1. A method for measuring the gloss of grains, in particular rice grains, the method comprising: emitting a light beam to the surface of a grain by means of a light emitting device; aligning a light sensing device in a sensing position in relation to the light emitting device sensing the light beam of the light emitting device reflected by the surface of the grains in direction of the light sensing device; capturing a photometric image of the surface of the grains by means of the light sensing device sensing the reflected light beam; assigning an intensity value to a plurality of image elements of the captured photometric image, wherein the photometric image is composed of the plurality of image elements; quantifying the reflected light beam in predefined ranges of intensities by means of a processing unit; cumulating, for each of the predefined ranges, the number of image elements having an intensity values, within a certain range to density value and assigning to each of the ranges the corresponding density value; capturing a spread value for the density values of the predefined ranges by means of the processing unit, wherein the spread value is captured by measuring the deviation of the density values of the predefined ranges; and assigning a quality surface measuring parameter to the captured photometric image, wherein the surface measuring parameter is a measure the spread value.