Patent ID: 8159539

Claim:
A smoke detecting method, comprising: (a) capturing a plurality of images; (b) determining whether a moving object exists in the plurality of images; (c) selecting the images having the moving object to be analyzed; (d) analyzing whether the moving object is moving toward a specific direction by performing following sub-steps: if the n th to (n+k) th images have the moving object, superimposing each of the (n+1) th to (n+k) th images on the respective preceding image thereof to generate k pieces of superimposed images, wherein n and k are natural numbers; in each of the superimposed images, determining a P 0 number of pixels showing an upper edge of the moving object in the preceding image and determining a P number of pixels showing an overlapped portion of the upper edge of the moving object in the superimposed image; calculating a first ratio of P to P 0 in the each superimposed image; calculating a second ratio of a quantity of the superimposed images having the first ratio larger than a first predetermined value to k; and determining that the moving object is moving toward the specific direction when the second ratio is larger than a second predetermined value; and (e) determining the moving object as a smoke when the moving object is moving toward the specific direction.