An image processing method comprises: identifying a weak edge comprising a plurality of weak edge pixels and a strong edge comprising a plurality of strong edge pixels in an input image; filtering at least a part of said input image to obtain a smoothed image, during which said weak edge in said input image is filtered with a first filter and said strong edge in said input image is filtered with a second filter having a smoothness less than that of said first filter; acquiring edge information of said input image based on said input image and said smoothed image; and generating an output image based on said edge information and said smoothed image. The present invention further relates to an image processing system and an imaging system.