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3.3. 2-D DWT TOOL
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tion level of wavelet coefficients.
All DWT coefficients at different levels are buffered in Toolware,
and they are dynamically packed together to form one display image as
needed. Level 0 represents the original data, or the image reconstructed
from its DWT coefficients. Obviously, the reconstructed image can be
different from the original one if certain DWT coefficients are manipulated by processing functions in the tool. The user needs to take
precaution in preserving the original image while saving new results
into the hard disk.
3.3.2
Wavelet decomposition
After an image is loaded into the 2-D tool, it can be decomposed by
clicking on the
button. Then, a list of wavelet decomposition sequences will pop up along with a choice of the decomposition structure.
Fig 3.6 shows an example, in which a five-level wavelet-packet structure is selected for decomposition of an image using the Daubechies
biorthogonal wavelet. The decomposition process is started and terminated automatically by clicking on the OK button.
Figure 3.6: Selection of the decomposition parameters
After Toolware has performed the decomposition based on selected
parameters, the decomposed image will pop up on the window, so that
the user can view the absolute value of the wavelet coefficients, see Fig
3.7. The displayed image is generated by using the truncated absolute