Наиболее часто используемым форматом зжатия видеоинформации является формат JPeg, который основан на дискретном преобразовании Фурье и кодировании Хоффмана. В данной статье описано само преобразование и формат файлов JPeg и рассмотрены следующие темы: Плавное преобразование цветового пространства, Дискретизация, Сдвиг Уровня, 8x8 Дискретное Косинусоидальное Преобразование (DCT), Зигзагообразная перестановка 64 DCT коэффициентов, Квантование, RunLength кодирование нулей (RLC), Конечный шаг - кодирование Хаффмана. (rus)

The purpose of this paper is to give avery short, nuts and bolts, introduction to the lifting scheme and provide references for further reading. The lifting scheme is a new method for constructing biorthogonal wavelets. The main dierence with classical constructions is that it does not rely on the Fourier transform. This way lifting can be used to construct second generation wavelets, wavelets which are not necessarily translates and dilates of one function. The latter we refer to as rst generation wavelets. (eng)

A wavelet-based watermark casting scheme and a blind watermark retrieval technique are investigated in this research. An adaptive watermark casting method is developed to rst determine significant wavelet subbands and then select a couple of signicant wavelet coefficients in these subbands to embed watermarks. A blind watermark retrieval technique that can detect the embedded watermark without the help from the original image is proposed. Experimental results show that the embedded watermark is robust against various signal processing and compression attacks.(eng)