(19)
(11) EP 0 715 744 A1

(12)

(43) Date of publication:
12.06.1996 Bulletin 1996/24

(21) Application number: 94925486.0

(22) Date of filing: 30.08.1994
(51) International Patent Classification (IPC): 
G08B 17/ 12( . )
(86) International application number:
PCT/EP1994/002888
(87) International publication number:
WO 1995/006927 (09.03.1995 Gazette 1995/11)
(84) Designated Contracting States:
DE DK FR GB IT NL SE

(30) Priority: 31.08.1993 EP 19930306865

(71) Applicant: SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.
NL-2596 HR Den Haag (NL)

(72) Inventor:
  • HIRST, William, Joseph, Senior
    Chester, Cheshire CH1 3SH (GB)

   


(54) METHOD AND APPARATUS FOR PREVENTING FALSE RESPONSES IN OPTICAL DETECTION DEVICES