CN101545776A - Method for obtaining digital photo orientation elements based on digital map - Google Patents

Abstract

The invention provides a method for obtaining digital photo orientation elements based on a digital map. The method comprises the following steps: step 1, a digital photo and a digital map corresponding to the digital photo are shot, wherein the digital photo comprises at least five ground object points, and the digital map comprises homologous points corresponding to the ground object points; the ground object points and the homologous points are totally called as control points; the digital photo is provided with a phone two-dimensional coordinate system, and the digital map is provided with a digital map coordinate system; step 2, coordinates of the control points in the digital map coordinate system and the phone two-dimensional coordinate system and coordinates of a photo principal point in the phone two-dimensional coordinate system are obtained, wherein the photo principal point is a perpendicular foot point of a shooting lens center on the photo; and step 3, a photogrammetric coordinate system D-XDYDZD is established. The invention utilizes the prior digital map as a condition to calculate the orientation elements of a common digital image, thereby providing a simple, convenient and rapid low-cost path for obtaining three-dimensional space information and having small field operation workloads and low expense.

Description

Digital photo orientation elements acquisition methods based on numerical map

Technical field

The present invention relates to a kind of method of obtaining photo orientation elements, relate in particular to a kind of method of utilizing numerical map to obtain common digital photo orientation elements.

Background technology

The element of orientation that calculates photo is photogrammetric and important content computer realm, utilizes the element of orientation of photo further to carry out three-dimensional measurement to photographic.At present, the method for the element of orientation of calculating photo mainly contains two kinds of methods: by the method that calculate at the reference mark and GPS/INS observes.

By the reference mark Calculation Method is the three-dimensional reference mark (being called gold point in the computer vision again) that utilizes some, rationally distributes, set up corresponding relation with corresponding imaging point, the parameter of calculating photo has very extensive studies and application, this method can realize equally frame of video the resolving of s internal and external orientation (Zhang Zuxun. digital photogrammetry and computer vision [J]. Wuhan University's journal information science version, 2004.12,12 (29)).Be widely used in photogrammetric field at present.

The method of utilizing GPS/INS observation is closely to develop during the last ten years and next new technology, adopt GPS/INS combined system (abbreviation POS system) when obtaining aeroplane photography the dimensional orientation of image (utilize GPS to determine to take the photograph the locus at station, utilize the IMU inertial measuring unit to obtain the attitude angle of image), to be directly used in the photo orientation of photogrammetric office work, purpose be replace photogrammetric encryption operation (CannonM E, Sun H.Experimentalassessment of a non-dedicate GPS receiver system for airborne attitudedetermination[J] .ISPRS Jour nal of Photogrammetry ﹠amp; Remote Sensing, 1996,51 (2): 99-108.).Equally, this technology also can be used for ground, by advanced sensor and equipment such as assembling GPS/CCD/INS/ or dead reckoning system on motor vehicle, can among the high-speed travel of vehicle, gather the spatial position data and the attribute data of road and road both sides atural object fast, as: road axis or sideline position coordinates, the position coordinates of target atural object, the road, the track, wide, bridge, the tunnel height, traffic sign, the gradient, data sync storage such as road equipment are in carried-on-vehicle computer system, handle through post editing, form abundant in content path space information database (Li Deren. traverse measurement technology and application thereof [J]. geospatial information .2006 August: 1-5).

Although the technical method precision that adopts is higher at present, its deficiency is arranged also.Can't accomplish the requirement of real-time by the reference mark Calculation Method, workload is big simultaneously.And GPS/INS observation fancy price is restricting its (He Xiufeng that applies always, Xu Yong, Sang Wengang. microminiature IMU/GPS integrated positioning orientation system research [J]. Wuhan University's journal information science version. the 30th volume o. 11th, in November, 2005: 991-994).

Summary of the invention

Technical matters: the technical problem to be solved in the present invention provides one and utilizes numerical map to calculate the method for common digital photo orientation elements, makes that to obtain three-dimensional spatial information easier, quick, cheap.

Technical scheme: for solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of digital photo orientation elements acquisition methods based on numerical map, this method comprises the steps:

Step 1: take digital photo and with the corresponding numerical map of this number photo, this number photo comprises at least 5 culture points, comprise the same place corresponding in the numerical map with culture point, culture point and same place are referred to as the reference mark, digital photo is provided with the photo two-dimensional coordinate system, and numerical map is provided with the numerical map coordinate system;

Step 2: obtain the coordinate of reference mark in the numerical map coordinate system and coordinate and the coordinate of photo principal point in the photo two-dimensional coordinate system in the photo two-dimensional coordinate system, the photo principal point is the intersection point point of photographic field lens center on photo;

Step 3: set up photogrammetric coordinate system D-X _DY _DZ _DThis photogrammetric coordinate system with approximate shooting point position be initial point, on the spot east to be X-axis, direction is a Y-axis vertically upward, south to the right hand three dimensional space coordinate that be the Z axle is on the spot, is coordinate in the photogrammetric coordinate system with the coordinate conversion of reference mark in the numerical map coordinate system;

Step 4: utilize coordinate and coordinate in photo two-dimensional coordinate system the element of orientation that obtain photo of reference mark in photogrammetric coordinate system, acquisition methods comprises the steps:

Step 41: utilize coordinate and the coordinate in photo two-dimensional coordinate system of reference mark in photogrammetric coordinate system, calculate photo 2 d dlt first parameter, second transformation parameter, the 3rd transformation parameter, the 4th transformation parameter, the 5th transformation parameter, the 6th transformation parameter, the 7th transformation parameter and the 8th transformation parameter according to the 2 d dlt principle, that is: $\left\{\begin{array}{c}x+\mathrm{\Δx}+\frac{l_1\·X+l_2\·Y+l_3}{l_7\·X+l_8\·Y+1}=0\\ y+\mathrm{\Δy}+\frac{l_4\·X+l_5\·Y+l_6}{l_7\·X+l_8\·Y+1}=0\end{array}\right.---\left(1\right)$

Wherein, $\left\{\begin{array}{c}\mathrm{\Δx}=k_1{r}^2(x-x_0)\\ \mathrm{\Δy}=k_1{r}^2(y-y_0)\end{array}\right.,$

(x, y) is the coordinate of reference mark in the photo two-dimensional coordinate system; (X, Y) is the coordinate of reference mark in photogrammetric coordinate system; k ₁Represent the object lens distortion parameter; Δ x, Δ y are the influence of object lens distortion to the photo two-dimensional coordinate system; l ₁, l ₂, l ₃, l ₄, l ₅, l ₆, l ₇, l ₈Represent two dimension directly linear first transformation parameter, second transformation parameter, the 3rd transformation parameter, the 4th transformation parameter, the 5th transformation parameter, the 6th transformation parameter, the 7th transformation parameter and the 8th transformation parameter respectively; (x ₀, y ₀) be the coordinate in the photo two-dimensional coordinate system of photo principal point, the photo principal point is the intersection point point of object lens center on photo;

Introduce the transition first parameter γ ₁, the transition second parameter γ ₂, transition the 3rd parameter γ ₃, order

$\left\{\begin{array}{c}{\mathrm{\γ}}_1=-(a_1{X}_S+b_1{Y}_S+c_1{Y}_S)\\ {\mathrm{\γ}}_2=-(a_2{X}_S+b_2{Y}_S+c_2{Y}_S)\\ {\mathrm{\γ}}_3=-(a_3{X}_S+b_3{Y}_S+c_3{Y}_S)\end{array}\right.,$ Can obtain:

$\left\{\begin{array}{c}{l}_1=\frac{{\mathrm{fa}}_1-x_0{a}_3}{{\mathrm{\γ}}_3}\\ l_2=\frac{{\mathrm{fb}}_1-x_0{b}_3}{{\mathrm{\γ}}_3}\\ l_3=\frac{{\mathrm{f\γ}}_1-x_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_4=\frac{{\mathrm{fa}}_2-y_0{a}_3}{{\mathrm{\γ}}_3}\\ l_5=\frac{{\mathrm{fb}}_2-y_0{b}_3}{{\mathrm{\γ}}_3}\\ l_6=\frac{{\mathrm{f\γ}}_2-y_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_7=\frac{a_3}{{\mathrm{\γ}}_3}\\ l_8=\frac{b_3}{{\mathrm{\γ}}_3}\end{array}\right.,$

Step 42: by 2 d dlt parameter acquiring photographic field lens focal length, promptly

$f=\sqrt{\frac{(l_1^2+l_4^2)-(l_2^2+l_5^2)}{l_8^2-l_7^2}}$ , wherein, f is the photographic field lens focal length;

Step 43: introduce rotation matrix $R=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right],$ If

$\left\{\begin{array}{c}x+\frac{f[a_{1}X+b_{1}Y+(-a_1{X}_S-b_1{Y}_S-c_1{Z}_S)]-x_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\\ y+\frac{f[a_{2}X+b_{2}Y+(-a_2{X}_S-b_2{Y}_S-c_2{Z}_S)]-y_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\end{array}\right.$

Can obtain:

$\left\{\begin{array}{c}{a}_1=\frac{l_1{\mathrm{\γ}}_3}{f}\\ a_2=\frac{l_4{\mathrm{\γ}}_3}{f}\\ a_3=l_7{\mathrm{\γ}}_3\\ b_1=\frac{l_2{\mathrm{\γ}}_3}{f}\\ b_2=\frac{l_5{\mathrm{\γ}}_3}{f}\\ b_3=l_8{\mathrm{\γ}}_3\end{array}\right.$ $\left\{\begin{array}{c}{\mathrm{\γ}}_1=\frac{l_3}{f}{\mathrm{\γ}}_3\\ {\mathrm{\γ}}_2=\frac{l_6}{f}{\mathrm{\γ}}_3\end{array}\right.$ $\left[\begin{array}{c}{c}_1\\ c_2\\ c_3\end{array}\right]=\left[\begin{array}{c}{a}_1\\ a_2\\ a_3\end{array}\right]\×\left[\begin{array}{c}{b}_1\\ b_2\\ b_3\end{array}\right]=\left[\begin{array}{c}{a}_2{b}_3-a_3{b}_2\\ a_3{b}_1-a_1{b}_3\\ a_1{b}_2-a_2{b}_1\end{array}\right]$

Step 44: obtain the element of orientation of photo, the element of orientation of photo comprises the coordinate (X of photography point in photogrammetric coordinate system _S, Y _S, Z _S) and the photography the angle of roll, the angle of pitch and photo rotation angle use respectively

, ω, κ represent;

Wherein

ω, κ acquisition methods are:

Coordinate (the X of photography point in photogrammetric coordinate system _S, Y _S, Z _S) acquisition methods is:

$\left\{\begin{array}{c}{a}_1{X}_S+b_1{Y}_S+c_1{Z}_S=-{\mathrm{\γ}}_1\\ a_2{X}_S+b_2{Y}_S+c_2{Z}_S=-{\mathrm{\γ}}_2\\ a_3{X}_S+b_3{Y}_S+c_3{Z}_S=-{\mathrm{\γ}}_3\end{array}\right.$

$\left[\begin{array}{c}{X}_S\\ Y_S\\ Z_S\end{array}\right]={\left[\begin{array}{ccc}{a}_1& b_1& c_1\\ a_2& b_2& c_2\\ a_3& b_3& c_3\end{array}\right]}^{-1}\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right]\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]$

F is the photographic field lens focal length, x ₀, y ₀Be the image coordinate of photo principal point, the photo principal point is the intersection point point of object lens center on photo.

Beneficial effect: beneficial effect of the present invention is: utilize prior digital map to be condition, calculate the element of orientation of common digital image, provide easy, quick, a cheap approach for obtaining three-dimensional spatial information, the field process amount is little, and cost is low.

Description of drawings

Fig. 1 is the process flow diagram of photo orientation elements computing method provided by the invention.

Embodiment

The present invention will be further described below in conjunction with accompanying drawing.

Computing method provided by the invention can realize the calculating of logarithmic code photo camera site, photography attitude, photo focal length and distortion, can be widely used in digital city construction and three-dimensional modeling, belong to close-range photogrammetry and computer vision field.The present invention is utilizing the 2 d dlt formula, according to the x in the digital elements of interior orientation ₀, y ₀Be approximately equal to 0 characteristics, proposed to calculate the method for elements of interior orientation, referring to Fig. 1, its step is as follows:

Step S11: obtain digital photo and with the corresponding numerical map of this number photo, this number photo comprises at least 5 culture points, comprise the same place corresponding with culture point in the numerical map, digital photo is provided with the photo two-dimensional coordinate system, and numerical map has the numerical map coordinate system;

Step S12: utilize the software of Visual C# platform development to obtain coordinate and culture point the coordinate in photo two-dimensional coordinate system of same place in the numerical map coordinate system;

Step S13: set up photogrammetric coordinate system, this coordinate system with approximate photography point position be initial point, on the spot east to be X-axis, direction is a Y-axis vertically upward, south to the right hand three dimensional space coordinate that is the Z axle is on the spot, is coordinate in the photogrammetric coordinate system with the coordinate conversion of same place in the numerical map coordinate system;

Step S14: utilize the coordinate of same place in photogrammetric coordinate system and the element of orientation of the coordinate Calculation photo of culture point in the photo two-dimensional coordinate system.

Step S14 comprises the steps:

Step S141: at first utilize the coordinate of reference mark in photogrammetric coordinate system and coordinate Calculation photo 2 d dlt parameter and the photo distortion parameter in the photo two-dimensional coordinate system;

Step S142: by the focal length of 2 d dlt calculation of parameter video camera;

Step S143: the elements of exterior orientation that the focal length during according to 2 d dlt parameter and video camera shooting further calculates photo (comprises the camera positions parameter X _S, Y _S, Z _SWith the photography attitude parameter

ω, κ), then with the camera positions parameter X _S, Y _S, Z _SBe transformed in the map coordinates system.

That is to say that method provided by the invention comprises:

The first step: the numerical map that obtains research range.

Second step: the digital photo of taking goal in research with ordinary digital camera.The number that requires during shooting to be positioned at the culture point on the same surface level when promptly utilizing digital camera to take, comprise at least 5 culture points more than 5, and these culture points should be on the same surface level on the spot, and imaging is clear, is convenient to identification.These culture points must be the points that numerical map exists simultaneously.

The 3rd step: select on numerical map and the digital photo same place one to one.Obtain the coordinate of same place in the numerical map coordinate system and the two-dimensional coordinate in photographic coordinate system by working out corresponding software.

The 4th step: set up photogrammetric coordinate system, concrete grammar sees Table 1.Be the coordinate in the photogrammetric coordinate system then with the coordinate conversion of same place in map coordinates system.

The relation of table 1 photogrammetric coordinate system and map coordinates system

Coordinate system	X	Y	Z
				Map coordinates system	North	East	Elevation
Photogrammetric coordinate system	East	Elevation	South
				Relation	X Photogrammetric＝Y Map	Y Photogrammetric＝Z Map	Z Photogrammetric＝-X Map

The 5th step: utilize the photogrammetric coordinate system of 5 above same places and the element of orientation of two-dimentional photo coordinate Calculation photo.

Calculate the element of orientation of photo, step is as follows:

1. calculate the 2 d dlt parameter

Consider image distortion, be the 2 d dlt formula:

$\left\{\begin{array}{c}x+\mathrm{\Δx}+\frac{l_1\·X+l_2\·Y+l_3}{l_7\·X+l_8\·Y+1}=0\\ y+\mathrm{\Δy}+\frac{l_4\·X+l_5\·Y+l_6}{l_7\·X+l_8\·Y+1}=0\end{array}\right.---\left(1\right)$

Wherein $\left\{\begin{array}{c}\mathrm{\Δx}=k_1{r}^2(x-x_0)\\ \mathrm{\Δy}=k_1{r}^2(y-y_0)\end{array}\right.,$ Comprise photo distortion parameter k ₁

In the formula: x, y are the image coordinate at reference mark;

X, Y are the photogrammetric coordinate systems at reference mark;

Δ x, Δ y are the influence of object lens distortion to image coordinate;

l ₁, l ₂, l ₃, l ₄, l ₅, l ₆, l ₇, l ₈It is the 2 d dlt parameter;

k ₁Represent the object lens distortion factor;

x ₀, y ₀x ₀, y ₀Be the image coordinate of photo principal point, the photo principal point is the intersection point point of object lens center on photo

According to principle of least square method, utilize the 2 d dlt parameter l in the indirect adjustment computing formula (1) ₁L ₈With distortion parameter k ₁

2. the relation between calculating orientation elements of photo and the 2 d dlt.

The condition identical according to the planar point elevation is transformed to the collinearity equation in photogrammetric:

$\left\{\begin{array}{c}x-x_0+f\frac{a_{1}X+b_{1}Y+(-a_1{X}_S-b_1{Y}_S-c_1{Z}_S)}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\\ y-y_0+f\frac{a_{2}X+b_{2}Y+(-a_2{X}_S-b_2{Y}_S-c_2{Z}_S)}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\end{array}\right.$

In the formula: f is the photographic field lens focal length;

a _i, b _i, c _iIt is rotation matrix $R=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right]$ In each the value.

The reduction of fractions to a common denominator is merged into:

$\left\{\begin{array}{c}x+\frac{f[a_{1}X+b_{1}Y+(-a_1{X}_S-b_1{Y}_S-c_1{Z}_S)]-x_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\\ y+\frac{f[a_{2}X+b_{2}Y+(-a_2{X}_S-b_2{Y}_S-c_2{Z}_S)]-y_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\end{array}\right.$

For explaining conveniently, introduce transition parameter γ ₁, γ ₂, γ ₃, order

$\left\{\begin{array}{c}{\mathrm{\γ}}_1=-(a_1{X}_S+b_1{Y}_S+c_1{Y}_S)\\ {\mathrm{\γ}}_2=-(a_2{X}_S+b_2{Y}_S+c_2{Y}_S)\\ {\mathrm{\γ}}_3=-(a_3{X}_S+b_3{Y}_S+c_3{Y}_S)\end{array}\right.$

Can simplify:

$\left\{\begin{array}{c}x+\frac{({\mathrm{fa}}_1-x_0{a}_3)X+({\mathrm{fb}}_1-x_0{b}_3)Y+[{\mathrm{f\γ}}_1-x_0{\mathrm{\γ}}_3]}{a_{3}X+b_{3}Y+{\mathrm{\γ}}_3}=0\\ y+\frac{({\mathrm{fa}}_2-y_0{a}_3)X+({\mathrm{fb}}_2-y_0{b}_3)Y+[{\mathrm{f\γ}}_2-y_0{\mathrm{\γ}}_3]}{a_{3}X+b_{3}Y+{\mathrm{\γ}}_3}=0\end{array}\right.---\left(2\right)$

$\left\{\begin{array}{c}{l}_1=\frac{{\mathrm{fa}}_1-x_0{a}_3}{{\mathrm{\γ}}_3}\\ l_2=\frac{{\mathrm{fb}}_1-x_0{b}_3}{{\mathrm{\γ}}_3}\\ l_3=\frac{{\mathrm{f\γ}}_1-x_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_4=\frac{{\mathrm{fa}}_2-y_0{a}_3}{{\mathrm{\γ}}_3}\\ l_5=\frac{{\mathrm{fb}}_2-y_0{b}_3}{{\mathrm{\γ}}_3}\\ l_6=\frac{{\mathrm{f\γ}}_2-y_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_7=\frac{a_3}{{\mathrm{\γ}}_3}\\ l_8=\frac{b_3}{{\mathrm{\γ}}_3}\end{array}\right.$ Work as x ₀=0, y ₀Obtained in=0 o'clock $\left\{\begin{array}{c}{l}_1=\frac{{\mathrm{fa}}_1}{{\mathrm{\γ}}_3}\\ l_2=\frac{{\mathrm{fb}}_1}{{\mathrm{\γ}}_3}\\ l_3=\frac{{\mathrm{f\γ}}_1}{{\mathrm{\γ}}_3}\\ l_4=\frac{{\mathrm{fa}}_2}{{\mathrm{\γ}}_3}\\ l_5=\frac{{\mathrm{fb}}_2}{{\mathrm{\γ}}_3}\\ l_6=\frac{{\mathrm{f\γ}}_2}{{\mathrm{\γ}}_3}\\ l_7=\frac{a_3}{{\mathrm{\γ}}_3}\\ l_8=\frac{b_3}{{\mathrm{\γ}}_3}\end{array}\right.---\left(3\right)$

In the formula: l ₁, l ₂, l ₃, l ₄, l ₅, l ₆, l ₇, l ₈It is the 2 d dlt parameter.

Parameter to formula (3) is carried out algebraic operation:

$l_1^2+l_4^2+f^2{l}_7^2=\frac{f^2}{{\mathrm{\γ}}_3^2}(a_1^2+a_2^2+a_3^2)=\frac{f^2}{{\mathrm{\γ}}_3^2}---\left(4\right)$

$l_2^2+l_5^2+f^2{l}_8^2=\frac{f^2}{{\mathrm{\γ}}_3^2}(b_1^2+b_2^2+b_3^2)=\frac{f^2}{{\mathrm{\γ}}_3^2}=l_1^2+l_4^2+f^2{l}_7^2---\left(5\right)$

Can resolve the image focal length by above two formulas:

$f^2=\frac{(l_1^2+l_4^2)-(l_2^2+l_5^2)}{l_8^2-l_7^2}---\left(6\right)$

Further obtain:

$\frac{1}{{\mathrm{\γ}}_3^2}=\frac{l_1^2+l_4^2+f^2{l}_7^2}{f^2}$ Or $\frac{1}{{\mathrm{\γ}}_3^2}=\frac{l_2^2+l_5^2+f^2{l}_8^2}{f^2}---\left(7\right)$

To (3) formula, can obtain six parameters in the rotation matrix for the people:

$\left\{\begin{array}{c}{a}_1=\frac{l_1{\mathrm{\γ}}_3}{f}\\ a_2=\frac{l_4{\mathrm{\γ}}_4}{f}\\ a_3=l_7{\mathrm{\γ}}_3\\ b_1=\frac{l_2{\mathrm{\γ}}_3}{f}\\ b_2=\frac{l_5{\mathrm{\γ}}_3}{f}\\ b_3=l_8{\mathrm{\γ}}_3\end{array}\right.---\left(8\right)$

Can obtain equally:

$\left\{\begin{array}{c}{\mathrm{\γ}}_1=\frac{l_3}{f}{\mathrm{\γ}}_3\\ {\mathrm{\γ}}_2=\frac{l_6}{f}{\mathrm{\γ}}_3\end{array}\right.---\left(9\right)$

$\left[\begin{array}{c}{c}_1\\ c_2\\ c_3\end{array}\right]=\left[\begin{array}{c}{a}_1\\ a_2\\ a_3\end{array}\right]\×\left[\begin{array}{c}{b}_1\\ b_2\\ b_3\end{array}\right]=\left[\begin{array}{c}{a}_2{b}_3-a_3{b}_2\\ a_3{b}_1-a_1{b}_3\\ a_1{b}_2-a_2{b}_1\end{array}\right]---\left(10\right)$

The photography attitude parameter

In the formula:

ω, κ are the photography photography attitude parameters of moment.

Wherein

ω, κ represent the angle of roll, the angle of pitch and the photo rotation angle of photographing respectively, and f is the photo focal length,

Resolving of camera positions parameter:

$\left\{\begin{array}{c}{a}_1{X}_S+b_1{Y}_S+c_1{Z}_S=-{\mathrm{\γ}}_1\\ a_2{X}_S+b_2{Y}_S+c_2{Z}_S=-{\mathrm{\γ}}_2\\ a_3{X}_S+b_3{Y}_S+c_3{Z}_S=-{\mathrm{\γ}}_3\end{array}\right.---\left(12\right)$

$\left[\begin{array}{c}{X}_S\\ Y_S\\ Z_S\end{array}\right]={\left[\begin{array}{ccc}{a}_1& b_1& c_1\\ a_2& b_2& c_2\\ a_3& b_3& c_3\end{array}\right]}^{-1}\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right]\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]---\left(13\right)$

3. the form in utilizing 2. is by 2 d dlt calculation of parameter photo orientation elements.

The present invention further is described below.

Be positioned at six points on the same ground level in choosing in the captured photo, on photo, measure the pixel coordinate, on numerical map, measure the two-dimensional map coordinate.The example observation data of each coordinate system sees Table 2.

Table 2 plane control structure control point coordinate

Calculation procedure and result are as follows:

(1) calculates two-dimentional DLT parameter and image distortion

Result of calculation is:

l ₁＝-0.0073896

l ₂＝-2.8547409

l ₃＝3159.7316

l ₄＝-0.3400813

l ₅＝0.0011163

l ₆＝353.6026

l ₇＝-0.000970

l ₈＝-0.0000002

k ₁＝-6.4×10 ^-10

(2) calculate focal length

$f=\sqrt{\frac{(l_1^2+l_4^2)-(l_2^2+l_5^2)}{l_8^2-l_7^2}}=2923.41$ (pixel)

(3) calculate γ ₁, γ ₂, γ ₃Value

Calculate earlier

${\mathrm{\γ}}_3=\sqrt{\frac{f^2}{l_1^2+l_4^2+f^2{l}_7^2}}=1024.054$

Calculate then

$\left\{\begin{array}{c}{\mathrm{\γ}}_1=\frac{l_3}{f}{\mathrm{\γ}}_3=1106.836\\ {\mathrm{\γ}}_2=\frac{l_6}{f}{\mathrm{\γ}}_3=123.865\end{array}\right.$

(4) calculate rotation matrix

$R=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right]=\left[\begin{array}{ccc}-0.002588& -0.119128& -0.992875\\ -0.999999& -0.000391& -0.000209\\ 0.000413& 0.992875& -0.119129\end{array}\right]---\left(5\right)$

(5) calculate elements of exterior orientation, change back then in the map coordinates system, result of calculation is:

(radian)

ω=0.000209 (radian)

κ=-0.000405 (radian)

X _S=1031.344 (rice)

Y _S=1104.133 (rice)

Z _S=10.445 (rice)

Claims (1)

1, a kind of digital photo orientation elements acquisition methods based on numerical map, it is characterized in that: this method comprises the steps:

Step 1: take digital photo and with the corresponding numerical map of this number photo, this number photo comprises at least 5 culture points, comprise the same place corresponding in the numerical map with culture point, culture point and same place are referred to as the reference mark, digital photo is provided with the photo two-dimensional coordinate system, and numerical map is provided with the numerical map coordinate system;

Step 2: obtain the coordinate of reference mark in the numerical map coordinate system and coordinate and the coordinate of photo principal point in the photo two-dimensional coordinate system in the photo two-dimensional coordinate system, the photo principal point is the intersection point point of photographic field lens center on photo;

Step 3: set up photogrammetric coordinate system D-X _DY _DZ _DThis photogrammetric coordinate system with approximate shooting point position be initial point, on the spot east to be X-axis, direction is a Y-axis vertically upward, south to the right hand three dimensional space coordinate that be the Z axle is on the spot, is coordinate in the photogrammetric coordinate system with the coordinate conversion of reference mark in the numerical map coordinate system;

Step 4: utilize coordinate and coordinate in photo two-dimensional coordinate system the element of orientation that obtain photo of reference mark in photogrammetric coordinate system, acquisition methods comprises the steps:

Step 41: utilize coordinate and the coordinate in photo two-dimensional coordinate system of reference mark in photogrammetric coordinate system, calculate photo 2 d dlt parameter according to the 2 d dlt principle, that is:

$\left\{\begin{array}{c}x+\mathrm{\Δx}+\frac{l_1\·X+l_2\·Y+l_3}{l_7\·X+l_8\·Y+1}=0\\ y+\mathrm{\Δy}+\frac{l_4\·X+l_5\·Y+l_6}{l_7\·X+l_8\·Y+1}=0\end{array}\right.$ Formula 1

Wherein, $\left\{\begin{array}{c}\mathrm{\Δx}=k_1{r}^2(x-x_0)\\ \mathrm{\Δy}=k_1{r}^2(y-y_0)\end{array}\right.,$

(x, y) is the coordinate of reference mark in the photo two-dimensional coordinate system; (X, Y) is the coordinate of reference mark in photogrammetric coordinate system; k ₁Represent the object lens distortion parameter; Δ x, Δ y are the influence of object lens distortion to the photo two-dimensional coordinate system; l ₁, l ₂, l ₃, l ₄, l ₅, l ₆, l ₇, l ₈Represent two dimension directly linear first transformation parameter, second transformation parameter, the 3rd transformation parameter, the 4th transformation parameter, the 5th transformation parameter, the 6th transformation parameter, the 7th transformation parameter and the 8th transformation parameter respectively; (x ₀, y ₀) be the coordinate in the photo two-dimensional coordinate system of photo principal point, the photo principal point is the intersection point point of object lens center on photo;

Introduce the transition first parameter γ ₁, the transition second parameter γ ₂, transition the 3rd parameter γ ₃, order

$\left\{\begin{array}{c}{\mathrm{\γ}}_1=-(a_1{X}_S+b_1{Y}_S+c_1{Y}_S)\\ {\mathrm{\γ}}_2=-(a_2{X}_S+b_2{Y}_S+c_2{Y}_S)\\ {\mathrm{\γ}}_3=-(a_3{X}_S+b_3{Y}_S+c_3{Y}_S)\end{array}\right.,$ Can obtain:

$\left\{\begin{array}{c}{l}_1=\frac{{\mathrm{fa}}_1-x_0{a}_3}{{\mathrm{\γ}}_3}\\ l_2=\frac{{\mathrm{fb}}_1-x_0{b}_3}{{\mathrm{\γ}}_3}\\ l_3=\frac{{\mathrm{f\γ}}_1-x_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_4=\frac{{\mathrm{fa}}_2-y_0{a}_3}{{\mathrm{\γ}}_3}\\ l_5=\frac{{\mathrm{fb}}_2-y_0{b}_3}{{\mathrm{\γ}}_3}\\ l_6=\frac{{\mathrm{f\γ}}_2-y_0{\mathrm{\γ}}_3}{{\mathrm{\γ}}_3}\\ l_7=\frac{a_3}{{\mathrm{\γ}}_3}\\ l_8=\frac{b_3}{{\mathrm{\γ}}_3}\end{array}\right.$

Step 42: by 2 d dlt parameter acquiring photographic field lens focal length, promptly

$f=\sqrt{\frac{(l_1^2+l_4^2)-(l_2^2+l_5^2)}{l_8^2-l_7^2}},$ Wherein, f is the photographic field lens focal length;

Step 43: introduce rotation matrix $R=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right],$ If

$\left\{\begin{array}{c}x+\frac{f[a_{1}X+b_{1}Y+(-a_1{X}_S-b_1{Y}_S-c_1{Z}_S)]-x_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\\ y+\frac{f[a_{2}X+b_{2}Y+(-a_2{X}_S-b_2{Y}_S-c_2{Z}_S)]-y_0[a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)]}{a_{3}X+b_{3}Y+(-a_3{X}_S-b_3{Y}_S-c_3{Z}_S)}=0\end{array}\right.$

Can obtain:

$\left\{\begin{array}{c}{a}_1=\frac{l_1{\mathrm{\γ}}_3}{f}\\ a_2=\frac{l_4{\mathrm{\γ}}_3}{f}\\ a_3=l_7{\mathrm{\γ}}_3\\ b_1=\frac{l_2{\mathrm{\γ}}_3}{f}\\ b_2=\frac{l_5{\mathrm{\γ}}_3}{f}\\ b_3=l_8{\mathrm{\γ}}_3\end{array}\right.$ $\left\{\begin{array}{c}{\mathrm{\γ}}_1=\frac{l_3}{f}{\mathrm{\γ}}_3\\ {\mathrm{\γ}}_2=\frac{l_6}{f}{\mathrm{\γ}}_3\end{array}\right.$ $\left[\begin{array}{c}{c}_1\\ c_2\\ c_3\end{array}\right]=\left[\begin{array}{c}{a}_1\\ a_2\\ a_3\end{array}\right]\×\left[\begin{array}{c}{b}_1\\ b_2\\ b_3\end{array}\right]=\left[\begin{array}{c}{a}_2{b}_3-a_3{b}_2\\ a_3{b}_1-a_1{b}_3\\ a_1{b}_2-a_2{b}_1\end{array}\right]$

Step 44: obtain the element of orientation of photo, the element of orientation of photo comprises the coordinate (X of photography point in photogrammetric coordinate system _S, Y _S, Z _S) and the photography the angle of roll, the angle of pitch and photo rotation angle use respectively ω, κ represent;

Wherein ω, κ acquisition methods are:

Coordinate (the X of photography point in photogrammetric coordinate system _S, Y _S, Z _S) acquisition methods is:

$\left\{\begin{array}{c}{a}_1{X}_S+b_1{Y}_S+c_1{Z}_S=-{\mathrm{\γ}}_1\\ a_2{X}_S+b_2{Y}_S+c_2{Z}_S=-{\mathrm{\γ}}_2\\ a_3{X}_S+b_3{Y}_S+c_3{Z}_S=-{\mathrm{\γ}}_3\end{array}\right.$

$\left[\begin{array}{c}{X}_S\\ Y_S\\ Z_S\end{array}\right]={\left[\begin{array}{ccc}{a}_1& b_1& c_1\\ a_2& b_2& c_2\\ a_3& b_3& c_3\end{array}\right]}^{-1}\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]=\left[\begin{array}{ccc}{a}_1& a_2& a_3\\ b_1& b_2& b_3\\ c_1& c_2& c_3\end{array}\right]\left[\begin{array}{c}-{\mathrm{\γ}}_1\\ -{\mathrm{\γ}}_2\\ -{\mathrm{\γ}}_3\end{array}\right]$

F is the photographic field lens focal length, x ₀, y ₀Be the image coordinate of photo principal point, the photo principal point is the intersection point point of object lens center on photo, a ₁, b ₁, c ₁, a ₂, b ₂, c ₂, a ₃, b ₃, c ₃Be respectively numerical value different in the rotation matrix.

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