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@@ -1,238 +0,0 @@ -gipfel -====== - -[homepage](http://www.flpsed.org/gipfel.html) - -Description ------------ -__gipfel__ helps to find the names of mountains or points of interest -on a picture. -It uses a database containing names and GPS data. With the given viewpoint -(the point from which the picture was taken) and two known mountains -on the picture, gipfel can compute all parameters needed to compute the -positions of other mountains on the picture. -gipfel can also be used to play around with the parameters manually. -But it's pretty difficult to find the right parameters for a given -picture manually. -You can think of gipfel as a georeferencing software for arbitrary images -(not only satelite images or maps). -gipfel also has an image stitching mode, which allows to generate -panorama images from multiple images that have been referenced with gipfel. -The nice thing about image stitching is that it reuses the code that -already exists for referencing images. -gipfel uses the non-linear -[least squares method](http://en.wikipedia.org/wiki/Least_squares) to -compute the viewing paramteres from the given data points. - -Requirements ------------- -* [fltk-1.x.x](http://www.fltk.org) -* [libtiff](http://www.remotesensing.org/libtiff/) -* [libjpeg](http://www.ijg.org/) -* [exiv2](http://www.exiv2.org/) -* [GSL - GNU Scientific Library](http://www.gnu.org/software/gsl/) -* gipfel works on UNIX-like systems (e.g. Linux, *BSD and probably others) - -Installation ------------- -Unpack the tar file and run `./configure; make; make install` - -Running -------- -To start gipfel, enter - - gipfel <image> - -where <image> is the actual picture in JPEG format. - -You should now see a control window and the actual picture. -Additionally a "Choose Viewpoint" window should pop up, where you can search -for the viewpoint from which the picture was taken. Select a viewpoint and -click "Ok". -Alternatively, you can enter the GPS coordinate of the viewpoint directly in -the control window (hit <Enter> for every data field). -You can now use the controls in the control window to modify the view -parameters. These are: -* View direction -* Nick angle -* Tilt angle -* Focal Length -* Visibility - -Play around with these parameters, until you see the names of -mountains, which you already recognize on the picture. -Now middle-click on the small cross at the left of the name to mark it. -It should turn red. Now you can drag it with the left mouse button pressed -to the position of the mountain on the picture. -If you have positioned at least two mountains all other mountains should -move to their correct positions in the picture. -You can try to set more than two mountains to ge a more accurate result. - -You may also want to have a look at the (outdated) -(screen video)[http://www.flpsed.org/images/gipfel.avi] -for an example session. - -Data File ---------- -As stated before, gipfel needs GPS input data. The input data must be -an ASCII file with one line per mountain / point of interest. -Each line must contain the following values separated by a comma: - - <SHORTNAME>,<NAME>,<DESCRIPTION>,<LATITUDE>,<LONGITUDE>,<HEIGHT> - -<SHORTNAME> and <DESCRIPTION> may be left empty. - -The following line is a valid example: - SMTSBG,Simetsberg,,47.56617,11.25358,1836 - -Fortunately, there is a [great website](http://www.alpin-koordinaten.de), -where you can download a suitable file containg quite a lot of data mostly -concerning the alps: -Click on the "Suchen" button and the click on the diskette symbol below -the first table then select "Fugawi 3 TXT" format and click on "Download". - -Obviously you can easily add your own entries to the data file or add them -to the database at http://www.alpin-koordinaten.de. - -Thanks to the kind permission of -[Jonathan de Ferranti](http://www.viewfinderpanoramas.org/) and the -creators of http://www.alpin-koordinaten.de, the standard gipfel -tarball includes a default datafile generated from these two sources. - -For the USA, you can download a data file -from [USGS](http://geonames.usgs.gov/domestic/download_data.htm) -The file can be transformed for gipfel with - awk 'BEGIN {FS="|"; OFS=","}; - $3 == "Summit" {print "usgs_" $1, $2,"" , $10, $11, $16};' - -GPS Tracks ----------- -Once you have determined the right parameters using the procedure described -above, you can load GPS tracks and display them on the picture. Use the -File->Load Track menu item. GPS tracks should be text files containing -one line per waypoint. Each line should be of the form: - -<LATITUDE>,<LONGITUDE>,<HEIGHT> - -GPS tracks are displayed with variable width depending on the distance -of the way points from the current view point and the scale value. -You can also modify the width using the "Track Width" slider. - -Loading and Saving Images -------------------------- -gipfel allows to save the image paramters in the comment section of -the JPEG image. Use the File->Save Image menu item. -Note, that in the saved image all previous JPEG comments are removed. -If you open an image containing gipfel image parameters, they are -automatcally set. - -Hidden Object Detection ------------------------ -gipfel tries to identify objects in its database, that are hidden by others. -This is done by assuming that every object/peak has the form of a cone -with a fixed steepness. If such imaginary cone would hide the view to a -point in the database, gipfel marks it as hidden. Hidden objects are -not shown by default, but you can enable the display of hidden objects using -the Option->Show Hidden menu entry. Hidden objects and hidden GPS way points -are displayed in blue. - -Refraction ----------- -Refraction caused by temperature and density gardients in the atmosphere is -taken into account according to the approximation described by -[Tom Chester](http://tchester.org/sgm/analysis/peaks/refraction_calculation.html). -under the assumption of a temperature change of 6.5C per 1000m and a -temperature T0 at view point level of 10C. - -Exif Data ---------- -gipfel tries to get useful information from the exif data of the -input image. It uses the "Focal Length in 35mm Film" and the -"GPS Longitude", "GPS Latitude", and "GPS Height" parameters, if they -exist. - -Lens Distortion ---------------- -Typical lenses especially wide-angle lenses diverge from the optimal -rectilinear projection. -gipfel can now partly correct the resulting errors. -To this end gipfel uses a standard distortion model with three parameters -(k0, k1, and x0). Depending on these values, the distance d of an image -point from the center is modified by (k0 * d + k1 * d ^ 2). -x0 is the main point offset in X direction. - -If you mark and position more than 3 mountains on an image, gipfel -tries to correct lens distortion. You can see that the flags turn -green in this case. -Once you have reasonable values for k0 and k1 for a special camera and -focal length you can save the distortion profile (Distortion/Save Profile). -Whenever you now open an image taken with this camera model and focal -length, gipfel will use this distortion profile. -The distortion profiles are stored in the - $HOME/.fltk/Johannes.HofmannATgmx.de/gipfel -directory and can also be edited manually. -Independent of the distortion profiles one can also modify the -distortion parameters per image. -Distortion correction is also used when stitching panorama images. - -Stitching Panorama Images -------------------------- -If you have multiple images from the same viewpoint referenced with gipfel -you can stitch them together to form a panorama image. -For stitching the input images must all have been correctly referenced -with gipfel and saved (see "Loading and Saving Images"). -You can then call - gipfel -s <img1> <img2> ... -to see the result in a window. Alternatively you can call - gipfel -s -j <outimg> <img1> <img2> ... -to save the result as a JPEG image to <outimg> or - gipfel -s -t <outimg> <img1> <img2> ... -to save the result as TIFF image. -To get multiple TIFF images as input for -<http://enblend.sourceforge.net/>, call gipfel like this: - for i in *.jpg; do gipfel -s -b -t tiff/$i $i; done - -The width and height of the result images can be adjusted with -additional -w and -h options. -You can use the -b switch to enable bicubic interpolation, which -gives smoother results but is a bit slower. - -gipfel simply scans all directions needed for the panorama and determines -where these directions would end up on the various pictures. It can then -record the corresponding color values from the input images. - -In contrast to other stitching programs, the input images don't need to -overlap. - -If you want to open a stitched image in gipfel to locate the mountains -on it, don't forget to choose Panoramic Projection! - -Troubleshooting ---------------- -* Obviously gipfel can only be as good as its input data. If there is no - data about the mountains on your picture, you are out of luck... - But as the data file format is pretty simple and GPS receivers are common, - you can build up your own datafile. -* gipfel only works with full normal unmodified pictures taken with a - non-distorting standard objektive. If you have a panorama picture, you - might want to try the "Panoramic Projection" support which - imlements a cylindrical projection (see "Projection" menu). -* I don't know, whether gipfel currently works correctly on pictures taken on - the southern hemisphere, but I would appreciate any feedback about it. - -Acknowledgements ----------------- -Thanks to the guys from http://www.alpin-koordinaten.de for their public -GPS database. -Also have look at their other [site](http://www.alpen-panoramen.de). -In newer versions I use [maxima](http://maxima.sourceforge.net/) for -symbolic computation and code generation. -I also want to thank my brother Martin for his suggestions and the -discussions. - -DISCLAIMER ----------- -gipfel must __not__ be used for real navigation. You should not rely on the -results of gipfel. - -Johannes Hofmann, <Johannes.Hofmann@gmx.de> |