International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B6. Istanbul 2004
Figure 6. The camera parameters module
Given a sample calibration certificate, the user will complete the
blank fields with that information. If he doesn't understand
what he is doing, he might also take a look at the theory shown
at chapter 2 of the e-book (Basic Principles of
Photogrammetry), which describes what every calibration
parameter means (Figure 7). Method and procedure names used
in the software are the same that are used throughout the book,
so, a simple search will return more detailed information on that
unknown parameter.
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A description of what each distortion parameter
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Figure 8. An example of the way E-FOTO stores its
information
Another useful piece of information is that E-FOTO generates
simple, readable files (stored as txt files). Information
generated with E-FOTO is recorded in this manner, so, any file
can be easily read (no encrypted or database hidden fields). The
teacher can use his students report files as a means of
identifying their mistakes. The students can use the files E-
FOTO generates as their own reports. An example is the file
generated by the Camera Calibration module (Figure 8).
98
A sample set of data comes with the binaries, so, the student
will have, at least, some configuration reports and some images
to explore. Moving on, another idea the teacher could want to
implement concerns the process called Interior Orientation. He
(or the student) will, then, click on the button "Interior
Orientation", on figure 2.
The interior orientation application will be shown. On the main
bar, the user will be invited to open previous project and camera
configuration files, then an image (again, E-FOTO comes with a
set of ready-to-use files). When opened, the user will be
prompted to select its first fiducial mark, and go on or let the
program search for similar ones.
At this point, the teacher might recall the “Image Correlation”
subject, which deserves an entire chapter of the e-book.
Important discussions on how all fiducial marks were located
using only one as a sample might appear, and the students will
be able to explore the source code and even understand how all
those mathematical operations are converted to a computer
language (Figure 10).
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Figure 10. Three useful pieces of information: the automatic
correlation output from the software, its theoretical explanation
from the e-book and its implementation, from the source code
Another interesting activity would be the comparison between
the results obtained from the same fiducial marks, but using two
different models: affine and similarity. Again, those are
described more deeply on the e-book. The software will present
the results as it is depicted on Figure 11.
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