An image processing method includes the steps of detecting edge information from an input image, identifying a plurality of lines from the edge information, dividing the input image into a plurality of areas based on the relative locations of the plurality of identified lines, calculating a similarity between adjacent areas of the plurality of divided areas, detecting boundaries between the adjacent areas as line segments partitioning the adjacent areas based on a degree of dissimilarity of the adjacent areas, wherein each of the line segments is at least a portion of the plurality of lines, and connecting the line segments forming the boundaries, and generating a connected shape using the boundaries.