lm_to_projdata needs a “time frame definitions file”. This can be 
any file for which STIR understands time definitions (use get_time_frame_info to check). The simplest option is to use a simple text file, currently only very briefly described in the doxygen for class TimeFrameDefinitions). It goes like this for 4 frames of 5.5s, 3 frames of 10s, a gap of 40s, 1 frame of 10s

	4 5.5
	3 10
	0 40
	1 10

This is the example provided here as the *.fdef file.
