In remote sensing, a filter used to enhance the appearance of the spatial distribution of data in an image to make it more interpretable to the human eye. Spatial-frequency filters examine the spatial variations in digital number of an image and are used to modify the image by selectively suppressing or separating certain spatial-frequency ranges. Spatial-frequency filters include directional filter, high-pass filter, medium-pass filter, and low-pass filter. See also median filter.
Subjects: Earth Sciences and Geography.