| 摘要 |
An apparatus and method for signal, image, or video compression that achieves high compression efficiency in a computationally efficient manner and corresponding decoder apparatus and methods are disclosed. This technique uses zerotree coding (126) of wavelet coefficients (100) in a much more efficient manner than the previous techniques. The key is the dynamic generation of the list of coefficient indices (114-120) to be scanned, whereby the dynamically generated list (114-120) only contains coefficient indices for which a symbol must be encoded. This is a dramatic improvement over the prior art in which a static list of coefficient indices is used and each coefficient must be individually checked to see whether a) a symbol must be encoded, or b) it is completely predictable. Additionally, using dynamic list generation (114-120), the greater the compression of the signal, the less time it takes to perform the compression. Thus, using dynamic list generation (114-120), the computational burden is proportional to the size of the output compressed bit stream (134) instead of being proportional to the size of the input signal or image. |
