public static ColorXyz convertHunterLabToXyz(final double l, final double a, final double b) {
        final double varY = l / 10;
        final double varX = a / 17.5 * l / 10;
        final double varZ = b / 7 * l / 10;

        final double y = Math.pow(varY, 2);
        final double x = (varX + y) / 1.02;
        final double z = -(varZ - y) / 0.847;

        return new ColorXyz(x, y, z);
    }
DIN99o.

@param l99o lightness of color.
@param a99o position between red and green.
@param b99o position between yellow and blue.
@return DIN99o colors converted to CIELab color space.
@see <a href=
     "https://de.wikipedia.org/w/index.php?title=Diskussion:DIN99-Farbraum">https://de.wikipedia.org/w/index.php?title=Diskussion:DIN99-Farbraum</a>
src/main/java/org/apache/commons/imaging/color/ColorConversions.java