▁particular ▁interest ▁when ▁morph ological ▁information ▁is ▁required , ▁further ▁study ▁can ▁be ▁undert aken ▁using ▁computer ▁algorithms , ▁such ▁as ▁is os ur faces ▁and ▁data ▁s lic ing ▁to ▁analy se ▁the ▁data . ▁ ▁As ▁T EM ▁samples ▁cannot ▁typically ▁be ▁viewed ▁at ▁a ▁full ▁ 1 8 0 ° ▁rotation , ▁the ▁observed ▁images ▁typically ▁suffer ▁from ▁a ▁" missing ▁w edge " ▁of ▁data , ▁which ▁when ▁using ▁Fourier - based ▁back ▁projection ▁methods ▁decre ases ▁the ▁range ▁of ▁resol v able ▁frequencies ▁in ▁the ▁three - dimensional ▁reconst ruction . ▁Mechan ical ▁ref in ements , ▁such ▁as ▁multi - axis ▁til ting ▁( two ▁t ilt ▁series ▁of ▁the ▁same ▁spec imen ▁made ▁at ▁orthogonal ▁directions ) ▁and ▁con ical ▁tom ography ▁( where ▁the ▁spec imen ▁is ▁first ▁t ilt ed ▁to ▁a ▁given ▁fixed ▁angle ▁and ▁then ▁im aged ▁at ▁equal ▁angular ▁rot ational ▁incre ments ▁through ▁one ▁complete ▁rotation ▁in ▁the ▁plane ▁of ▁the ▁spec imen ▁grid ) ▁can ▁be ▁used ▁to ▁limit ▁the ▁impact ▁of ▁the ▁missing ▁data ▁on ▁the ▁observed ▁spec imen ▁morph ology . ▁Using ▁focused ▁ion ▁beam ▁mill ing , ▁a ▁new ▁technique ▁has ▁been ▁proposed ▁which ▁uses ▁pill ar - sh aped ▁spec imen ▁and ▁a ▁dedicated ▁on - axis ▁tom ography ▁holder ▁to ▁perform ▁ 1 8 0 ° ▁rotation ▁of ▁the ▁sample ▁inside ▁the ▁pole ▁piece ▁of ▁the ▁objective ▁l ens ▁in ▁T EM . ▁Using ▁such ▁arrang ements , ▁quant itative ▁electron ▁tom ography ▁without