Fast two-dimensional inverse discrete cosine transform for HDTV or videophone systems

The authors propose a new fast two-dimensional inverse discrete cosine transform (2D-IDCT) algorithm which is developed on the basis of the DCT computational kernel matrices. With the symmetrical properties of kernel matrices, one can greatly reduce the number of multiplications. With carefully grouping the DCT coefficients, the computational complexity can be further reduced, for example, if the 2D-DCT coefficients are coded and transmitted according to the zig-zag scanning. The proposed fast 2D-IDCT algorithm which takes the advantage of zero-valued DCT elements is suitable for high throughput HDTV receiving systems. The DCT is generally recognized as the best way to encode digital picture information, because it results in virtually the same energy compact performance as the Karhunen-Loeve transform (KLT). The DCT has the advantage of lower computational complexity than the KLT