Video sharpening with controlled granularity is used to smooth sharpening effects in the output video signal. Video Sharpening is essential for output video processing devices to enhance the subjective video quality.

Basic video sharpening boosts the middle and high frequencies of the progressive image in vertical and horizontal directions.  To have a high level of perceptual quality, it is necessary to boost the middle frequencies more than the high frequencies. The basic video sharpener is a FIR.

basic video sharpener with controlled granularity
Figure 1: Basic Video Sharpening with Controlled Granularity

To control sharpening smoothly the high frequency part of the filter is extracted (as shown in figure 1) to a separate path, multiplied by the sharpening control coefficient and added back to the delayed (by FIR delay) input signal.

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