%0 Conference Paper %B Proceedings of the European Signal Processing Conference (EUSIPCO) %D 2007 %T A 'gas of Circles' Phase Field Model and its Application to Tree Crown Extraction %A Peter Horvath %A Ian Jermyn %E Marek Domanski %E Ryszard Stasinski %E Maciej Bartkowiak %B Proceedings of the European Signal Processing Conference (EUSIPCO) %C Poznan, Poland %8 2007 %9 Conference paper