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filter_Tile
cfg
vpi_out
cur_tile_y
cur_tile_uv
ref_tile_y
ref_tile_uv
mmr interface
noise_calc
(firmware)
vpi_in
vpi_in
vpi_in
vpi_in
vpi_out
spatial strength
Temporal filter trigger noise
Noise IIR coeff
Maxnoise
Temporal strength
Pure black threshold
Pure white threshold
tile_noise
a0
Threshold
frame_cntl
filtered_tile_y
filtered_tile_uv
Total_Frame_noise
α
0
1
temporal_filter_trigger_noise
Internal Modules
188
SPRUHI7A – December 2012 – Revised June 2016
Copyright © 2012–2016, Texas Instruments Incorporated
High-Definition Video Processing Subsystem (HDVPSS)
This IIR low pass filter will make the measured noise level change slowly across frames. The register
noise_IIR_coefficient
controls how fast it changes.
The thresholds of the spatial filter will be the filtered frame noise scaled by
spatial_strength
.
Threshold = spatial_strength * Frame_noise_filtered
α
0
is the offset of the motion vs blending factor function. It is controlled by the total noise level
Total_Frame_noise
as shown in
. The total noise of all three channels is
Total_Frame_noise = Frame_n Frame_n Frame_noise_V
where
temporal_filter_trigger_noise
is a register to control the slope of the function in
. This
function will make
α
0
to be close to 1 if the measured noise level is low, and therefore the temporal filter to
be very weak to avoid ghosting artifacts.
Figure 1-136.
α
0
versus totalFrame_noise function
1.2.10.3.5 Hardware Implementation
The NF hardware consists of the main filter_Tile processing unit which contains the main spatial and
temporal filter logics and a number of support logics which include mainly MMR configuration module, VPI
data in and out interface modules, frame noise calculation module (noise_calc) as shown in
.
Figure 1-137. Hardware Implementation Block Diagram