title: Edge Detection using MarvinJ JavaScript
body: <p>I am a beginner in Image Processing.I want to use MarvinJ javascript library to detect horizontal ,vertical and diagonal line (edge detection) given a image.
  I have came across a lot of code examples which told that using prewitt one can do edge detection,like the one below.</p>
  
  <pre><code>function clickExampleFiltersEdge(){
      imageProcessed.clear(0xFF000000);
      Marvin.prewitt(imageOriginal, imageProcessed);
      Marvin.invertColors(imageProcessed, imageProcessed);
      Marvin.thresholding(imageProcessed, imageProcessed, 150);
      repaint();
  } 
  </code></pre>