1. A method of generating a super-resolution image, the method comprising: inputting an image; generating an estimated high-resolution image of a current time by fusing an input image and an estimated high-resolution image of a previous time corresponding to the input image; calculating a number of invalid pixels each of which has an image registration error not less than a threshold value; comparing the number of the invalid pixels to a limit pixel number; and determining the estimated high-resolution image of the current image as an image of the current time if the number of the invalid pixels is less than the limit pixel number, and generating a high-resolution image of the current image without considering the estimated high-resolution image of the previous time before the initialization if the number of the invalid pixels is not less than the limit pixel number, wherein the image registration error corresponds to a degree of misalignment between the input image and the estimated high-resolution image of the previous time.