SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The peaking block increases the amplitude of high frequency luminance information in horizontal direction to increase the sharpness of a video image before it is scaled. As shown in Figure 9-82, the high-frequency luminance is increased using an 11-tap High-Pass filter with adjustable gain. The non-linear coring function removes low-level noise and the modified luminance is then added to the original luminance signal. The implementation details are shown in Figure 9-82.
Parameter | Description | Bits | Default |
---|---|---|---|
VIP_CFG_SC19[7:0] CFG_HPF_COEF0 to VIP_CFG_SC20[15:8] CFG_HPF_COEF5 | FIR coefficients | 8 | [0 0 0-4 0 8] |
VIP_CFG_SC20[18:16] CFG_HPF_NORM_SHIFT | Right shift | 3 | 4 |
VIP_CFG_SC21[8:0] CFG_NL_LO_THR | Coring threshold | 9 | 16 |
VIP_CFG_SC22[8:0] CFG_NL_HI_THR | High threshold | 9 | 400 |
VIP_CFG_SC21[23:16] CFG_NL_LO_SLOPE | Lo slope= -CFG_NL_LO_SLOPE/16 | 8 | 16 |
VIP_CFG_SC22[18:16] CFG_NL_HI_SLOPE_SHIFT | Hi slope = 2(CFG_NL_HI_SLOPE_SHIFT-3) | 3 | 4 |
VIP_CFG_SC20[28:20] CFG_NL_LIMIT | Clipping limit | 9 | 200 |
VIP_CFG_SC0[14] CFG_Y_PK_EN | Control | 1 | 0 |
Parameters for the Peaking filters are defined in VIP_CFG_SC19 through VIP_CFG_SC22 registers. The frequency responses of the peaking-filter with different sets of coefficients are shown in Figure 9-83. If the source of the input video is NTSC or PAL format, the peaking filter can be configured to reject the color subcarrier frequency.