code: function (inData, outData, width, height, options) {
          options = defaultOptions(options, {strength: 1});
          var a = -clamp(options.strength, 0, 1);
          convolve5x5(inData, outData, width, height,
              [
                  [a, a, a, a, a],
                  [a, a, a, a, a],
                  [a, a, 1 - a * 24, a, a],
                  [a, a, a, a, a],
                  [a, a, a, a, a]
              ]);
      }
docs: A 5x5 high-pass filter