Accord.Imaging.Filters.FillHoles.ProcessFilter C# (CSharp) Method

        protected override unsafe void ProcessFilter( UnmanagedImage image )
        {
            int width  = image.Width;
            int height = image.Height;

            // 1 - invert the source image
            Invert invertFilter = new Invert( );
            UnmanagedImage invertedImage = invertFilter.Apply( image );

            // 2 - use blob counter to find holes (they are white objects now on the inverted image)
            BlobCounter blobCounter = new BlobCounter( );
            blobCounter.ProcessImage( invertedImage );
            Blob[] blobs = blobCounter.GetObjectsInformation( );

            // 3 - check all blobs and determine which should be filtered
            byte[] newObjectColors = new byte[blobs.Length + 1];
            newObjectColors[0] = 255; // don't touch the objects, which have 0 ID

            for ( int i = 0, n = blobs.Length; i < n; i++ )
            {
                Blob blob = blobs[i];

                if ( ( blob.Rectangle.Left == 0 ) || ( blob.Rectangle.Top == 0 ) ||
                     ( blob.Rectangle.Right == width ) || ( blob.Rectangle.Bottom == height ) )
                {
                    newObjectColors[blob.ID] = 0;
                }
                else
                {
                    if ( ( ( coupledSizeFiltering ) && ( blob.Rectangle.Width <= maxHoleWidth ) && ( blob.Rectangle.Height <= maxHoleHeight ) ) |
                         ( ( !coupledSizeFiltering ) && ( ( blob.Rectangle.Width <= maxHoleWidth ) || ( blob.Rectangle.Height <= maxHoleHeight ) ) ) )
                    {
                        newObjectColors[blob.ID] = 255;
                    }
                    else
                    {
                        newObjectColors[blob.ID] = 0;
                    }
                }
            }

            // 4 - process the source image image and fill holes
            byte* ptr = (byte*) image.ImageData.ToPointer( );
            int offset = image.Stride - width;

            int[] objectLabels = blobCounter.ObjectLabels;

            for ( int y = 0, i = 0; y < height; y++ )
            {
                for ( int x = 0; x < width; x++, i++, ptr++ )
                {
                    *ptr = newObjectColors[objectLabels[i]];
                }
                ptr += offset;
            }
        }
    }