1. A top-view image generating method comprising: detecting a ground feature point from at least one of front, rear, left, and right images respectively provided from a plurality of cameras installed in a vehicle; estimating a first posture angle of a camera providing the at least one image, based on the detected ground feature point; generating a first top-view image by rotation-converting the at least one image, based on the estimated first posture angle; detecting a first lane from the first top-view image; detecting a second lane succeeding the first lane from another image, from which the ground feature point is not detected, of the front, rear, left, and right images; estimating a second posture angle of a camera providing the other image from which the second lane is detected, based on a correspondence relationship between a feature pattern of the detected first lane and a feature pattern of the detected second lane; generating a second top-view image by rotation-converting the other image, based on the estimated second posture angle; and synthesizing the first top-view image and the second top-view image to generate a final top-view image.