Contents
ROS API
cob_marker
cob_marker allows to find 6DOF markers of different types, like datamatrix, Qr, natural landmarks, ...Action Goal
/object_detection/detect_object/goal (cob_object_detection/DetectObjectsActionGoal)- Goal for executing object detection procedure
Action Result
/object_detection/detect_object/result (cob_object_detection/DetectObjectsActionResult)- List of detect object instances including a confidence and pose estimate
Action Feedback
/object_detection/detect_object/feedback (cob_object_detection/DetectObjectsActionFeedback)- Feedback holds number to indicate the approximate progress
Subscribed Topics
/camera/rgb/image_color (std_msgs/Image)- color image
- pointcloud with depth data
- instrinstric information about camera
Parameters
algorithm (string)- selects marker algorithm. possible values: zxing, dmtx
- try harder option of zxing
- timeout of marker recognition of dmtx (specifies how many markers can be recognized depending on the execution speed)
Installation
Install zxing with C-Port and the development package of dmtx.
Usage/Examples
Plug in Kinect or Kinect-style camera and start
roslaunch cob_marker marker.launch
cob_marker provides now an action on the topic "/cob_marker/object_detection". Each action triggers marker recognition to avoid high CPU usage. The usage of the action is the same as with cob_object_detection.
Algorithms
zxing is the java implementation of various kind of marker recognition (bar codes, Qr, datamatrix ...)
dmtx only recognizes datamatrix. But it is faster than zxing in general.
Generate a marker code
permalink, e.g. for milk http://datamatrix.kaywa.com/img.php?s=39&d=milk
Print it out with a size of around 20cm x 20cm.
