// Create the CIImage from a file
CIImage xamarinCheck = CIImage.FromCGImage (UIImage.FromFile ("XamarinCheck.png").CGImage);

var width = xamarinCheck.Extent.Width;
var height = xamarinCheck.Extent.Height;

// Create a CIBumpDistortion filter with the input image, center raduis and scale
var bump_distortion = new CIBumpDistortion () {
	Image = xamarinCheck,
	Center = new CIVector (width/2f, height/2f),
	Radius = .4f * height,
	Scale = .5f
};

// Get the distorted image from the filter
var output = bump_distortion.OutputImage;

// To render the results, we need to create a context, and then
// use one of the context rendering APIs, in this case, we render the
// result into a CoreGraphics image, which is merely a useful representation
//
var context = CIContext.FromOptions (null);

var cgimage = context.CreateCGImage (output, output.Extent);

// The above cgimage can be added to a screen view, for example, this
// would add it to a UIImageView on the screen:
myImageView.Image = UIImage.FromImage (cgimage);