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