code: @Override
  	public void spawnTracks() {
  		for (int setIndex = 0; setIndex < sets.length; setIndex++) {
  			SetTrackInfo<Desc> info = sets[setIndex];
  
  			// setup data structures
  			if( info.isAssociated.length < info.featDst.size ) {
  				info.isAssociated = new boolean[ info.featDst.size ];
  			}
  
  			// see which features are associated in the dst list
  			for( int i = 0; i < info.featDst.size; i++ ) {
  				info.isAssociated[i] = false;
  			}
  
  			for( int i = 0; i < info.matches.size; i++ ) {
  				info.isAssociated[info.matches.data[i].dst] = true;
  			}
  
  			// create new tracks from latest unassociated detected features
  			for( int i = 0; i < info.featDst.size; i++ ) {
  				if( info.isAssociated[i] )
  					continue;
  
  				Point2D_F64 loc = info.locDst.get(i);
  				addNewTrack(setIndex, loc.x,loc.y,info.featDst.get(i));
  			}
  		}
  
  	}
docs: Takes the current crop of detected features and makes them the keyframe