Based on the optimization of causal implementation for the lifting schemes and the interleaving mode for sub-band coefficients, this research presents an enhanced low-memory implementation of discrete wavelet transform called the ELDWT (Enhanced Low-Memory Discrete Wavelet Transform). In comparison with the conventional global implementation of DWT, the ELDWT has the advantages that its memory budget is independent of the image height and different DWT filter banks cad be utilized in different decomposition/reconstruction levels. When the difference between the filters’ lengths is greater than two, the ELDWT has lower memory requirement and less system latency than those of the line-based DWT (LBWT). When a 5-level decomposition with the MPEG Default 9/3 filter bank is adopted, the overall memory is reduced by 22.7% in comparison with the LBWT.