1. An apparatus for transforming between a 2-dimensional 1-level DWT coefficient and a 2-dimensional 8Ã—8 DCT coefficient obtained from NÃ—M image data, the apparatus comprising: a first fundamental matrix calculating unit calculating a first fundamental matrix by multiplying an NÃ—N forward DWT transform matrix and an NÃ—N matrix that has diagonal components corresponding to a transpose matrix of an 8Ã—8 DCT transform matrix and the remaining components corresponding to an 8Ã—8 matrix with all elements being zero; a second fundamental matrix calculating unit calculating a second fundamental matrix by multiplying an MÃ—M matrix, which has diagonal components corresponding to an 8Ã—8 DCT transform matrix and the remaining components corresponding to an 8Ã—8 matrix with all elements being zero, and a transpose matrix of an MÃ—M forward DWT transform matrix; and a DWT coefficient calculating unit calculating a 2-dimensional 1-level DWT coefficient by multiplying the first fundamental matrix, a 2-dimensional 8Ã—8 DCT transform coefficient, and the second fundamental matrix.