An image processing method includes: detecting a first quadrangle in an image, where the first quadrangle includes four vertexes, the four vertexes correspond to four photographed points; determining distance information of the four photographed points relative to a camera capturing the image; determining locations of the four photographed points based on the distance information of the four photographed points and location information of the points on the image; and determining, based on the locations of the four photographed points, that the four photographed points are coplanar, where the four photographed points form a second quadrangle, determining a side ratio of two neighboring sides of the second quadrangle when a side angle and a side length relationship of the second quadrangle satisfy a preset condition, and correcting the first quadrangle to a rectangle, where two neighboring sides of the rectangle are in the side ratio.