dc_level.h File Reference
DC level shift.
More...
Detailed Description
In order to further improve codec perfomance, input signal must be centered around zero before applying wavelet transform. One can accomplish this by subtracting mean value from each image sample. This preprocessing step results in wavelet coefficient magnitude decrease, which in turn, reduces number of bits required for image encoding. After decoding, one have to perform the inverse operation, i.e. add stored mean value to each reconstructed image sample.