The invention provides a low illumination smog
video detection method based on image correlation; the method comprises the following steps: compressing a recorded
video image and converting into a gray scale image, and carrying out four-
frame difference operation on the obtained gray scale image, thus extracting a motion object in the
video image; selecting a property threshold to convert the interframe difference result into a
binary image; carrying out median filtering on the obtained
binary image, thus initially reducing image noises; calculating
interframe correlation of various connecting zones of the
binary image in order, removing non-smog motion areas with small image correlation, and obtaining an accurate smog area image. The method can directly observe the smog developing conditions, thus removing temperature,
humidity, air pressure and smell factor influences, improving the smog detection accuracy, and keeping the
false alarm rate within 10% under conservative
estimation; in addition, the method can replay an extracted smog area developing process, thus accurately positioning the smog source position.