Video and Image Processing Suite User Guide

ID 683416
Date 2/12/2021

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8.4.5. Diagonal Symmetry

There are 4 axes of symmetry in the 2D coefficient array across a horizontal line, a vertical line, and 2 diagonal lines through the center tap.

In this case, the number of horizontal taps (N) and the number of vertical taps (M) must be even, and they must have same value (N = M). With diagonal symmetry enabled, there are only Tu = ((N+1)/2) unique coefficient values in either the horizontal or vertical directions, and a total of (Tu*(Tu+1))/2 unique coefficient values.

With run-time control of the coefficients enabled, the register map only includes addresses to update the (Tu *( Tu +1))/2 unique coefficient values, indexed for an example 5×5 array as shown in the figure below.