▁measurements ▁in ▁those ▁materials ▁having ▁sufficient ▁internal ▁vol um et ric ▁image ▁contrast ▁was ▁demonstrated ▁by ▁Brian ▁Bay ▁c . ▁ 2 0 0 0 . ▁The ▁method ▁is ▁a ▁direct ▁extension ▁of ▁ 2 D - D IC ▁and ▁is ▁known ▁as ▁either ▁vol um et ric ▁digital ▁image ▁correlation ▁( V - D IC ) ▁or ▁digital ▁volume ▁correlation ▁( D VC ). ▁Even ▁though ▁successful ▁S tere o D IC ▁experiments ▁were ▁performed ▁in ▁a ▁labor atory ▁setting , ▁the ▁system ' s ▁complex ▁cal ibr ations ▁limited ▁its ▁useful ness ▁to ▁optical ▁ben ches ▁and / or ▁well - control led ▁labor atory ▁conditions . ▁▁ ▁During ▁an ▁ 1 8 - month ▁s abb at ical ▁at ▁NASA ▁Lang ley ▁( 1 9 9 2 – 9 3 ) ▁spons ored ▁by ▁Charles ▁E . ▁Harris , ▁S utton ▁worked ▁directly ▁with ▁James ▁C . ▁New man ▁Jr , ▁David ▁Daw ic ke , ▁Robert ▁P ias ci k , ▁Edward ▁Phill ips ▁and ▁Bud dy ▁Po e ▁on ▁issues ▁related ▁to ▁crack ▁extension ▁as ▁part ▁of ▁the ▁US ▁A ging ▁A ircraft ▁Program . ▁During ▁this ▁time , ▁S utton ▁was ▁exposed ▁to ▁the ▁critical ▁need ▁for ▁a ▁field - cap able , ▁three - dimensional ▁de formation ▁measurement ▁system ▁that ▁could ▁be ▁used ▁on ▁full - scale ▁a ero - struct ures ▁under going ▁complex ▁loading . ▁With ▁this ▁information ▁and ▁with ▁Harris ' ▁support , ▁S utton ▁and ▁Stephen ▁Mc Ne ill ▁worked ▁with ▁their