code: function (inData, outData, width, height) {
          var c = 1 / 25;
          convolve5x5(inData, outData, width, height,
              [
                  [c, c, c, c, c],
                  [c, c, c, c, c],
                  [c, c, c, c, c],
                  [c, c, c, c, c],
                  [c, c, c, c, c]
              ]);
      }
docs: A 5x5 low-pass mean filter