( ( ( Since , ) ( ( the images ) ( reflect ( gradients ( in ( ( refractive index ) ( induced ( by ( thermal gradients ) ) ) ) ) ) ) ) ) ( , ( they ( ( ( ( can not ) simply ) ( be ( ( ( converted and ) interpreted ) ( as ( thermal images ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (, ,) (S (NP (DT the) (NNS images)) (VP (VBP reflect) (NP (NP (NNS gradients)) (PP (IN in) (NP (NP (JJ refractive) (NN index)) (VP (VBN induced) (PP (IN by) (NP (JJ thermal) (NNS gradients)))))))))) (, ,) (NP (PRP they)) (VP (MD can) (RB not) (ADVP (RB simply)) (VP (VB be) (VP (VBN converted) (CC and) (VBN interpreted) (PP (IN as) (NP (JJ thermal) (NNS images)))))) (. .)))
Since, the images reflect gradients in refractive index induced by thermal gradients, they can not simply be converted and interpreted as thermal images.
(ROOT (S (NP (DT An) (NN image)) (VP (VBZ is) (NP (NP (DT a) (NN copy)) (PP (IN of) (NP (NP (DT an) (NN image)) (VP (VBN formed) (PP (IN by) (NP (NN reflection) (CC or) (NN refraction)))))))) (. .)))