[GRASS-dev] DEM creation from stereo pairs

GRASS GRASS developer
1

Can anyone recommend open source tools for creating a DEM from stereo image pairs?

Thanks
Michael Barton
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

2

Michael,
don't know if it matches your needs as it is not an automatic process
but I remember a long time ago I used e-foto, formerly only available on
windows. It was a very rough photogrammetry station which allowed to
digitize contour lines on the basis of stereo couples. Nowadays I see
the project is still alive and was ported to Qt :
http://www.efoto.eng.uerj.br
Hope it can help,
Bye,
Vincent

Le vendredi 11 décembre 2009 à 21:02 -0700, Michael Barton a écrit :

Can anyone recommend open source tools for creating a DEM from stereo
image pairs?

Thanks
Michael Barton
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

3

Thanks. I'm looking into this. To run on Mac and Linux, one needs to compile this from within QT. I haven't done that and don't know what is required.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 2:17 AM, Vincent Bain wrote:

Michael,
don't know if it matches your needs as it is not an automatic process
but I remember a long time ago I used e-foto, formerly only available on
windows. It was a very rough photogrammetry station which allowed to
digitize contour lines on the basis of stereo couples. Nowadays I see
the project is still alive and was ported to Qt :
http://www.efoto.eng.uerj.br
Hope it can help,
Bye,
Vincent

Le vendredi 11 décembre 2009 à 21:02 -0700, Michael Barton a écrit :

Can anyone recommend open source tools for creating a DEM from stereo
image pairs?

Thanks
Michael Barton
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
grass-user Info Page

4

Compiling from Qt seems quite easy on Linux :
after unzipping the source code archive, from within each module
directory, you just have to run qmake-qt4 to compile .pro files, then
make install in order to create (local) executables.
I tried with 'exterior' module, it works fine.

Vincent.

Le samedi 12 décembre 2009 à 08:31 -0700, Michael Barton a écrit :

Thanks. I'm looking into this. To run on Mac and Linux, one needs to
compile this from within QT. I haven't done that and don't know what
is required.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 2:17 AM, Vincent Bain wrote:

> Michael,
> don't know if it matches your needs as it is not an automatic process
> but I remember a long time ago I used e-foto, formerly only
> available on
> windows. It was a very rough photogrammetry station which allowed to
> digitize contour lines on the basis of stereo couples. Nowadays I see
> the project is still alive and was ported to Qt :
> http://www.efoto.eng.uerj.br
> Hope it can help,
> Bye,
> Vincent
>
>
>
> Le vendredi 11 décembre 2009 à 21:02 -0700, Michael Barton a écrit :
>> Can anyone recommend open source tools for creating a DEM from stereo
>> image pairs?
>>
>> Thanks
>> Michael Barton
>> ____________________
>> C. Michael Barton
>> Director, Center for Social Dynamics & Complexity
>> Professor of Anthropology, School of Human Evolution & Social Change
>> Arizona State University
>>
>> Phone: 480-965-6262
>> Fax: 480-965-7671
>> www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu
>>
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> grass-user mailing list
>> grass-user@lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/grass-user
>>
>

5

and don't know what
is required.

Oh,
on Debian-based distros, qmake-qt4 should be in the libqt4-dev package

Vincent.

6

Thanks for the advice. We'll give this a try.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 10:13 AM, Vincent Bain wrote:

and don't know what
is required.

Oh,
on Debian-based distros, qmake-qt4 should be in the libqt4-dev package

Vincent.

7

Vince,

I just remembered a very useful free program for dealing with images: Hypercube. When I checked it, it looks like the current version makes DEM's from stereo pairs. Also makes anaglyphs. Only seems to be versions for Mac and Windows. No Linux. The PDF docs give a complete description for how to create DEM's (under the "applications" heading).

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 14, 2009, at 12:30 AM, Vincent Bain wrote:

Michael,
qmake and qmake-qt4 binaries are different. Is the libqt4-dev library
installed on your system ? If so, there should exist a file called
qmake-qt4 in /usr/bin/ or somewhere else (maybe try whereis qmake-qt4)

Did you get to run Stereo ? I'm stuck at the same point as you (even
with Alt-R available, nothing happens)

Vincent

Le dimanche 13 décembre 2009 à 16:57 -0700, Michael Barton a écrit :

Hi Vicent,

Where here is where I'm at.

cmb-MBP-2:dem_2.0 cmbarton$ /usr/local/Trolltech/Qt-4.1.0/bin/qmake
cmb-MBP-2:dem_2.0 cmbarton$ make
make: *** No rule to make target `dem.rc', needed by `dem.app/Contents/
Resources/dem.rc'. Stop.
cmb-MBP-2:dem_2.0 cmbarton$

I have qt 4.4 as default on my system. This doesn't do anything for
efoto it seems. 4.1 does seem to get part there not much farther. Here
is an example of my output.

Michael

____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 13, 2009, at 6:35 AM, Vincent Bain wrote:

As for the make command, qmake-qt4 will find on its own the
target .pro
files.
So just type:
qmake-qt4

good luck,
Vincent

Le samedi 12 décembre 2009 à 14:43 -0700, Michael Barton a écrit :

So how do you actually use qmake?

I do have qt 4.4 and it is in my path (/usr/bin)

I cd'ed to the directory of an efoto module (dem), and typed the
following

qmake
qmake dem.pro
qmake -makefile
qmake -makefile dem.pro
qmake -makefile -macx dem.pro

So far, I've had nothing that works

Any suggestions?

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 10:10 AM, Vincent Bain wrote:

Compiling from Qt seems quite easy on Linux :
after unzipping the source code archive, from within each module
directory, you just have to run qmake-qt4 to compile .pro files,
then
make install in order to create (local) executables.
I tried with 'exterior' module, it works fine.

Vincent.

Le samedi 12 décembre 2009 à 08:31 -0700, Michael Barton a écrit :

Thanks. I'm looking into this. To run on Mac and Linux, one needs
to
compile this from within QT. I haven't done that and don't know
what
is required.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social
Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Dec 12, 2009, at 2:17 AM, Vincent Bain wrote:

Michael,
don't know if it matches your needs as it is not an automatic
process
but I remember a long time ago I used e-foto, formerly only
available on
windows. It was a very rough photogrammetry station which
allowed to
digitize contour lines on the basis of stereo couples. Nowadays I
see
the project is still alive and was ported to Qt :
http://www.efoto.eng.uerj.br
Hope it can help,
Bye,
Vincent

Le vendredi 11 décembre 2009 à 21:02 -0700, Michael Barton a
écrit :

Can anyone recommend open source tools for creating a DEM from
stereo
image pairs?

Thanks
Michael Barton
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social
Change
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: www.public.asu.edu/~cmbarton, http://csdc.asu.edu

_______________________________________________
grass-user mailing list
grass-user@lists.osgeo.org
grass-user Info Page

8

Michael:

Can anyone recommend open source
tools for creating a DEM from stereo image pairs?

have a look at:
  http://grass.osgeo.org/gdp/stereo-grass/

I'm pretty sure there was a FOSS conference paper on that method
a few years ago.

not really what you want, but this is quite interesting:
  http://www.ecademix.com/JohannesHofmann/gipfel.html

Hamish

9

Thanks Hamish

On Dec 12, 2009, at 1:40 PM, Hamish wrote:

Michael:

Can anyone recommend open source
tools for creating a DEM from stereo image pairs?

have a look at:
http://grass.osgeo.org/gdp/stereo-grass/

I'm pretty sure there was a FOSS conference paper on that method
a few years ago.

Unfortunately, the requisite "stereo" package not only has not been maintained since 1997 (according to the stereo-grass page), but its web page has disappeared too.

not really what you want, but this is quite interesting:
http://www.ecademix.com/JohannesHofmann/gipfel.html

Not what we are looking for, but cool.

Michael

10

Hamish:

> have a look at:
> http://grass.osgeo.org/gdp/stereo-grass/
>
> I'm pretty sure there was a FOSS conference paper on that
> method a few years ago.

Michael:

Unfortunately, the requisite "stereo" package not only has
not been maintained since 1997 (according to the stereo-grass
page), but its web page has disappeared too.

the question is, how well did it work back then? working code
remains working code. :slight_smile:

you might try to look for a copy of the website on archive.org,
if not maybe I or one of us has an old copy of the source
somewhere in the old dusty attic.

shrug
Hamish

11

Am Samstag, 12. Dezember 2009 22:18:37 schrieb Hamish:

Hamish:
> > have a look at:
> > http://grass.osgeo.org/gdp/stereo-grass/
> >
> > I'm pretty sure there was a FOSS conference paper on that
> > method a few years ago.

Michael:
> Unfortunately, the requisite "stereo" package not only has
> not been maintained since 1997 (according to the stereo-grass
> page), but its web page has disappeared too.

the question is, how well did it work back then? working code
remains working code. :slight_smile:

you might try to look for a copy of the website on archive.org,
if not maybe I or one of us has an old copy of the source
somewhere in the old dusty attic.

shrug
Hamish

Well, the package did work and sometimes still does.
it's job.

The accuracy of the process after tweaking it a bit for small rounding mishaps
is about 12 to 14 bits (16bits data input). In comparison a hugin-based
process achieves a little -literally- 1 bit more of accuracy at about 5 times
the amount of time for data preparation (human) and 3-fold data processing
time (cpu-time).

In the old times of stereo I even had to reduce resolution of the source
images in order to get them processed with 256M of RAM (8 Mega-Pixels
(3344x2508) down to 4 MP (2364x1772) at that time)

It still provided about pixel accuracy with regards to optical problems
(mirage/thermal inversion/turbulence of the air caused by heat/cold).

To make it more feasible:
Using a mounted camera 8 MP (which is common these days in this work field),
provides at a field of view of 45° a angular distance of about 48 arc seconds
or about 1/75 of a degree which gives a accuracy of about 23cm at a distance
of 1000 meters. The atmospheric effect at that distance is way beyond (~ 3
meters)
If you are after taking photos in less ambitious way, let's say shooting an
excavation from 100m or less, the accuracy is -> 2.3cm at best, obviously
better near the center of field (less lens distortion, ...) and nearer to the
lens (less atmospheric (d)ef(f)ects).

Even if we take a sefety measure of factor 5 for each photo taken using a
shaky tripod or even factor 10 from a kite mounted camera and multiply all
worse effects instead of flattening out, the accuracy still exceeds most needs
at archeological sites (2.54cm = 1 inch) at distances of up to 25 m by a
factor of 8.

The worst case i had with stereo was a misplacement by 1.5m at 100m distance
using scans of ballon-mounted photograph from the late 30ies combined with
a 2003 photo taken using 4MP camera. (BTW, the 4MP was the culprit in the end)

One of the miracles using stereo was the ability to revisit a place in the
desert by triangulation using stereo after 8 years with 30cm accuracy and
pretty unsharp joshua-trees in the background (at distances of ~15m and ~25m
unsharp, 6 team photos taken in front of a car, taking the rim as rule using a
4MP camera). GPS Data was misleading by 4-8 meters.

The main reason for using stereo is it's ability to combine different sorts of
source materials (plates/film/digital imagery) in pretty short time. (I use it
still as stated above for small projects, where only a few points in 3d-space
need to be 'surveyed')
As stereo takes more than 2 pictures it is even more powerful than most
standard off-the-shelf commercial solutions.

The main reasons against it's use is the lack of automation in the process,
the lack of dedicated support (I'm not able to provide it, though stereo would
really deserve it) as well as the lack of camera/lens adjustment combined with
a really awful codebase.

Hope that helps a bit,
Christoph