SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Figure 10-3 illustrates the block-diagram of motion-adaptive Deinterlacer. The general concept behind motion adaptive deinterlacing is that spatial filtering works very well for images with motion, while temporal filtering works very well for static images. So, the intuitive way is to combine them together. Motion detection is used to switch or fade between the use of spatial deinterlacing and temporal deinterlacing, as shown in the following formula:
ŷ(j, i, n) = αyspat(j, i, n) + (1 - α)ytemp(j, i, n)
where yspat(j, i, n) is the spatial interpolation output, ytemp(j, i, n) is temporal interpolation output, α is the motion detection output ranging from 0 to 1, ŷ(j, i, n) is the final output from deinterlacer, and j, i, n are the vertical, horizontal, and temporal indexes, respectively. From the previous formula, the final output is controlled by the motion detector output, α. The higher the motion, the higher value of α, and the output favors spatial interpolation. If the motion is absent or very low, the temporal interpolation has higher weight.
Temporal interpolation can be disabled by programmable control registers. In that case we have:
ŷ(j, i, n) = yspat(j, i, n)
Chroma interpolation is handled in the same manner as luma with regards to the above equations. There is a separate control for disabling temporal interpolation for chroma, such that luma can perform the full mixture, and chroma can only be spatial. If luma temporal interpolation is disabled, chroma temporal interpolation is also disabled.
Figure 10-3 provides a simple description of how a motion-adaptive deinterlacer operates. The actual interpolation used is edge directed interpolation. Edge directed interpolation is only performed spatially prior to the output mixing.
The Deinterlacer consists of: