level).  File format is BMP.

The images must be photographs taken with a metric camera for that characteristics
are known.  So the user must have at one's disposal the calibration certificate of the
camera.

To enable the absolute orientation of the photos, a sufficient number of control points
discernible on the two photos must be known.

1.2.Possibilities

A  complete  photogrammetric  treatment  is  possible  with  Digital  Photogrammetric
Sofware.  The following general workflow can be use to realise it:

INNER

ORIENTATION

Pixel coordinates => Photo coordinates

Calibration Certificate

Left Image

Right Image

EXTERIOR ORIENTATION

RELATIVE ORIENTATION ABSOLUTE ORIENTATION

Photo coordinates => Model coordinates Model coordinates => Ground coordinates

Homologous points

Control points

EPIPOLAR

RESAMPLING

Determination of the bounding box

IMAGE MATCHING

GENERATION OF THE

DEM

ORTHORECTIFICATION

VRML MODEL GENERATION

2.  TO MOVE IN THE IMAGES

The  views  of  the  different  steps  of  the  photogrammetric  orientation  (inner,  relative
and absolute orientation) are organised in three different views of the same image.

The view 1 is the over view that shows the entire image.
The view 2 corresponds to the original size of the image and is the part of the view 1
included in the white rectangle.
The view 3 is a detail view that shows the part of the image within the white rectangle
of the view 2.

When  you  want  to  track  down  a  point  in  the  image,  place  the  cursor  in  the  view  1
near  by  this  point and  click  on  the  right  mouse  button.   The  white  rectangle  is  then
centred on the selected point and the part of the image included inside appears in the
view 2.  Next do the same thing with the view 2 to locate more accurately the point.

3.  TO TRACK DOWN POINTS IN THE IMAGES

Before  tracking  down  a  point  in  the  image,  you  must  select  the  line  of  the  current
point in the chart below the image.  Then the cursor becomes a hair cross.

Points can

be selected in all the three views. To be more accurate, it’s better to

locate it in the view 3 (refer at 2: to move in the images)
When you have adjusted the view on the point, place the centre of the hair cross on
this. Then click two times on the left mouse button to select the point. The image
coordinates appear on the correspondent line of the chart below the image. . When
the hair cross isn’t just on the point, it can be moved by holding the left mouse button
and move the mouse.

INNER ORIENTATION

RELATIVE AND ABSOLUTE

ORIENTATION

4.  TO MOVE IN THE CHARTS

Some additional functions have been added to make easier the displacements in the
relative and absolute orientations charts.
After  the  selection  of  the  current  line  (by  clicking  on  this  in  the  chart  with  the  left
mouse  button),  you  can  move  from  line  to  line  or  laterally  with  the  help  of  the
direction arrows of the keyboard.

5.  TO MAKE A ZOOM

It’s possible to increase or decrease the size of the white rectangle in the views 1 and
2, modifying in this way respectively the views 2 and 3.
After the selection of the view within you want to make the zoom, click concurrently
on Alt and * to decrease the zoom and on Alt and / to increase it.  Then the view of
the superior level will automatically change.

6.  THE THREADS

Sometimes, by mistake or inexperience, the user can choose parameters that lead to
process the data for long time. In this case, it’s useful to know how many times the
process will take.
The thread is useful for estimating the duration of a specific task.

Another interesting functionality is that a process putted in a thread can be
interrupted at each time the user wants.

DATA PROCESSING

1.INNER ORIENTATION

An inner orientation must be done for every image.  This process allows establishing
a relation between the pixel and image coordinates.  This relation is determined with
the  help  of  the  fiducial  marks  photo  coordinates  given  in  the  calibration  certificate
(see annex 1).

To change the pixel coordinates into photo coordinates, you must encode the values
of the photo coordinates of the fiducial marks.  Then a parallel between these values
and the pixel coordinates will can be drawn.



Encode the calibration certificate

A. The camera has never been encoded.

In the project window, choose the option New CC. The following dialog box will pop
up:

The first thing to do is the choice of the units, that will be the units used in all the
project. For more facilities, the units can be these of the calibration certificate. With

the  help  of  the  arrows  on  the  left  of  the  case  called  Unit,  you  can  increase  or
decrease the value of the units.  When you have determined it, you must think that all
the values will be expressed in these units.

The  following  step  is  the  encoding  of  the  values  that  you  have  in  the  calibration
certificate:

-  f  focal length: the value must be written  in the Focale case

-  PP position of the principal point:

The value of



corresponds to the E

case

The value of



corresponds to the N

case

- position of the fiducial marks:

The superior part of the left window is devoted to receive the photo coordinates of
the fiducial marks. By clicking on the arrows below the chart can you determinate
the number of fiducial marks. Next, the ID, X Coord and Y Coord (corresponding
to the photo coordinates) of every fiducial marks can be encoded.

- lens distortion:

The superior part of the right window is devoted to receive the values of the lens
distortion. You can also determinate the number of radial distance and mean
radial distortion values by clicking on the arrows on the left of the case. Then the
chart can be completed with the radial distances in the left column and the mean
radial distortions in the right column.

All these informations can be saved in a “.cc” file with the option save CC or by
answering YES at the

question “Do you want to SAVE Calibration Certificate?” when

you quit.

B.  The camera is the same that these that has already been encoded for precedent
photos.

Then the calibration certificate previously encoded can be got  back.   Click on  Load
CC in the CC File Path case and take the appropriate file.



Location of fiducial marks

Now  that  the  photo  coordinates  of  the  fiducial  marks  are  known,  the  parameters  of
the  transformation  of  the  pixel  coordinates  will  be  computed.    Those  will  depend  of
two  things:  the  pixel  coordinates  values  of  the  fiducial  marks  and  the  orientation  of
the X and Y axes.

In the project window, choose the option Left or Right IO to make the inner
orientation of every one. The following window will appear:

There are three views  of the same image.   The right  superior view  is the over  view
that  shows  the  entire  image.    The  left  view  corresponds  to  the  original  size  of  the
image.  The right inferior view is a detail view that shows the part of the image within
the cursor of the left view.

The  first  step  is  the  determination  of  the  photo  orientation.    According  to  it,  the
parameters of transformation will change.  You have the choice between four cases.

This step will transform the start system in the ideal case (see the theory about this
part)

In the chart below the image, you find in the two first columns the values of the photo
coordinates given in the calibration certificate. The pixel coordinates are directly
registered in the XImg and YImg columns when you track down the fiducial marks on
every image. To move and locate points on the image, see the section
Functionnalities of the software.

Parameters of transformation will appear as from three fiducial marks and residues
as from four fiducial marks.



Correction of the radial lens distortion

In the menu Inner orientation module, choose the Radial Distortion option. The
window in that the parameters of the polynome are computed will pop up:

In this window,  the  values of the radial distances and of the mean radial  distortions
previously encoded will automatically appear.  You have the possibility to choose the
polynomial order but it must be less than the number of associated radial distances
and  mean  radial  distortions.    The  you  can  compute  the  polynomial,  in  the  third
column appear the residues.

2. EXTERIOR ORIENTATION

2.1. Relative orientation by rotations

Relative  orientation  allows  determining  the  relative  positions  of  the  two  bundles  of
rays  by  creating  spatial  stereomodel  in  an  arbitrary  coordinate  system.    Tracking
down  homologous  points  on  the  left  and  right  images  is  necessary  to  make  this
orientation.

In the project  window, click on the button  RO by Rotations.   The following  window
box will appear:

By  clicking  with  the  right  mouse  button  on  a  grey  case  of  the  chart  under  the  left
image,  you  can  choose  to  add  a  point  with  the  option  Add  Point.    Then  you  must
track  down  the  homologous  point  on  the  left  and  right  images:    The  left  and  right
image coordinates of the point will appear in the current line of the chart

It is possible to delete one point by clicking on the ID with the right mouse button and
by choosing the option Delete This Point.

As from five homologous points, it is possible to have values of RO Final Parameters
(expressed  in  Radians)  by  clicking  on  Reset  the  first  time  and  after  Iterate.    Then
values of the chart will change: the parallax will decrease, new RO Final Parameters
are computed and new model coordinates (X

Coord, Y

Coord) are computed for every

image. Stop the iterations when you think that the parallax values are small enough
and that RO Final parameters don’t significantly change.

2.2.  Absolute orientation

The purpose of absolute orientation is the transformation from model coordinates to
ground coordinates.  To realise it, you must have points that ground coordinates are
known.    These  points  are  called  the  control  points  (CTRL)  and  will  serve  to  the
computing  of  the  parameters  allowing  the  transformation from model  coordinates  to
ground coordinates.

Another  type  of  points  is  the  checkpoint  (CHECK).    It  corresponds  to  points  that
ground coordinates are known but that are not used for the computing of the absolute
orientation  parameters.    The  residues  on  these  points  give  an  idea  on  the  global
accuracy.

Last type is the tie point (TIE).  It corresponds to points that ground coordinates are
unknown and for that ground coordinates are computed with the absolute orientation
parameters.

In the project window, click on  AO & Restitution.  Then appears the window of  the
absolute orientation

As  for  the  relative  orientation,  you  can  add  or  delete  points  by  clicking  on  the  right
mouse button when you are in the chart..  The following window will appear:

This window allows the encoding of the control, the check and  the tie points.  In the
point  class,  write  ctrl  for  control  points,  check  for  checkpoints  and  tie  for  tie  points.
When ground coordinates of the current point are known, they can be encoded in this
chart.    Coordinates  can  also  be  encoded  in  the  general  chart  below  the  image  by
selecting the correspondent case.

When points are located, control points appear in blue, checkpoints in green and tie
points  in  red.    As  for  three  control  points,  absolute  orientation  parameters  can  be
computed by clicking on Reset and then Iterate.

Stop  the  iterations  when  the  residues  on  the  control  and  checkpoints  are  small
enough (in the window, the residues are expressed in the same units that the units of
the check and control points).  The values of the absolute orientation parameters are
in the grey window.

3. RESTITUTION

3.1.  Monoscopic Restitution

In the project window, click on AO & Restitution - menu Module option Application.

This  module  allows  to  track  down  additional  points  for  that  ground  coordinates  are
unknown  and  to  compute  their  ground  coordinates  with  the  absolute  orientation
parameters.    For  the  location  of  the  homologous  points,  proceed  in  the  same  way
that  for  the  others  modules.    The  ground  coordinates  of  the  new  points  will  directly
appear. These points will receive the type resti points.

3.2. Geo

– Coding

Create a Configuration File (.cl) that has the following structure (ex: tess.cl):

BEGIN_CODES
point
line
spline
END_CODES
BEGIN_LAYERS
road
hedge
fence
END_LAYERS

Then you choose for every point its code and its layer. A file with the ID, the type, the
layer, the code and the coordinates of the points is created. This file can directly be
employed in topographic programs.

you put here all the layers that you want to use

you put here all the codes that you want to use

3.3. Image Matching techniques

In the project window, click on AO & Restitution - menu Configuration option Auto
Find

– ON

This  module  allows  the  automatic  detection  on  the  right  image  of  the  homologous
point tracked down on the left image.

In this program, an area based matching is  used to identify the homologous points.
This method works with pattern, target and search window.  Points are associated if
they have similar grey values.  Before starting, you must configure the parameters of
the matching. The parameters of the matching that you can change are:

The  size  of  the  pattern  and  target  window:  there  are  the  windows  surrounding  the
matched pixel

The  size  of  the  search  window:  the  search  window  contains  the  matched  pixels  for
which correlation coefficients are computed

The  minimum  correlation  value:  if  this  value  isn’t  reached,  the  window  “not
correlation”  will  appear  and  the  cursor  will  be  on  an  approximate  position  of  the
homologous point.

The maximum of mean difference

When you have chosen to activate the auto-correlation, the homologous point on the
right image of the left image current point will automatically appear in the right
window. Sometimes the program can’t find the homologous point and then sends the
message “No Correlation”. Sometimes the point is not exactly the homologous of this

of the left image.  In these two cases, you have always the possibility to displace the
point on the two images or to delete it.  When the two points are tracked down, their
ground  coordinates  are  computed  in  accordance  with  the  absolute  orientation
parameters.

4. EPIPOLAR RESAMPLING

The  resolution  of  the  created  image  can  also  be  chosen.    This  parameter  will
determinate its size in Ko.

Empty  images  are  then  created.    Every  point  in  these  images  undergoes  inverse
transformation to catch in the original image its grey value.

Epipolar  images  have  only  horizontal  parallaxes.    These  images  offer  the  big
advantage  to  simplify  the  automatic  correlation  procedure,  because  it  works  in  a
single direction.

4.1.  Application

In the project  window, click on  Epipolar Images.   The following dialog box  will pop
up:

Load the necessary files.

Click  on  Compute  Bounding  Box  to  have  the  limits  of  this.    These  limits  can  be
changed.  The X-limits depend on the overlay.  The user can directly change the Y-
limits.

The options are:

 you can choose to use the relative orientation parameters or put other values

for dω

, dφ

, dκ

, and dκ

. Indeed, this module is completely independent

of the rest of the treatment and can be used with values found by another
program.

 the overlay that will change the x min value of the left image and the x max

value of the right image

 the resolution that will determinate the size of the created epipolar image (the

size appear above the y min and y max values).

When all these parameters are fixed, click on Process. You must directly give a
name and a File Path for the created image.

5. IMAGE MATCHING

5.1. Application

In the project window, click on Matching:

First  choose  the  two  images  on  which  the  matching  is  made.    Indeed,  image
matching  can  be  made  on  the  original  images  or  on  the  epipolar  images.    In
accordance with the chosen images, the parameters of configuration can differ.
Click  on  Generate  in  the  Matched  Hmlg  Points  part.    A  dialog  box  allowing  the
configuration of the matching will appear:

When you click on Configure Correlation Process, the same window that in the
automatic detection of homologous points will appear (see the absolute orientation to
configure it).

The superior part of the window contains various parameters:

 Size of the cell: The chosen images are broken down into several cells in that

homologous points are searched.

 Step in the cell is the number of points that it increments when homologous points

are found

 Matched Points Nbr is the number of matched points that must be find in each

cell. As soon as this number is reached, points are computed in the following cell.

These three parameters must be chosen in accordance with the desired number of
matched points.

 Overlay

Original image (15*15)

Matched point

Non-matched point

Example :

Size of the cell X :5
Size of the cell Y :5
Step in the cell X :2
Step in the cell Y :3
Matched Points Nbr : 3

For the predicted position of homologous points, there are two options:

 Loading a homolog file; the predicted position are calculated in accordance with

the relative positions of the previously tracked down points.

 Computing an average shift X and Y values in pixels. The shift values are given

by the respective differences between the X and Y image coordinates of two
homologous points. For one computed point in the left image, the homologous
point on the right image will be search in a zone displaced of the shift X and shift
Y values compared with the position on the left image.

When all these parameters are fixed, click on Process Matching. A window informs
you on the course of the.process:

The under graph shows the cells within homologous points are searched.  If the cell
remains green, then a sufficient number of homologous points for that the correlation
coefficient  is  sufficient  have  been  found.    If  the  cell  remains  red,  then  a  number
inferior to the number asked by the user have been found.

When  the  matching  is  finished,  it  is  possible  to  visualize  the  matched  points  by
clicking Visualize.  This module allows deleting eventual non-homologous points.  To
delete these points, click on its ID and press Del.

N.B: It is also  possible to visualize a file with already matched points  by clicking on
Find and by choosing the adequate file.

6. GENERATION OF THE DIGITAL ELEVATION  MODEL (DEM)

6.1.  Application

In the project window, click on Matching.  The following window will appear:

For generating a DEM, you need a file containing ground coordinates.   To have this
file,  either  load  an  already  OAApply  file  by  clicking  on  Find  or  generate  a  new  file
with Generate.  This new file is generated as from an hmlg file that must be load in
the Matched Hmlg Points case.

The hmlg file can be constituted of homologous points tracked down on the epipolar
images

– then mark the Epipolar Img case – or of homologous points tracked down

on the original images:

 For the epipolar images, you must load the cc and OAparam files.
 For the original images, you must load the Left and Right OIparam, cc,

ORparam and OAparam files.

When the OAApply file is loaded or generated, you can click on Generate in the DEM
part. The DEM config window will appear:

The predicted values that are proposed correspond respectively to:

 degree of elevation is 1. So the distance is elevated at the degree 1. The fact of

increasing the degree of elevation allows to reduce the importance of the points
that are more far of the evaluated point.

 the number of points by dial is 4. This number depends of the already determined

points and their distribution.

 the bounding box is the framework built on the points the ground coordinates of

which are known.  The user can change the area of the DEM if he wants to make
the DEM only within a part of the original image.  He musts then enter the ground
coordinates of the X and Y minimum and maximum of the desired area.  It is also
possible  to  make  a  DEM  on  a  larger  area  but  the  points,  which  are  out  of  the
framework,  will  be  less  accurate  because  they  have

n’t known points in each

direction surrounding them.



the mean of the distance between each point known in the ground coordinates

and its nearest neighbour. This distance can be increased to accelerate the
procedure if few points are desired. It can be also reduced if the DEM must be
more accurate.

7. ORTHORECTIFICATION

7.1. Application

In the project window, click on Ortho:

To  construct  the  orthophotograph,  dem  file,  epipolar  images,  cc  and  OAparam  files
must be loaded.

The first step is the choice of the future orthophotograph size.  The default size given
by the program is the size of the area covered by the DEM. This can be changed but
must have limits inferior of those of the DEM.  The predicted step corresponds also to
the step of the DEM.  This factor will determine the resolution of the orthophotograph.

For  every  point  in  the  orthophotograph,  the  DEM  case  in  that  it  is  localised  is
computed.    The  Z  value  of  the  current  point  is  then  interpolated  with  a  bilinear
interpolation.

Every point in the photograph must also receive the grey value of the corresponding
pixel  in  the  epipolar  image.    This  operation  is  realised  by  a  transformation  of  the

2. Load the images

The program processes digital images with 8 bits/pixel (grey level). File format is
BMP.

The corresponding images for the Sart-Tilman are

- 1_7159.bmp for the left image
- 1_1760.bmp for the right image.

In  the  project  window,  click  on  the  browser  and  choose  1_7159.bmp  for  the  left
image and 1_7160.bmp for the right image.

3. Inner orientation

An inner orientation must be done for every image.  This process allows establishing
a relation between the pixel and image coordinates.  This relation is determined with
the  help  of  the  fiducial  marks  photo  coordinates  given  in  the  calibration  certificate
(see annex 1).



Encode the calibration certificate

In the project window, choose the option New CC. The following dialog box will pop
up:

The units of the calibration certificate are millimeters (10

-3

m). All the necessary data

are in the annex 1

When the entire certificate is encoded, save it. A CC file is created.



Location of fiducial marks

In the project window, choose the option Left and Right IO. The following window will
appear:

Below the images automatically appear the photo coordinates of the fiducial marks.

The first step is the determination of the photo orientation. According to it, the
parameters of transformation will change. In the example, the photo orientation is :

Then, you must track down the fiducial marks on the image.

Parameters of transformation will appear as from three fiducial marks and residues
as from four fiducial marks.



Correction of the radial lens distortion

In the menu Inner Orientation Module, choose the option Radial Distortion:
Then you can compute the coefficients of the polynomial after having chosen the
polynomial order. The values of the residues appear in the third column.

Before leaving the inner orientation, you must save the parameters:

menu Inner Orientation Module option Save OIparam. An OIParam File is created.
This operation must be done for the left and for the right image.

4. Relative orientation

Relative  orientation  allows  determining  the  relative  positions  of  the  two  bundles  of
rays  by  creating  spatial  stereomodel  in  an  arbitrary  coordinate  system.    Tracking
down  homologous  points  on  the  left  and  right  images  is  necessary  to  make  this
orientation.

Before starting the relative orientation, you must load the OIparam files of the left and
right images in the project window.

Click on the button RO by Rotations.  The following window box will appear:

By clicking with the right mouse button on a grey case of the left inferior part of the
screen, you can choose to add a point with the option Add Point. Then you must
track down the homologous point on the left and right images:

The left and right image coordinates of the point will appear in the left inferior part of
the screen.

NB: It is possible to delete one point by clicking on the ID with the right mouse button
and by choosing the option Delete This Point.

As from five homologous points, RO Final Parameters (expressed in Radians) can be
computed by clicking on Reset the first time and after Iterate. Then values of the
chart will change: the parallax will decrease, new RO Final Parameters are computed
and new model coordinates (X

Coord, Y

Coord) are computed for every image. Stop

the iterations when you think that the parallax values are small enough and that RO
Final parameters don’t significantly change.

Before  leaving  the  RO  orientation,  save  the  parameters  by  choosing  the  Save
Relative  Orientation  option  in  the  Relative  Orientation  Module  menu.    An
ORparam File is created for every couple of images.

It  is  also  possible  to  save  the  file  with  the  image  coordinates  of  the  homologous
points  by  choosing  the  Save  Hmlg  File  option  in  the  Relative  Orientation  Module
menu.  An hmlg File is created.

Another  possibility  is  the  loading  of  an  already  realised  Hmlg  File.    Either  you  load
this file in the project dialog box before starting the RO by Rotations or you load the
file  by  choosing  the  option  Load  Hmlg  File  option  in  the  Relative  Orientation
Module menu.

5. Absolute orientation

The purpose of absolute orientation is the transformation from model coordinates to
ground coordinates.  Control and check points are in the annex 2.

In the project window, click on AO & Restitution.  There are two steps:



Determination of the parameters (menu Module option Determination)

As for the inner orientation, you can add or delete points by clicking on the right
mouse button. The following window will appear:

This window allows the encoding of the control, the check and the tie points.  In the
point  class,  write  ctrl  for  control  points,  check  for  checkpoints  and  tie  for  tie  points
(statues of the points can be changed in the following steps).

Then you can track down these points on the two images.  On the over view, control
points  will  appear  in  blue,  checkpoints  in  green  and  tie  points  in  red.    As  for  three
control points, absolute orientation parameters can be computed by clicking on Reset
and then Iterate.

Stop  the  iterations  when  the  residues  on  the  control  and  checkpoints  are  small
enough.

To save the absolute orientation parameters:
menu Absolute Orientation Module option Save

– OA Params

A Oaparam file is created

To save the ground coordinates of the points:
menu Absolute Orientation Module option Save - Hmlg & Ground Points
An OA hmlg file is created, with the image coordinates of the homologous points
An OActrl file is created, with the ground coordinates of these points. Tie points will
not have ground coordinates. To have them, see the Restitution module

It is also possible to load files before realised:
menu Absolute Orientation Module option Load - Homolog Points to load the
image coordinates of the homologous points
menu Absolute Orientation Module option Load - Ground Points to load the
ground coordinates of the homologous points



Restitution (menu Module option Application)

This  module  allows  to  track  down  additional  points  for  that  ground  coordinates  are
unknown  and  to  compute  their  ground  coordinates  with  the  absolute  orientation
parameters.    The  ground  coordinates  of  the  new  points  will  directly  appear.    These
points will receive the type resti points.

To save the ground coordinates of these new points:
menu Absolute Orientation Module option Save

– OAApply

An OAApply File is created

To load already tracked down points:
menu Absolute Orientation Module option Load OAApply

To make the eventual future realisation of plans easier, you can use the
geocodification module. This module allows generating files that can directly be
employed in topographic programs.

Create a Configuration File (.cl) that has the following structure

BEGIN_CODES

point

line
spline
END_CODES
BEGIN_LAYERS

road
hedge
fence
END_LAYERS

So you choose for every point its code and its layer. A file with the ID, the type, the
layer, the code and the coordinates of the points is created. This file can directly be
employed in topographic programs.

you put here all the layers that you want to use

you put here all the codes that you want to use



Automatic detection of homologous points (menu Configuration option AutoFind

– ON)

This module allows the automatic detection on the right image of the homologous
point tracked down on the left image. For the configuration of the correlation window,
refer to the points 3.5 and 3.6 of the data processing part.

6. Epipolar resampling

Epipolar images are images for that the



-parallaxes are removed.

The necessary inputs are:

- the original images (left and right)
- the calibration certificate
- the inner orientation parameters

In the project window, click on Epipolar Images. The following dialog box will pop up:

When you click on Configure Correlation Process, the same window that in the
automatic detection of homologous points (see the absolute orientation) will appear.

The superior part of the window contains various parameters. These are described
at the point 5 of the data processing part

For the predicted position of homologous points, there are two options:



Loading a homolog file



Computing an average shift X and Y values in pixels

When all these parameters are fixed, click on Process Matching.  A window showing
the progress of the treatment appear.  If you have made an error of configuration or if
the treatment is too long you have the possibility to stop it by clicking on Stop.

When the matching is finished, it is possible to visualize the matched points by
clicking Visualize.

ex: MatchEpi.hmlg

So you can delete eventual non-homologous points.  It is also possible to load a file
with already matched points by clicking on Find and by choosing the adequate file.



DEM Generation

A DEM is a numeric representation of the heights of a surface.  It is a regular grid of
points, localised with their planimetric coordinates, for that the heights were
interpolated as from known points.

For this step, you need a file containing ground coordinates.  To have this file, either
load an already OAApply file by clicking on Find or generate a new file with
Generate.  This new file is generated as from an hmlg file that must be load in the
Matched Hmlg Points case.  The hmlg file can be constituted of homologous points
tracked down on the epipolar images

– then mark the Epipolar Img case – or of

homologous points tracked down on the original images.

For the epipolar images, you need the cc and OAparam files.

For the original images, you need the Left and Right OIparam, cc, ORparam and
OAparam files.

ex: ST.OAApply

When the OAApply file is loaded, you can click on Generate in the DEM part. The
DEM config window will appear:

Annex 1

CALIBRATION

No.

AF/ZEISS JENA LMK 266632B/1

DATE

14. 3. 94

CAMERA CALIBRATION CERTIFICATE

LMK LENS CONE

No.

266632B

TYPE

ZEISS JENA LMK

CALIBRATION

No.

AF/ZEISS JENA LMK 266632B/1

DATE OF CALIBRATION

14.3.94

LENS TYPE:

ZEISS JENA LMK

Serial No

: 2666632B

FILTER TYPE

: NONE FITTED

ORIGIN OF MEASUREMENTS o:

The point of Symmetry

SIGN CONVENTION:

Distortion is positive if away from origin

CALIBRATED AT A TEMPERATURE OF 20°C

CALIBRATION PERFORMED BY:

D T PHILPOT

MEASUREMENTS

CALIBRATED PRINCIPAL DISTANCE:

152.314 mm

COORDINATES OF POINT OF SYMMETRY

x = -0.021

y = +0.003

COORDINATES OF PRINCIPAL POINT OF AUTOCOLLIMATION

x = -0.017

y = -0.003

RADIAL DISTORTION IN MILLIMETRES

Back of camera

Radius (mm)

100

120

140

Semi diagonal (5)

0,003

0,004

0,003

0,001

0,000

-0,001

-0,005

Semi diagonal (6)

0,003

0,002

0,003

0,002

0,000

-0,002

Semi diagonal (7)

0,004

-0,001

0,000

-0,002

-0,006

Semi diagonal (8)

0,003

0,002

-0,001

0,002

0,004

-0,003

Mean

0,003

0,001

-0,004

CALIBRATION RESULTS FOR ZEISS RMK

CAMERA

ZEISS LMK 266632B

DATE

15 MARCH 1994

CENTRE OF GRAVITY

x = 110.0101

y = 109.9923

FIDUCIAL COORDINATES (SIDES)

x1 = 111.9978

x2 = -112.012

x3 = -0.01112

x4 = 0.009875

y1 = 0.020375

y2 = -0.00562

y3 = 111.9883

y4 = -111.998

DISTANCES

1-2 = 224.0100

3-4 = 223.9870

FIDUCIAL COORDINATES (CORNERS)

x5 = 109.9978

x6 = -109.992

x7 = -110.001

x8 = 110.0108

y5 = 110.0083

y6 = -110.007

y7 = 109.9843

y8 = -109.989

DISTANCES (DIAG)

7-8 = 311.1170

5-6 = 311.1312

DISTANCES (SIDE)

7-5 = 219.999

5-8 = 219.998

8-6 = 220.003

6-7 = 219.992

ROV001

– CTRL

middle of the sewage

234944.589

142672.707

242.564

ROV002

– CTRL

middle of the circular slab

234936.900

142094.695

232.874

ROV003

– CTRL

middle of the sewage

234566.378

142849.604

233.904

ROV004

– CTRL

extremity of the sewage

ROV005

– CTRL

middle of the sewage

234859.241

142401.975

246.506

ROV006

– CHECK

bottom of the parking banisters

234866.893

142323.762

244.944

234451.001

142059.345

245.169

ROV008

– CHECK

middle of the sewage

234444.199

142440.695

241.045

ROV009

– CHECK

extremity of the stile

234422.382

142348.426

242.670

ROV007

– CHECK

middle of the sewage

234644.270

142036.037

241.687