Effect of Lens Color on Target Visibility for Air-Sea Rescue

Abstract

V i s u a l d c t e c t i u n or l i f e r a f t s i n t h e sea p r e s e n t s a d i f f i c u l t t a s k t o personnel engaged i n a i r searcli mil r e s c u e o p e r a t i o n s . A possi-ble means of a i d i n g t h i s t,isk is t o u s c a n a p p r o p r i a t e sun-glass f i l t e r w i t h l i g h t t r a n s m i s s i o n p r o p e r t i e s designed t o reduce g l a r e and atmospheric a t t e n u a t i o n , w h i l e enliaacing target-to-bockgroriIld c o n t r a s t . To exaniiw and e v a l u a t e t h i s p o s s i b i l i t y , t a r g e t a c q u i s i t i o n perforinance assoc i a t e d w i t h tlic l o l l o w i n g t y p e s of s u n g l a s s e s w a s compared w i t h t h a t of t h e unaided eye: (1) Haze master ( y e l l o w ) , (2) 0;ikley-l)oc ( p i n k ) , ( 3 ) Cosmetan (brown) and ( 4 ) N-15 ( g r a y ) . The expcriiiicrita 1 approach involved t h e iise of a c i r c u l a r 1 : l O O O s c a l e t e r r a i n model and a s s o c i a t e d t e c h n i q u e s s i m u l a t i n g a n a i r -s e a r e s c u e o p e r a t i o n . Eacli s u b j e c t searched f o r t a r g e t s wl1iJ.c making a simulated banking t u r n around the model. 'The performance of t e n s u b j e c t s f o r each expcrimcntol l c n s c o n d i t i o n was measured i n t e r m of response time and number of t a r g e t s found. R e s u l t s based on t h e s e measures showed t h e Oakley-I)oc l e n s t o b e t h e b e s t and t h e Cosmctan t o be clie worst of the l e n s a l t e r n a t i v c s . Ilowever, no f i l t e r w a s round t o be s u p e r i o r t o t i l e unaided eye. Tlit. data : i r e i n agreement w i t l i a number of recent t a r g e t a c q u i s i t i o n s t u d i e s wliich show no advantage i n u s i n g ycllow I c n s c s . 'Tlic. r c s u l t s a r e , moreover, cons i s t e n L w i t 1 1 t lie ~~S~I I I I I~L~O I I LILIL supposed ciiliancemeut p r o p e r t i e s ofc o l o r e d l e n t i c~c ; iiiCiy wcl I b e o r f s c t Iry losses in 1ik:llt transiuission a s s o c i a t e d with clieir u s c .