Integer DCT—II by Lifting Steps
Gerlind Plonka, Manfred Tasche · International series of numerical mathematics · 2003
In image compression, the discrete cosine transform of type II (DCT-II) is of special interest. In this paper we use a new approach to construct an integer DCT-II first considered in [15]. Our method is based on a factorization of the cosine matrix of type II into a product of sparse, orthogonal matrices. The construction of the integer DCT-II of length 8 works with lifting steps and rounding-off. We are especially interested in the normwise error and the componentwise error when the integer DCT-II is compared with the exact DCT-II.