A simple variant of down-sampling achieved by discarding information, for instance by using only every other sample of video data (2 times decimation). Decimation can bring aliasing problems if not accompanied by appropriate pre-filtering.
Is reducing the output sampling rate by ignoring all but every Nth sample. When a digital filter reduces the bandwidth of a signal of interest so the filter output is over-sampled if the input sample rate is preserved. See appnote: AN9603
A form of subsampling which discards existing samples (pixels, in the case of spatial decimation, or pictures, in the case of temporal decimation). The resulting information is reduced in size but may suffer from aliasing.