A discrete wavelet transform in a finite field GF(p) is proposed for halftone images. Circulant matrices of a transform based on dual-band filter banks are presented. The fields for orthogonal and biorthogonal transforms of halftone image Daubechies wavelets db4 and db6 are determined. A modification of wavelet coefficients without a change in the original image brightness range demonstrates the feasibility of the proposed transforms. (C) 2020 Optical Society of America
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