Early fire detection method and apparatus

#1. Field of the Invention

#The present invention generally relates to electrical, condition responsive systems. More particularly, this invention relates to a method and apparatus for detecting a fire in a monitored area.

#2. Description of the Related Art

#FIG. 1 illustrates the various forms of data that are encountered and analyzed using a preferred embodiment of the present invention.

#FIG. 2 is a flow chart showing the various process steps carried out in one embodiment of the present invention.

#FIG. 2a illustrates a typical bitmap pattern of the present invention, where the dynamic and static component pixels have been filled, respectively, with diagonal hatching and cross hatching.

#Referring now to the drawings wherein are shown preferred embodiments and wherein like reference numerals designate like elements throughout, there is shown in FIG. 2 an embodiment of the present invention in the form of a method for detecting fire in a monitored area.

#This method is generally seen to comprise the steps of: (a) detecting and capturing, at a prescribed frequency, video images of the monitored area in the form of two-dimensional bitmaps whose spatial resolution is determined by the number of pixels comprising said bitmaps, (b) cyclically accumulating a sequential set of these captured bitmaps for analysis of the temporal variations in the brightness values observed at each of the pixels, wherein these temporal variations are expressible in terms of a static and a dynamic component of the variations in pixel brightness values, (c) examining these set of bitmaps to identify a static cluster and a dynamic cluster of contiguous pixels having brightness values that, respectively, exceed prescribed static and dynamic threshold magnitudes, (d) comparing the patterns of the shapes of said identified, static and dynamic clusters to identify those exhibiting patterns which match to a predetermined matching level those exhibited by the comparable static core and dynamic, flickering coronal regions of a turbulent, open flame, and (e) signaling the detection of a fire in the monitored area when the degree of match, between the identified, static and dynamic clusters and the comparable regions of an open flame, exceeds the predetermined matching level.

#FIG. 1 further illustrates this method by generally illustrating the various forms of data that are encountered and analyzed using this method. In this embodiment, a digital video camera provides a means for detecting and capturing, at a prescribed frequency (e.g., 16 frames per second) and spatial resolution (e.g., 160×120 pixels), video frames or bitmap images of an area that is to be temporally monitored for the outbreak of an open flame fire. These frames, F1, F2, . . . Fi, are stored in an accumulation buffer, the storage capacity of which determines the size of the sequential data sets that are cyclically analyzed to identify the presence of an open flame (e.g., an accumulation buffer providing storage for 16 frames, with the analysis cycle being of one second duration).