A 2-D orientation-adaptive prediction filter in lifting structures for image coding
Gerek, Ö. N.
Çetin, A. Enis
IEEE Transactions on Image Processing
Institute of Electrical and Electronics Engineers
106 - 111
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Lifting-style implementations of wavelets are widely used in image coders. A two-dimensional (2-D) edge adaptive lifting structure, which is similar to Daubechies 5/3 wavelet, is presented. The 2-D prediction filter predicts the value of the next polyphase component according to an edge orientation estimator of the image. Consequently, the prediction domain is allowed to rotate ±45° in regions with diagonal gradient. The gradient estimator is computationally inexpensive with additional costs of only six subtractions per lifting instruction, and no multiplications are required.