阅读说明：本技术 一种无线摄影测量系统及其测量方法 (Wireless photogrammetry system and measurement method thereof ) 是由 郑顺义 王晓南 成剑华 任关宝 张吉锦 于 2021-07-21 设计创作，主要内容包括：本发明涉及一种无线摄影测量系统及其测量方法,无线摄影测量系统包括：无线扫描仪和软件客户端；无线扫描仪包括图像采集终端、扫描模块、无线传输模块和电源；图像采集终端拍摄标志点的图像；扫描模块提取图像上各个标志点及其在图像上的位置,通过无线传输模块将各个标志点的位置发送给软件客户端；电源为无线扫描仪提供工作用电源；软件客户端接收各个标志点在图像上的位置,根据图像采集终端位置点、标志点和成像点三点共线原理确定各个标志点的坐标；通过网络传输图像到软件,用电池支持扫描仪工作,使扫描仪可以摆脱线缆,达到去掉电源数据线缆的目的,从而解决进行摄影测量时需要拖着线缆、工作效率降低的问题,工作起来更灵活,高效。(The invention relates to a wireless photogrammetry system and a measurement method thereof, wherein the wireless photogrammetry system comprises: a wireless scanner and a software client; the wireless scanner comprises an image acquisition terminal, a scanning module, a wireless transmission module and a power supply; the image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of each mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module; the power supply provides a working power supply for the wireless scanner; the software client receives the positions of all the mark points on the image, and determines the coordinates of all the mark points according to the collinear principle of three points, namely the position point of the image acquisition terminal, the mark points and the imaging points; the image is transmitted to the software through the network, the work of the scanner is supported by the battery, so that the scanner can get rid of the cable, and the purpose of removing a power supply data cable is achieved, thereby solving the problems that the cable needs to be dragged and the work efficiency is reduced when the photogrammetry is carried out, and the work is more flexible and efficient.)

1. A wireless photogrammetry system, the wireless photogrammetry system comprising: a wireless scanner and a software client;

the wireless scanner comprises an image acquisition terminal, a scanning module, a wireless transmission module and a power supply;

the image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of the mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module; the power supply provides working power supply for the wireless scanner;

and the software client receives the positions of the mark points on the image, and determines the coordinates of the mark points according to the collinear principle of three points, namely the position point of the image acquisition terminal, the mark points and the imaging points.

2. The wireless photogrammetry system of claim 1 wherein the process of the scanning module extracting each of the marker points and their positions on the image comprises:

resampling the image to improve the contrast of the image;

and determining the number of the ellipses in the image and the central coordinates of each ellipse.

3. The system of claim 1, wherein the software client determines coordinates of the landmark points after stitching the landmark points, and wherein determining the coordinates of the landmark points after stitching the landmark points comprises:

and copying each mark point to a memory, coding and identifying each mark point in the memory, and determining the number and the coordinates of the extracted mark points through a fusion algorithm.

4. The system of claim 1 or 3, wherein the software client is configured to establish an object space coordinate system and an image space coordinate system, the object space coordinate system is a space coordinate system in which the image capturing terminal position point, the marker point and the imaging point are located, and the image space coordinate system is a coordinate system with the image capturing terminal position point as an origin;

and determining the coordinates of the mark points according to the collinear principle of the position points, the mark points and the imaging points of the image acquisition terminal and the corresponding relation of the object space coordinate system and the image space coordinate system.

5. The wireless photogrammetry system of claim 4,

the corresponding relation between the object space coordinate system and the image space coordinate system is as follows:

wherein (X, Y, -f) and (X, Y, Z) are coordinates of the imaging point in the image space coordinate system and the object space coordinate system, respectively,is an unit orthogonal matrix;

the general equation of the collinearity of the three points of the image acquisition terminal position point, the mark point and the imaging point is as follows:

wherein (X)_A，Y_A，Z_A) And (X)_s，Y_s，Z_s) And the coordinates of the image acquisition terminal position point and the mark point in the object space coordinate system are respectively.

6. The system according to claim 1, wherein the wireless transmission module is a WiFi module, and before the image capturing terminal captures the image of the landmark point, the WiFi module is automatically connected to configured WiFi, and after a connection relationship with the software client is created, a working thread is created to start working of the wireless scanner.

7. A measurement method of a wireless photogrammetry system, the wireless photogrammetry system comprising: a wireless scanner and a software client; the wireless scanner comprises an image acquisition terminal, a scanning module and a wireless transmission module;

the measuring method comprises the following steps:

step 1, the wireless transmission module establishes a connection relation with the software client;

step 2, the image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of the mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module;

and the software client receives the positions of the mark points on the image, and determines the coordinates of the mark points according to the collinear principle of three points, namely the position point of the image acquisition terminal, the mark points and the imaging points.

8. The measurement method according to claim 7, wherein the step 1 comprises:

step 101, starting up the wireless scanner, automatically connecting configured WIFI, creating a network server, and waiting for connection;

102, starting the software client, establishing the client after connecting WI-FI, and requesting to establish a connection relation with the wireless scanner;

103, after the connection relation between the software client and the wireless scanner is established, sending a message inspection device;

104, after receiving an acquisition instruction input by a user, the software client creates a working thread and informs the wireless scanner of creating the working thread;

step 105, the wireless scanner creates a worker thread.

Technical Field

The invention relates to the technical field of measurement scanners, in particular to a wireless photogrammetry system and a measurement method thereof.

Background

The development of high-end manufacturing industry has higher requirements on product quality, so that the measurement and detection of industrial products have higher requirements, and the measurement and detection of industrial products are light and handy, portable, real-time and intelligent in processing and good in human-computer interaction are all considered.

The types of high-precision photogrammetry systems currently available are divided into two categories: the wired photogrammetric scanning system is an offline photogrammetric system which takes a high-definition digital camera as an auxiliary. The wired photogrammetry system scans the mark points, the measurement precision is high, but for some scenes with a large number of mark points deployed in a large range, the problem that long cables are needed to be used in a connected mode and the flexibility is not high exists. The offline photogrammetry system separates shooting and measurement, cannot calculate in real time, cannot feed back the measurement progress in real time, and is not high in working efficiency.

Disclosure of Invention

The invention provides a wireless photogrammetry system and a measurement method thereof, aiming at the technical problems in the prior art, on the basis of using a wired scanner, by adding hardware equipment, transmitting images to software through a network and supporting the scanner to work by a battery, the scanner can get rid of cables, thereby solving the problems that the cables need to be dragged and the working efficiency is reduced when the photogrammetry is carried out, and the work is more flexible and efficient. The problem that the service efficiency is low in a large scene, the precision is low, the measured pain point cannot be observed in real time in an off-line mode can be solved, and the use of a user is greatly facilitated. The working efficiency is improved, and a data basis is provided for high-precision measurement or scanning of large workpieces.

According to a first aspect of the present invention, there is provided a wireless photogrammetry system comprising: a wireless scanner and a software client;

the wireless scanner comprises an image acquisition terminal, a scanning module, a wireless transmission module and a power supply;

the image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of the mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module; the power supply provides working power supply for the wireless scanner;

and the software client receives the positions of the mark points on the image, and determines the coordinates of the mark points according to the collinear principle of three points, namely the position point of the image acquisition terminal, the mark points and the imaging points.

On the basis of the technical scheme, the invention can be improved as follows.

Optionally, the process of extracting each of the mark points and the position thereof on the image by the scanning module includes:

resampling the image to improve the contrast of the image;

and determining the number of the ellipses in the image and the central coordinates of each ellipse.

Optionally, the process of determining the coordinates of the landmark points by the software client after splicing the landmark points includes:

and copying each mark point to a memory, coding and identifying each mark point in the memory, and determining the number and the coordinates of the extracted mark points through a fusion algorithm.

Optionally, the software client establishes an object space coordinate system and an image space coordinate system, the object space coordinate system is a space coordinate system in which the image acquisition terminal position point, the marker point and the imaging point are located, and the image space coordinate system is a coordinate system with the image acquisition terminal position point as an origin;

and determining the coordinates of the mark points according to the collinear principle of the position points, the mark points and the imaging points of the image acquisition terminal and the corresponding relation of the object space coordinate system and the image space coordinate system.

Optionally, the corresponding relationship between the object space coordinate system and the image space coordinate system is as follows:

wherein (X, Y, -f) and (X, Y, Z) are the coordinates of the imaging point in the image space coordinate system and the object space coordinate system, respectively, a₁、b₁、c₁、a₂、b₂、c₂、a₃、b₃、c₃Is a parameter representing a relative positional relationship;

the general equation of the collinearity of the three points of the image acquisition terminal position point, the mark point and the imaging point is as follows:

wherein (X)_A，Y_A，Z_A) And (X)_s，Y_s，Z_s) And the coordinates of the image acquisition terminal position point and the mark point in the object space coordinate system are respectively.

Optionally, the wireless transmission module is a WiFi module, before the image acquisition terminal shoots the image of the landmark point, the WiFi module is automatically connected to configured WiFi, and after a connection relationship with the software client is created, a working thread is created to start the work of the wireless scanner.

According to a second aspect of the present invention, there is provided a measurement method of a wireless photogrammetry system, the wireless photogrammetry system comprising: a wireless scanner and a software client; the wireless scanner comprises an image acquisition terminal, a scanning module and a wireless transmission module;

the measuring method comprises the following steps:

step 1, the wireless transmission module establishes a connection relation with the software client;

step 2, the image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of the mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module;

and the software client receives the positions of the mark points on the image, and determines the coordinates of the mark points according to the collinear principle of three points, namely the position point of the image acquisition terminal, the mark points and the imaging points.

Optionally, step 1 includes:

step 101, starting up the wireless scanner, automatically connecting configured WIFI, creating a network server, and waiting for connection;

102, starting the software client, establishing the client after connecting WI-FI, and requesting to establish a connection relation with the wireless scanner;

103, after the connection relation between the software client and the wireless scanner is established, sending a message inspection device;

104, after receiving an acquisition instruction input by a user, the software client creates a working thread and informs the wireless scanner of creating the working thread;

step 105, the wireless scanner creates a worker thread.

According to the wireless photogrammetry system and the measurement method thereof provided by the embodiment of the invention, the wireless scanner transmits data to the software client through a wireless network to perform calculation, so that high-precision mark point coordinates are obtained. The method adopts a mixed tracking and positioning method integrating marker point tracking and back tracking, and determines the coordinates of the marker points according to the collinear principle of three points of the position point of the image acquisition terminal, the marker points and the imaging points and the corresponding relation of the object space coordinate system and the image space coordinate system by establishing an object space coordinate system and an image space coordinate system. The wireless scanner uses blue light LED light filling.

Drawings

Fig. 1 is a schematic view of a space coordinate of an image acquisition terminal according to an embodiment of the present invention when acquiring an image;

fig. 2 is a flowchart of a measurement method of a wireless photogrammetry system according to an embodiment of the present invention.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

In some usage scenarios, a large number of landmark code points are attached to the surface of a product or object in an uncertain manner, for which the coordinates are unknown, requiring measurement calculations. The invention provides a wireless photogrammetry system, comprising: a wireless scanner and a software client.

The wireless scanner comprises an image acquisition terminal, a scanning module, a wireless transmission module and a power supply.

The image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of each mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module. The power supply provides operating power for the wireless scanner.

In specific implementation, the wireless scanner uses a blue LED for light supplement. The image acquisition terminal can use a high-resolution camera, focus about 1200mm, meet photogrammetry conditions, and can clearly shoot the coding points so as to calculate the coordinates of the mark points.

The wireless transmission module can be a wireless network card, the wireless network card is communicated with the software client through the wireless router, the shot image is transmitted to the software client, specific calculation is carried out, and the three-dimensional coordinates of the mark points are determined.

Furthermore, the power supply is a battery for supplying power to the camera and the wireless network card, so that the wireless scanner can work normally. The embedded system controls the camera and the battery, controls the acquisition work and the image transmission of the camera, and manages the charging process.

And the software client receives the positions of the mark points on the image and determines the coordinates of the mark points according to the collinear principle of the position point of the image acquisition terminal, the mark points and the imaging points.

On the basis of using the wired scanner, hardware equipment is added, images are transmitted to software through a network, and the scanner is supported by a battery to work, so that the scanner can get rid of cables, the problems that the cables need to be dragged and the working efficiency is reduced when photogrammetry is carried out are solved, and the work is more flexible and efficient. The problem that the service efficiency is low in a large scene, the precision is low, the measured pain point cannot be observed in real time in an off-line mode can be solved, and the use of a user is greatly facilitated. The working efficiency is improved, and a data basis is provided for high-precision measurement or scanning of large workpieces.

Example 1

Embodiment 1 provided in the present invention is an embodiment of a wireless photogrammetric system provided in the present invention, and the embodiment includes: a wireless scanner and a software client.

The wireless scanner comprises an image acquisition terminal, a scanning module and a wireless transmission module.

The image acquisition terminal shoots an image of the mark point; the scanning module extracts each mark point on the image and the position of each mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module.

In a possible embodiment, the process of the scanning module extracting each mark point and its position on the image includes:

resampling the image improves the contrast of the image.

The number of ellipses in the image and the central coordinates of each ellipse are determined.

The standard landmark points are circles, which is mathematically a special case of an ellipse. The wireless scanner pre-processes the image to reduce the amount of data. When the acquired image is used as preview, the compression ratio is higher, and the image quality is lower.

And the software client receives the positions of the mark points on the image and determines the coordinates of the mark points according to the collinear principle of the position point of the image acquisition terminal, the mark points and the imaging points. In a possible embodiment, the process of determining the coordinates of the landmark points after splicing the landmark points by the software client includes:

and copying each mark point to the memory, coding and identifying each mark point in the memory, and determining the number and the coordinates of the extracted mark points through a fusion algorithm.

In specific implementation, the mark points adopt partially coded mark points and non-coded mark points. The transmitted mark points on the image are two-dimensional mark points, and the extracted coordinates of the mark points are the coordinates of the three-dimensional mark points.

It can be understood that the software client establishes an object space coordinate system and an image space coordinate system, the object space coordinate system is a space coordinate system in which the image acquisition terminal position point, the marker point and the imaging point are located, and the image space coordinate system is a coordinate system with the image acquisition terminal position point as an origin.

And determining the coordinates of the mark points according to the collinear principle of the position points, the mark points and the imaging points of the image acquisition terminal and the corresponding relation of an object space coordinate system and an image space coordinate system.

Fig. 1 is a schematic diagram of spatial coordinates when an image is acquired by an image acquisition terminal according to an embodiment of the present invention.

Referring to fig. 1, the image capturing terminal location point S has a coordinate (X) in the object space coordinate system_s，Y_s，Z_s) A is any object space point with the coordinate (X) in the object space coordinate system_A，Y_A，Z_A). a is the image formation of A on the image, and the corresponding image space coordinates and image space auxiliary coordinates are (X, Y, -f) and (X, Y, Z), respectively. When the S, A, a three points are located on a straight line during photographing, the image space auxiliary coordinates of the imaging point and the object space coordinates of the object space point have the following relationship.

Can therefore obtain

Where λ is equal to γ, is a dimensionless coefficient, representing a continuous equation relationship.

The image space coordinates have the following relationship with the image space auxiliary coordinates:

wherein the content of the first and second substances,is an orthonormal matrix of units.

Unfolding the above formula to obtain

Substituting the formula of the first step into the formula of the second step can obtain a general equation with three points collinear:

in a possible embodiment, the wireless transmission module is a WiFi module, before the image acquisition terminal shoots the image of the mark point, the WiFi module is automatically connected with configured WiFi, and after a connection relation with the software client is created, a working thread is created to start the work of the wireless scanner.

Example 2

Embodiment 2 of the present invention is an embodiment of a measurement method of a wireless photogrammetry system provided by the present invention, the wireless photogrammetry system is a wireless photogrammetry system provided by embodiment 1 of the present invention, as shown in fig. 2, which is a flowchart of a measurement method of a wireless photogrammetry system provided by an embodiment of the present invention, and as can be seen by referring to fig. 2, the embodiment of the measurement method of the wireless photogrammetry system includes:

step 1, the wireless transmission module creates and establishes a connection relation with the software client.

In one possible embodiment, step 1 includes:

step 101, starting up a wireless scanner, automatically connecting configured WIFI, creating a network server, and waiting for connection.

And 102, starting the software client, establishing the client after connecting the WI-FI, and requesting to establish a connection relation with the wireless scanner.

And 103, after the connection relation between the software client and the wireless scanner is established, sending a message to the inspection equipment.

And 104, after receiving the acquisition instruction input by the user, the software client creates a working thread and informs the wireless scanner to create the working thread.

Step 105, the wireless scanner creates a worker thread.

Step 2, the image acquisition terminal shoots the image of the mark point; the scanning module extracts each mark point on the image and the position of each mark point on the image, and sends the position of each mark point to the software client through the wireless transmission module.

And 3, receiving the positions of the mark points on the image by the software client, and determining the coordinates of the mark points according to the collinear principle of the position points, the mark points and the imaging points of the image acquisition terminal.

And when the work is finished, the software end thread stops working, and the wireless scanner thread stops working.

In the above description, steps 2 and 3 are repeated to collect all the marker points.

It is to be understood that the wireless photogrammetry method provided by the present invention corresponds to the wireless photogrammetry systems provided in the foregoing embodiments, and the relevant technical features of the wireless photogrammetry method can refer to the relevant technical features of the wireless photogrammetry system, which are not described herein again.

According to the wireless photogrammetry system and the measurement method thereof provided by the embodiment of the invention, the wireless scanner transmits data to the software client through a wireless network to perform calculation, so that high-precision mark point coordinates are obtained. The method adopts a mixed tracking and positioning method integrating marker point tracking and back tracking, and determines the coordinates of the marker points according to the collinear principle of three points of the position point of the image acquisition terminal, the marker points and the imaging points and the corresponding relation of the object space coordinate system and the image space coordinate system by establishing an object space coordinate system and an image space coordinate system. The wireless scanner uses blue light LED light filling.

It should be noted that, in the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to relevant descriptions of other embodiments for parts that are not described in detail in a certain embodiment.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.