A function that helps to apply LUT to image. Make sure to change the canvas IDs or to create temporary canvases.

Apply LUT (LookUpTable).js

/**
 * Created by Karlen on 13-Aug-14.
 */

var imageContext = document.getElementById('imageCanvas').getContext('2d'),
    lutContext = document.getElementById('lutCanvas').getContext('2d');

function applyLUT(image, lut) {
    var imageData, lutData, iData, lData;

    imageContext.clearRect(0, 0, image.naturalWidth, image.naturalHeight);
    imageContext.drawImage(image, 0, 0);
    imageData = imageContext.getImageData(0, 0, image.naturalWidth, image.naturalHeight);
    iData = imageData.data;

    lutContext.clearRect(0, 0, lut.naturalWidth, lut.naturalHeight);
    lutContext.drawImage(lut, 0, 0);
    lutData = lutContext.getImageData(0, 0, lut.naturalWidth, lut.naturalHeight);
    lData = lutData.data;

    for (var i = 0, l = iData.length; i < l; i += 4) {
        var r, g, b;

        r = Math.floor(iData[i] / 4);
        g = Math.floor(iData[i + 1] / 4);
        b = Math.floor(iData[i + 2] / 4);

        var lutX, lutY, lutIndex;

        lutX = (b % 8) * 64 + r;
        lutY = Math.floor(b / 8) * 64 + g;
        lutIndex = (lutY * lut.naturalWidth + lutX) * 4;

        var lutR, lutG, lutB;

        lutR = lData[lutIndex];
        lutG = lData[lutIndex + 1];
        lutB = lData[lutIndex + 2];

        iData[i] = lutR;
        iData[i + 1] = lutG;
        iData[i + 2] = lutB;
    }

    imageData.data = iData;
    imageContext.clearRect(0, 0, image.naturalWidth, image.naturalHeight);
    imageContext.putImageData(imageData, 0, 0);
}

@CesarVonc Do you have image comparison of both options? I wonder how different they are.