SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
Table 10-7 below shows a high level block diagram of the edge sharpener function.
In edge sharpener filter module, enabled when VISS_FCP_EE_YEE_MERGESEL[0] YEE_MERGESEL = 1, edge clarity is enhanced without producing a halo artifact. In this module, edge intensity is derived by the following 2D linear filter with fixed coefficients shown in Figure 6-120.
The gain (g) and threshold values for shrink/clip function (thresholdLOW, thresholdHIGH) are determined by register values (VISS_FCP_EE_YES_E_GAIN, VISS_FCP_EE_YES_E_THR1, VISS_FCP_EE_YES_E_THR2). The precision of g is in U12Q6, thresholdLOW is in U16Q6 and that of thresholdHIGH is in U10.
This edge intensity is then clipped by a threshold value in the formula shown in Figure 6-121.
The threshold value (grad) is a function of the activity around the target pixel, which is derived from gradient values. Gain (ggrad) and offset (gbase) are specified by VISS_FCP_EE_YES_G_GAIN and VISS_FCP_EE_YES_G_OFT.
Capping with gradient value prevents overly enhancing edges, and suppresses halo artifacts around edges.