This task applies a Lee adaptive filter to smooth noisy data that has both an additive and a multiplicative component.
Lee filtering is a standard deviation-based (sigma) filter that filters data based on statistics calculated within individual filter windows. Unlike a typical low-pass smoothing filter, the Lee filter and other similar sigma filters preserve image sharpness and detail while suppressing noise. The filtered pixel is replaced by a value calculated using the surrounding pixels.
Lee, Jong-Sen, “Digital Image Enhancement and Noise Filtering by Use of Local Statistics,” IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol PAMI-2, No.2, March 1980, pp. 165-168.
e = ENVI()
File = Filepath('elev_t.jpg', Subdir=['examples','data'])
Raster = e.OpenRaster(File)
Task = ENVITask('AdditiveMultiplicativeLeeAdaptiveFilter')
Task.INPUT_RASTER = Raster
Task.NOISE_STANDARD_DEVIATION = 0.5
Task.ADDITIVE_NOISE_MEAN = 1.5
Task.MULTIPLICATIVE_NOISE_MEAN = 1.5
DataColl = e.Data
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)
Result = ENVITask('AdditiveMultiplicativeLeeAdaptiveFilter')
Input properties (Set, Get): ADDITIVE_NOISE_MEAN, INPUT_RASTER, MULTIPLICATIVE_NOISE_MEAN, NOISE_STANDARD_DEVIATION, OUTPUT_RASTER_URI, WINDOW_SIZE
Output properties (Get only): OUTPUT_RASTER
Properties marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Properties marked as "Get" are those whose values you can retrieve but not set.
This task inherits the following methods from ENVITask:
This task inherits the following properties from ENVITask:
This task also contains the following properties:
Specify the additive noise mean. The default value is 0.
Specify a raster on which to perform additive and multiplicative Lee adaptive filtering.
Specify the multiplicative noise mean. The default value is 1.0.
Specify the noise standard deviation. The default value is 0.25.
This is a reference to the output raster of filetype ENVI.
Specify a string with the fully qualified filename and path of the associated OUTPUT_RASTER. If you do not specify this property, or set it to an exclamation symbol (!), a temporary file will be created.
Specify a square filtering window size. The default value is 3 pixels.
ENVITask, ENVISubsetRaster, AdditiveLeeAdaptiveFilter Task, BitErrorAdaptiveFilter Task, EnhancedFrostAdaptiveFilter Task, EnhancedLeeAdaptiveFilter Task, FrostAdaptiveFilter Task, GammaAdaptiveFilter Task, KuanAdaptiveFilter Task, LocalSigmaAdaptiveFilter Task, MultiplicativeLeeAdaptiveFilter Task