OTB.Despeckle: Perform speckle noise reduction on SAR image.

SAR images are affected by speckle noise that inherently exists in and which degrades the image quality. It is caused by the coherent nature of back-scattered waves from multiple distributed targets. It is locally strong and it increases the mean Grey level of a local area. Reducing the speckle noise enhances radiometric resolution but tend to decrease the spatial resolution.Several different methods are used to eliminate speckle noise, based upon different mathematical models of the phenomenon. The application includes four methods: Lee [1], Frost [2], GammaMAP [3] and Kuan [4]. We sum up below the basic principle of this four methods: * Lee : Estimate the signal by mean square error minimization (MMSE) on a sliding window. * Frost : Also derived from the MMSE criteria with a weighted sum of the values within the window. The weighting factors decrease with distance from the pixel of interest. * GammaMAP : Derived under the assumption of the image follows a Gamma distribution. * Kuan : Also derived from the MMSE criteria under the assumption of non stationary mean and variance. It is quite similar to Lee filter in form.

Inputs

Input image.

format
href
Please set a value for in.

Output image.

string
Please set a value for out.

Available memory for processing (in MB)

integer

filter

string
Please set a value for filter.

Radius in pixel

integer
Please set a value for filter.lee.rad.

Number of looks in the input image.

number
Please set a value for filter.lee.nblooks.

Radius in pixel.

integer
Please set a value for filter.frost.rad.

factor use to control theexponential function used to weight effect of the distance between thecentral pixel and its neighborhood. Increasing the deramp parameter willlead to take more into account pixels farther from the center andtherefore increase the smoothing effects.

number
Please set a value for filter.frost.deramp.

Radius in pixel.

integer
Please set a value for filter.gammamap.rad.

Number of looks in the input image.

number
Please set a value for filter.gammamap.nblooks.

Radius in pixel.

integer
Please set a value for filter.kuan.rad.

Number of looks in the input image.

number
Please set a value for filter.kuan.nblooks.

Outputs

Output image.

format
transmission

Execution options

successUri
inProgressUri
failedUri

format

mode

Execute End Point

View the execution endpoint of a process.

View the alternative version in HTML.

{"id": "OTB.Despeckle", "title": "Perform speckle noise reduction on SAR image.", "description": "SAR images are affected by speckle noise that inherently exists in and which degrades the image quality. It is caused by the coherent nature of back-scattered waves from multiple distributed targets. It is locally strong and it increases the mean Grey level of a local area. Reducing the speckle noise enhances radiometric resolution but tend to decrease the spatial resolution.Several different methods are used to eliminate speckle noise, based upon different mathematical models of the phenomenon. The application includes four methods: Lee [1], Frost [2], GammaMAP [3] and Kuan [4]. We sum up below the basic principle of this four methods: * Lee : Estimate the signal by mean square error minimization (MMSE) on a sliding window. * Frost : Also derived from the MMSE criteria with a weighted sum of the values within the window. The weighting factors decrease with distance from the pixel of interest. * GammaMAP : Derived under the assumption of the image follows a Gamma distribution. * Kuan : Also derived from the MMSE criteria under the assumption of non stationary mean and variance. 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Increasing the deramp parameter willlead to take more into account pixels farther from the center andtherefore increase the smoothing effects.", "description": "factor use to control theexponential function used to weight effect of the distance between thecentral pixel and its neighborhood. Increasing the deramp parameter willlead to take more into account pixels farther from the center andtherefore increase the smoothing effects.", "schema": {"type": "number", "default": 0.1, "format": "double"}, "id": "filter.frost.deramp"}, "filter.gammamap.rad": {"title": "Radius in pixel.", "description": "Radius in pixel.", "schema": {"type": "integer", "default": 1}, "id": "filter.gammamap.rad"}, "filter.gammamap.nblooks": {"title": "Number of looks in the input image.", "description": "Number of looks in the input image.", "schema": {"type": "number", "default": 1, "format": "double"}, "id": "filter.gammamap.nblooks"}, "filter.kuan.rad": {"title": "Radius in pixel.", "description": "Radius in pixel.", "schema": {"type": "integer"}, "id": "filter.kuan.rad"}, "filter.kuan.nblooks": {"title": "Number of looks in the input image.", "description": "Number of looks in the input image.", "schema": {"type": "number"}, "id": "filter.kuan.nblooks"}}, "outputs": {"out": {"title": "Output image.", "description": "Output image.", "extended-schema": {"oneOf": [{"allOf": [{"$ref": "http://zoo-project.org/dl/link.json"}, {"type": "object", "properties": {"type": {"enum": ["image/tiff", "image/jpeg", "image/png"]}}}]}, {"type": "object", "required": ["value"], "properties": {"value": {"oneOf": [{"type": "string", "contentEncoding": "base64", "contentMediaType": "image/tiff"}, {"type": "string", "contentEncoding": "base64", "contentMediaType": "image/jpeg"}, {"type": "string", "contentEncoding": "base64", "contentMediaType": "image/png"}]}}}]}, "schema": {"oneOf": [{"type": "string", "contentEncoding": "base64", "contentMediaType": "image/tiff"}, {"type": "string", "contentEncoding": "base64", "contentMediaType": "image/jpeg"}, {"type": "string", "contentEncoding": "base64", "contentMediaType": "image/png"}]}, "id": "out"}}}

http://demo.mapmint.com/ogc-apihttp://localhost/ogc-api/processes/OTB.Despeckle.html
Last modified: Sat Feb 19 15:43:34 CET 2022