<put algortithm description here>
<put parameter description here>
Default: 50
<put parameter description here>
Default: 500
<put parameter description here>
Default: 500
processing.runalg('otb:exactlargescalemeanshiftsegmentationstep3optional', -in, -inseg, -minsize, -tilesizex, -tilesizey, -out)