Generating, at {TAIL ~ each vignetted light sensor}, {HEAD ~ a measurable electrical quantity} responsive to the associated vignetted light field, 
at
Generating , at { TAIL ~ each vignetted light sensor } , { HEAD ~ a measurable electrical quantity } responsive to the associated vignetted light field ,
OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH