Photogrammetry2 Ghadi Zakarneh

7/21/2019 Photogrammetry2 Ghadi Zakarneh

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Palestine Polytechnic University

College of Engineering & Technology

Civil and Architectural Engineering Department

Surveying & Geomatics Engineering

PHOTOGRAMMETRY II

Text Book:

lements of Photogrammetry

Paul R. Wolf

Bon A. Dewitt

Lecturer:

Eng Ghadi Zakarneh

Hebron-Palestine

2007


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TABLE OF CONTENTS

Chapter 1:

Tilted Photographs

Chapter 2:

Analytical Photogrammetry

Chapter 3:

Stereoplotters

Chapter 4:

Close Range Photogrammetry

Chapter 5:

Ground Control

Chapter 6:

Aerotriangulation

Chapter 7:

Project Planning

Appendix:

Accuracy Standards

Units Conversions


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Photogrammetry II Ch01: Tilted Photographs By: Eng.Ghadi Zakarneh

Ch01

Tilted Photographs

1 -1Palestine Polytechnic University(PPU)



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TILTED PHOTOGRAPHS

1- Introduction

1. In practice it is impossible to maintain the optical axis of the camera truly vertical.

2.

Unavoidable aircraft tilts cause photographs to be exposed with the camera axistilted slightly from vertical, and the resulting pictures are called tilted

photographs.3. Optical axis deviates from vertical is usually less than 1 and it rarely exceeds 3.

Six independent parameters called the elements of exterior orientation express thespatial position and angular orientation of a tilted photograph.

1. The spatial position: XL, yL,and ZL

The three-dimensional coordinates of the exposure station in a ground

coordinate system.

2. Angular orientation:

The amount and direction of tilt in the photo. Three angles are sufficient

to define angular orientation,

1. the tilt-swing-azimuth (t-s-) system

2. The omega-phi-kappa (, , ) system.

2- Angular Orientation In Tilt, Swing, and Azimuth

In the following figure:

exposure stationL principle pointo

camera axisLo

the vertical lineLn The photographic nadir point n

The ground nadir point gN

The datum nadir point dN

Principal plane (vertical planeLno)

Princip l line noa Tiltt :is the anglet, ornLobetween the optical axis and vertical lineLn.

Swings:is defined as clockwise angle measured in the plane of the photographfrom the positive y-axis to downward or nadir end of the principal line. Azimuth :is the clockwise angle measured from the ground Y axis (usually

North) to the datum principal line.




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3- Coordinates systems for tilted photographs

In the following figure the yx coordinates system is an auxiliary coordinates system

used in tilted photographs.




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its origin at the photographic nadir point n

axis coincides with the principle line (positive in the direction from n to o).y

Positive is 90 clockwise from positivex y

Conversion from the xy fiducial system to yx coordinates system:

-Rotation

-a translation of origin fromoton.

The coordinates of image point a after rotation are x and y , depending on the

measured fiducial coordinates of pointa( :aa yx , )

Auxiliary coordinates -x y is obtained by adding the translation distance on

to ,y :




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4- Angular Orientation In Omega-phi-kappa

As previously stated, besides the tilt-swing-azimuth system, angular orientation of atilted photograph can be expressed in terms of three rotation angles:

1. Omega

2.

Phi3. Kappa

(a) Rotation about the x axis through angle omega.

(b) Rotation about the y axis through angle phi.(c) Rotation about the z2 axis through angle kappa.

5- Scale of tilted photographs

Vertical Photo: Variations in object distances were caused only by topographic

relief.

Tilted Photo: Relief variations also cause changes in scale, but scale in various parts

f the photo is further affected by the ma nitude and angular orientation of the tile.o g




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Scale on a tilted photograph for any point:




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6- Ground coordinates from Tilted photographs

Using the above figure we have for X:

And for X:




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7- Relief Displacement on A Tilted Photograph

1. Tilted Photo:Image displacements on tilted photographs caused by topographicrelief occur much the same as they do on vertical photos, except that relief

displacements on tilted photographs occur along radial lines from the nadir point.

2. Vertical Photo: Relief displacements on a truly vertical photograph are also

radial from the nadir point, but in that special case the nadir point coincides with

the principal point.

3. Relief displacement is zero for images at the nadir point and increases withincreased radial distances from the nadir.

Magnitude of relief displacement depends upon flying height,

height of object,

amount of tilt, and Location of the image in the photograph.

8- Determining the elements of the exterior orientation

The most common method is called space resection, using the collinearity equations, the

condition of collinearity is that the the exposure station of a photograph, object point, andits photo image all lie in a straight line.

Where the collinearity equations are:

)()()(

)()()(

333231

131211

LALALA

LALALA

oaZZmYYmXXm

ZZmYYmXXmfxx

++

++=

)()()(

)()()(

333231

232221

LALALA

LALALAoa

ZZmYYmXXm

ZZmYYmXXmfyy

++

++=




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Where ms in term of Omega ,Phi , and kappa . and Tilt, Swing , and Azimuth are :

The collinearity equations development:

The image coordinates x-y in the tilted photo with respect their correspondingcoordinates in the rotated image(vertical image):




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If , divide D-2 and D-3 by D-4 , thenfza = is cancelled, and we

add corrections of the principle point ( ). We get:00 ,yx

)()()(

)()()(

333231

131211

LALALA

LALALA

oaZZmYYmXXm

ZZmYYmXXmfxx

++

++=

)()()(

)()()(

333231

232221

LALALA

LALALAoa

ZZmYYmXXm

ZZmYYmXXmfyy

++

++=

Or can be written as:

The values of Omega , Phi , kappa, tilt , swing and azimuth can be calculated asfollows:




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9- Rectification of Tilted Photographs

Rectification is the process of making equivalent vertical photographsfrom tilted photo negatives.

The resulting equivalent vertical photos are called rectifiedphotographs.

Rectified photos theoretically are truly vertical photos, and as suchthey are free from displacements of images due to tilt.

Orthophoto rectification & Differential rectificationThese relief displacements and scale variations can also be removed ina process called differential rectification or orthorectification. the

resulting products are then called orthophotos. Orthophotosare often

preferred over rectified photos because of their superior geometric

quality.

10- Rectification Methods

1. Geometry of Rectification

This methods in never used




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2. Analytic rectification

There are several methods available for performing analytical rectification each ofthe analytical methods performs rectification point by point, and each requires that

sufficient ground control appear in the tilted photo. One method is the 2D projective

coordinates transformations that remove the effects of the small tilts.

XY: ground coordinates

_xy: photo coordinates

3. Optical-Mechanical Rectification

In practice, the optical-mechanical method is widely used, although digital methods are

rapidly surpassing this approach. The optical-mechanical method relies on instrumentscalledRectifiers.

4. Digital rectificationRectified photos can be produced by digital techniques that incorporate a

photogrammetric scanner and computer processing. This procedure is a special case of

the more general concept of georeferencing.




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11- Correction of Relief for Ground Control Points used in Rectification

This procedure requires that the coordinates which can be computed from

space resection, the X, Y, and Z (or h) coordinates for each ground control point be

known:

LLL ZYX ,,

Coordinates of the displaced (image) point are computed by:




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12- Atmospheric Correction in Tilted Photographs




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Photogrammetry II Ch02: Analytical Photogrammetry By: Eng.Ghadi Zakarneh

Ch02

Analytical

Photogrammetry




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ANALYTICAL PHOTOGRAMMETRY

1- Introduction

1. Analytical photogrammetryis a term used to describe the rigorous mathematical

calculation of coordinates of points in object space based upon cameraparameters, measured photo coordinates and ground control.

2. Unlike the elementary methods presented in earlier chapters, this process

rigorously accounts for any tilts that exist in the photos. Analytical

photogrammetry generally involves the solution of large, complex systems of

redundant equations by themethod of least squares.

3. Analytical photogrammetry forms the basis of many modem hardware and

software systems, including: stereoplotters (analytical and softcopy), digitalterrain model generation, orthophoto production, digital photo rectification, and

aerotriangulation.

4. This chapter presents an introduction to some fundamental topics and elementary

applications in analytical photogrammetry.

5. The coverage here is limited to computations involving single photos andstereopairs

2- Image Measurements

1.

A fundamental type of measurement used in analytical photogrammetry is an xand y photo coordinate pair.

2. Since mathematical relationships in analytical photogrammetry are based on

assumptions such as "light rays travel in straight lines" and "the focal plane of aframe camera is flat," various coordinate refinements may be required to correct

measured photo coordinates for distortion effects that otherwise cause these

assumptions to be violated.3. A number of instruments and techniques are available for making photo

coordinate measurements.

3- Control Points

Object space coordinates of ground control points, which may be either image-

identifiable features, are generally determined via some type of field survey technique

such as GPS.

It is important that the object space coordinates be based on a three-dimensional

Cartesian systemwhich has straight, mutually perpendicular axes.




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4- Collinearity Condition

Perhaps the most fundamentaland useful relationshipin analytical photogrammetry is

the collinearity condition. Collinearity is the condition that the exposure station, any

object point, and its photo image all lie along a straight linein three-dimensional space.

)()()(

)()()(

333231

1312110

LALALA

LALALAa

ZZmYYmXXm

ZZmYYmXXmfxx

++

++=

)()()(

)()()(

333231

2322210

LALALA

LALALAa

ZZmYYmXXm

ZZmYYmXXmfyy

++++

=

Or written as:

rfqxF a+== 0

sfqyG a+== 0Where:

)()()( 333231 LALALA ZZmYYmXXmq ++=

)()()( 131211 LALALA ZZmYYmXXmr ++=

)()()( 232221 LALALA ZZmYYmXXms ++=

Using Taylor theorem the previous equations are linearized according to the

following form:




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A

A

A

A

A

A

L

L

L

L

L

L

a

a

dZdZ

FdY

dY

FdX

X

FdZ

Z

FdY

Y

F

dXX

Fd

Fd

Fd

Fdx

x

FF

00000

00000

0)(0

+

+

+

+

+

+

+

+

+

+=

A

A

A

A

A

A

L

L

L

L

L

L

a

a

dZdZ

GdY

dY

GdX

X

GdZ

Z

GdY

Y

G

dXX

Gd

Gd

Gd

Gdx

y

GG

00000

00000

0)(0

+

+

+

+

+

+

+

+

+

+=

To simplify the solution, the following arrangements are applied to the equations

above:

1-

dxaand dyaare corrections forxaandyameasurements, so that they are treated

as residuals.

2- (F)oand (G)oare the evaluations of F and G using initial estimates for relative

orientation parameters.

This enables us to write equations (4-12-a) and (4-13-a) in the following form:

JdZbdYbdXbdZb

dYbdXbdbdbdbv

AAAL

LLxa

++++

++=

16151416

1514131211

KdZbdYbdXbdZb

dYbdXbdbdbdbv

AAAL

LLya

++++

++=

26252426

2524232221

Where,

( ) ( )ZmYmq

fZmYm

q

xb 1213323311 +++=

[ ] [

])coscoscos()coscos(sin

)cossin()cossin()sin(sincos12

+

++++=

ZY

X

q

fZYX

q

xb

( )ZmYmXmq

fb ++= 23222113

)()( 113114 mq

fm

q

xb +=




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)()( 123215 mq

fm

q

xb +=

)()( 133316 mq

fm

q

xb +=

q

rfqx

q

FJ

)()( 0 +==

( ) ( )ZmYmq

fZmYm

q

yb 2223323321 +++=

[ ] [

])sincos(cos)coscossin(

)sin(sin)sincos()sin(sincos22

ZY

Xq

fZYX

q

yb

++

+++=

( )ZmYmXm

q

fb +=

13121123

)()( 213124 mq

fm

q

yb +=

)()( 223225 mq

fm

q

yb +=

)()( 233326 mq

fm

q

yb +=

q

sfqy

q

GK

)()(0

+==

Where,

LA XXX =

LA YYY =

LA ZZZ =




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5- Coplanarity Condition

Coplanarity is the condition that the two exposure stations of a stereopair, any object

point, and its corresponding image points on the two photos all lie in a common plane. In

the figure below, points L1, L2, a1, a2 and A all lie in the same plane.

Epipolar plane:any plane containing the two exposure stations and an object point, in

this instance plane L1AL2

Epopolar line:the intersection of the epipolar plane with the left and right photoplanes.

Given the left photo location of image a1, its corresponding point a2 on the right photo is

known to lie along the right epipolar line. The coplanarity condition equation is:




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6- Space Resection By Collinearity

Space resection is a method of determining the six elements of exterior

orientation (, , , XL, YL, and ZL) of a photograph.

This method requires a minimum of three control points, with known

XYZ object space coordinates, to be imaged in the photograph.

If the ground control coordinates are assumed to be known and fixed, then the linearized

forms of the space resection collinearity equations for a point A are :

axLLL vJdZbdYbdXbdbdbdb +=++ 161514131211

ayLLL vJdZbdYbdXbdbdbdb +=++ 262524232221

Since the collinearity equations are nonlinear, and have been linearized using

Taylor's theorem, initial approximations are required for the unknown orientation

parameters.

For the typical case of near-vertical photography, zero values can be used as

initial approximations for and .

0===

meanL

meanL

YY

XX

=

=

1

1

HZL =1

For the photograph, we have 6 unknowns, and each control point has 2-observations

(x,y), so 3 controlpoints give us exact solution, 4 controlpoints or more we can apply

least squaressolution. The matrix form for the solution, if we have four control points A,

B, C, and D, is:




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=V=A =X =L

Use ?6500 =LZ




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7- Space Intersection By Collinearity

If space resection is used to determine the elements of exterior orientation for both photos

of a stereopair, then object point coordinates for points that lie in the stereo overlap area

can be calculated.

The procedure is known as space intersection, so called because corresponding rays tothe same object point from the two photos must intersect at the point. So common point

with unknown ground coordinates (pass points) can be used in addition to the ground

control points that are still required for scaling and rotation of the model:

JdZbdYbdXbdZb

dYbdXbdbdbdbv

AAAL

LLxa

++++

++=

16151416

1514131211

KdZbdYbdXbdZb

dYbdXbdbdbdbv

AAAL

LLya

++++

++=

26252426

2524232221

Each control point has 2-observations (x,y) in each photograph, this means in two

photographs we have 4-observations for each control or pass point. For each

photograph we have 6 unknowns, this means we have 12 unknowns for both

photographs, in addition for each pass point we have 3unknowns (X,Y,Z).




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8- Analytical Stereomodel

1. Aerial photographs for most applications are taken so that adjacent photos overlap

by more than 55 percent. Two adjacent photographs that overlap in this manner

form a stereopair; and object points that appear in the overlap area constitute a

stereomodel.

2. The mathematical calculation of three-dimensional ground coordinates of points

in the stereomodel by analytical photogrammetric techniques forms an analytical

stereomodel

The process of forming an analytical stereomodel involves three primary steps:

1.

Interior orientation,

2.

Relative orientation, and3. Absolute orientation.

After these three steps are achieved, points in the analytical stereomodel will have object

coordinates in the ground coordinate system.




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9- Analytical Interior Orientation

Interior orientation for analytical photogrammetry is the step which mathematically

recreates the geometry that existed in the camera when a particular photograph was

exposed.

This requires camera calibration information as well as quantification of the effects of

atmospheric refraction. These procedures, commonly called photo coordinate

refinement.

The processare

1. With coordinates of fiducials and image pointswhich have been measured by a

comparator or related device.

2. A 2D coordinate transformation is used to relate the comparator coordinates to the

fiducial coordinate system as well as to correct for film distortion.

3. The lens distortion and principal-point information from camera calibration are

then used to refine the coordinates so that they are correctly related to the

principal point and free from lens distortion.

4. Atmospheric refraction corrections can be applied to the photo coordinates to

complete the refinement,

5. Finish the interior orientation.

The observation equations for this mathematical model are:

xVXcbyax +=++

yVYfeydx +=++

where,

x and y are the machine coordinates.

X and Y are the fiducial coordinates.

XV and are the residuals in the observed values.YV

athroughf are the transformation parameters.




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The following matrix form represents the mathematical model of the two

dimensional affine coordinate transformation, when 4 fiducial points are used:

AX=L+V

Where,

=

1000

0001

1000

0001

1000

0001

1000

0001

44

44

33

33

22

22

11

11

yx

yx

yx

yx

yx

yx

yx

yx

A , , ,

=

f

e

d

c

b

a

X

=

4

4

3

3

2

2

1

1

Y

X

Y

X

Y

X

Y

X

L

=

4

4

3

3

2

2

1

1

y

x

y

x

y

x

y

x

v

v

v

v

v

v

v

v

V

The least squares solution for the above parameters in matrixXis given by:

X= (ATA)

-1A

TL

10- Analytical Relative Orientation

Analytical relative orientationis the process of determining the relative angular attitudeand positional displacement between the photographs that existed when the photos were

taken. This involves defining certain elements of exterior orientation and calculating the

remaining ones. The resulting exterior orientation parameters will not be the actual values

that existed when the photographs were exposed; however, they will be correct in a

"relative sense" between the photos.

1. In analytical relative orientation, it is common practice to fix the exterior

orientation elements , , , XL, and YL of the left photo of the stereopair to zero

values.

2. Also for convenience, ZL of the left photo (ZL1) is set equal f of, and XL of the

right photo (XL2) is set equal to the photo base b.

3. This leaves five elements of the right photo that must be determined




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Using collinearity equations and, with the input data of the coordinates of image

point in each photo, each point gives two equations in the left photo and two equations in

the right photo. Each point has three unknown model coordinates X, Y, and Z, in addition

to the five relative orientation unknown parameters ( 2, 2 , k2,YL2, and ZL2). To solve

this system of equations the least number of pass points needed is n. The nis calculated

as follows:

4n=3n+5

Then

n=5 (minimum number of pass points)

The following matrix form is used:

AX=L+V

The least squares solution for parameter is solved using the following equation:

X= (ATA)

-1A

TL




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If six pass points were used (A through F) for the solution, then matrix A is formed as

shown in the next page. X and L are as follows:

123

2

2

2

2

2

=

F

F

F

E

E

E

D

D

D

C

C

C

B

B

B

A

A

A

L

L

dZ

dY

dX

dZdY

dX

dZ

dY

dX

dZ

dY

dX

dZ

dY

dX

dZ

dY

dX

dZ

dY

d

d

d

X

( )( )( )( )( )( )( )( )

( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )

1242

2

2

2

2

2

2

2

2

2

2

2

1

1

1

1

1

1

1

1

1

1

1

1

=

f

f

e

e

d

d

c

c

b

b

a

a

f

f

e

e

d

d

c

c

b

b

a

a

K

J

K

J

K

J

K

J

K

J

K

J

K

J

KJ

K

J

K

J

K

J

K

J

L

( )

( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )( )

( )( )( )( )( )

1242

2

2

2

2

2

2

2

2

2

2

2

1

1

1

1

1

1

1

1

1

1

1

1

=

yf

xf

ye

xe

yd

xd

yc

xc

yb

xb

ya

xa

yf

xf

ye

xe

yd

xd

yc

xc

yb

xb

ya

xa

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

v

V




35/138


Where,

1, denotes the left photo.

2, denotes the right photo.

Showing the zero elements we have




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11- Calculating model coordinates

After the solution of relative orientation parameters for the stereopair, the model

coordinates of any point can be calculated by using the collinearity equations. Since the

collinearity equations are non-linear equations, they have to be linearized to their model

coordinates, as described below:

++++

=)()()(

)()()(

333231

131211

LALALA

LALALAa

ZZmYYmXXm

ZZmYYmXXmfx

++++

=)()()(

)()()(

333231

232221

LALALA

LALALAa

ZZmYYmXXm

ZZmYYmXXmfy

The above Equations are rearranged in following form:

q

rfVxF xaa =+=

q

sfVyG yaa =+=

Where,

)()()( 333231 LALALA ZZmYYmXXmq ++=

)()()( 131211 LALALA ZZmYYmXXmr ++=

)()()( 232221 LALALA ZZmYYmXXms ++=

Those equations can be solved for X, Y, and Z using least squares solution, since

there are four equations for x and y for any point in the two photos. The solution by using

least squares can be solved as follows:

AX=L+V




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Where,

142

2

1

1

1422

22

11

11

13

34

222

222

111

111

,,,

0

0

0

0

=

=

=

=

y

x

y

x

V

V

V

V

V

GG

FF

GG

FF

LdZdY

dX

X

Z

G

Y

G

X

GZ

F

Y

F

X

F Z

G

Y

G

X

GZ

F

Y

F

X

F

A

Where,

( )2

3111

q

mrmqf

X

F =

( )2

3212

q

mrmqf

Y

F =

( )2

3313

q

mrmqf

Z

F =

( )2

3121

q

msmqf

X

G =

( )2

3222

q

msmqf

Y

G =

( )23323

qmsmqf

ZG =

As discussed above the collinearity equations are non-linear equations, and can be

solved iteratively. The initial coordinates of the model points are calculated from the first

photo(with assumption of verticallity)as follows:

xf

HX

im

=

yf

HY

im

=

avem ZZ i =




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12- Analytical Absolute Orientation

1. For a stereomodel computed from one stereopair, analytical absolute orientation

can be performed using a 3D conformal coordinate transformation.

2.

This requires at least two horizontal and three vertical control points, but

additional control points provide redundancy, which enables a least squares

solution.

3. In the process of absolute orientation, stereomodel coordinates of control points

are related to their 3D coordinates in a ground based system. It is important for

the ground system to be a true Cartesian coordinate system, such as local vertical,

since the 3D conformal coordinate transformation is based on straight, orthogonal

axes.

In the three dimensional conformal coordinates transformation there are three

rotations , , and k about the three axes x, y, and z respectively(This is shown in the

figure below). Also, there are three translations Tx, Ty, and Tz, and a scale factor, thus

giving seven parameters. The transformation equations are developed as the follows:

Omega Phi Kappa

xpppP TzmymxmsX +++= )( 312111

ypppP TzmymxmsY +++= )( 322212

zpppP TzmymxmsZ +++= )( 332313

Where,

sis the scale factor. Tx,Ty, and Tzare the translations in x, y, and z directions.

m's are functions of rotation angles , , andk.Their values are computed from the

following equations:




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coscos11=m

sincoscossinsin12 +=m

sinsincossincos13 +=m

sincos21 =m

coscossinsinsin22 +=m

cossinsinsincos23 +=m

sin31=m

cossin32 =m

coscos33 =m

If three full control points were used, the matrices form solution is:

AX=L+V

=

97969594939291

87868584838281

77767574737271

67666564636261

57565554535251

47464544434241

37363534333231

27262524232221

17161514131211

aaaaaaa

aaaaaaa

aaaaaaaaaaaaaa

aaaaaaa

aaaaaaa

aaaaaaa

aaaaaaa

aaaaaaa

A

17

=

z

y

x

dT

dTdT

d

d

d

ds

X

, ,

190

0

0

0

0

0

0

0

0

)(

)(

)()(

)(

)(

)(

)(

)(

=

RR

RR

RR

QQ

QQ

QQ

PP

PP

PP

ZZ

YY

XXZZ

YY

XX

ZZ

YY

XX

L

19

=

ZR

YR

XR

ZQ

YQ

XQ

Zp

Yp

Xp

V

V

VV

V

V

V

V

V

V

The least squares solution for the above system is:




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X= (ATA)

-1A

TL

where,

)()()( 31211111 ppp zmymxms

Xa ++=

=

012 ==

Xa

[ ]szyxX ppp )(cos)(sinsin))(cossin(

++=a13

=

1=

=xT

X15

a

016 =

=yT

Xa

017 =

=zT

Xa

)()()( 32221221 ppp zmymxms

Ya ++=

=

[ ]szmymxmYa ppp )()()( 33231322 =

=

[ ]szyxYa ppp ))(sin(sin)(sincossin())(coscossin(23

++=

=

[ ]symxmYa pp )()( 122224 =

=

025 =

=xT

Ya

126 =

=yT

Ya

027

=

=

zT

Ya

)()()( 33231331 ppp zmymxms

Za ++=

=

[ ]szmymxmZa ppp )()()( 32221232 ++=

=




42/138


[ ]szyxZa ppp ))(sincos()(sincos(cos))(coscoscos(33

++=

=

[ ]symxmZa pp )()( 132334 =

=

035 ==

xTZa

036 =

=yT

Za

137 =

=ZT

Za

XpV , , , .., and are the residuals in the coordinates of the control points.YpV ZpV ZRV




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13- Analytical Self-Calibration

Analytical self-calibration is a computational process wherein camera calibration

parameters are included in the photogrammetric solution, generally in a combined

interior-relative-absoluteorientation.

The process uses collinearity equations that have been augmented with additional terms

to account for adjustment of the calibrated focal length, principal-point offsets, and

symmetric radial and decentering lensdistortion. In addition, the equations might

include corrections foratmospheric refractionas presented.

Where,




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Photogrammetry II Ch03: Stereoplotters By: Eng.Ghadi Zakarneh

Ch03

Stereoscopic

Plotting Instruments




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STEREOPLOTTERS

1- Introduction

Stereoplotters (Stereoscopic plotting instruments) are instruments designed to

provide a rigorous solutions for object point positions from their corresponding image

positions on overlapping pairs of photos. In general, stereoplotters are manufactured to a

high degree of precision and accurate results may be obtained from them.

Transparencies or diapositives are prepared to exacting standards from the

negatives. Then, they are placed in two stereoplotter projectors, this process is called

interior orientation.

Through, a process calledrelative orientation,the two projectors are oriented sothat the diapositives bear the exact relative angular orientation to one another in the

projectors that the negatives had in the camera at the instant they were exposed. So that

light rays projected through the photos from the corresponding images on the left and

right photos intersect below. Thus, a stereo model is created.

After relative orientation is completed,absolute orientationis performed. In this

process the model is brought to the desired scale and leveled with respect to a reference

datum.

The stereoplotters combine three distinct systems:

(1)A projection system, which creates the true three-dimensional stereomodel.

(2)A viewing system, which makes it possible for an operator to see that model

(3) A measuring (or tracing) system, which enables measurements of the

stereomodel to be made and recorded.




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2- Classifications of stereoplotters

Classifications methods of stereoplotters depend on common characteristics of

plotters, some of these methods are the following:

1-Classifications based on projections system:

A-Direct optical projection instruments: these instruments create

models using direct optical projection, and the operator can see themodel directly by his eyes.

B-Mechanical or optical-mechanical projections instruments: these

instruments create the three dimensional model using combinations of

optical and mechanical methods, and the operator can see the model

stereoscopically.

2-Clasifications based on accuracy capability: (first, second, third ), and this

classification is rarely used because accuracy is not a function of instrument only.

3-Clasifications based on analogue solution type:

A-approximate: these instruments assume a vertical photos, to create a three

dimensional model. When the photos were tilted accurate solution is not

achieved.




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B-theoretically correct: these instruments deal with photos through the

operations of interior, relative and absolute orientation, accurate solution can

be achieved whether the photos were vertical or tilted.

4-Analytical stereoplotters: see item 3-4

5-Digital stereoplotters: see item 3-5

3- Direct Optical Projection Stereoplotters

The main parts are:

1. Main frame

2. Reference table

3. Tracing table

4. Platen

5. Guide rods

6. Projectors

7. Illumination lamps

8. Diapositives

9. Leveling screws

10. Projector bar

11. Tracing pencil

4- Projection System

Light rays projected through projector objective l

and intercepted below on platen

enses

Requires operation in dark room

Lens formula must be satisfied

Intersection must occur within depth of field of

projector lens

To recreate relative angular relationships




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Projectors must have rotational and translational movement capabilities

6 possible for each projector

5- Viewing Systems

Anaglyphic system: using color filters usually red and green, to separate the right

and the left projectors. If the green filter in the left projector and the red filter in

the right project, then if the user uses green glass in left eye and red glass in the

right eye, he will see 3D stereomodel.

- Simple and cheap.

- Using colored diapositives is precluded. And there is a Loss in model

color (model is not bright).

Stereo-image alternator (SIA): shutters are used in the left and right projectors.

These shutters run simultaneously with shutters in the corresponding eyes.

Polarized Viewing systems(PPV): similar to anaglyphic system but the use of

polarizing filters

6- Interior Orientation

Recreates geometry of the taking camera

Four steps

1. Centering diapositives on the projectors

2. Setting off the proper principal distance3. Preparation of the diapositive

4. Compensation for image distortions

Preparation of the diapositive

Direct contact printing

Principal distance will equal focal length of taking camera

Projection printing




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Seldom used today

Necessary for reduced-sized diapositives

Must meet the following:

Compensation for lens distortion

Use a correction plate in projection printing of diapositive, followed

by use of distortion-free lens

Vary the projector principal distance by means of a cam

Reconstructing true geometry

Use projector lens whose distortion characteristics negate cameras

distortion

7- Relative Orientation

Recreate the same relative relationship between diapositives that existed at the

time of the photography

Condition: each model point and the two projection centers form a plane in

miniature

Just like that which existed for the corresponding ground point and the

two exposure stations

Since px is a function of elevation, it can be removed by raising or lowering

platen (Z-wheel)

What remains is py removed using a rotational or translational element to a

projector on the stereoplotter

6 von Gruber points (pass points) used to clear y-parallax

5 points used to clear the model

6th point used to check the model




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The possible movements of the projectors are:

There are two method to apply the relative orientation:

1- Independent method:

Both right and left projectors are used:




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2- Dependent method:

8- Absolute Orientation

After relative orientation, a true 3-D model is formed, we have to Level model with

respect to datum, and the Unknown scale of model is fixed to the desired scale for

mapping

Selecting model scale:

Model scale constrained by scale of photography and limitations of stereoplotter

Model scale represented by

Recalling scale of photography, model scale can be represented as

When model scale determined, initial model air base is set off

More convenient before relative orientation

Scale closer to required model scale

Initial model base obtained by multiplying photo base by actual

enlargement ratio

Model scale changed by varying model base

If by and bz settings same for each projector, model base consists only of bx

motion




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Scaling the model:

Minimum of 2 horizontal control points are needed

Unique solution no check

Place floating mark over point A and mark location on plotting sheet

Similarly for point B

Distance shown as AB

If AB does not equal AB, compute change to bx

-If by and bz not equal, need to move the right projector from position II

to II

Leveling the model:

Requires minimum of 3 vertical control pts.

No check

Proper gears must be placed in instrument for consistent vertical scale

Two components of tilt




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Iterative procedures for leveling the models:

1. Set floating mare on model point A and index tracing table dial to read control

elevation of point

2. Read model elevation of control point D

3. If difference exists, X-tilt () applied

If model elevation is higher than control elevation, model is tilted up in

near

4. Repeat steps 1-3 until model is level in the direction from A to D

5. Reindex tracing table dial to read control elevation of point A with floating

mark set on model point A

6. Read model elevation of control point B

7. If model elevation does not agree with control elevation, introduce Y-tilt ( )

in similar fashion as set 3

8. Repeat steps 5-7 until model is level in that direction

9. Check point D to see if model elevation still conforms to control elevation

If line AD is not parallel to Y-axis of stereoplotter then it will be likelynot to conform

10.Check point C to see if model elevation conforms to control elevation

If elevation does not conform, may indicate an error in relative

orientation or blunder in the vertical control




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Methods of introducing corrective tilts instrument dependent

Reference table may be tilted in X and Y directions making them

parallel to model datum

Using leveling screws to rotate projector bar

Introducing corrective tilts to each projector individually




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9- Analytical stereoplotters

Most of operation in photogrammetry have been automated because of the use of

computers, which enabled to solve most of mathematics for photogrammetry, examples

of these operations are reading data from comparators digitally, and recording the output

data digitally. By linking encoders servo systems and computers, the analytical

stereoplotter had been developed.

The basic components of the analytical stereoplotters are as follows, see fig. (3-9):

1- Precise stereocomparator.

2- Coordinatograph.

3- Computer.

4- Servomotors and encoders to enable the computer to drive the other

components of analytical stereoplotter for photogrammetric operations.

Figure: Analytical stereoplotter

Analytical stereoplotters compute mathematical models using collinearity

equations, instead of using mechanical or optical models.

The input of analytical stereoplotter to solve collinearity equation can be classified into:

1- External input: to solve collinearity equations which consists of camera

interior orientation parameters and ground coordinates of control points.

2- Internal input: using the instrument itself to enter the image coordinates.




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Then using these data and collinearity the computer calculates model and ground

coordinates and the output data are displayed on a screen or they are printed on a hard

copy, or transmitted to the coordinatograph.

Advantages of Analytical stereoplotters:

1- No optical and mechanical limitations.

2- Capable of using vertical, tilted, oblique, and high oblique photographs.

3- More accuracy is achieved because intersections of light rays do not use optical

or mechanical projections. They can also correct for camera lens distortions and

photo shrinkage and expansion, and they can consider atmospheric and earth

curvature corrections.

Analytical stereoplotters orientations

Similar to analogue instruments analytical plotters are oriented in three steps;

interior, relative and absolute orientation. The difference in these types of instruments lies

in the fact that these steps are simulated mathematically. In the analytical stereoplotters

computers guide the user to enter the necessary data for all operations, using the

keyboard for external data and stereocomparators for internal data.

Orientation of analytical stereoplotter is shown in the following steps, and described in

figure below:

A- Interior Orientation

Interior orientation using analytical stereoplotter can be implemented in the order below :

1- Stereopair of photos with (x,y) and ( yx , ) fiducial coordinates are placed in

stereocomparators stages (x1,y1) and (x2,y2).

2- Principle distances and fiducial coordinates are entered to the computers.

3- Using stereocomparator pointing mark at least three fiducials are needed,

and its preferred to use more fiducial points for least squares solutions.




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4- Tow dimensional coordinates transformation is applied to convert

comparator stages coordinates (x1,y1) and (x2,y2) to fiducial coordinates

systems (x,y) and ( yx , ).

5-

Corrections of shrinkage and expansion are included in the coordinates

transformation.

6- Principle point and lens distortion correction can also be considered.

7- The calculated parameters of coordinates transformations are stored in the

computer.

Figure: Analytical Stereoplotter concepts

B- Relative Orientation

The following steps of relative orientation are implemented:

1. (x,y) and ( ) coordinates of at least five points are entered using the

stereocomparator stages .

yx ,

2. The collinearity equations are then solved to find out the relative orientation

parameters by using least squares solution.

3. Relative orientation parameters are stored in the computer.




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Using the relative orientation parameters the model coordinates ( ZYX ,, ) of any point

can be calculated by entering its fiducial coordinates (x,y) and ( ) by using the

stereocomparator .

yx ,

C- Absolute Orientation

At least two horizontal control points and three vertical control points are needed to

transform the model coordinates into ground coordinates through what is known as the

absolute Orientation step. Absolute orientation in the analytical stereoplotters is carried

out as follows:

1. Ground coordinates of control points are input to computer manually .

2. Their corresponding images (x,y) and (x,y) coordinates are input using the

stereocomparator .

3. The computer calculates the model coordinates of the control points.

4. Three dimensional coordinates transformations are applied to covert model

coordinates to ground coordinates.

5. Parameters of absolute orientation are stored in the computer.

After computing the orientation parameters, ground coordinates (Xg,Yg,Zg) of any point

can be calculated by entering its fiducial coordinates (x,y) and ( yx , ).




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10- Digital stereoplotter

The digital stereoplotter is a stereoplotter with digital input and output. They use

scanned image instead of hardcopy. The fundamental features are the fully digital

environment using digital images and the production of digital output in an interactive

and automated fashion.

A digital stereoplotter is definitely something other than an Analytical Plotter. In

1981 Sarjakoski defined the digital stereoplotter as analytical stereoplotter with images

stored in digital format. The concept goes much further and the major difference is the

availability of the image information in the computer and the potential for automating the

photogrammetric measurement and interpretation tasks in the fully digital system.

Digital photogrammetric workstation is not necessarily a part of a GIS system,

although some users prefer it to be a part of the GIS system. The output of digital

stereoplotter can be used as an input to the GIS.

The fundamental components of the digital stereoplotter are:

1- Computer, databases and graphics systems.

2- Interaction and automation.

3-

The peripheral input and output devices.




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Photogrammetry II Ch04: Close Range Photogrammetry By: Eng.Ghadi Zakarneh

4 -1

Ch04

Close Range

Photogrammetry

Palestine Polytechnic University(PPU)Surveying & Geomatics Engineering


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4 -2

CLOSE RANGE PHOTOGRAMMETRY

1- Introduction

Terrestrial photogrammetryis an important branch of the science of photogrammetry. Itdeals with photographs taken with cameras located on the surface of the earth.

The term close-range photogrammetry is generally used for terrestrial photographshaving object distances up to about 300 m.

Terrestrial photography may be:

Static: photos of stationary objects. Stereopairs can be obtained by using a singlecamera and making exposures at both ends of a baseline.

Or dynamic: photos of moving objects. Two cameras located at the ends of abaseline must make simultaneous exposures.

2- Applications of Close Range photogrammetry

Surveying Industry(e.g. aircraft manufacture) Archeology Medicine ..etc

H.W: write a report about an application of close range photogrammetry?- Group of 2 students.

- Copy past from the internet is not allowed (your own writing).- Students have to prepare a 10 minutes presentation.- A 10 minutes discussion will be held.

- The report has 10% of your final result.

3- Terrestrial Cameras

Two general classifications:

Metric: for photogrammetric applications. They have fiducial marks. Theyare completely calibrated before use. Their calibration values for focal

length, principal- point coordinates, and lens distortions can be applied

with confidence over long periods. Non-metric: manufactured for amateur or professional photograph) where

pictorial quality is important but geometric accuracy requirements aregenerally not considered paramount.

A phototheodolite is an instrument that incorporates a metric camera with a surveyors

theodolite. With this instrument, precise establishment of the direction of the optical axiscan be made.

Palestine Polytechnic University(PPU)Surveying & Geomatics Engineering


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A stereometric camera system consists of two identical metric cameras which are

mounted at the ends of a bar of known length. The optical axes of the cameras areoriented perpendicular to the bar and parallel with each other. The length of the bar

provides a known baseline length between the cameras, which is important for

controlling scale.

4- Horizantal and Oblique Terrestrial Photos

Classification of terrestrial photos depending on the orientation of the camera :

Horizontal: if the camera axis is horizontal when the exposure is made. , the plane

of the photo is vertical. So if metric camera is used the x-axis is horizontal and thethe y-axis is vertical.

Oblique: the camera axis is inclined either up or down in an angle fromhorizontal. If is upward is called elevation angle. If its downward it called

depressing angle.




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5- Camera Inclination

Determining the angle of inclination of the camera axis of a terrestrial photo relies on thefollowing two fundamental principles of perspective geometry(as in the figure below):

1. Horizontal parallel lines intersect at a vanishing point on the horizon v.2. Vertical parallel lines intersect at the nadirn(or zenith).

3. The line from n through the principal point o intersects the horizon at a rightangle at pointk.




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The phot coordinates system can be established as in the following figure, where:

1. The origin isk.2.

The x-axis is positive in the right side of the origin in the horizon line.

3. The y-axis is positive perpendicularly to x-axis upwards.




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Two ways to determine the the depression angle:

First:

=

f

yotan

koyo =

is depression angle if is negative(as in the figure above), else it is an

elevation angle.

koyo =

Second:

For the depression angle:

Where, n is the nadir point.

If the angle is elevation angle:




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6- Horizontal and Vertical Angles

Horizontal angle between the vertical planes, (Laa), containing image pointaand thevertical plane,Lko, containing the camera axis is:

is positive if it is clockwise, and negative if it is counter clockwise.

Vertical angle a to image pointacan be calculated from the following equation:




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7- Camera axis and exposure station position

The method as explained in the figure below is calledthree point resection.

This needs the following steps:

1. Three known points horizontal positions (A,B,C) drawn to scale on a map plate.

2. has to be known.3. The angles between the three points have to be calculated.

4. Graphical three-point resection procedure, using transparent template containing

the three rays and the camera axis.5. The template is placed on the base map and adjusted in position and rotation until

the three rays simultaneously pass through their respective plotted control points.

6. the position of L is fixed according to the map coordinates system.

Other method, the position of L can be calculated resection problem numerically, as in

surveying.

The elevation of the exposure station is the height of the camera lens above the datum.

Assume that the position and elevation of point A are known. And a is calculated, then:




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8- Location points by intersection from two photos




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and can be determined by three points resection. , , ,and a can be calculated as explained before.

Then the position of a point A is calculated as follows:




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9- Analytical solution for close range photogrammetry

The analytical solution for close range photogrammetry can be applied using the same

methods in aerial photogrammetry, and this need the following steps:

1. Interior orientation using affine coordinates transformations, we

get xy-coordinates in the fiducial coordinates system.2. Relative Orientation using collinearity equations, we get model

coordinates.3. Absolute Orientation using 3D conformal coordinates

transformations. We ground coordinates X,Y, and elevations.

Important NOTE: in the relative orientation the X-axis is in the base between theexposure stations. And the Z-axis is the line Vertical to the image plane. The Y-axis is

perpendicular to the XZ-plane, positive upwards. See figure below.




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Photogrammetry II Ch05: Ground Control By: Eng.Ghadi Zakarneh

Ch05

Ground Control

5 - 1Palestine Polytechnic University(PPU)



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GROUND CONTROL

1- Introduction

Photogrammetric control or ground control consists of any points whose positions areknown in an object- space reference coordinate system and whose images can be

positively identified in the photographs.

Photogrammetric control can be:

- Full control: X, Y, Z ground coordinates is known.- Horizontal control: X, Y ground coordinates are only known.

- Vertical control: Z (elevations) is known.

Requirements of ground control:- They should be sharp.

- They should be in favorable locations.

For Horizontal control, their horizontal positions on the photographs must be precisely

measured; images of horizontal control points must be very sharp and well defined.

Horizontal control are intersections of sidewalks, intersections of roads, manhole covers,small lone bushes, isolated rocks, corners of buildings, fence corners, power poles, points

on bridges, intersections of small trails or watercourses, etc.

Images for vertical control need not be as sharp and well defined horizontally. Pointsselected should be well defined vertically. Best vertical control points are small, flat or

slightly crowned areas. The small areas should have some natural features nearby, such

as trees or rocks, which help to strengthen stereoscopic depth perception. Large, openareas such as the tops of grassy hills or open fields should be avoided.

2- Number and Location of Ground ControlSpace resection problem: for determining the position and orientation of a tilted photo, aminimum of three XYZ control points is required. The images of the control points

should ideally form a large, nearly equilateral triangle. Although three control points are

the required minimum for space resection, redundant control is recommended to increasethe accuracy of the Photogrammetric solution and to help detecting mistakes.




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In astripit is recommended to have 2 horizontal and 3 vertical control points at each fifth

model.

In case ofblock adjustment, it is recommended to full control points at the beginningand the end of each strip, horizontal and vertical control have to be well distributed

within the block.




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3- Planning the Control Survey

The control points should have accuracy much better than required accuracy of the

produced map. One method is usingNational map accuracy standards (NMAS):

1. Horizontal control:

-

At least 90% of the palnimetric features are required to be plotted within

inch

30

1or (0.8mm) of their true position. If the map scale is larger than

1:20,000.

- At least 90% of the palnimetric features are required to be plotted within

inch

50

1or (0.5mm) of their true position. If the map scale is smaller

than 1:20,000

- The Horizantal control accuracy should not be greater than4

1or

3

1of the

map accuracy.

Example:

If it is required to have a map plotted with scale 1:600, what is the required horizontal

control accuracy?

0.8 mm is equivalent to 0.48m

This mean the accuracy of the Horizontal control should be m16.0m

2. Vertical control: 90% of the points should be within 0.5 of the contour interval.

The vertical control should be better than 0.2 or 0.1 of the contour interval.

4- Field Survey methods

Traverse




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Triangulation

GPS

Differential Leveling

Trigonometric leveling




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5- Artificial Targets

In some areas such as prairies, forests, and deserts, natural points suitable for

Photogrammetric control may not exist. In these cases artificial points calledpanel points

may be placed on the ground prior to taking the aerial photography. Their positions are

then determined by field survey or in some cases by aerotriangulation. This procedure iscalledpremarking or paneling.

Advantages of artificial targets:

Excellent image quality. Unique appearance.

Disadvantages:

Extra work and expenses The can be moved before taking the photographs, the position is changed, this

leads to wrong solutions.

They may not appear in a favorable location in the photographs.

The targets should have a good color contrast. This can be achieved by using light colors

on dark backgrounds.

A typical shape is shown in the following figure.

The target has a central sizeD of 0.03 to 0.1 mmdepending on the photo scale. And the

legs have the size ofDX5D.

Example:

If the photo scale is 1:12000 is planned. What should be the artificial target size, if its

photo size is required to be 0.05mm?

0.05mm is equivalent 0.6m

Other known shapes of the artificial targets are shown in the figure below.




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Photogrammetry II Ch06: Aerotriangulation By: Eng.Ghadi Zakarneh

Ch06

Aerotriangulation




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AEROTRIANGULATION

1- Introduction

Aerotriangulation is the term most frequently applied to the process of determining theX, Y, and Z ground coordinates of individual points based on photo coordinate

measurements.

The photogrammetric procedures discussed so far were restricted to one stereo model. It

is quite unlikely that a photogrammetric project is covered by only two photographs,

however. Most mapping projects require many models; large projects may involve asmany as one thousand photographs, medium sized projects hundreds of photographs.

Advantages of Aerotriangulation

1. Minimizing the field surveying by minimizing the number of required control

points.2. Most of work is done in laboratory.

3. Access to the property of project area is not required.4. Field survey in steep and high slope areas is minimized.

5. Accuracy of the field surveyed control points can easily be verified by

aerotriangulation.

Classifications of Aerotriangulation processes1. Analog: involved manual interior, relative, and absolute orientation of the

successive models of long strips of photos using stereoscopic plotting instruments

having several projectors.2. Semianalytical aerotriangulation: involves manual interior and relative orientation

of stereomodels within a stereoplotter, followed by measurement of model

coordinates. Absolute orientation is performed numerically hence the term

semianalytical aerotriangulation.3. Analytical methods :consist of photo coordinate measurement followed by

numerical interior, relative, and absolute orientation from which ground

coordinates are computed.

2- Pass points for aerotriangulation

The points may be images of natural, well-defined objects that appear in the required

photo areas, but if such points are not available, pass points may be artificially marked byusing a special stereoscopic point-marking device.




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3- Semianalytical Aerotriangulation

Often referred to as independent model aerotriangulation.

It is a partly analog and partly analytical procedure.

Manual relative orientation in a stereoplotter of each stereomodel of a strip or

block of photos.

Models are numerically adjusted to the ground system by either a sequential or a

simultaneous method.

3-1 Independent model Sequential method

In the sequential approach to semianalytical aerotriangulation, each stereopair of a

strip is relatively oriented in a stereoplotter, the coordinate system of each modelbeing independent of the others.

Model coordinates of all control points and pass points are read and recorded in

each individual stereomodel.

Coordinates of the perspective centers (model exposure stations) are alsomeasured to get good geometric solution. Each independent model and included

as common points in the transformation.




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As in figure below of common points d, e, f, and of model 2-3 are made to

coincide with their corresponding model 1-2 coordinates. Once the parameters for

this transformation have been.

2O

Using these points the parameters of the 3D coordinates transformations are

calculated.

parameters are applied to the coordinates of points g, h, i, and in the system ofmodel 2-3 to obtain their coordinates in the model 1-2 system. These points are

used to apply the transformation between model 2-3 and 3-4.

3O

And repeat the process for successive models.

All models have the coordinate system of the first model.




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Adjustment of strip model to ground coordinates

To transform from model coordinates to ground coordinates 3D conformal

coordinates transformation can applied. To find the parameters of the 3D conformal

coordinate transformation 3 full control points are needed as minimum, or at least 2

horizontal and 3 vertical control points.Random errors will accumulate in a systematic manner in long strips. So control

points in the first model are used to orient it to the ground system. The other control

points are used as check points to represent the errors as smooth curves.

An example of polynomial representation of the errors is shown in the equationbelow. These equations have 30 parameters, so we need at least 10 full control points

to find these parameters for the strip.

After calculating the parameters, for any new point, the adjusted coordinates are

calculated directly by measuring the model coordinates XYZ of the point.




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3-2 Independent models Simultinuous Aerotriangulation

Simultaneous transformation method is applied using three dimensional coordinatestransformation:

This has 7 parameters:

- Scale factor S.

- Three rotations ),,( k .

- And three translations .),,(ZYXTTT

For the figure below we have 6 models, this means we have 6X7=42 parameters. Thisneeds at least 42 observation equations to solve for the unknown parameters.




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For the figure, each control point provides 3 observation equations. As follows:

We have 6 control control point A-F, this gives us 6X3=18 equation.

Other type of observation equations is for the pass or tie points and the exposure stations

points; these points coordinates are equal for the both common models. These equations

are written as follows:

The common points are as follows:- , , , are common points between 2 models , so we have 4X3=12

observation equations.

2O 3O 6O 7O

- Points 3,6,7,9,10,15,14,12,11,18 are common between 2 models, so we have

10X3=30 observation equations.

- Points B and E are common between 2 models, so we have 2X3=6 observationequations.

- points 8 and 13 are common between 4models, so we can make 6 model

combimations, so we have 2X6X3=36 observation equations.

The total number of observation equations=24+12+30+6+36=108 observation

equations.

4- Analytical Aerotriangulation

analytical aerotriangulation consist of the following basic steps:(1) Relative orientation of each stereomodel.

(2) Connection of adjacent models to form continuous strips and/or blocks.(3) Simultaneous adjustment of the photos from the strips and/or blocks to field-

surveyed ground control.

Advantages of Aerotriangulation: Analytical aerotriangulation tends to be more accurate than analog or

semianalytical methods, largely because analytical techniques can more

effectively eliminate systematic errors such as film shrinkage, atmosphericrefraction distortions, and camera lens distortions.

X and Ycoordinates of pass points can be located to an accuracy of within

about 1 / 15,000 of the flying height, and Z coordinates can be located to

an accuracy of about 1/10,000 of the flying height.




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planmetric accuracy of 1/350,000 of the flying height and vertical

accuracy of 1 / 180,000 have been achieved.

Freedom from the mechanical or optical limitations imposed by

stereoplotters.

5- Simultaneous Bundle Adjustment

Bundle adjustment is The process to adjust all photogranimetric measurements to ground

control values in a single solution.

The process is so named because of the many light rays that pass through each lens

position constituting a bundle of rays. As shown in the figure below.

The solution depends basically on the collinearity condition, where the collinearity

equations are:

The solution of the above equations give the exterior orientation parameters of all imagesincluded in the adjustment (omega, phi, kappa, XL,YL,ZL).

For the adjustment we have:

- 2 observations(x,y) for any control or tie point in the photo.- 6 unknowns for each photo (omega, phi, kappa, XL, YL, ZL).

- 3 unknowns for each tie point; ground coordinates(X, Y, and Z).




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Example:

For the bundle adjustment of the following for images, what is the number of unknowns,observations, and how will the design matrix A appear?

Number of observations:

4 x 6 x 2 = 48 observations (collinearity equations). Number of unknowns:

4 x 6 + 3 x 4 = 36 unknowns




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Example:

For the following model what is the number of unknowns, observations, and how will thedesign matrix A appear?




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Photogrammetry II Ch07: Project Planning By: Eng.Ghadi Zakarneh

Ch07

Project Planning




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Photogrammetry II Ch07: Project Planning By: Eng.Ghadi Zakarneh

PROJECT PLANNING

1- Introduction

When a project is planned the following should be considered: Scales

Accuracies

The project planning has the following catogories:

Planning aerial photography

Planning ground control

Selecting instruments and procedures to achieve desired results

Estimating costs and delivery schedules

The flight planning has two part:

1.

Flight map : Shows where photos are to be taken2. Specifications : how the photos will be taken Camera and film requirements

Scale

Flying height End and side lap

Tilt and crab tolerances

2- Endlap and Sidelap

percent of Endlap : overlapping successive photos. Normally 60% and minimum value50%.

Percent of Sidelap: overlapping adjacent flight strips. Normally 30%.



7/21/2019 Photogrammetry2 Ghad

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Photogrammetry2 Ghadi Zakarneh