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Inverse pyramid decomposition of wavelet spectrum for image compression

In this paper, a novel approach is presented for compression of digital images. It consists of finding the wavelet spectrum of an image into certain number of sub-bands after given levels of regular or irregular decomposition. Then each sub-band is decomposed with the inverse pyramid algorithm using some linear orthogonal transform such as DCT. Depending on whether a lossless or lossy compression is desired all or only some of the spectral coefficients from the inverse pyramid are preserved and then entropy coding is applied. Higher compression ratios are achieved at high image quality levels compared to some popular algorithms from the practice.