Creating Custom Markers using ALVAR
The good people at VTT have created a program for creating marker images that is available when
you install the ALVAR libraries. (As of this writing, the source code for the sample programs can be found in the "Example programs" section at
Compiling the Sample Program
To generate the example program provided by Alvar, "SampleMarkerCreator", you will need to install a variety
of utilities and programs, including OpenCV 1.0, GLUT 3.7, and CMake 2.6. OpenCV will have been installed already if you followed the directions in the GoblinXNA Installation Guide to install Alvar. In addition, to compile the program you will need either
Microsoft Visual Studio 2003, 2005, or 2008, or MinGW and GNU Make.
Let's start off by obtaining the GLUT libraries. A variety of compiled and uncompiled code can be found
at http://www.opengl.org/resources/libraries/glut/glut_downloads.php, and for Intel systems the precompiled libraries can be found at
http://www.opengl.org/resources/libraries/glut/glutdlls37beta.zip. Unzip these to your desired location (you will point to them later.)
Next install CMake 2.6, found at
http://www.cmake.org/files/v2.6/cmake-2.6.4-win32-x86.exe. When you are asked, choose to save the file and then launch it. In Google Chrome it looks like
this (see the bottom of the screen shot):
When asked if you wish to allow the program to run, choose "Yes".
On the first screen click "Next", and on the next screen click "I Agree" (after carefully reading the disclaimer
and pondering its ramifications, of course). Then you need to tell it to add itself to the path for the current user (or all users if you wish):
You can accept the default installation location or choose one of your own. Likewise, you can select the
Start Menu folder. Then click Install. If all goes well you should see this screen, and can click "Finish".
At this point you probably need to log off and on again so that your environment variables are reloaded
and the CMake executable will be in your path. Next you can generate the development environment by locating the build script in the Alvar installation directory, located here on my machine (don't launch it yet):
To run this you need to be an administrator. Using the Start Menu, find the Command Terminal in the menu
and right-click it:
In the context menu that appears, choose to "Run as administrator". Then navigate to the location of your
generate.bat file and run that. (Depending upon your path, you may need to surround the command in double quotes.) It will take a moment to build, but then you should see this:
Next launch the GUI version of CMake:
Before you proceed, note that you must not change the location where the binaries will be built. But fill
out the rest of the requirements as shown below (substituting your own paths for mine.)
Click "Configure", and then click "Generate". This will create the sample projects - on my system, located
at C:\Program Files\Alvar 1.4.0\build\msvc90\build\sample. When you open the SampleMarkerCreator.vcproj file, you might witness this warning:
Choose "Restart Visual Studio under different credentials", then choose to allow this program to make changes
to your computer.
To create the samplemarkercreatord.exe file, I recommend choosing Build ... Build Solution <F6> from
the top menu. This will produce the executable at C:\Program Files\Alvar 1.4.0\build\msvc90\build\sample\Debug.
Running the Sample Program
To run the program, open a command prompt and navigate to the file. Upon running it, you will
Alvar Library 1.4.0 Copyright (c) VTT 2008-2010
Compiled on Windows 5.1 x86 (Jul 7 2010)
Day 303/365 of usage period for this version
This is an example of how to use the 'MarkerData' and 'MarkerArtoolkit'
classes to generate marker images. This application can be used to
generate markers and multimarker setups that can be used with
SampleMarkerDetector and SampleMultiMarker.
samplemarkercreatord.exe [options] argument
65535 marker with number 65535
-f 65535 force hamming(8,4) encoding
-1 "hello world" marker with string
-2 catalog.xml marker with file reference
-3 www.vtt.fi marker with URL
-u 96 use units corresponding to 1.0 unit per 96 pixels
-uin use inches as units (assuming 96 dpi)
-ucm use cm's as units (assuming 96 dpi) <default>
-s 5.0 use marker size 5.0x5.0 units (default 9.0x9.0)
-r 5 marker content resolution -- 0 uses default
-m 2.0 marker margin resolution -- 0 uses default
-a use ArToolkit style matrix markers
-p prompt marker placements interactively from the user
Prompt marker placements interactively
units: 1 cm 0.393701 inches
marker side: 9 units
marker id (use -1 to end) :
If you simply run the program without passing any arguments you are put into interactive mode. This mode
is very handy, especially for beginners, since it defaults to logical choices that create good markers.