Matlab files in this directory:

pa_head_callback	callback function for head gui.
pa_head_check_parm	This function check the parameter fields.
pa_head_close	This function close head GUI.
pa_head_create	This function creates head parameter gui.
pa_head_get_parm	This function gets parameters from head GUI.
pa_head_load_display_factor	create display_factor object to make 2D/3D view of Head file.
pa_head_merge_parm	merge head_parm which has head gui has and inputted head_parm fields.
pa_head_set_parm	This function sets parameters to head GUI.
pa_head_util	This function is subcontracting function of head GUI.