[ptx] hugin as a project editor

[Bernard Lang]

Hi,

I am not sure how this list works, nor what kind of comments are
appropriate, nor whether these should rather be sent to the forge.  I
am a novice user, but I have tried to understand the logic of the
panorama softare. So far, I used only hugin and enblend, on a Mandriva
Linux, with some difficulty as some of you may have noticed (not
solved yet, but I had little time).

Apologies if I missed important points in the existing documentation.

My (probably nive) understanding of hugin is that it can be seen as a
project editor. I think it is a neat architecture (that I would like
to see more often in software), but may be it should be made more
clear to the user and possibly built upon for functionality.

Essentially, it collects information about your pictures, the way they
were taken, properties of the pictures (verticals, horizontals,
correlated points between picture), and how they have to be put
together (at least geometrically, since enblend takes care of color
and light).[1]

Then, once the project file is built, one just has to run it to get
the result.  The project file is a kind of program taking pictures as
input, and producing other pictures [2]. And hugin is an
editor-interpreter-debugger for that program.

This architecture (if correct) suggests some improvements, actually
just adding what is usually available with other such systems.

Taking just the editor point of view, a common feature of editors is
to automatically save the edited file every 3 or 4 minutes, and also
to keep a back-up version of a file being edited.  This is for example
standard with my favorite text editor emacs.

Indeed, I have experienced crashes, and lost all the work of defining
control points.  I am not necessarily saying the software was
responsible for crashing, but when doing a long piece of processing,
over very large data, such things may occur (and hugin has apparently
not reached version 1).  Anyway, it might be nice to systematically
save the project file in a temporary project file ( "#project.pto#" in
my configuration of emacs) before starting any computation that might
be significant, or when must time has elapsed since the previous save.
Similarly, when the hugin session reopens an older file "project.pto",
this older file should be preserved in something like
"project.pto.back" or ".project.pto~", or whatever variant of the name
is considered convenient (this could be user definable), when a
modified version is saved for the first time in place of the
older-version of the project file (use of "save" rather than "save
as").

Another thing that might be nice would be to save the project file in
the EXIF data of the resulting picture ... but that is probably quite
another story.  I have no idea whether the EXIF standard allows such a
thing.  An there is usually much more processing than just what is
done by hugin, not to mention the fact that the result might be a
collection of (TIFF) images to be further processed.

note

[1] it could collect other kinds of information.  One example is
stating the angle between two lines defined by control
points. Sometimes, this information is more readily available than
horizontals and verticals, and can be sufficient to improve a
parspective by geometric transformation of the picture.

[2] indeed, one can change the input pictures, for the purpose of
editing, for example by taking pictures that have been color edited to
get more contrast and better identification of control points.
(though this could also be made a module of the control points editor
... but is certainly not urgent).


Bernard


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