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How to create a custom convolution filter (ArcObjects .NET 10.4 SDK)
ArcObjects Help for .NET developers > Developing with ArcGIS > Learning ArcObjects > Managing data > Working with image and raster data > Processing raster data > Pixel filters > How to create a custom convolution filter (ArcObjects .NET 10.4 SDK)

How to create a custom convolution filter


Creating a custom convolution filter

To create a custom convolution filter by specifying a kernel, see the following code example:
[C#] 
public static void CustomConvolutionFilter(IRaster raster)
{
    //The following code sample sets up a horizontal line detection filter and applies it to a raster
    //to create a convolution filter using a custom kernel.
    IRasterConvolutionFilter newFilter=new RasterConvolutionFilterClass();
    newFilter.SetSize(3, 3);
    double[] kernel=new double[9]
    {
         - 1,  - 1,  - 1, 2, 2, 2,  - 1,  - 1,  - 1
    };
    newFilter.PutCoefficients(ref kernel);

    //Apply the filter to the raster.
    IPixelOperation pixelOperation=(IPixelOperation)raster;
    pixelOperation.PixelFilter=(IPixelFilter)newFilter;

    //Save the result.
    ISaveAs saveas=(ISaveAs)raster;
    saveas.SaveAs(@"c:\temp\convolution_output.img", null, "IMAGINE Image");
}
[VB.NET] 
Public Shared Sub CustomConvolutionFilter(ByVal raster As IRaster)
'The following code sample sets up a horizontal line detection filter and applies it to a raster
'to create a convolution filter using a custom kernel.

'Define the kernal
Dim NewFilter As IRasterConvolutionFilter=New RasterConvolutionFilterClass()
NewFilter.SetSize(3, 3);
Dim kernel() As Double=New Double(9) {-1, -1, -1, 2, 2, 2, -1, -1, -1}
NewFilter.PutCoefficients( kernel)

'Apply the filter to the raster.
Dim pixelOperation As IPixelOperation=CType(raster, IPixelOperation)
pixelOperation.PixelFilter=CType(NewFilter, IPixelFilter)

'Save the result.
Dim saveas As ISaveAs=CType(raster, ISaveAs)
saveas.SaveAs("c:\temp\convolution_output.img", Nothing, "IMAGINE Image")
End Sub





To use the code in this topic, reference the following assemblies in your Visual Studio project. In the code files, you will need using (C#) or Imports (VB .NET) directives for the corresponding namespaces (given in parenthesis below if different from the assembly name):
Development licensing Deployment licensing
ArcGIS for Desktop Advanced ArcGIS for Desktop Advanced
ArcGIS for Desktop Standard ArcGIS for Desktop Standard
ArcGIS for Desktop Basic ArcGIS for Desktop Basic
Engine Developer Kit Engine