[GRASSLIST:1695] Re: Stereo photogrammetry w/o known camera position

[Markus Neteler]

Hi Christoph,

with a small patch I could compile the

stereo-0.2/widget > diff 3dkit.c 3dkit.c.org 
111c111
< #ifdef __i686__
---
> #ifdef __i386__

I have loaded grayscaled tiff from "imagery/spearfish" (gs13.1, gs14.1
aerial photos, exported with r.out.tiff, then xv conversion to grayscale)
successfully into "stereo" program.

It's looking promising for GRASS! However, a direct link to GRASS would
be very useful to determine the control points etc.

BTW: Once as a student I made stereo images from "imagery/spearfish"
http://www.geog.uni-hannover.de/users/neteler/stereo/welcome.html
You need red/green or red/blue glasses to enjoy.

I would welcome to see "stereo/3D" measurement integrated into GRASS.
Please consider to develop such a module.

Many thanks for your offer,

kind regards

 Markus Neteler


On Mon, Apr 02, 2001 at 11:41:51AM -0700, C.Hoegl at gmx.net wrote:
> Hi GRASSlist,
> has anybody implemented/used Stereo-0.2 together with Grass?
> 
> I myself used it a lot during the last month in order to generate
> cheap DEM Data for our telescope project. (http://dts.astronomy.net)
> 
> It seemed to be logical to offer it in a polished form to other GIS
> (eh GRASS users) users as well. (currently it's glued to GRASS 
> with some ugly shellscripts and stereo needs a bit of rewrite as well)
> 
> Currently I use it as follows:
> (You may calibrate using any 4+Polygon like TP's etc. which are
> visible in at least two photos)
> 
> Put a multi-colored cube wireframe of known dimensions out in the
> location (level it using some standard method), write down it's
> relative coordinates. (used for Image calibration later on)
> Take as many photographs as seem appropriate (always with
> cube included). (at least 2 photos are necessary)
> Calibrate images using known info (relative cube coordinates) within
> stereo (display). Triangulate points of interest. ...
> with additional import and manipulation within grass to follow.
>  
> 
> If there is enough interest in merging stereo to grass, i will
> write/rewrite a grassmodule / stereo.
> (perhaps as an extension to OrthoRectificationSupport)
> 
> Pros:
> pretty random Camera placement (cam location hasn't to be known!)
> pretty high quality results (depending on calibration points)
> one person usage of complete system (it's easy to deploy
> a "calibration" object and taking photos of it.)
> reusable datasets (Photos taken may be reviewed afterwards
> for other - former unknown - topics without having to 
> survey the points of interest again.)
> cheap (A simple camera/scanner system)  
> fast (doing some snapshots at more or less random positions
> really doesn't cost to much time)
> interoperates well with GPS/Remote Sensing)
> 
> 
> Cons:
> currently buggy software / no plug and play module as of now
> you can only measure what you can identify (as good/bad as v.digit)
> 
> 
> Plans:
> Reimplementing stereo within tk and a c library.
> Providing hooks for grass and image registration.
> 
> 
> Let me know if there is already some tool/module out there (GPL or sim.)
> (i.ortho.* doesn't count as it requires camera location as well
> as other accurate data not always at hand (according to GRASS Handbook))
> 
> best regards,
> Christoph Hoegl
> 
> (Stereo is a (pretty old) GPL package for stereo photogrammetry))
> ---------------LSM Entry-----------------------------------
> Begin3
> Title:          Stereo
> Version:        0.2
> Entered-date:   06OCT97
> Description:    Stereo-photometrology package. A tool
>                 for loading up high res grey tiff/targa
>                 files of stereo photographs and
>                 taking accurate 3D measurents from them.
> Keywords:       XLib, X Window System, X11, stereo,
>                 photometrology, CAD, measurement,
>                 Cooledit
> Author:         psheer at icon.co.za (Paul Sheer)
> Maintained-by:  Nobody
> Primary-site:   sunsite.unc.edu /pub/Linux/apps/math
>                 3193kB stereo-0.2.tar.gz
>                 1kB stereo.lsm
> Platforms:      Linux, and any Unix clone running X11
> Copying-policy: GPL
> End
> ------------------LSM Entry------------------------------- 
> 

-- 
Markus Neteler *  University of Hannover
Institute of Physical Geography and Landscape Ecology
Schneiderberg 50 * D-30167 Hannover * Germany
Tel: ++49-(0)511-762-4494  Fax: -3984