| 摘要 |
In accordance with a feature of the present invention, a bit plane approach is used in representing coded levels or values. Although, this approach will require more codes to be generated (since each bit plane is separately encoded), the codes themselves, and/or the entropy codes therefor, will require less bits for their representation, and in many cases the net result will be a substantial reduction in the bits necessary to encode the original signal. In accordance with an embodiment of the invention, there is disclosed a method for encoding and decoding an input signal, comprising the following steps: applying a transform to said signal to obtain a transformed signal; quantizing the transformed signal to obtain a sequence of quantized values, the quantized values being representable in the form of ordered digital bits; for each order of said digital bits, encoding a bit plane of the sequence to obtain encoded values; and decoding the encoded values to recover said input signal. In a preferred embodiment of the invention, the ordered digital bits are binary bits, and there are several orders of said bits. In this embodiment, the step of quantizing the transformed signal to obtain a sequence of quantized values includes: determining the largest of the quantized values; and determining the number of orders, N, of said binary bits as the number of binary bits necessary to represent said largest value. In accordance with another embodiment of the invention, there is disclosed a method for encoding and decoding an input signal, comprising the following steps: applying a wavelet transform to the signal to obtain a transformed signal; forming a wavelet tree from the transformed signal, elements of the tree having values that depend on coefficients of the transformed signal; quantizing the wavelet tree element values, the quantized element values being representable in the form of ordered digital bits; for each order of said digital bits, encoding a bit plane of said wavelet tree element values to obtain encoded values; and decoding the encoded values to recover the input signal. Further features and advantages of the invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.
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