AC prediction.
One defined decoder option for JPEG is AC Prediction. In the decoder
a quadratic surface is fitted to the DC component of a block and its 8 neighbours
and the surface is used to predict AC coefficients for the blocks that will remove
blocking artifacts. Is quite effective in smooth areas and increases compression
ratios for same perceived quality by about 2%. Figure 1.4 shows the effects of AC
prediction. [2].
![[00b.bmp]](0000000b.gif)
![[00c.bmp]](0000000c.gif)
Fig 1.4 AC prediction