Digital Signal Processing Reference
In-Depth Information
Figure 5.7.
These IP functions abstract away all the mathematical details,
enabling designers to implement highly complex scaling algo-
rithms in a matter of minutes. Using such functions you can
generate a set of scaling coefficients using standard polynomial
interpolation algorithms, or use your own custom coefficients.
Figure 5.8
shows the GUI of an IP function provided by Altera
for polyphase video scaling. The scaler allows implementation of
both simple, nearest neighbor/bilinear scaling, as well as poly-
phase scaling. For polyphase scaling, the number of vertical and
horizontal taps can be selected independently. The number of
phases can also be set independently in each dimension. This IP
function uses an interpolation algorithm called the Lanczos
function to calculate the coefficients.
