KR101346206B1 - Aviation surveying system for processing the aviation image in gps - Google Patents

Abstract

The present invention relates to a GPS based aerial measurement system for precisely processing orthophoto to manufacture an accurate orthophoto map based on an aerial photograph. The GPS based aerial measurement system for precisely processing orthophoto includes: an image output module; an image adjustment module; a GPS module; an interaction formula calculation module; a distortion ratio check module; a coordinate set-up module; and a coordinate adjustment module. The GPS based aerial measurement system for precisely processing orthophoto enables users to check the coordinate of a ground control point on an image which has been taken with high reliability by adjusting the coordinate of the ground control point based on an actual measurement. [Reference numerals] (11) Ground control point DB; (12) Image DB; (21) Image output module; (22) Image control module; (23) Interaction formula calculation module; (24) Distortion ratio check module; (25) Coordinate set-up module; (26) GPS module; (27) Coordinate adjustment module; (30) Photographing device

Description

AVIATION SURVEYING SYSTEM FOR PROCESSING THE AVIATION IMAGE IN GPS

The present invention relates to a GPS-based aerial survey system for precise processing of orthoimages for producing precise orthoimage maps based on aerial photographs.

As is well known, aerial surveying is preferred for the production of numerical orthodontic image maps (hereinafter referred to as 'image maps'), and aerial photographs collected through the aerial surveys are subject to orthodontic correction based on the 'Work Regulations on Image Mapping'. Is done.

The official name of orthodontic correction is "orthodeviation correction", which refers to a task of removing the undulation displacement caused by the distortion of the object and the undulation of the terrain caused by the central projection during photography. Therefore, "ortho image" means an image that has undergone orthogonal deviation correction on the terrain, features, etc. of the image acquired by the central projection.

The conventional method of making orthoimages from aerial photographs is to create a corrected aerial photograph through an internal expression process of correcting the distortion of the aerial photograph itself, and to indicate the relationship between the corrected aerial photograph and the ground coordinates. Six expressions were obtained by performing the external expression by the bundle adjustment method using the collinear condition equation and the ground reference point by GPS survey, and the orthoimage was produced using the six expressions and the numerical elevation data. For reference, programs that can produce ortho images using IKONOS images in commercial R / S tools are currently available for Socet Set ver4.3 or higher, ZI Imaging 3.0 or higher, ERDAS IMAGING 8.5.1 or higher, PCI 7.0 or higher, JX4A, ER- The program OrthoWarp ER can be used for Mapper.

Subsequently, the conventional method uses the Newton-Rapson method for making a corrected aerial photo and an orthoimage through an internal expression process. Since it is a method of finding a close solution by iterative updating of initial values, a lot of time is required for the calculation process. In addition, an aerial photo scanned and stored on a computer usually has a data capacity of about 400 megabytes per sheet. However, if a separate aerial photo with distortion correction is manufactured and stored as in the prior art, the data capacity is required. There was a problem.

In order to solve this problem, a method of producing orthogonal images of aerial photographs has been proposed.

By the way, although the prior art is a technique for reducing the load on the computer required when performing the conventional method, the orthogonal image coordinate calculation and distortion value calculation for each reference point of the aerial photograph must be performed one by one. The burden to bear was not greatly reduced. In addition, due to these reasons, orthodontic correction of aerial photographs cannot be performed in real time on aircraft that collect aerial photographs through aerial survey.

Patent Documents 1.Registration No. 10-0544345 (January 23, 2006)

Accordingly, the present invention has been invented to solve the above problems, it is possible to quickly process the orthodontic correction of aerial photographs (hereinafter referred to as "shooting image") collected by aerial survey in the aircraft, the image taken on the aircraft is taken ground GPS-based aerial survey system for precise processing of orthoimages, which enables the real-time control of the location of the ground reference point coordinates in real time, and the positioning of the ground reference point coordinate values applied to the photographed images with high reliability. The task is to solve the provision.

According to an aspect of the present invention,

Image output module operating by applying a captured image coordinate system consisting of a plurality of X-axis and Y-axis is arranged in a grid so as to output the captured image while operating in accordance with the control value, so as to check the coordinates of each point in the captured image ;

An image control module for generating a control value for controlling the operation of the image output module and transferring the control value to the image output module;

GPS module for checking the current position of the aircraft in GPS coordinates;

Coordinate value of ground control point coordinate

(x _a , y _a : taken image coordinate value, δr: distortion amount, f: focal length, P _x , P _y , P _z : ground reference point coordinate value, S _x , S _y . S _z : expression element, m ₁₁ M ₃₃ : rotation matrix)

A relational calculation module for calculating an output image coordinate value through a;

Transfer the input two or more ground reference point coordinate values to the relational image calculation module to calculate the coordinates of the photographed image, and confirm the position of the photographed image coordinate value received from the relational calculation module based on the photographed image coordinate system, and photograph the image. The first distance, which is the distance between the origin of the image coordinate system and the photographed image coordinate value, is calculated for each point, and the second distance, which is the distance between the ground reference point coordinate value and the input ground reference point coordinate value of the origin identified by the GPS module, is calculated. Computing each point by each point, and confirming the first distance difference confirmed for each point based on the second distance difference confirmed for each point to determine the distortion ratio that is the increase or decrease ratio of the first distance difference for each point according to the distance to the origin. Distortion ratio checking module;

A ground reference point is set along the latitude direction and the longitude direction around the origin, and the position of the ground reference point is set in the photographed image by checking the distance between the ground reference points that change with the distortion ratio. Coordinates for generating a ground reference point coordinate system composed of a plurality of latitude and longitude axis in a lattice form, and linking the ground reference point coordinate system and the photographed image coordinate system to link the photographed image coordinate values corresponding to the ground reference point coordinate values. Value setting module; And

Select the ground object to be checked in the photographed image to check the first coordinate value of the ground reference point coordinate system where the ground object image overlaps, and retrieve the actual ground reference point coordinate value of the ground to be checked from the ground reference point DB. Check the correction target coordinate value applied to the reference point coordinate system, and shift the longitude axis and latitude axis corresponding to the correction target coordinate value to become the longitude axis and latitude axis corresponding to the first coordinate value, A coordinate correction module adapted to apply to the photographed image by modifying the other longitude and latitude axes adjacent to the latitude axis according to the distortion ratio;

GPS-based aerial survey system for the precision processing of ortho images, including.

According to the present invention, the final orthogonal image may be generated by orthodontic correction of the photographed image collected by the aerial survey, and the ground reference point coordinate value may be applied to the photographed image collected by aerial photographing to determine the coordinate value of the photographed image. Not only can be confirmed and utilized in real time, there is an effect that can minimize the system burden in the above-described process.

In addition, the present invention has the effect of confirming the ground reference point coordinate value in the photographed image with high reliability by correcting the positioning of the ground reference point coordinate value based on the actual measurement.

In addition, the present invention through the generation of orthoimages and the application of the ground reference point coordinate value of the captured image, immediately confirms whether or not the distortion rate of any of the captured image of the aerial survey within the allowable range, and re-check The effect is that you can easily determine whether to shoot.

1 is a block diagram showing each module configured in the aerial survey system according to the present invention;
2 is a flowchart sequentially illustrating a process of generating a ground reference point coordinate system in a photographed image performed by an aerial survey system according to the present invention;
3 is a diagram illustrating a state in which the aerial survey system according to the present invention displays a point corresponding to the ground reference point coordinate value in the photographed image coordinate system in order to calculate a distortion ratio of the photographed image;
4 is a diagram illustrating a ground reference point coordinate system for inputting a ground reference point in a photographed image by an aerial survey system according to the present invention;
FIG. 5 is a view illustrating a ground reference point coordinate value of a specific point of a photographed image selected by an operator in the ground reference point coordinate system of FIG. 4;
FIG. 6 is a view illustrating a state in which an aerial survey system checks a matching state between a ground reference point coordinate system and a photographed image;
7 is a view showing a modified state of the ground reference point coordinate system of the aerial survey system according to the present invention,
8 is a flowchart showing a process of orthogonal processing of photographed images progressed by the aerial survey system according to the present invention;
9 is a view showing a shooting geometry formed during the operation of the aerial survey system according to the present invention,
10 is a view showing a relationship between a coordinate value of a photographed image formed when driving an aerial survey system according to the present invention and a photographing direction vector u;
11 is a graph showing a state in which the aerial survey system according to the present invention corrects the distortion of the photographed image.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, It will be possible. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a block diagram showing each module configured in the aerial survey system according to the present invention, will be described with reference to this.

The aerial survey system according to the present invention is orthogonal correction of the captured image taken by the photographing apparatus 30 in real time, and the coordinates of the ground reference point applied to the photographed image with a minimum time and system load with the corresponding orthoimage output. It is a system that outputs composite image to captured image.

The aerial survey system according to the present invention for this purpose is the ground reference point DB (11) for storing the information about the ground reference point, and the image to store the location information of the ground reference point coordinate value to the photographed image taken by the photographing device 30 to store DB 12, an image output module 21 for outputting the captured image stored in the image DB 12, and an image output module 21 for the operator to control the captured image output to the image output module 21 An image control module 22 for controlling the image, a relational calculation module 23 for calculating the captured image coordinate value from the ground reference point coordinate value by using the relational expression between the captured image coordinate value and the ground reference point coordinate value, and a distortion ratio of the captured image. Distortion ratio confirmation module 24 for calculating a, a coordinate value setting module 25 for linking the ground reference point coordinate value corresponding to each position in the photographed image, and a GPS module for measuring the current position of the aircraft by GPS And a coordinate correction module 27 for checking the position of the ground reference point coordinate value linked to the photographed image and correcting it when checking an error.

The ground reference point DB 11 stores each ground reference point information about specific points of the ground. In order to process an internal expression and an external expression of a captured image, a reference point should be set on the captured image. The aerial survey system according to the present invention can proceed to the ground reference point stored in the ground reference point DB (11) the reference point to be captured in the photographed image. For reference, the ground reference point information is a coordinate value of GPS coordinates of a specific point selected on the ground. In the present embodiment, the ground reference point DB 11 stores the ground reference point coordinate value of the ground point located in the photographed image.

The image DB 12 stores a photographed image photographed by the photographing apparatus 30, and a ground reference point coordinate value linked to the photographed image. The process and technical details of linking the ground reference point to the photographed image will be described in detail below.

The image output module 21 is a conventional display device for outputting a photographed image and an orthogonal image stored in the image DB 12. A general monitor or a touch screen may be applied. In general, an image output module 21 such as a monitor or a touch screen may include a photographing image coordinate system AX in which a plurality of X-axis lines and Y-axis lines are arranged in a grid so as to check coordinate values of each point of the output image. 3). Therefore, when a specific point is selected on the captured image, the image output module 21 tracks and confirms the captured image coordinate value of the specific point in the corresponding screen.

The image control module 22 is an operation means for controlling the image output from the image output module 21, generates a control value according to the operator's operation and transfers it to the image output module 21. The image control module 22 may be implemented by a touch screen technique, or a separate keyboard or joystick may be applied.

The relational expression calculating module 23 calculates the photographed image coordinate values from the ground reference point coordinate values presented by the distortion ratio checking module 24 by utilizing the relational expression between the photographed image coordinate values and the ground reference point coordinate values. The relational equation may be a modified collinear condition described below.

The distortion ratio checking module 24 checks the position of the ground reference point applied to the photographed image, checks the actual distortion state of the photographed image, calculates the distortion ratio, and confirms the image arrangement state of the photographed image.

The coordinate value setting module 25 generates the ground reference point coordinate system based on the distortion ratio calculated by the distortion ratio checking module 24, and the coordinate value of the photographed image and the coordinate value of the ground reference point are linked to the coordinate system. do.

The GPS module 26 checks the current position of the aircraft by measuring the GPS. Since the device for GPS measurement is a well-known and public technique, the description of the operation principle and configuration of the GPS module 26 will be omitted.

The coordinate correction module 27 compares the coordinate information of the ground reference point coordinate system coupled to the photographed image and the actual coordinate information of a specific point photographed in the photographed image, and adjusts the ground reference point coordinate system to the actual coordinate information. More detailed description of the coordinate correction module 27 will be described in detail while explaining a driving process of the aerial survey system.

The aerial survey system according to the present invention described above can directly check the coordinate value of the ground reference point for each coordinate value of the photographed image through a coordinate system setting without any complicated calculation process. Accurate results can be obtained with minimal system load and time without going through.

The structure of the aerial survey system according to the present invention will be described in detail while sequentially explaining the processing method.

FIG. 2 is a flowchart illustrating a process of generating a ground reference point coordinate system in a photographed image which is performed by an aerial survey system according to the present invention. FIG. 3 is a ground diagram for calculating a distortion ratio of a photographed image by the aerial survey system according to the present invention. 4 is a view illustrating a state corresponding to a reference point coordinate value displayed on a photographed image coordinate system, and FIG. 4 is a diagram illustrating a ground reference point coordinate system for inputting a ground reference point in a photographed image by an aerial survey system according to the present invention; 5 is a view showing a ground reference point coordinate value for a particular point of the photographed image selected by the operator displayed in the ground reference point coordinate system of Figure 4, Figure 6 is a aerial survey system according to the present invention the ground reference point coordinate system and photographing FIG. 7 is a view illustrating a state of matching between images, and FIG. 7 is a ground survey apparatus for an aerial survey system according to the present invention. Is a view sequentially showing a modified form of the point coordinate bars, it will be explained with reference to.

S10; Distortion Ratio Check Step

When the operator selects a specific ground object in the photographed image being output to the image output module 21 and inputs the ground reference point coordinate value of the ground, the distortion ratio check module 24 receiving the ground reference point coordinate value receives the ground. The reference point coordinate value is transmitted to the relational calculation module 23, and the relational calculation module 23 calculates a corresponding photographed image coordinate value by utilizing a relational expression between the photographed image coordinate value and the ground reference point coordinate value. Here, the modified collinear condition equation may be exemplified.

As shown in FIG. 3, the relational calculation module 23 inputs the ground reference point coordinate value input by the operator to the corrected collinearity condition equation to calculate the coordinate value of the corresponding photographed image, and the distortion ratio checking module 24 is a relational expression. The photographed image coordinate value, which is a result received from the calculation module 23, is applied to the coordinate system AX of the photographed image. In the present embodiment, the first selection point AP is located at the photographed image coordinate values (-6, -4) around the origin O as a result of the calculation using the corrected collinear condition equation, and the second selection point BP. Is located at the coordinates (6, 6) of the photographed image around the origin (O) as a result of the calculation through the corrected collinear condition, and the third selection point (CP) is the origin (O) as a result of calculating through the corrected collinear condition ) Is located at the coordinates (8, -11) of the captured image.

Subsequently, the distortion ratio confirmation module 24 determines a first distance between the origin O and each selection point AP, BP, CP based on the photographed image coordinate values of the identified selection points AP, BP, CP. Calculate

Subsequently, the distortion ratio checking module 24 confirms the ground reference point coordinate values of the selection points AP, BP, CP input by the operator, and the ground reference point coordinate values of the origin point O measured by the GPS module 26. Based on this, the second distance between the origin O and each selection point AP, BP, CP is calculated.

As described above, the first distance is a distance between the selection point (AP, BP, CP) on the background of the photographed image and the origin (O), and the second distance is the selection point (AP, BP, on the ground reference point). CP) and the distance between the origin (O). Therefore, the second distance is the actual distance between the position of the origin point P and the positions of the selection points AP, BP, and CP, and the first distance is a distorted distance where a change in distance occurs due to distortion of the photographed image. Here, the coordinate value of the origin (O) is a GPS coordinate value confirmed by the GPS module 26, which is the position of the aircraft at the time of taking the photographed image.

The distortion ratio checking module 24 checks the difference ratio for each distance of the first distance difference to the second distance difference between the points. In other words, as to the selection points AP, BP, and CP farther from the origin point O, whether the first distance difference is greater than the second distance difference between the points is determined, and the first distance difference for each point according to the distance is determined. It is to check the distortion ratio which is the increase or decrease ratio of. For example, the first distance between the origin O and the fourth selection point is 10 and the second distance is 300 m, the first distance between the origin O and the fifth selection point is 21 and the second distance is 600 m. When the first distance between (O) and the sixth selection point is 33 and the second distance is 900 m, the first distance is 10 (10-0), 11 (21-10), 12 (33-21), etc. for each point. The second distance shows a difference of 300 (300-0), 300 (600-300), 300 (900-600), etc. for each point. As a result, the difference ratio by distance to the first distance relative to the second distance difference increases to 10%, and as a result, the photographed image is distorted at a distortion rate of 10% as the distance increases.

For reference, the photographed image photographed by the camera is distorted as the distance from the photographing center. Therefore, the shape deformation and increase in size of the photographing object become deeper toward the outside of the photographed image. As a result, the photographed image is located farther from the actual position and distorted into a larger shape as it goes outward.

S20; Ground control point coordinate system generation step

The coordinate value setting module 25 generates a ground reference point coordinate system BX dedicated to the photographed image according to the distortion ratio checked by the distortion ratio confirmation module 24. To this end, the coordinate value setting module 25 checks the orientation of the photographed image to determine the axial direction of the ground reference point coordinate system BX, and determines the distance between ground reference points to be applied to the photographed image.

Subsequently, the coordinate value setting module 25 inputs the ground reference point in the latitude direction and the longitude direction located at the interval with respect to the origin O, and the ground reference point along the latitude direction and the longitude direction with the distortion ratio identified above. 4 and 5, the ground reference point coordinate system BX is formed by arranging a plurality of latitude and longitude lines connecting the ground reference points in a lattice form.

In the ground reference point coordinate system BX shown in the present embodiment, the distance between the ground reference points increases as far from the origin O by the distortion ratio confirmed by the distortion ratio check module 24.

Subsequently, as shown in FIG. 4, the coordinate value setting module 25 causes the ground reference point coordinate value and the captured image coordinate value to be linked by linking the ground reference point coordinate system BX and the captured image coordinate system AX. It is possible to immediately check which coordinate value the photographic ground position corresponds to. Here, the photographing image coordinate system AX is a well-known and common technique that is naturally generated to determine the output point of the image when the image output module 21 outputs the photographed image, and is an aerial survey system according to the present invention. Utilizes the above techniques.

As a result, since the ground reference point coordinate system BX generated by the coordinate value setting module 25 is associated with the photographing image coordinate system AX to give an orthogonal image processing effect, the operator selects a point TP of the photographing image or the When the ground reference point coordinate value of one point TP is input, the photographing image coordinate system AX associated with the one point TP is immediately identified and output.

Therefore, in order to process the orthoimage of the photographed image, the ground reference point in the photographed image can be corrected to correspond to the coordinates of the photographed image without complicated calculation through a complex relational expression. Can be processed quickly.

S25; Ground control point coordinate system calibration step

The coordinate correction module 27 checks the ground reference point coordinate system (BX) applied to the photographed image, compares the ground reference point coordinate value of the ground object photographed in the photographed image, and checks whether the ground reference point coordinate system (BX) is applied to the photographed image. Check it.

In more detail, the coordinate correction module 27 selects the ground object ST to be checked, and is a first ground reference point coordinate value of the ground object ST to be verified based on the ground reference point coordinate system BX. Check the coordinate value (OP1). For reference, the first coordinate value OP1 may be a coordinate value of one point of the ground reference point coordinate system BX in which the image of the ground object ST to be checked overlaps.

Subsequently, the coordinate correction module 27 retrieves the actual ground reference point coordinate value of the ground object ST to be checked from the ground reference point DB 11, and applies the retrieved ground reference point coordinate value to the ground reference point coordinate system BX. Check the target coordinate value (TP2).

Here, since a difference occurs in the positions of the first coordinate value OP1 and the correction target coordinate value TP2 in which the ground object ST to be checked is located, the coordinate correction module 27 causes an error in the ground reference point coordinate system BX. Check that there is. In order to correct such an error, the coordinate correction module 27 displays the 'hardness axis' of the correction target coordinate value TP2 having a difference between the first coordinate value OP1 and the longitude position as shown in FIG. 7. Move to the 'hardness axis' where the coordinate value OP1 is located. In addition, the coordinate correction module 27 moves other 'hardness axes' configured in the ground reference point coordinate system BX to be adjacent to the 'hardness axis' according to the distortion ratio applied to the ground reference point coordinate system BX (FIG. 7 ( b) Reference), The ground reference point coordinate value of the ground object (ST) to be checked should be accurately displayed at the corresponding point of the corrected ground reference point coordinate system.

In the present exemplary embodiment, the first coordinate value OP1 having only the difference in longitude and the correction target coordinate value TP2 is illustrated, but in addition, there may be only a latitude difference (OP2), or both a longitude and a latitude may be different ( OP3).

FIG. 8 is a flowchart sequentially illustrating an orthogonal processing of photographed images performed by an aerial survey system according to the present invention, and FIG. 9 is a view illustrating a photographing geometry formed when the aerial survey system is driven according to the present invention. Is a diagram showing the relationship between the coordinate values of the photographed image formed during operation of the aerial survey system according to the present invention and the photographing direction vector u, and FIG. 11 is a graph illustrating a state in which the aerial survey system corrects the distortion of the photographed image. The drawings are described as follows.

S30; Base point selection step

During the aerial survey, the photographing apparatus 30 mounted on the aircraft measures the ground in real time and stores the image in the image DB 12, and the image output module 21 outputs the photographed image of the orthodontic region to be photographed. In addition, the GPS module 26 measures the shooting position of the current aircraft in real time, and links the captured shooting image.

Subsequently, the operator selects a reference point from the photographed image output to the image output module 21, and the relational calculation module 23 receives the input and checks it.

Aerial photographs are stored in a file through a scanning process. Images captured as a file through a scanning process do not have ground coordinates, so the intersections, bridges, A waterway or road bend vertex and a mountain peak are determined as reference point coordinates (x _a , y _a ).

For reference, the operator operates the image control module 22 to select the reference point within the photographed image output to the image output module 21, and the relational calculation module 23 receives the reference point and confirms it.

S40; Ground control point search step

The operator selects a reference point in the photographed image, retrieves the ground reference point coordinate values (P _x , P _y , P _z ) corresponding to the selected point from the ground reference point DB 11, and presents the aerial survey system according to the present invention. Enter the ground reference point in the input field (not shown).

Since the aerial survey process aims to update the background image of the existing digital map, the ground reference point corresponding to the reference point selected by the operator can be immediately identified.

S50; First operation step

The determining of the facial expression six elements may be referred to as the step of performing the internal expression and the external expression of the photographed image.

Internal expression corrects the distortion of the aerial photograph itself.

For reference, the photographed image taken from the ground of the aircraft is distorted by various factors such as the characteristics of the camera, the refraction of the atmosphere, the curvature of the earth. If there is no distortion on the photographed image due to such distortion, _a point that should have a corrected coordinate value of (x _a ', y _a ') has a coordinate value of (x _{a ,} y _a ) due to the distortion. The internal expression is to rearrange (x _a , y _a ), which is each coordinate value of the photographed image having distortion, to (x _a ', y _a '), which is a new correction coordinate value whose distortion is corrected.

On the other hand, the outer face is a reference point of image distortion is corrected through an internal face by calculating the expression 6 elements (ω, Φ, ψ, S _x, S _y. S _z) unknown unknown when air taken from the GCP Establish a relationship between the coordinate values (x _a ', y _a ') and the ground reference point coordinate values (P _x , P _y , P _z ).

The present invention does not need to produce an orthogonal image in which distortion is corrected by performing internal expression separately. Therefore, a new corrected collinear conditional expression including internal expressions is established and the expression 6 elements are calculated from the corrected collinearity conditional equation.

For reference, orientation elements (orientation elements) are elements that determine the position and attitude of the camera required for the expression of the aerial photo, and are composed of the element of the base line and the rotation angle around the base line.

As can be seen in Figure 9, the relationship between the vector indicating the position of the aircraft in the earth center, the vector indicating the position of the ground reference point photographed from the earth center and the vector indicating the shooting direction can be expressed as shown in Equation 1 below. have.

와

는 지구 중심좌표계로 표현되지만,

는 [도 10]와 같이 사진좌표계에 의해서 표현된다. 서로 다른 좌표계를 지니고 있는 벡터를 동일 좌표계로 맞추기 위하여 x, y, z방향으로의 회전행렬이 정의되어야 하며, 이 회전행렬 M은 아래와 같다.
Where μ is any scale variable. In [Equation 1]

Wow

Is expressed in the Earth's central coordinate system,

Is represented by the photo coordinate system as shown in FIG. In order to fit vectors with different coordinate systems into the same coordinate system, a rotation matrix in the x, y, and z directions must be defined, and the rotation matrix M is as follows.

Here, ω, Φ and Ψ represent rotation angles in the x, y and z directions.

는 도 10에서 보는 바와 같이, 촬영이미지의 좌표값인 (x_a ,y_a) 그리고 초점거리 f에 의해서 [수학식 3]으로 결정될 수 있다.
Also,

10 may be determined by Equation 3 by (x _a , y _a ), which is a coordinate value of the captured image, and a focal length f.

)에 의해 정의되며 [수학식 3]은 아래와 같이 다시 쓰여질 수 있다.
However, when photographing, distortion caused by the lens, distortion of the earth curvature, and distortion caused by the refraction of the atmosphere occurs. This amount of distortion δr is the distance from the center of the captured image (

Equation 3 can be rewritten as

Here, the distortion amount δr is defined as follows.

Here, Δr ₁ represents the distortion of the lens, Δr ₂ represents the distortion with respect to the earth curvature, and Δr ₃ represents the distortion with respect to the refraction of the atmosphere. These values are defined by the height of the aircraft and the characteristics of the photographing apparatus 30 (refractive index, focal length, etc.) of the photographing apparatus, and the solution is generally easily obtained in photogrammetry, so a detailed description thereof is omitted. do.

Equation 1 can be expressed from Equations 2 and 4 as follows.

Wherein m ₁₁ to m ₃₃ are elements of M.

[Equation 6] is obtained from the shooting geometry of the aircraft, μ is an unknown unknown and can be expressed as follows by eliminating μ.

[Equation 7] and [Equation 8], which are the relational expressions calculated by the relational calculation module 23 through the above-described procedure, are coordinate values ((x _a ', y _a ') = (x _a (1) -δr) and y _a (1-δr) and the relationship between the coordinates (P _x , P _y , P _z ) of the ground reference point.

Using the corrected collinear condition equation (Equation 7,8), the internal expression for correcting the distortion of the photographed image and the external expression for applying the ground reference point coordinate value to the reference point coordinate value of the photographed image may be simultaneously performed.

Coordinate value of the shot image in the modified collinearity condition (x _a, y _a) and coordinate values of the ground control points _{(P x, P y, P} z), and coordinates of a photographed image (x _a, y _a) corresponding By substituting the amount of distortion obtained from, the expression six elements (ω, Φ, ψ, S _x , S _y . S _z ) are calculated.

Since there are six unknowns of the six expression elements, six equations are required. Therefore, the coordinate values (x _a , y _a ) of the photographed image and the coordinate values (P _x , P _y , P _z ) of the ground reference point corresponding thereto are required to be three or more points. Typically, 5 or 6 points are used for the coordinates. The process of obtaining the facial expression six elements uses a method used in the bundle block adjustment method that is generally applied in aerial surveying.

For reference, the luminous flux adjustment method is a representative georeferencing method for determining the external expression elements of a plurality of superimposed images.

The first operation step (S50) of producing the ortho images is to convert the aerial photographs by the central projection into the orthoimages by the orthographic projection. In other words, the deviation caused by the central projection is eliminated. The production of orthoimages is closely related to external expressions. This is because the production can be said of the orthoimage is to move the center coordinate of the projected image shooting (x _a, y _a) an ortho-coordinate of the projected orthoimage (x _b, y _b). That is, the coordinate value (x _a , y _a ) of each photographed image is obtained from the coordinate values (P _x , P _y , P _z ) of the ground reference point using the corrected collinear condition equation, and the coordinate value ( By extracting the brightness value (Brightness Value or Digital Number) possessed by x _a , y _a ) and giving the extracted brightness value to each orthoimage coordinate value (x _b , y _b ), an ortho image is produced. Since the captured image scanned and stored in the image DB 12 has coordinate values (x _a , y _a ) and brightness values thereof, the coordinates of the captured image corresponding to the orthogonal image coordinate values (x _b , y _b ) If the values (x _a , y _a ) are obtained, ortho images can be easily produced.

S60; Second operation stage

When the relational calculation module 23 calculates the facial expression six elements through the first operation step S30, the unknown in the corrected collinear condition equation [Equation 7,8] is the ground reference point coordinate value (P _x , P _y , P _z). ) And the image coordinates (x _a , y _a ).

이다. 따라서 단순한 방법으로는 해를 구할 수 없다. Here, the coordinate value of the ground reference point is confirmed through a search of the ground reference point DB (11) which is the numerical elevation data. Therefore, the actual unknown becomes the coordinate value (x _a , y _a ) of the captured image. However, (1-δr) on the left side of the corrected collinearity condition equation is a function related to r (distance from photo origin) (refer to [Equation 5]), and r is also _a function related to x _a , y _a

to be. Therefore, no solution can be obtained in a simple way.

Therefore, in order to simplify the calculation process, the relational calculation module 23 of the present invention uses the r-f (r) table.

Square both sides of Equations 7 and 8 and add the following equations.

)를 나타낸다.
Where U ₁ , U _{2 ,} U ₃ Is defined as below, and f (r) is the distance from the origin in the distortion-corrected

).

는 전술한 바와 같이 카메라의 특성과 촬영시의 고도에 의해 정의되어 있는 값이므로, 촬영된 촬영이미지에 대해 r에 대한 f(r)의 값을 쉽게 계산가능하며, 이를 [도 11]와 같이 r-f(r) 테이블화할 수 있다. 상기 [도 11]를 참조하여 f(r)로부터 r을 계산하는 방법에 대해 예를 들면, 지상기준점 좌표값 (P_x, P_y, P_z)이 주어지면, 상기 지상점을 이용하여 [수학식 11, 12 및 13]으로부터 U₁(P_x, P_y, P_z), U₂(P_x, P_y, P_z), U₃(P_x, P_y, P_z)를 계산하고, [수학식 9]을 이용하여 f(r)을 계산한다. [도 11]에 보이는 것처럼 f(r)=120이라면, r과 f(r)의 테이블을 이용하여 r=122.037값을 찾는다. 상기와 같은 방법을 이용하면, 원하는 모든 지상점에 대하여 f(r)을 구하고, f(r)에 해당하는 r값을 쉽게 찾을 수 있다.In Equation 9 above

Since is a value defined by the characteristics of the camera and the altitude at the time of shooting as described above, it is possible to easily calculate the value of f (r) for r with respect to the captured shot image, which is rf as shown in FIG. (r) can be tabled. For example, a ground reference point coordinate value (P _x , P _y , P _z ) is given for the method of calculating r from f (r) with reference to FIG. 11 above. Calculate U ₁ (P _x , P _y , P _z ), U ₂ (P _x , P _y , P _z ), U ₃ (P _x , P _y , P _z ) from Equations 11, 12 and 13, Calculate f (r) using [Equation 9]. As shown in FIG. 11, if f (r) = 120, r = 122.037 is found using the tables of r and f (r). Using the above method, f (r) can be obtained for all desired ground points, and r value corresponding to f (r) can be easily found.

In addition, since f (r) / r = 1-δr, Equation 7 and Equation 8 may be expressed as follows.

[Equation 14] and [Equation 15] are substantially the same as [Equation 7] and [Equation 8].

Therefore, if the ground reference point coordinate values (P _x , P _y , P _z ) are input through numerical elevation data, the value of f (r) is determined, and the value of r is determined from f (r) determined through the rf (r) table. , The coordinate values (x _a , y _a ) of the distorted aerial photograph image are easily and quickly calculated from the corrected collinear condition equation ([Equation 7,8] or [Equation 14,15]).

When the coordinate values (x _a , y _a ) of the aerial image are extracted, the brightness value of the coordinate values (x _a , y _a ) of the captured image is converted to the coordinate values (x _b , y _b ) of the orthoimage. Grant. This process is performed for all coordinates, resulting in an orthoimage of the desired area. For reference, the captured image coordinate values (x _a , y _a ) of the coordinate values (x _b , y _b ) of the orthoimage may correspond to the ground reference point coordinate values (P _x , P _y ) of the numerical elevation data.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

11; Ground control point DB 12; Image DB 21; Image output module
22; Image control module 23; Relational calculation module 24; Distortion Ratio Check Module
25; Coordinate value setting module 26; GPS module AP, BP, CP; Selection point
AX; Image coordinate system BX; Ground reference point coordinate system O; Origin
OP1, OP2, OP3; First, second, and third coordinate values TP2; Coordinate value

Claims (1)

Image output module operating by applying a captured image coordinate system consisting of a plurality of X-axis and Y-axis is arranged in a grid so as to output the captured image while operating in accordance with the control value, so as to check the coordinates of each point in the captured image ;
An image control module for generating a control value for controlling the operation of the image output module and transferring the control value to the image output module;
GPS module for checking the current position of the aircraft in GPS coordinates;
Coordinate value of ground control point coordinate

(x _a , y _a : taken image coordinate value, δr: distortion amount, f: focal length, P _x , P _y , P _z : ground reference point coordinate value, S _x , S _y . S _z : expression element, m ₁₁ M ₃₃ : rotation matrix)
A relational calculation module for calculating an output image coordinate value through a;
Transfer the input two or more ground reference point coordinate values to the relational image calculation module to calculate the coordinates of the photographed image, and confirm the position of the photographed image coordinate value received from the relational calculation module based on the photographed image coordinate system, and photograph the image. The first distance, which is the distance between the origin of the image coordinate system and the photographed image coordinate value, is calculated for each point, and the second distance, which is the distance between the ground reference point coordinate value and the input ground reference point coordinate value of the origin identified by the GPS module, is calculated. Computing each point by each point, and confirming the first distance difference confirmed for each point based on the second distance difference confirmed for each point to determine the distortion ratio that is the increase or decrease ratio of the first distance difference for each point according to the distance to the origin. Distortion ratio checking module;
The ground reference point is set along the latitude direction and the longitude direction around the origin, and the position of the ground reference point is set in the photographed image by checking the distance between the ground reference points that change with the distortion ratio. Coordinates for generating a ground reference point coordinate system composed of a plurality of latitude and longitude axes in a lattice form, and linking the ground reference point coordinate system and the photographed image coordinate system to link the photographed image coordinate values corresponding to the ground reference point coordinate values. Value setting module; And
Select the ground object to be checked in the photographed image to check the first coordinate value of the ground reference point coordinate system where the ground object image overlaps, and retrieve the actual ground reference point coordinate value of the ground to be checked from the ground reference point DB. Check the correction target coordinate value applied to the reference point coordinate system, and shift the longitude axis and latitude axis corresponding to the correction target coordinate value to become the longitude axis and latitude axis corresponding to the first coordinate value, A coordinate correction module adapted to apply to the photographed image by modifying the other longitude axis and the latitude axis adjacent to the latitude axis according to the distortion ratio;
GPS-based aerial survey system for precision processing of ortho images comprising a.

Images