Building wall defect measurement method based on image and system thereof

The invention discloses a building wall defect measurement method based on an image and a system thereof. The method comprises the following steps: acquiring the image of a building wall surface, processing, displaying and computing and measuring the image; specifically, based on a to-be-measured picture, painting a line with hand on the to-be-measured picture displayed in an operation interface by using a mouse to measure the building wall defect, and acquiring one or a plurality of defect information such as crack length, crack width, filler or circular spot area of the building on the wall surface, wherein the method is suitable for measuring the defect information such as crack length, crack width, filler or circular spot area of the building aiming at the outer surface of any reinforced concrete structure building. The measurement precision is high and can achieve 0.1mm; and meanwhile, the functions of online measurement or off-line re-measurement can be simultaneously realized, the operation is simple and convenient and the system is easy to use.