Table of Contents
Tag Recognition Using Webcam
Introduction
We will learn to do tag recognition using your web-cam. Before we continue any further lets make sure you have the necessary package. Open up a terminal and enter :
roscd ar_recog
This should take you to the folder of the package “ar_recog”. If you don't have the package please download it from the brown repository. Open up a terminal and enter the following line:
svn checkout http://brown-ros-pkg.googlecode.com/svn/trunk/brown-ros-pkg-read-only
Print out a tag
We obviously need an image tag before we test the code.
Step 1:Go to the folder of the package “ar_recog” Step 2:open up the file “Ar_patts.zip”. Step 3:Print out your desired image tag.
Test the code
1. Enter the following commands each in a new terminal.
roscore rosrun gscam gscam
2.Open up a new terminal and enter the lines one after the other :
roscd ar_recog cmake . rosmake
Make sure you get 0 failures for rosmake.
cd bin rosparam set aov .67 rosrun ar_recog ar_recog image:=/gscam/image_raw
Enter the following commands each in a new terminal:
rosrun image_view image_view image:=/gscam/image_raw rosrun image_view image_view image:=/ar/image
Testing the image tag
Considering the fact that you have a printed image tag. Hold it in-front of the camera in such a way that your fingers don't touch the surface of the tag. I pasted the tag on to the surface of a box lid.
When you test with the image tag you should see a green line outlining the image tag.
Getting the coordinates
To have a deeper insight of the image tag being recognized open up a terminal and enter:
rostopic echo /tags
This shows you the movement of image tag along the x,y,z axes.