Effortless Critical Representation of Laplacian Pyramid

The Laplacian pyramid (LP) is a multiresolution representation introduced originally for images, and it has been used in many applications. A major shortcoming of the LP representation is that it is oversampled. The dependency among the LP coefficients is studied in this paper. It is shown that whenever the LP compression filter is interpolatory, the redundancy in the LP coefficients can be removed effortlessly by merely discarding some of the LP coefficients. Furthermore, it turns out that the remaining, now critically sampled, LP coefficients are actually the coefficients of a wavelet filter bank. As a result, a new algorithm for designing a nonredundant wavelet filter bank from non-biorthogonal lowpass filters is obtained. Our methodology presented in this paper does not depend on the spatial dimension of the data or the dilation matrix for sampling.