All-day field astronomical measurement system calibration method and device

Abstract

The embodiment of the invention discloses an all-time field astronomical measurement system calibration method and device. A specific embodiment of the method comprises the following steps: setting an infrared control point with a fixed position; controlling the all-day field astronomical measurement system to perform back-measurement observation on the infrared control points from a plurality of observation directions to obtain an observation data set; and according to the observation data set and a pre-constructed observation equation, through a least square method, carrying out measurement calibration to obtain a horizontal direction value and a vertical direction value corresponding to the infrared control point, a camera main distance, a first-order radial distortion coefficient and an image plane rotation angle, and respectively carrying out disc left image main point coordinate calibration and disc right image main point coordinate calibration. According to the embodiment, high-precision camera parameters can be obtained.

Description

Technical Field

[0001] The embodiments disclosed herein relate to the fields of astronomical geodesy and astronomical navigation, specifically to a method and apparatus for calibrating an all-weather field astronomical measurement system. Background Technology

[0002] Astronomical surveying boasts advantages such as strong autonomy, good concealment, strong anti-interference capabilities, and high directional accuracy. It plays a crucial role in various professional fields, including ground reference system positioning and orientation, geoid shape determination, and engineering orientation. To reduce human error and improve measurement efficiency, most mainstream astronomical surveying equipment currently uses cameras to replace human aiming. However, because the sensors equipped with these devices only detect visible light, image quality is affected by strong sunlight, cloud absorption, and scattering, making all-weather astronomical measurements impossible.

[0003] The information disclosed in this background section is only intended to enhance the understanding of the background of the inventive concept, and therefore may contain information that does not form prior art known to those skilled in the art. Summary of the Invention

[0004] The summary portion of this disclosure is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description portion. This summary portion is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0005] Some embodiments of this disclosure propose a method and apparatus for calibrating an all-weather field astronomical measurement system to solve the technical problems mentioned in the background section above.

[0006] In a first aspect, some embodiments of this disclosure provide a calibration method for an all-weather field astronomical measurement system, the method comprising: setting up infrared control points with fixed locations. Among them, infrared control points Corresponding horizontal value and vertical direction value The calibration process remained unchanged; the all-weather field astronomical measurement system was controlled from multiple observation directions, focusing on the infrared control points. A series of observations were conducted to obtain a set of observation data, which includes: left-side observation data and right-side observation data. The left-side observation data includes: horizontal observation values. Vertical observation values and image collection Right-hand observation data includes: horizontal observation values Vertical observation values and image collection ; according to the observation data set and the pre-constructed observation equation, the measurement check is performed by the least square method to obtain the corresponding horizontal direction value and vertical direction value of the infrared control point , camera principal distance , first-order radial distortion coefficient and image plane rotation angle ; according to the corresponding horizontal direction value and vertical direction value of the infrared control point , camera principal distance , first-order radial distortion coefficient and image plane rotation angle , the left image principal point coordinate check and the right image principal point coordinate check are respectively performed.

[0007] In the second aspect, some embodiments of the present disclosure provide a calibration device for an all-weather field astronomical measurement system, the device comprising: a setting unit configured to set a fixed-position infrared control point , wherein the corresponding horizontal direction value and vertical direction value of the infrared control point remain unchanged during the calibration process; a control unit configured to control the all-weather field astronomical measurement system to perform measurement observation on the infrared control point from at least one observation direction to obtain an observation data set, wherein the observation data comprises: left disc observation data and right disc observation data, wherein the left disc observation data comprises: horizontal direction observation value , vertical direction observation value and image set , and the right disc observation data comprises: horizontal direction observation value , vertical direction observation value and image set ; a measurement check unit configured to perform measurement check according to the observation data set and the pre-constructed observation equation by the least square method to obtain the corresponding horizontal direction value and vertical direction value of the infrared control point , camera principal distance , first-order radial distortion coefficient and image plane rotation angle ; a left disc check and right disc check unit configured to perform left disc check and right disc check according to the corresponding horizontal direction value and vertical direction value of the infrared control point , camera principal distance , first-order radial distortion coefficient and image plane rotation angle The principal point coordinates of the left-side image and the principal point coordinates of the right-side image were checked separately.

[0008] Thirdly, some embodiments of this disclosure provide an electronic device, including: one or more processors; and a storage device having one or more programs stored thereon, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method described in any implementation of the first aspect above.

[0009] Fourthly, some embodiments of this disclosure provide a computer-readable medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the method described in any of the implementations of the first aspect above.

[0010] The above embodiments of this disclosure have the following beneficial effects: Through the all-weather field astronomical measurement system calibration method of some embodiments of this disclosure, during measurement and calibration, firstly, the principal image point is located as the physical center of the image plane, and the target point (infrared control point) is calculated using observation data. ) Direction value (infrared control point) Corresponding horizontal value and vertical direction value Simultaneously, the principal distance of the (infrared) camera is obtained. First-order radial distortion coefficient and image plane rotation angle Secondly, during the left-hand and right-hand calibration, the target point (infrared control point) is... Using the direction value as a known quantity, the coordinates of the camera's principal point are calculated using observation data from both the left and right sides of the camera. This method is specifically designed for all-weather field astronomical measurement systems. It effectively solves the problems of not being able to use conventional three-dimensional calibration fields and digital camera calibration methods such as the Zhang Zhengyou method due to small field of view, and it also solves the problem of not being able to measure the direction value of a given image control point with the human eye due to the lack of an eyepiece and crosshair reticle. In fact, this method is not only applicable to all-weather field astronomical measurement systems, but can also be used for the calibration of coaxial cameras on image total stations. This method can obtain high-precision camera parameters and has high application value. Attached Figure Description

[0011] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements are not necessarily drawn to scale.

[0012] Figure 1 This is a flowchart of some embodiments of the calibration method for an all-weather field astronomical measurement system according to the present disclosure;

[0013] Figure 2 is a schematic diagram of an optical path corresponding to an astronomical measurement system;

[0014] Figure 3 is a structural schematic diagram of some embodiments of a calibration device for an all-weather field astronomical measurement system according to the present disclosure;

[0015] Figure 4 is a structural schematic diagram of an electronic device suitable for use to implement some embodiments of the present disclosure. DETAILED DESCRIPTION

[0016] Embodiments of the present disclosure will be described in more detail with reference to the drawings. Although some embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be interpreted as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly and completely understood. It should be understood that the drawings and embodiments of the present disclosure are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure.

[0017] It should also be noted that, for ease of description, only parts related to the present application are shown in the drawings. The embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0018] It should be noted that the terms "first", "second", etc. mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not intended to limit the order or interdependence of the functions performed by these devices, modules or units.

[0019] It should be noted that the adjectives "one", "multiple" mentioned in the present disclosure are illustrative and not limiting, and those skilled in the art should understand that, unless otherwise explicitly stated in the context, it should be understood as "one or more".

[0020] The names of the messages or information exchanged between the devices in the embodiments of the present disclosure are only for illustrative purposes and are not intended to limit the scope of the messages or information.

[0021] The present disclosure will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0022] Reference Figure 1 , shows a flow 100 of some embodiments of a calibration method for an all-weather field astronomical measurement system according to the present disclosure. The calibration method for the all-weather field astronomical measurement system comprises the following steps:

[0023] Step 101, setting an infrared control point with a fixed position .

[0024] In some embodiments, the execution subject (e.g., a computing device) of the full-time field astronomical measurement system calibration method can set a fixed-position infrared control point .

[0025] Wherein, the infrared control point The corresponding horizontal direction value And the vertical direction value Remains unchanged during the calibration process.

[0026] It should be noted that the above computing device can be hardware or software. When the computing device is hardware, it can be implemented as a single server or a single terminal device. When the computing device is software, it can be installed in the above-mentioned hardware devices. It can be implemented as a single software or software module. Herein, no specific limitation is made, for example, the above-mentioned execution subject can be a (field) infrared theodolite system formed by embedding an infrared CMOS (Complementary Metal-Oxide-Semiconductor, complementary metal oxide semiconductor) sensor in a high-precision theodolite frame.

[0027] In order to better assist understanding of the present disclosure, see the following analysis:

[0028] Firstly, the sky radiation in the infrared band is much lower than that in the visible light band, and the penetration of thin clouds, smoke, haze and other substances is also stronger than that in the visible light band. Therefore, the (field) infrared theodolite system formed by embedding an infrared CMOS sensor in a high-precision theodolite frame can adjust the star observation band from the visible light band to the short-wave infrared band, thereby realizing full-time astronomical measurement. Precise calibration of the infrared camera in the (full-time field) astronomical measurement system is a prerequisite for high-precision astronomical measurement. There is currently no calibration method for the infrared camera of the full-time field astronomical measurement system.

[0029] Secondly, traditional astronomical measurement is restricted by many factors, such as being able to be carried out only on clear nights, the star observation band being the visible light band, etc., which seriously affects the accuracy and efficiency of astronomical measurement. Therefore, the (full-time field) astronomical measurement system formed by fusing an infrared (CMOS) sensor with a (high-precision) theodolite can break through the day-night limit and realize full-time astronomical measurement. Specifically, due to the volume limitation of the telescope system in the (high-precision) theodolite, the (full-time field) astronomical measurement system removes the eyepiece and crosshair scale plate in the telescope in the theodolite, and embeds an infrared image sensor below the telescope, so that the light is reflected onto the infrared CMOS sensor after passing through the objective optical system. The infrared CMOS sensor converts the optical signal into a digital signal and stores it in a storage device after processing by a related processing chip.

[0030] As an example, refer to Figure 2 The corresponding optical path schematic diagram of the astronomical measurement system shown in the figure, in which the infrared light is reflected to the infrared CMOS sensor through the reflecting prism in the objective lens along the optical path.

[0031] Further, since the infrared CMOS sensor and the theodolite in the astronomical measurement system of the present disclosure share the telescope, and the field of view angle of the telescope is very small. Therefore, the conventional digital camera calibration method (for example, indoor three-dimensional calibration field calibration method and Zhang Zhengyou method) has a greater difficulty in implementation and low calibration accuracy. Specifically, when using the indoor three-dimensional calibration field calibration method, due to the small field of view angle of the telescope, the number of image control points contained in the collected image is extremely small, or even no image control points, and thus the calibration cannot be performed. When using the Zhang Zhengyou calibration method, unless the astronomical measurement system is placed far away from the position of the checkerboard, the image cannot completely cover the entire checkerboard. However, due to the limitation of the geographical environment in the field, it is extremely difficult to place far away.

[0032] Based on this, the present disclosure considers that the astronomical measurement system is a system composed of an infrared CMOS sensor and a theodolite, and the infrared CMOS sensor and the theodolite share a set of optical systems. Therefore, by taking advantage of the characteristics that the infrared CMOS sensor rotates with the aiming part of the theodolite in the horizontal plane and the telescope rotates in the vertical plane, the aiming part of the theodolite and the telescope are rotated to observe a single infrared control point from different directions (multiple directions), so as to realize the calibration of the astronomical observation system.

[0033] Step 102, controlling the all-day field astronomical measurement system to respectively perform a measurement return observation on the infrared control point from multiple observation directions to obtain a set of observation data.

[0034] In some embodiments, the above execution subject can control the all-day field astronomical measurement system to respectively perform a measurement return observation on the infrared control point from multiple observation directions to obtain a set of observation data. In practice, in order to improve the observation accuracy and reduce the influence of accidental errors, it is necessary to perform a measurement return observation in multiple observation directions. In addition, multiple measurement return observations can also be performed for the same observation direction.

[0035] The observation data includes: disc left observation data and disc right observation data. The disc left observation data refers to the data obtained by observing at the disc left position. The disc right observation data refers to the data obtained by observing at the disc right position. The disc left position represents that the vertical disc is located on the left side of the observer. The disc right position represents that the vertical disc is located on the right side of the observer. The vertical disc is one of the core components of the theodolite, also known as the verticality disc or the verticality disc, which is used to measure the vertical angle.

[0036] The disc left observation data includes: a horizontal direction observation value Vertical observation values and image collection Right-hand observation data includes: horizontal observation values Vertical observation values and image collection Specifically, the left-side observation data includes horizontal observations. Vertical observation values These are the horizontal and vertical observations of the theodolite's line of sight in the left-face position, respectively. The left-face observation data includes the image set... This refers to multiple images acquired from the left-hand position. Right-hand observation data includes horizontal observations. Vertical observation values These are the horizontal and vertical observations of the theodolite's line of sight in the right-hand position, respectively. The right-hand observation data includes a set of images. This refers to multiple images captured from the right side of the screen.

[0037] Among them, for image sets and image collection In the image, infrared control points can be located using image processing techniques (e.g., target recognition algorithms). In particular, infrared control points The pixel coordinates in the image are .in, This represents the x-coordinate of the infrared control point in the pixel coordinate system. Indicates infrared control point The vertical coordinate in the pixel coordinate system. Therefore, the infrared control point. The coordinates in the image plane coordinate system and the pixel coordinate system satisfy the following constraints:

[0038] ;

[0039] in, and This refers to the x and y coordinates included in the principal point pixel coordinate system. Specifically, the principal point pixel coordinates refer to the coordinates of the intersection point of the camera lens's principal optical axis and the camera's imaging plane within the pixel coordinate system. Indicates infrared control point The horizontal coordinate in a planar coordinate system Indicates infrared control point The ordinate in the image plane coordinate system.

[0040] In some alternative implementations of certain embodiments, the aforementioned executing entity controls the all-weather field astronomical measurement system to measure infrared control points from multiple observation directions. A resection observation is performed to obtain an observation data set, including:

[0041] Step S1: for each observation direction in the above plurality of directions, the following resection observation steps are performed:

[0042] Step S11: along the above observation direction, an infrared control point is observed from the left side of the disc, and image acquisition is performed to obtain observation data including horizontal direction observation value , vertical direction observation value and image set .

[0043] In practice, multiple resection observations can also be performed in a single observation direction to obtain multiple observation data.

[0044] Step S12: along the above observation direction, an infrared control point is observed from the right side of the disc, and image acquisition is performed to obtain observation data including horizontal direction observation value , vertical direction observation value and image set .

[0045] In practice, multiple resection observations can also be performed in a single observation direction to obtain multiple observation data.

[0046] Step 103: according to the observation data set and the pre-constructed observation equation, the resection calibration is performed by least square method to obtain the corresponding horizontal direction value and vertical direction value of the infrared control point , as well as the camera principal distance , first-order radial distortion coefficient and image plane rotation angle .

[0047] In some embodiments, the above execution body can perform resection calibration according to the observation data set and the pre-constructed observation equation by least square method to obtain the corresponding horizontal direction value and vertical direction value of the infrared control point , as well as the camera principal distance , first-order radial distortion coefficient and image plane rotation angle .

[0048] wherein the horizontal direction value and the corresponding vertical direction value of the theodolite's collimation axis, the infrared control point Horizontal coordinate in image plane coordinate system and vertical coordinate , combined with camera principal distance of the infrared camera to be tested Horizontal coordinate included in image principal point pixel coordinate and vertical coordinate Infrared control point Horizontal direction value in theodolite coordinate system and vertical direction value The specific calculation formula is as follows:

[0049] .

[0050] In addition, since the infrared CMOS sensor shares an optical system with the theodolite, the field of view angle is very small (for example, the field of view angle < 2°), therefore, the observation equation adopts first-order radial distortion compensation, and the first-order radial distortion coefficient satisfies the following constraints:

[0051] ;

[0052] wherein, represents the horizontal coordinate of the infrared control point in the image plane coordinate system, represents the vertical coordinate of the infrared control point in the image plane coordinate system, represents the first-order radial distortion coefficient, characterizes the horizontal correction amount of the infrared control point in the image plane coordinate system due to distortion, characterizes the vertical correction amount of the infrared control point in the image plane coordinate system due to distortion.

[0053] Wherein, the installation of the infrared CMOS sensor requires that its upper and lower edges are parallel to the collimation axis of the telescope, and its left and right edges are parallel to the horizontal axis of the instrument. However, during the installation of the infrared CMOS sensor, the upper, lower, left and right edges often cannot strictly satisfy the above position constraints, i.e. there is an image plane rotation angle , which further causes the coordinates of the infrared control point in the image plane to deviate from its true value, therefore, the true value of the infrared control point in the image plane can be represented by the following formula:

[0054] ;

[0055] wherein, represents the horizontal coordinate of the true value of the infrared control point in the image plane, represents the vertical coordinate of the true value of the infrared control point The ordinate of the true value in the image plane.

[0056] In practice, in the process of calibration of the measurement, the image principal point is located at the physical center of the image plane, so the mean value of the horizontal observation value and the mean value of the vertical observation value can be obtained according to the horizontal observation value and the vertical observation value of the measurement observation. Specifically, for the infrared control point , the mean value of the horizontal observation value and the mean value of the vertical observation value can be represented by the following formula:

[0057] ;

[0058] Wherein, represents the mean value of the horizontal observation value of the observation data corresponding to the observation direction . represents the mean value of the vertical observation value of the observation data corresponding to the observation direction . represents the serial number of the measurement. and represent the horizontal observation value and the vertical observation value included in the left disc observation data in the observation data corresponding to the observation direction of the measurement . and represent the horizontal observation value and the vertical observation value included in the right disc observation data in the observation data corresponding to the observation direction of the measurement .

[0059] Wherein, the mean value of the pixel coordinates (the mean value of the horizontal pixel coordinates and the mean value of the vertical pixel coordinates) of the infrared control point is obtained based on the observation data obtained by the measurement of times of the measurement in the observation direction , and can be represented by the following formula:

[0060] ;

[0061] Wherein, represents the mean value of the horizontal pixel coordinates. represents the mean value of the vertical pixel coordinates.

[0062] Wherein, the horizontal pixel coordinates and the vertical pixel coordinates included in the pixel coordinates of the image principal point can be represented by the following formula:

[0063] ;

[0064] Wherein,​​ represents the length of the infrared CMOS sensor. represents the width of the infrared CMOS sensor.

[0065] Therefore, the infrared control point The mean value (the horizontal coordinate mean value and the vertical coordinate mean value ) in the image plane coordinate system can be represented by the following formula:

[0066] .

[0067] wherein the observation equation is shown in the following formula:

[0068] ;

[0069] wherein, represents the horizontal coordinate of the infrared control point in the image plane coordinate system, represents the vertical coordinate of the infrared control point in the image plane coordinate system, represents the image plane rotation angle, represents the horizontal direction value corresponding to the infrared control point , represents the vertical direction value corresponding to the infrared control point , represents the camera principal distance, represents the first-order radial distortion coefficient, represents the horizontal direction value corresponding to the collimation axis of the theodolite, represents the vertical direction value corresponding to the collimation axis of the theodolite.

[0070] In practice, the infrared control point is measured times from observation directions, and observation equations can be obtained, so that the horizontal direction value and the vertical direction value corresponding to the infrared control point , the camera principal distance , the first-order radial distortion coefficient , and the image plane rotation angle can be solved by least squares method iteration. As an example, taking 10 observation directions as an example, the value of is [1, 10], and the specific calculation process is as follows:

[0071] ;

[0072] In the above set of observation equations, the value to be solved is the infrared control point. Corresponding horizontal value and vertical direction value and camera principal distance First-order radial distortion coefficient and image plane rotation angle .

[0073] Wherein, the initial value of the unknown parameter is set to... .in, Infrared control point Corresponding horizontal value initial value, Infrared control point Corresponding vertical direction value initial value, Camera principal distance initial value, First-order radial distortion coefficient The initial value. The estimated value of the unknown parameter is... .in, Infrared control point Corresponding horizontal value The estimated value, Infrared control point Corresponding vertical value The estimated value, Camera principal distance The estimated value, First-order radial distortion coefficient The estimated value. The correction for the unknown parameter is... .in, Infrared control point Corresponding horizontal value number of corrections, Infrared control point Corresponding vertical direction value number of corrections, Camera principal distance number of corrections, First-order radial distortion coefficient The correction number. Therefore, we have .

[0074] in, Indicates the first The mean of the horizontal observation values ​​corresponding to each observation direction. Indicates the first The mean of the vertical observation values ​​corresponding to each observation direction can also be expressed as: pixel mean of horizontal coordinate pixel mean of vertical coordinate , which can also be expressed as Let the corresponding estimated values be and , the correction numbers of the observed values be and , then we have and .

[0075] Further, linearize the observation equation (i.e. use Taylor series expansion at and take the first order term of the expansion), let and , and use to represent the constant term vector, to represent the coefficient matrix of , and to represent the coefficient matrix of , and to represent the transpose of the matrix, thus the error equation can be obtained as follows:

[0076] ;

[0077] Let there be a correction number represented by an imaginary number (where ), then the error equation can be expressed as:

[0078] .

[0079] Let be the variance matrix, the covariance matrix and the weight matrix of the pixel coordinate mean in the direction of the collimation axis respectively; let be the variance matrix, the covariance matrix and the weight matrix of the observed value mean (horizontal observed value mean and vertical observed value mean) of the corresponding observed data in the observation direction respectively; let be the variance matrix, the covariance matrix and the weight matrix of the virtual observation . Among them, since and are independent of each other, taking the unit weight variance as 1, then the stochastic model can be expressed by the following formula:

[0080] .

[0081] According to the least square criterion, we have the following formula:

[0082] ;

[0083] in, This represents the least squares solution with unknown parameters.

[0084] Furthermore, substituting the error equation into the least squares criterion and following the method for finding the free extrema of a function, we obtain the following formula:

[0085] .

[0086] Transposing the above equation and substituting the error equation, we get the following formula:

[0087] .

[0088] Therefore, the unknown parameter correction number The least squares solution is expressed as follows:

[0089] .

[0090] Unknown parameter corrections The power of the reverse formation It can be represented as follows:

[0091] .

[0092] Finally, based on the initial values ​​of the unknown parameters and the least squares solution of the corrections to the unknown parameters, the least squares solution of the unknown parameters is expressed as follows:

[0093] .

[0094] In practice, to improve the accuracy of the solution, the least squares solution of the unknown parameters obtained in this step can be used as the initial value of the unknown parameters for the next step and substituted into the error equation for iterative solution until the accuracy requirements are met.

[0095] Step 104, based on infrared control points Corresponding horizontal value and vertical direction value and camera principal distance First-order radial distortion coefficient and image plane rotation angle The principal point coordinates of the left-side image and the principal point coordinates of the right-side image were checked separately.

[0096] In some embodiments, the aforementioned execution entity can be based on infrared control points. Corresponding horizontal value and vertical direction value and camera principal distance First-order radial distortion coefficient and image plane rotation angle , respectively.

[0097] In practice, because the astronomical observation target is a moving celestial body, the left or right observation is required in actual measurement, so the left and right camera parameter calibration is required respectively. For example, the infrared control point corresponding horizontal direction value and vertical direction value , and the camera principal distance , the first order radial distortion coefficient and the image plane rotation angle are substituted into the left observation data or the right observation data, and the left image principal point coordinate calibration or the right image principal point coordinate calibration is performed through the least square method.

[0098] Specifically, for the first observation direction, the infrared control point is measured times of return observation, then the horizontal direction observation value mean and the vertical direction observation value mean corresponding to the left observation data can be expressed by the following formula:

[0099] .

[0100] Wherein, represents the return number. and represent the horizontal direction observation value and the vertical direction observation value included in the left observation data corresponding to the observation data of the first return of the first observation direction.

[0101] The horizontal direction observation value mean and the vertical direction observation value mean corresponding to the right observation data can be expressed by the following formula:

[0102] .

[0103] Wherein, represents the return number. and represent the horizontal direction observation value and the vertical direction observation value included in the right observation data corresponding to the observation data of the first return of the first observation direction.

[0104] The pixel coordinate mean (horizontal coordinate pixel mean and vertical coordinate pixel mean ) corresponding to the left observation data can be expressed by the following formula:

[0105] .

[0106] The mean pixel coordinates (mean pixel value on the horizontal axis) corresponding to the right-side observation data. and the mean pixel value of the vertical axis This can be expressed by the following formula:

[0107] .

[0108] Then the infrared control point corresponding to the left-side observation data In a planar coordinate system, the mean (mean of the horizontal coordinate) and the mean of the ordinate This can be expressed by the following formula:

[0109] .

[0110] in, and This refers to the x and y coordinates of the principal pixel corresponding to the left-hand observation data. Specifically, the principal pixel refers to the coordinates of the intersection point of the camera lens's optical axis and the camera's imaging plane in the pixel coordinate system.

[0111] The infrared control point corresponding to the right-hand observation data. In a planar coordinate system, the mean (mean of the horizontal coordinate) and the mean of the ordinate This can be expressed by the following formula:

[0112] .

[0113] in, and This refers to the x and y coordinates of the principal pixel corresponding to the left-hand observation data. Specifically, the principal pixel refers to the coordinates of the intersection point of the camera lens's optical axis and the camera's imaging plane in the pixel coordinate system.

[0114] Therefore, the observation equation for left-side observation data can be expressed by the following formula:

[0115]

[0116] Therefore, the observation equation for right-hand side observation data can be expressed by the following formula:

[0117]

[0118] from Each observation direction corresponds to an infrared control point. conduct The secondary measurement return observation, then for the left disc observation data and the right disc observation data, can respectively obtain An observation equation, since the infrared control point The corresponding horizontal direction value And the vertical direction value And the specific value of the camera principal distance The first-order radial distortion coefficient And the image plane rotation angle Has been solved, so 5 parameters are substituted into the observation equation, and the least square method is iteratively solved, so the horizontal coordinate And the vertical coordinate Of the left disc observation data corresponding to the image principal point pixel coordinate, and the horizontal coordinate And the vertical coordinate Of the right disc observation data corresponding to the image principal point pixel coordinate can be obtained. Thus, the left disc image principal point coordinate calibration and the right disc image principal point coordinate calibration are realized.

[0119] The above-mentioned various embodiments of the present disclosure have the following beneficial effects: through the all-weather field astronomical measurement system calibration method of some embodiments of the present disclosure, in the measurement return calibration, first, the image principal point is positioned as the physical center of the image plane, the direction value (the corresponding horizontal direction value And the vertical direction value Of the target point (the infrared control point ) is calculated by using the observation data, and the (infrared) camera principal distance The first-order radial distortion coefficient And the image plane rotation angle Are solved. Secondly, in the left disc and right disc calibration, the direction value of the target point (the infrared control point ) is taken as a known quantity, and the camera image principal point coordinates are solved by using the left disc observation data and the right disc observation data. This method is specially designed for the all-weather field astronomical measurement system, which not only can effectively solve the problem that the small field of view cannot use the conventional three-dimensional calibration field and the digital camera calibration method of Zhang Zhengyou method, but also can solve the problem that the given image control point direction value cannot be measured by the human eye due to the absence of the ocular and the crosshair scale plate. In fact, this method is not only applicable to the all-weather field astronomical measurement system, but also can be used for the calibration of the coaxial camera of the image total station, and this method can obtain high-precision camera parameters and has high application value. Further referring to

[0120] As an implementation of the method shown in the above-mentioned figures, the present disclosure provides some embodiments of an all-weather field astronomical measurement system calibration device, and these device embodiments are used for realizing the method shown in Figure 3 Figure 1 ​The all-day field astronomical measurement system calibration device can be applied to various electronic devices corresponding to the method embodiments shown.

[0121] As Figure 3 shown, the all-day field astronomical measurement system calibration device 300 of some embodiments includes a setting unit 301, a control unit 302, a measurement circle calibration unit 303, and a left disc calibration and right disc calibration unit 304, wherein the setting unit 301 is configured to set a fixed position infrared control point , wherein the infrared control point corresponding horizontal direction value and vertical direction value remain unchanged during the calibration process; the control unit 302 is configured to control the all-day field astronomical measurement system to perform measurement circle observation on the infrared control point from multiple observation directions respectively, to obtain a set of observation data, wherein the observation data includes left disc observation data and right disc observation data, wherein the left disc observation data includes a horizontal direction observation value , a vertical direction observation value , and a set of images , and the right disc observation data includes a horizontal direction observation value , a vertical direction observation value , and a set of images ; the measurement circle calibration unit 303 is configured to perform measurement circle calibration on the infrared control point corresponding horizontal direction value and vertical direction value , and camera principal distance , first-order radial distortion coefficient , and image plane rotation angle according to the set of observation data and a pre-constructed observation equation by least squares method; and the left disc calibration and right disc calibration unit 304 is configured to perform left disc calibration and right disc calibration respectively according to the infrared control point corresponding horizontal direction value and vertical direction value , and camera principal distance , first-order radial distortion coefficient , and image plane rotation angle .

[0122] It can be understood that the units described in the all-day field astronomical measurement system calibration device 300 correspond to each step in the method described with reference to Figure 1 . Therefore, the operations, features and beneficial effects described above for the method also apply to the all-day field astronomical measurement system calibration device 300 and the units contained therein, and will not be repeated here.

[0123] Reference will now be made to the following description Figure 4 which illustrates a structural schematic diagram of an electronic device (e.g., a computing device) suitable for implementing some embodiments of the present disclosure. Figure 4 The electronic device shown is merely an example and should not bring any limitation to the functions and use range of the embodiments of the present disclosure. As Figure 4 As shown, the computer device includes a processor, a memory and a network interface connected through a system bus, wherein the memory can include a non-volatile storage medium and an internal memory. The non-volatile storage medium can store an operating system and a computer program. The computer program includes program instructions which, when executed, can cause the processor to perform any of the above methods. The processor is used to provide computing and control capabilities to support the operation of the entire computer device. The internal memory provides an environment for the computer program in the non-volatile storage medium to run, which, when executed by the processor, can cause the processor to perform any of the above methods. The network interface is used for network communication, such as sending assigned tasks, etc. Those skilled in the art can understand that Figure 4 The structure shown in the figure is only a block diagram of part of the structure related to the present disclosure scheme, and does not constitute a limitation on the computer device to which the present disclosure scheme is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0124] It should be understood that the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc.

[0125] In one embodiment, the processor is configured to run a computer program stored in the memory to perform the following steps: setting a fixed position infrared control point , wherein the infrared control point corresponding to the horizontal direction value and the vertical direction value remains unchanged during the calibration process; controlling the all-day outdoor astronomical measurement system to observe the infrared control point The observation data set is obtained by performing a resection observation, wherein the observation data comprises: disc left observation data and disc right observation data, wherein the disc left observation data comprises: horizontal direction observation values , vertical direction observation values and an image set , and the disc right observation data comprises: horizontal direction observation values , vertical direction observation values and an image set ; the infrared control point corresponding horizontal direction values and vertical direction values , camera principal distance , first order radial distortion coefficient and image plane rotation angle are obtained by performing resection calibration on the observation data set and the pre-constructed observation equation by using the least square method; and disc left calibration and disc right calibration are respectively performed according to the infrared control point corresponding horizontal direction values and vertical direction values , camera principal distance , first order radial distortion coefficient and image plane rotation angle .

[0126] The embodiment of the present disclosure further provides a computer readable storage medium, and the computer readable storage medium stores a computer program. The computer program comprises program instructions. The method realized by executing the program instructions can refer to each embodiment of the method of the present disclosure.

[0127] The computer readable storage medium can be an internal storage unit of the computer device, for example, a hard disk or a memory of the computer device. The computer readable storage medium can also be an external storage device of the computer device, for example, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card and the like.

[0128] It should be noted that, in this document, the term “comprising” or “including” or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or system. Without more limitations, the element defined by the statement “comprising a” does not exclude the presence of other identical elements in the process, method, article or system including the element.

[0129] The above description is merely exemplary of some embodiments of the present disclosure and of the principles thereof. It is to be understood that the present disclosure is not limited to the above-described technical solutions, and the scope of the application involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combinations of the technical features described above. Meanwhile, the present disclosure should also cover other technical solutions formed by the arbitrary combinations of the technical features described above or equivalent features thereof without departing from the above-described inventive concept. For example, the technical solutions formed by the mutual replacement of the above-described features and the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) form the technical solutions.

Claims

1. A method for calibrating an all-sky field astronomical measurement system, characterized in that Comprising: Setting a fixed position infrared control point wherein the infrared control point corresponding horizontal direction value and vertical direction value remains unchanged during calibration; The control all-day field astronomical measurement system respectively carries out measuring return observation on the infrared control points from multiple observation directions to obtain an observation data set, wherein the observation data includes: disc left observation data and disc right observation data , wherein the disc left observation data includes: horizontal direction observation value , vertical direction observation value and image set , and the disc right observation data includes: horizontal direction observation value , vertical direction observation value and image set ; According to the observation data set and the pre-constructed observation equation, the measurement is checked and calibrated by the least square method to obtain the infrared control point The corresponding horizontal direction value And the vertical direction value And the camera main distance The first order radial distortion coefficient And the image plane rotation angle ; According to the infrared control point The corresponding horizontal direction value And the vertical direction value And the camera principal distance The first order radial distortion coefficient And the image plane rotation angle , respectively, the left image principal point coordinate calibration and the right image principal point coordinate calibration are carried out.

2. The method of claim 1, wherein, The control all-day field astronomical measurement system respectively carries out measuring return observation on the infrared control point from multiple observation directions, and obtains an observation data set. For each of the plurality of observation directions, performing the following measurement step: Along the observation direction, from the left side of the disk towards the infrared control point By conducting repeated observations and acquiring images, the horizontal observation values ​​included in the left-side observation data were obtained. Vertical observation values and image collection ; Performing retro-observation along the observation direction from the right side of the disc to the infrared control point Performing retro-observation along the observation direction from the right side of the disc to the infrared control point , and performing image collection to obtain horizontal direction observation value included in disc right observation data of the observation data , vertical direction observation value , and image set 3. The method of claim 2, wherein, The observation equation is as follows: wherein, represents an infrared control point represents a horizontal coordinate in the image plane coordinate system, represents an infrared control point represents a vertical coordinate in the image plane coordinate system, represents a rotation angle of the image plane, represents an infrared control point corresponding horizontal direction value, represents an infrared control point corresponding vertical direction value, represents a camera principal distance, represents a first order radial distortion coefficient, represents a horizontal direction value corresponding to the collimation axis of the theodolite, represents a vertical direction value corresponding to the collimation axis of the theodolite.

4. The method of claim 3, wherein, The observation equation employs first order radial distortion compensation, a first order radial distortion coefficient satisfies the following constraints: wherein represents an infrared control point represents the horizontal coordinate in the image plane coordinate system, represents an infrared control point represents the vertical coordinate in the image plane coordinate system, represents the first order radial distortion coefficient, represents the distortion of the infrared control point represents the horizontal correction in the image plane coordinate, represents the distortion of the infrared control point represents the vertical correction in the image plane coordinate.

5. An all-sky field astronomical survey system calibration device, characterized by comprising: Comprising: A setting unit configured to set a fixed-position infrared control point wherein the infrared control point corresponding horizontal direction value and vertical direction value remains unchanged during the calibration process; The control unit is configured to control the all-weather field astronomical measurement system to measure the infrared control points from multiple observation directions. A series of observations were conducted to obtain a set of observation data, which includes: left-side observation data and right-side observation data. The left-side observation data includes: horizontal observation values. Vertical observation values and image collection Right-hand observation data includes: horizontal observation values Vertical observation values and image collection ; The measuring-rod calibration unit is configured to calibrate the measuring rod according to the observation data set and the pre-constructed observation equation by a least square method to obtain the infrared control point corresponding horizontal direction values and vertical direction values , and a camera principal distance , a first-order radial distortion coefficient , and an image plane rotation angle ; The left-disc-checking and right-disc-checking units are configured to perform left-disc-image-principal-point coordinate checking and right-disc-image-principal-point coordinate checking, respectively, according to the infrared control points corresponding horizontal direction values and vertical direction values , and a camera principal distance , a first-order radial distortion coefficient , and an image plane rotation angle .

6. An electronic device, comprising: Comprising: One or more processors; A storage device having stored thereon one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 4.

7. A computer readable medium characterized by A computer program is stored thereon, wherein the computer program is executed by a processor to implement the method according to any one of claims 1 to 4.

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