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17.4 Implementation 379
image denoising techniques at the receiver, and emphasize that denoising should be
immediately applied to channel output.
The denoising processes for low-pass and high-pass frames are identical. We use
different denoising techniques to deal with packet losses and random-valued noises.
In particular, we adopt the classic median filter [419] to handle losses. Under ideal
interleaving, packet loss creates randomly dispersed pixel “holes” in the frame. These
holes are filled with the median of surrounding eight pixel values. We have tried more
advanced median filters such as the directional weighted median filter [428], but the
performance improvement is marginal at moderate packet loss ratios.
Then BM3D [420] is adopted to