Advances in Visual Data Compression and Communication

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18.5 Compressive Sampling 405

Figure 18.3 Pyramidal structure of 5-level wavelet decomposition and chunk division for Lena.

The variance metadata are quantized into integers and then encoded by Exponential-

Golomb codes. After this step, they are transmitted using 1/2 rate channel coding,

QPSK, and STBC. The chunk division details are shown in Figure 18.3. The 10 upper

left wavelet bands correspond to 10 chunks, while each of the remaining 6 bands is

split into several chunks of equal size. The chunks in the upper-left corner are smaller

than the others because there are fewer coefficients in the lowest-frequency band, and

coefficients from