocessing device and is used for acquiring speckle images of the reference datum plane under different conditions and transmitting the speckle images of the reference datum plane to the image preprocessing device;

the second image acquisition circuit is electrically connected with the image preprocessing device and is used for acquiring the speckle images of the surface of the object to be detected under different conditions and transmitting the speckle images of the surface of the object to be detected to the image preprocessing device.

3. The pseudo-random speckle based three-dimensional measurement system of claim 2, wherein the image pre-processing means comprises a first image pre-processing circuit and a second image pre-processing circuit, wherein,

the first image preprocessing circuit is electrically connected with the first image acquisition circuit, the system calibration device and the height calculation device, and is used for preprocessing the speckle image of the reference datum plane to obtain the centroid coordinate of the scattered spots and transmitting the preprocessed speckle image of the reference datum plane and the centroid coordinate of the scattered spots to the system calibration device and the height calculation device;

the second image preprocessing circuit is electrically connected with the second image acquisition circuit and the height calculation device, and is used for preprocessing the speckle image of the surface of the target to be detected to obtain the centroid coordinate of the scattered spot, and transmitting the preprocessed speckle image of the surface of the target to be detected and the centroid coordinate of the scattered spot to the height calculation device.

4. The pseudo-random speckle based three-dimensional measurement system of claim 3, wherein the height calculation means comprises a speckle image matching circuit and a height information acquisition circuit, wherein,

the speckle image matching circuit is electrically connected with the first image preprocessing circuit, the second image preprocessing circuit and the height information acquisition circuit, and is used for matching the preprocessed speckle images of the reference datum plane with the preprocessed speckle images of the surface of the target to be detected and transmitting the matching result to the height information acquisition circuit;

the height information acquisition circuit is electrically connected with the system calibration device, the speckle image matching circuit and the three-dimensional data processing device, and is used for calculating to obtain a mass center offset according to mass center coordinates of the scattered spots, calculating to obtain height values of the scattered spots relative to the reference datum plane according to calibration parameters of the scattered spots on the speckle image of the reference datum plane, and transmitting the obtained height values of the scattered spots relative to the reference datum plane to the three-dimensional data processing device.

5. The pseudo-random speckle based three-dimensional measurement system according to claim 4, wherein the image preprocessing device is further configured to separately locate each scattered spot on the speckle image of the reference plane and the speckle image of the target surface to be measured, and separately number each scattered spot according to the coordinate distribution of the speckle image of the reference plane and the speckle image of the target surface to be measured.

6. The pseudo-random speckle based three-dimensional measurement system of claim 4, wherein the system calibration means is further configured to detect a repetitive pattern of speckle images of the reference plane transmitted by the image preprocessing means.

7. The pseudo-random speckle-based three-dimensional measurement system according to claim 4, wherein the three-dimensional data processing device is further configured to perform three-dimensional reconstruction and data analysis on the height values of the speckle points on the speckle images of the target surface to be measured transmitted by the height calculation device with respect to a reference datum plane, and perform combination stitching and local predetermined area mapping on the height values of the scattered speckles on the speckle images of all the target surface to be measured to obtain the three-dimensional profile information of the target surface to be measured.

8. The pseudo-random speckle-based three-dimensional measurement system according to any one of claims 1 to 7, wherein the centroid offset is the centroid offset of a speckle point in the speckle image of the object surface to be measured relative to the speckle image of the reference plane.

9. The pseudo-random speckle based three-dimensional measurement system according to any one of claims 1-7, further comprising a personal computer, a camera, a speckle generator, a calibration block, and a data cable, wherein the personal computer, the camera, and the speckle generator are electrically connected by the data cable.

10. A three-dimensional measuring method based on pseudo-random speckle, which is performed by the three-dimensional measuring system of any one of claims 1 to 9, wherein the three-dimensional measuring method comprises:

respectively collecting speckle images of a reference plane and a target surface to be detected;

performing image processing according to the speckle images of the reference datum plane and the speckle images of the surface of the target to be measured to obtain the centroid coordinates of the corresponding scattered spots;

obtaining corresponding calibration parameters according to the speckle images of the reference datum plane;

matching the preprocessed speckle image of the reference datum plane with the preprocessed speckle image of the surface of the target to be detected;

calculating the centroid offset according to the speckle images of the reference datum plane and the centroid coordinates of the scattered spots in the speckle images of the surface of the target to be measured;

calculating the height value of each speckle point relative to the reference datum plane according to the calibration parameters of each scattered speckle point on the speckle image of the reference datum plane and the mass center offset;

and obtaining the three-dimensional profile information of the surface of the target to be detected according to the height value of each speckle point on the speckle image of the surface of the target to be detected relative to the reference datum plane.

11. The pseudo-random speckle-based three-dimensional measuring method according to claim 10, wherein the collecting the speckle image of the reference plane and the speckle image of the surface of the object to be measured separately comprises:

collecting speckle images of the reference datum plane under different conditions;

and collecting speckle images of the surface of the target to be measured under different conditions.

12. The pseudo-random speckle based three-dimensional measuring method according to claim 11, wherein the image processing according to the speckle image of the reference base plane and the speckle image of the object surface to be measured to obtain the centroid coordinates of the corresponding scattered spots comprises:

preprocessing the speckle image of the reference datum plane to obtain the centroid coordinates of the scattered spots and the preprocessed speckle image of the reference datum plane;

and preprocessing the speckle image of the surface of the target to be detected to obtain the centroid coordinates of the scattered spots and the preprocessed speckle image of the surface of the target to be detected.

13. A three-dimensional measuring device based on pseudo-random speckle, comprising: at least one processor and storage, at least one of the processor executing computer-executable instructions stored by the storage, at least one of the processor executing the pseudo-random speckle based three-dimensional measuring method of any one of claims 10 to 12.