A brief but interesting discussion of the article can be found here: http://www.adafruit.com/blog/2011/06/12/new-cave-mapping-technique-uses-gunshots-as-impuls

A brief but interesting discussion of the article can be found here: http://www.adafruit.com/blog/2011/06/12/new-cave-mapping-technique-uses-gunshots-as-impulse-functions/ http://www.adafruit.com/blog/2011/06/12/new-cave-mapping-tec... Note Mark's comment in particular.