1. An image enlargement device comprising: an image enlargement filter that generates a first enlarged image of an input image; a first wavelet transform portion that generates, by applying wavelet transform to the first enlarged image, a first sub-band component indicating an image obtained by extracting a low frequency component in a horizontal direction of the first enlarged image and a low frequency component in a vertical direction of the first enlarged image; a second sub-band component indicating an image obtained by extracting a high frequency component in a horizontal direction of the first enlarged image; a third sub-band component indicating an image obtained by extracting a high frequency component in a vertical direction of the first enlarged image; and a fourth sub-band component indicating an image obtained by extracting a high frequency component in a horizontal direction of the first enlarged image and a high frequency component in a vertical direction of the first enlarged image; a second wavelet transform portion that generates, by applying the wavelet transform to the first enlarged image, a fifth sub-band component indicating an image obtained by extracting a low frequency component in a horizontal direction of the first enlarged image and a low frequency component in a vertical direction of the first enlarged image; a sixth sub-band component indicating an image obtained by extracting a high frequency component in a horizontal direction of the first enlarged image; a seventh sub-band component indicating an image obtained by extracting a high frequency component in a vertical direction of the first enlarged image; and an eighth sub-band component indicating an image obtained by extracting a high frequency component in a horizontal direction of the first enlarged image and a high frequency component in a vertical direction of the first enlarged image; a first inverse wavelet transform portion that regards a predetermined sub-band component and the second sub-band component, the third sub-band component, and the fourth sub-band component, which are output from the first wavelet transform portion, as a wavelet transform image; performs inverse wavelet transform, thereby generating a first edge signal; a second inverse wavelet transform portion that regards the predetermined sub-band component and the sixth sub-band component, the seventh sub-band component, and the eighth sub-band component, which are output from the second wavelet transform portion, as the wavelet transform image; performs the inverse wavelet transform, thereby generating a second edge signal; an image enlargement portion that generates a second enlarged image; and an accentuation process portion that applies an accentuation process to the second enlarged image by using the first edge signal and the second edge signal; wherein the first wavelet transform portion and the second wavelet transform portion use wavelet transforms different from each other; and the first inverse wavelet transform portion and the second inverse wavelet transform portion use inverse wavelet transforms different from each other.