Noun
A morphological filter (idempotent operator) whose image is a subset of the domain.
- Examples
-
It is clear that overfilters and underfilters are dual in the sense of the duality principle.
A filter that is positioned beneath something.
- Examples
-
More examples (1)
The paving downstream consisted of 18x18x8-inch blocks laid on edge over a brick base which in turn was underlain with a gravel or brick chip filter. Since there was some controversy as to whether an underfilter was necessary, the first test was made with the filter omited.^([sic])
Since there is no underfilter, the top flow line emerges on the downstream slope.
A single sheet of filter paper is used as an underfilter.
More examples (1)
In addition, the flow from the underfilter, which had previously been clear, became cloudy, indicating that the filter had failed to block particles from the core.
Verb
To filter insufficiently.
- Examples
-
It is not possible to overfilter your tank but marine aquaria are frequently underfiltered.
You don't want to underfilter. Nor do you want to filter beyond what is economically justifiable.
More examples (1)
Underfiltering by using too high a cut-off frequency leaves too much noise in the reconstructed images (bottom row).