Design of lossless LOT and its performance evaluation

In lossless transforms, integer input signals are transformed into integer transform coefficients and losslessly reconstructed. Lossless versions of the discrete cosine transform and wavelet transforms have been proposed. In this paper, we design a lossless version of the lapped orthogonal transform (LOT). The fast LOT is decomposed into block transforms. Then the lossless LOT is obtained by replacing them by the corresponding lossless ladder networks. We investigate two cases of 31-band and 64-band decomposition in which the 4-point and 8-point lossless LOT are used, respectively. We compare them with the conventional lossless methods in terms of lossless and lossy compression efficiency. The proposed methods are found to have good performance