How to filter ranges of a portion of a laser scan

edit

You could use two laser scan filters in series. The first one could filter angle and the second could filter range. (Or swap the order to get the effect you want.)

One fast solution could be to use range filter onto a topic, and angle filter onto another topic, and then go on to combine the data from the 2 topics (using ira_laser_tools, for example) onto the desired topic.

Edit1: To clarify, range filter would give 360 data beyond robot radius(circumscribed), even if not centered on the robot. So , say, /scanrange has 360 degree data beyond 0.1m from the scanner. Angle filter would remove the region from behind the robot. So, /scanangle has 270 degree data (excludes the wires, motor controllers, etc.) but from 0m of the scanner. The scan merger would essentially create a union of the 2 scans, hopefully leaving you with desired data.