using the deviation from a direction vector the weight for pixels weight is determined

strange directional blur

import hageldave.imagingkit.core.ImageLoader;
import hageldave.imagingkit.core.Img;
import hageldave.imagingkit.core.util.ImageFrame;
import hageldave.imagingkit.filter.implementations.ConvolutionFilter;

	public class testmain {
		public static void main(String[] args) throws InterruptedException {
			Img img = ImageLoader.loadImgFromURL("http://www.wellcomeimageawards.org/WI-6561.24_WIA_2017_PP_holding_screen.jpg");
			ConvolutionFilter c = new ConvolutionFilter();
			float[] kernel = new float[17*17];
			float xdir = 1;
			float ydir = 2;
			for(int y = 0; y < 17; y++){
				float yf = (y-(17/2))*1.0f/(17/2);
				for(int x = 0; x < 17; x++){
					float xf = (x-(17/2))*1.0f/(17/2);
					if(x == 8 && y == 8){
						kernel[y*17+x] = 1;
					} else {
						float parallelity = parallelity(xf, yf, xdir, ydir);
						kernel[y*17+x] = (float) (Math.pow(parallelity,3)*(1-Math.sqrt(xf*xf+yf*yf)/1.42));
					}
				}
			}
			c.setConvolutionKernel(17, 17, kernel);
			Img kernelImg = new Img(17, 17);
			kernelImg.forEach(px->px.setRGB_fromNormalized(kernel[px.getIndex()], kernel[px.getIndex()], kernel[px.getIndex()]));

			c.normalizeConvolutionKernel();
//			c.applyTo(img, true);
			ImageFrame.display(kernelImg);


		}


		static float parallelity(float x1, float y1, float x2, float y2){
			float l1 = (float) Math.sqrt(x1*x1+y1*y1);
			float l2 = (float) Math.sqrt(x2*x2+y2*y2);
			x1 /= l1; y1 /= l1;
			x2 /= l2; y2 /= l2;

			// scalar product returns cosine of angle between vectors
			return Math.abs(x1*x2+y1*y2);
		}

	}