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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B6. Istanbul 2004
of Adobe's Photoshop program were carried out. Learning
programs where computational tasks are carried out on-line
were produced by means of the Java language. An efficient tool
for generation of animations and interactive elements is
Macromedia Flash MX. The interactions are written (or
automatically generated) in the ActionScript programming
language. Some parts of the learning programs require
programming in php script, which is executed on-line at the
server computer. The results are HTML code files, which are
sent via the Internet to the client computer (compare left side of
figure 2).
5.4 Self-evaluation tests
Interactive quizzes have been created in order to enable a self-
evaluation. They are carried out at the Internet. Various
programs and services are available from different sources. For
example, the QuizMaker for QuizServer of R. Shadian,
University of Hawaii, USA, allows for different types of
quizzes. You may select "true-false" or "multiple choice". Radio
buttons are used to mark the answer of the user, and the
program then tests whether the delivered answer is correct.
Images and graphics can be used in the quiz as well.
5.5 Assignments
The assignments (tasks) are mainly questions that are written in
HTML code and called by the hypertext "Receive tasks". They
are then displayed on the right side of the described user
interface (compare figure 3). The final assignments (tasks) are
written as e-mail including attachments in the Word format and
sent to the participants by a mail program.
6. THE LEARNING PROGRAMS OF THE COURSE
"AUTOMATIC ORIENTATION OF AERIAL IMAGES
ON DATABASES"
The course "B" of the EuroSDR e-learning includes three
learning programs. They form the core of the course and give
the participants practical experience about procedures and
problems at automatic measurements of image points as well as
insight in the methods of automatic orientation of aerial images
on databases. Details of the research project are published in
(Hóhle, 1999).
The first learning program, "LDIPInter", introduces correlation
techniques and gives assignments (tasks) for calculation of
image positions in 1D and 2D, with and without sub-pixel
accuracy and applies the techniques to the automatic measuring
of crosses and the automatic orientation of aerial images. The
second learning program, "Auto Orient", deals with practical
details of the "Automatic orientation of aerial images on
databases". The third program, which will be used in 2004 for
the first time, is "LDIPInter2". The name stands for "Learning
Digital Photogrammetry", part 2, and the program deals with
several correlation (matching) techniques: ^ Area-based
matching, feature-based matching and least squares matching.
An application of the techniques is also included: The test of
digital elevation models by means of two orthoimages.
All three programs have a knowledge part and a task part. The
given answers and solutions to the given tasks are tested and
feedback is given to the user. The figures 5 and 6 give some
ideas about the contents and the layout of the last two programs.
93
Theme 3: Area Based Matching
IU?
E inter2
Task 3.2: Apply different geometric and radiometric models.
Method Geometric model Radiometric model | Number of parameters
A Shifs only “> 2
B8 Heimat
transformation .. 4
t AfFfiotr ansformation E €
b AV nteansformation
Ing resampling Shift anc scale e
Template Search area
Resampled a. 0.012 J | Ry
search area [— E
uu "row 0.012 3 a
m Number of E a
iterations 3
Which fs the most accurate method? [D | [Check | The answer is correct
Figure 5. Task part of the learning program "LDIPInter2".
In the theme on Area Based Matching the user can
test different geometric and radiometric models. The
achieved accuracy in the co-ordinate measurements
will be displayed and the question "Which is the
most accurate method?" has to be answered. The
given answer is analysed and the learning program
displays a comment.
Theme 4: Application "Checking of Digital Elevation Be
Models " ) inter
Interz
Ma - Tr Lu be checken and
\ /
b
^
\ /
\ /
\ 7f h
P,N dX 4 ted to
DEM ——
Heo] [x] [mes] [see] [ae]
ee
j information
Figure 6. Knowledge part of "LDIPInter2".
The matching of image patches is applied to
automatic parallax measurement between two
orthoimages. The parallaxes are then converted to
errors of the digital elevation models and the DEM
can in this way be improved. The learning program
explains the method by means of running text lines.
More information is given in windows which pop up
when the user clicks on the hypertext. The literature
to this method, (Hôhle et al.), can be downloads
from a server.
7. SOME EXPERIENCES FROM E-LEARNING
The participants of the first Euro-SDR e-learning courses
evaluated the courses by means of questionnaires. Also the
teachers of the courses discussed their experiences. The first
findings were published in (Höhle, 2003), (Tempfli, 2003) and