The Development of a Unmanned Watching System Using Video Cameras

T h i s p a p e r d e s c r i b e s a t e c h n i q u e f o r d e t e c t i n g t r e s p a s s e r s i n r e a l t ime . a p p l i c a b l e b o t h i n d o o r s and o u t d o o r s , b a s e d on image p rocess ing . The main p a r t o f t h e proposed sys t em consists o f a v ideo camera, an image p rocesso r and a micro-processor. Images a r e i n p u t from t h e v ideo camera t o t h e image p rocesso r e v e r y 1 /60 second, and i n t r u d i n g o b j e c t s i n t h e image a r e d e t e c t e d b y m e a s u r i n g c h a n g e s o f i n t e n s i t y l e v e l i n s e l e c t e d s e n s o r a reas . The s y s t e m e x h i b i t s t h e f o l l o w i n g f e a t u r e s : ( 1 ) i n t r u d e r s c a n b e d e t e c t e d i n r e a l t ime . (2) shapes and l o c a t i o n s o f a c t i v e s e n s o r a r e a s can b e s e l e c t e d based on d e t e c t i o n a p p l i c a t i o n . ( 3 ) s p u r i o u s d e t e c t i o n s are p r e v e n t e d by u s i n g n o i s e r e m o v a l f i l t e r s , (4 ) h i g h det e c t i o n s e n s i t i v i t y is g u a r a n t e e d u n d e r a n y env i ronmen ta l cond i t ion . I n t h i s p a p e r , t h e s y s t e m c o n f i g u r a t i o n a n d t h e d e t e c t i o n m e t h o d a r e d i s c u s s e d . Exper imenta l r e s u l t s under a range o f environmen ta l c o n d i t i o n s a r e given. T e c h n i q u e s u s e d t o d e t e c t i n t r u d e r s i n a h a z a r d o u s s i t e , s u c h a s a power p l a n t o r subs t a t i o n , o r i n a n unmanned b u i l d i n g a t n i g h t , a r e q u i t e s i g n i f i c a n t i n t h e f i e l d o f unmanned watching systems. T r a d i t i o n a l l y , t h e f o l l o w i n g t y p e o f methods have been used t o d e t e c t intrudersr1' : (1) s e t t i n g v a r i o u s k i n d s o f s e n s o r s s u c h a s i n f r a r e d o r t e n s i o n senso r s . (2 ) s e t t i n g v i d e o c a m e r a s and a human who moni to r s TVs con t inuous ly , ( 3 ) c o m b i n i n g ( 1 ) w i t h ( 2 ) , t h a t is, t h e v i d e o c a m e r a s a r e a u t o m a t i c a l l y c o n t r o l l e d t o d i s p l a y t h e d e t e c t i o n a r e a on a m o n i t o r when i n t r u d e r s a r e d e t e c t e d by a sensor . I n ( 1 ) . m a j o r d e f e c t s a r e t h a t t h e a c t i v e d e t e c t i o n a r e a is o n l y a l i n e , and is f i x e d , and t h a t t h e d e t e c t i o n a r e a cannot b e changed e a s i l y . Method ( 2 ) h a s t h e a d v a n t a g e o f prov i d i n g f o r more in fo rma t ion , namely, a n image o f t h e i n t r u d e r . However, a human b e i n g s a r e v e r y i l l s u i t e d t o t h i s t y p e o f m o n i t o r i n g work , and t h e r e s p o n s i b i l i t y is t o o heavy. A l s o , t h i s m e t h o d t e n d s t o b e e x p e n s i v e . Method ( 3 ) o f f e r s same merits a s Method (2 ) . However, t h e c o s t o f t h e s y s t e m i s v e r y h i g h b e c a u s e i t u s e s a s p e c i a l c o n t r o l u n i t t o d i r e c t a v ideo camera toward t h e p o i n t where an i n t r u d e r might en te r . To s o l v e t h e s e problems, unmanned watching s y s t e m s b a s e d on v i d e o c a m e r a s h a v e b 117 -727 veloped, and r e s e a r c h has been r epor t ed o f d e t e c t i n g and t r a c i n g n o o b j e c t s u s ing m u l t i p l e i m a g e processing.'@ However. t h e s e sys t ems cannot d e t e c t moving o b j e c t s i n r e a l time b e c a u s e a l l p i x e l s i n a n i m a g e a r e p roc e s s e d . Methods o f r e a l t i m e measuremen t o f p e d e s t r i ap,f,y8y and t r a f f i c f l o w h a v e been r e p o r t e d . However, t h e s e me thods a r e n o t s u i t a b l e f o r w a t c h i n g s y s t e m s b e c a u s e o f r e s t r i c t i o n s on d e t e c t a b l e o b j e c t s and de tec t a b l e pass ing d i r e c t i o n s o f t h e ob jec t s . T h i s p a p e r d e s c r i b e s a t e c h n i q u e u s e d t o d e t e c t i n t r u d e r s i n r e a l time wi thou t s p u r i o u s d e t e c t i o n s , i n bo th indoor and outdoor environments, u s ing a micro-processor. I n t h e proposed method, t h e d e t e c t i o n a r e a is l i m i t e d t o a f i n i t e a r e a s u r r o u n d e d by f e n c e s a n d l o r wa l l s . Therefore , t h e d e t e c t i o n a r e a can be reduced, because it is adequate t o w a t c h o n l y o v e r t h e b o u n d a r y s u r r o u n d i n g t h e d e t e c t i o n a r e a , which i n t r u d e r s must c ross . I n o u r s y s t e m . s e v e r a l a c t i v e a r e a s a r e s e t on a m o n i t o r s c r e e n b a s e d on p o s s i b l e i n t r u d e r s ' p a t h s ( s e e F i g u r e I ) , and t r e s p a s s e r s a r e det e c t e d i n r e a l t i m e b y m e a s u r i n g c h a n g e s o f image i n t e n s i t y l e v e l i n t h e s e a c t i v e areas . S p u r i o u s d e t e c t i o n s c a u s e d by c l i m a t i c c h a n g e s , o p t i c a l a n d e l e c t r i c n o i s e , o r b l o o m i n g phenomenon i n t h e v i d e o c a m e r a a r e p r e v e n t e d by u s i n g n o i s e r e m o v a l f i l t e r s i n bo th t i m e and space domains. Dummy observing p i x e l s a r e a l s o u t i l i z e d . The sys tem c o n f i g u r a t i o n and t h e i n t r u d e r d e t e c t i o n method a r e d i s c u s s e d be low. F o r d e m o n s t r a t i o n , e x p e r i m e n t a l r e s u l t s u n d e r v a r i o u s c o n d i t i o n s a r e a l s o provided. SYSTEn CONFIGURATION The hardware c o n f i g u r a t i o n o f o u r unmanned watching sys tem is shown i n F i g u r e 2. The main p a r t o f t h e s y s t e m c o n s i s t s o f a s e t o f v i d e o c a m e r a s ( f o u r s e t s a r e t h e c u r r e n t maximum), t h e c h a n n e l s w i t c h i n g u n i t and t h e c o n t r o l u n i t . O t h e r e q u i p m e n t i n c l u d e s t h e t a r g e t s l i g h t e d a t n i g h t , s p o t l i g h t s t o i l l u m i n a t e i n t r u d e r s a t n i g h t , s w i t c h i n g r e l a y t o t u r n on and o f f t h e l i g h t i n g e q u i p m e n t . power s u p p l y . VTR t o r eco rd t h e image o f a t r e s p a s s e r , and TV monitor. IAPR Workshop on CV -Special Hardware and Industrial Applications OCT.12-14. 1988, Tokyo