Roper Photometric manual Ratio Imaging Multi-Frame Ratio, Ccd E

Ratio Imaging: Multi-Frame Ratio

This script performs ratio imaging with the CCD37-10 CCD. Only three small subregions are needed, but to get a good statistical base for the images, you must take a sequence of 100 identical exposures. The subimage setup is:

	+--------------------------------------------		+		s1,p1	s2,p2
		###	<	-- region 3	380,300	440,390
CCD37-10		###
Image Array---->		#####	<	-- region 2	175,26	320,290
		#####
		######	<	-- region 1	300,5	400,25
		######
	+--------------------------------------------		+<--	origin point: 0,0
		storage array

These coordinates are INCLUSIVE. 300,5 to 400,25 is a region of 101 serial columns and 21 parallel rows.

This experiment swings in a filter (relatively slowly), sends a trigger pulse, exposes for 100 milliseconds, reads out, then repeats.

H/W A:	experimental hardware goes to first position, sends trigger pulse,
H/W B:	the first position runs for 100 milliseconds,
H/W C:	change filters (about 40 milliseconds of delay)
H/W D:	the second position runs for 100 milliseconds
H/W E:	change filters (about 40 milliseconds of delay), loop back to A
CCD A:	prepare for exposure, clear CCD, wait for trigger...
CCD B:	expose for 100 milliseconds
CCD C:	shift_image_to_storage, readout, clear CCD, wait for trigger...
CCD D:	expose for 100 milliseconds
CCD E:	shift_image_to_storage, readout, loop back to A

The only problem is that you cannot use a signal to differentiate between CCD B and CCD D. In the future, camera hardware might be enhanced so that it produces a flash signal in CCD E. Then you would use the enhancement to trigger step H/W A.

script_begin();
shutter_open();
loop_begin(200);	/* SEQUENCE OF 100 IMAGE PAIRS(200 total loops)		*/
clear_parallel(4);	/* CCD A&C: make sure CCD is cleared		*/
clear_until_trig();	/*	clear until the experiment is ready	*/
expose(100);	/* CCD B&D: expose with this filter		*/
shift_image_to_storage();	/* takes 1.23 msec, shift image under mask		*/
shift_mode_s();	/* CCD C&E: READOUT...		*/
shift(37);	/*	move REGION 1 up to serial register	*/
pixel_readout(300,101,1, 21,1);	/*	s1:s2 of 300:400 is 101 total pixels	*/
pixel_display( 101, 21 );	/*	actual size of the region	*/
pixel_readout(175,146,1,265,1);	/*	REGION 2 is at the serial reg	*/
pixel_display( 146, 265 );
shift(9);	/*	move REGION 3 up to the serial regist*/
pixel_readout(380, 61,1,265,1);
pixel_display( 61, 265 );
loop_end();
shutter_close();
script_end(1);	/* leave CCD in continuous clear mode		*/

NOTE: The CCD37-10 has a 512x512 image array, but a 512x544 storage array. Discard (5+32) rows to move region 1 to the serial register.

16Advanced Camera Operation Manual