cornerstoneSobel.js

element = cornerstone.getEnabledElements()[0];

pixels = element.image.getPixelData();

new_pixels = Sobel(pixels, element.image.width, element.image.height);

pixels.set(new_pixels);
element.needsRedraw = true;



function Sobel(data, width, height) {

  var kernelX = [
    [-1,0,1],
    [-2,0,2],
    [-1,0,1]
  ];

  var kernelY = [
    [-1,-2,-1],
    [0,0,0],
    [1,2,1]
  ];

  var sobelData = [];

  function bindPixelAt(data) {
    return function(x, y, i) {
      i = i || 0;
      return data[((width * y) + x) + i];
    };
  }

  pixelAt = bindPixelAt(data);

  for (y = 0; y < height; y++) {
    for (x = 0; x < width; x++) {
      var pixelX = (
          (kernelX[0][0] * pixelAt(x - 1, y - 1)) +
          (kernelX[0][1] * pixelAt(x, y - 1)) +
          (kernelX[0][2] * pixelAt(x + 1, y - 1)) +
          (kernelX[1][0] * pixelAt(x - 1, y)) +
          (kernelX[1][1] * pixelAt(x, y)) +
          (kernelX[1][2] * pixelAt(x + 1, y)) +
          (kernelX[2][0] * pixelAt(x - 1, y + 1)) +
          (kernelX[2][1] * pixelAt(x, y + 1)) +
          (kernelX[2][2] * pixelAt(x + 1, y + 1))
      );

      var pixelY = (
        (kernelY[0][0] * pixelAt(x - 1, y - 1)) +
        (kernelY[0][1] * pixelAt(x, y - 1)) +
        (kernelY[0][2] * pixelAt(x + 1, y - 1)) +
        (kernelY[1][0] * pixelAt(x - 1, y)) +
        (kernelY[1][1] * pixelAt(x, y)) +
        (kernelY[1][2] * pixelAt(x + 1, y)) +
        (kernelY[2][0] * pixelAt(x - 1, y + 1)) +
        (kernelY[2][1] * pixelAt(x, y + 1)) +
        (kernelY[2][2] * pixelAt(x + 1, y + 1))
      );

      var magnitude = Math.sqrt((pixelX * pixelX) + (pixelY * pixelY))>>>0;

      sobelData.push(magnitude);
    }
  }

  return sobelData;

}