New family of orthonormal transforms with time localizability based on DFT
Kook Yeon Kwak, Richard A. Haddad · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1994
The library of orthonormal bases includes Short Time Fourier Transform and Wavelet Transform bases. The widely-used DFT lacks flexibility in dealing with signals possessing a time-varying spectrum. Such signals require a variable time-frequency-localizability feature for adequate resolution. In this paper, we introduce new orthonormal transforms which are constructed from the DFT yet have variable time-frequency-localizability feature and fast computing capability. We create a framework for constructing Time Localization Linear Transform (TLLT) upon the concept that time localizability can be recovered by inverse transform of selected partial collection of forward transform coefficients. By coding the coefficients of TLLT, we can combine the adaptability of Vector Quantization with the speed of linear transform.