Re: Stereo to photogrammetry

[P3D Colin Moyer <cmoyer@xxxxxxx>]

Thank you Clifford J. Mugnier, and George Themelis for the comments on
photogrammetry.

>>It is not clear to me why you will be recording these pictures.  At first,
>>it sounds as if you are doing stereo photography for documentation.  The
>>use of the word "photogrammetry" implies that you want to do measurements
>>on the pictures to recreate true sizes of objects.  Since you are looking
>>and can handle the ojects (unlike aerial or SEM photogrammetry) why don't
>>you measure them directly with a ruler???
>
>I agree; why don't you use a ruler?


There are a few simple reasons, why not use a ruler.

For one, calipers are usually used, some of which feed the information
straight into a computer data base, however, many of the "things to be
measured" are too small for this to be accurate enough.  Often when flakes
are removed from stone, cliffs or steps in the material appear, which are
tricky to measure.  One of the measurements required is the angle of the
working retouched edge of a tool, calculating this can be problematic if
there are several steps in the edge of the material.  Some of the artifacts
are only an inch or two in length with very small retouch scars.  In short,
if you can blow up an artifact and use photgrammetry you could make some
improvements (or is this wishful thinking?).


Another key problem is political so to speak, when you dig a site, you
rarely can take the artifacts with you, if you forget to take a measurement
or think of something later you want to measure that you didn't originally,
you normally have to go back to where the artifact came from, in this case,
a museum or University in France.  People are very touchy about their
"cultural heritage."  Flying back to take measurements is too time
consuming and expensive in many cases.  Having a visual record on CD or
Film or whatever that you could take measurements from would be a good
option.  Besides, then you can provide images to other researchers in a
portable format, so that they can take measurements without having to fly
to France.  And we all know what problems airports can be.

Besides, I need an excuse to take stereo photos and have it LOOK like work.
One of the best parts of trying to sort out all of this stuff is that I
have developed an interest in taking stereo photos in general.

I would like to publicly thank Jamie Drouin for feuling this interest, and
Dennis Wagner for his technical help as well.

I hope to post some of my pictures of artifacts on the 'net soon.

                Colin Moyer.

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