interface' and in computation'. For the first programming task,
detailed knowledge of and experiences with the toolboxes
were necessary. Such information can be gained from the
books "Inside Macintosh" which are also delivered on a CD-
ROM. Parallel with the programming, the testing of the
finished modules took place. The efforts for careful testing are
considerable but they are well invested. When running the
program, some problems occurred due to insufficient memory
at the PowerBook. 4 Mb of RAM proved to be sufficient, but
no other programs should be loaded into the memory. The
runtime version of the "LDIP" prototype has about 250 kbytes.
The development efforts of the prototype version are about
150 hours of programming; design, testing and documenta-
tion efforts are not included. On the whole, the development
efforts are relatively high. They can only be justified if the
program can be used several times.
The production of a CD-ROM is planned to be carried out on
a multi session CD-ROM writer and all the images will be in
the TIF format. The image data are originally stored by means
of a Photo-CD, a DAT cassette or 3.5" discs. The format of
the original data was partially in Photo-CD format (YCC) which
has to be converted by means of the program "Photoshop".
2.6 Experiences from the use
The use of the program is twofold. The first use is a presenta-
tion in the lecture room together with an overhead projector.
The quality of the presentation depends on the applied
plasma screen (LCD). The used one, Telex 6001, makes pos-
sible the presentation in colour, even though the PowerBook
520 has a black and white screen only. The light intensity at
the projection can be a problem at larger audiences and at
bright lecture rooms.
The second use, in an exercise room with 12 Macintosh
computers, model LC475, is carried out by one teacher only.
He himself uses 1 Macintosh LC475 together with a LCD and
an overhead projector. The students did not have experience
with Macintosh computers beforehand. The exercise with the
contents explained in section 2.4.1-2.4.4 of this article takes
about 1.5 hours. At this computer model it was necessary to
emulate the Motorola processor 68030 instead of the built-in
68040 processor in order to run the execute file of "LDIP".
3. CONCLUSION
CAL in digital photogrammetry requires a large amount of
data and complex calculations. The new personal computers
with their high processing speed and large internal and
external storage capacity (such as CD-ROM) as well as the
Photo-CD services make a new type of learning program
possible. These CAL programs include speech, image
libraries and programs with heavy calculations. The user
interface is simpler and more attractive due to icons, sound
and various windows. The efforts for development are
relatively high and require detailed knowledge of toolboxes as
well as good programming experience. There are also very
advanced author programs available which will ease the
production of good CAL programs for authors with less
experience in programming.
64
THEME 4: AUTOMATIC MEASUREMENT
of Real Réseau Images
EP
mers has fine crosses in the image
325 u camera
INFORMATION
Fig. 6. Second level of information about réseau cameras.
The new figure is a dynamic one. By clicking on the icon
"IMAGING", three imaging rays run from right to left and hit
the film at three points: the image point p' and two imaged
réseau crosses. A third level of information can be displayed;
this hypertext window contains related literature.
REFERENCES
Dold, J. et al., 1993. Das Rolleimetric 3D-IndustriemeBsystem.
Zeitschrift für Photogrammetrie und Fernerkundung 2/93, S.
50.::62.
Hóhle, J., 1992. Rechnergestützte Ausbildung und Übung in
Photogrammetrie und Landinformationssystemen. In: Pro-
ceedings of the XVII ISPRS Congress, Washington D.C./
U.S.A., Commission VI, Invited paper, 6 p.
Hóhle, J., 1994. Teaching and Learning Photogrammetry
Using PC, CD-ROM and Photo-CD. In: Proceedings, Interna-
tional Society of Photogrammetry and Remote Sensing,
Commission VI Symposium "Facing the Change and the
Challenge", October 10-13th, Bejing/China, pp. 66-70.
Hóhle, J., 1995. Computer-Assisted Learning in Photogram-
metry and Image Processing. In: Proceedings of the Confe-
rence "Computer Based Learning in Science" (CBLIS '95), 30
June to 4 July, Opava/Czech Republic, pp. 269-279.
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996
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