1. An image processing method, including: estimating corners of a contour of an object area in an obtained image; searching for contour lines of the object area between every two points which are offset from the estimated corners within a predetermined degree along a direction away from the object area respectively, and determining intersection points of the contour lines as final corners of the contour of the object area; and determining contour lines between the final corners as a final contour of the object area, wherein the searching includes: offsetting the estimated corners within the predetermined degree respectively along a principal orientation away from the object area and along a direction away from the object area and being perpendicular to the principal orientation, so as to obtain offset points in the principal orientation and offset points in the direction perpendicular to the principal orientation respectively; tracking contour lines of the object area in the principal orientation between every two offset points in the principal orientation respectively, and tracking contour lines of the object area in the direction perpendicular to the principal orientation between every two offset points in the direction perpendicular to the principal orientation respectively; and determining intersection points between the contour lines in the principal orientation and the contour lines in the direction perpendicular to the principal orientation in the object area.