1. A method for evaluating a mixture including a plurality glass pieces, the method comprising: taking an image of an object from the mixture, the object possibly being either a single piece from the mixture or at least two pieces from the mixture; determining, from the image, angles of an outline of the object; evaluating the angles to determine whether the object is at least two pieces; evaluating a characteristic of the object; detecting, from the image, a light transmittance boundary line within the outline of the object, the light transmittance boundary line having an endpoint on the outline; evaluating a position of an endpoint on the outline to determine whether the light transmittance boundary line is present on a single piece of the mixture; and identifying the single piece of the mixture as a piece of glass with a label when the light transmittance boundary line is determined to be present on a single piece of the mixture.