Image noise reduction

UIImage+ CINoiseReduction.swift

extension UIImage {
    var noiseReducted: UIImage? {
        guard let openGLContext = EAGLContext(api: .openGLES2) else { return self }
        let ciContext = CIContext(eaglContext: openGLContext)

        guard let noiseReduction = CIFilter(name: "CINoiseReduction") else { return self }
        noiseReduction.setValue(CIImage(image: self), forKey: kCIInputImageKey)
        noiseReduction.setValue(0.02, forKey: "inputNoiseLevel")
        noiseReduction.setValue(0.40, forKey: "inputSharpness")

        if let output = noiseReduction.outputImage,
            let cgImage = ciContext.createCGImage(output, from: output.extent) {
            return UIImage(cgImage: cgImage, scale: scale, orientation: imageOrientation)
        }

        return nil
    }
}