var filtersFactory = (function(){
	var ob = {};
	ob.createFilter = createFilter;
	ob.createAlphaToLuminanceFilter = createAlphaToLuminanceFilter;

	function createFilter(filId){
		var fil = document.createElementNS(svgNS,'filter');
		fil.setAttribute('id',filId);
        fil.setAttribute('filterUnits','objectBoundingBox');
        fil.setAttribute('x','0%');
        fil.setAttribute('y','0%');
        fil.setAttribute('width','100%');
        fil.setAttribute('height','100%');
        return fil;
	}

	function createAlphaToLuminanceFilter(){
        var feColorMatrix = document.createElementNS(svgNS,'feColorMatrix');
        feColorMatrix.setAttribute('type','matrix');
        feColorMatrix.setAttribute('color-interpolation-filters','sRGB');
        feColorMatrix.setAttribute('values','0 0 0 1 0  0 0 0 1 0  0 0 0 1 0  0 0 0 0 1');
        return feColorMatrix;
	}

	return ob;
}())