The invention provides correction apparatus which comprises {HEAD ~ a series connection} of the visual system with a photo sensor , an amplifier , a counter and {TAIL ~ a comparator}  
The invention provides correction apparatus which comprises { HEAD ~ a series connection } of the visual system with a photo sensor , an amplifier , a counter and { TAIL ~ a comparator }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH