Patent ID: 6710345
Filing Date: 2004-03-23
Classification: F23N,G08B

Abstract:
A method of identifying the presence of a flame in a scene under surveillance, comprising:(a) forming an image of the scene on a two dimensional array of detector elements wherein each element views the image of different part of the scene; (b) detecting thermal emissions from the scene using the array; (c) examining signals from the detector elements and identifying a cluster of detector elements producing signals above a predetermined threshold; (d) repeatedly examining the relationship between the thermal emission received by a first element in the cluster at a particular point in time and the thermal emission received by a second element in the cluster at a subsequent time using a cross correlation function to detect temporal variations in temperature due to turbulence; (e) repeating step (d) for a range of time intervals between a signal from the first element and a signal from the second element and for all adjacent pairs of elements in the cluster; (f) identifying a maximum value of the cross correlation function and the corresponding time interval in order to determine whether the turbulence is characteristic of a flame; and (g) determining whether the turbulence is characteristic of a flame by comparing the maximum value of the cross correlation function and the corresponding time interval with respective threshold values.