how to detect specific objects?

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I want to detect specific objects. i'm using a Hokuyo UTM-30LX-EW with ros and the urg_node. i played around with leg_detector and rviz and now i want to detect a specific object like different cases. What is the best way to continue? I though i would first use something like a kalman filter to create a cleaner map, and than starting a better segmentation? I want to recognize different cases especially from different positions. Is there already a package which i can use? Or should I choose an other way?

Thanks in advance