3.6. Press the "Advanced" («Дополнительно») button and set, if required, the Intra type of the Deslauriers-Dubuc wavelet filter (9,7)
Thus, as a result of multiple wavelet decomposition, a very small image (in the upper left of the screen) is obtained in the approximation array, which takes up a small amount of information, and a large area of the detail array filled with zeros or small coefficients (in Fig. 6, zero values correspond to gray with value 128), which are well compressed by statistical compressors, which allows you to get fairly high compression ratios.
For the simplest Haar wavelet with only 2 coefficients, the effect of the low-pass filter can be represented by averaging two neighboring points, and the high-pass filter can be represented by numerical differentiation. As a result of processing, two arrays A [N / 2] and D [N / 2] are formed, the elements of which are defined as:
 ,  , where .
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