There are a number of image filters available in RSGISLib, including texture filters. The interface is designed to make it easy to apply a number of filters, which form a filter bank, to an image. A base name for the output is provided and for each filter a different file ending is appended. For example to apply a mean and median filter to an image using the XML interface the following is used:
<rsgis:commands xmlns:rsgis="http://www.rsgislib.org/xml/"> <rsgis:command algor="imagefilter" option="filter" image="injune_p142_casi_sub_singleband.kea" output="Filtered/injune_p142_casi_sub_singleband" format="KEA" extension="kea" datatype="Float32" > <rsgis:filter size="3" type="Mean" fileending="mean" /> <rsgis:filter size="3" type="Median" fileending="median" /> </rsgis:command> </rsgis:commands>
The above example will produce two files ‘Filtered/injune_p142_casi_sub_singleband_mean.kea’ and ‘Filtered/injune_p142_casi_sub_singleband_median.kea’.
The filters can also be accessed using the new Python interface, where each filter is provided as a ‘FilterParameters’ object.
inputImage = 'injune_p142_casi_sub_singleband.kea' outputImageBase = 'Filtered/injune_p142_casi_sub_utm_single_band' gdalFormat = 'KEA' outExt = 'kea' dataType = rsgislib.TYPE_32FLOAT filters = [] filters.append(imagefilter.FilterParameters(filterType = 'Mean', fileEnding = 'mean', size=3) ) filters.append(imagefilter.FilterParameters(filterType = 'Median', fileEnding = 'median', size=3) ) imagefilter.applyfilters(inputImage, outputImageBase, filters, gdalFormat, outExt, dataType)
The Leung-Malik (2001) filter bank is available through RSGISLib for extracting textural features from images and is accessible using the XML interface:
<rsgis:commands xmlns:rsgis="http://www.rsgislib.org/xml/"> <rsgis:command algor="imagefilter" option="filter" filterbank="LM" image="injune_p142_casi_sub_singleband.kea" output="LM/injune_p142_casi_sub_singleband_utm" format="KEA" extension="kea" datatype="Float32" /> </rsgis:commands>
and Python bindings:
inputImage = 'injune_p142_casi_sub_singleband.kea' outputImageBase = 'LM/injune_p142_casi_sub_utm_single_band' gdalFormat = 'KEA' outExt = 'kea' dataType = rsgislib.TYPE_32FLOAT imagefilter.LeungMalikFilterBank(inputImage, outputImageBase, gdalFormat, outExt, dataType)
[1] Leung, T., Malik, J., 2001. Representing and recognizing the visual appearance of materials using three-dimensional textons. International Journal of Computer Vision 43 (1), 29-44.