Verfahren zum optischen Sortieren von Schüttgut

The invention relates to a method for optically sorting bulk material in a colour sorting machine, the material being conveyed by way of a conveyor belt and moving past an observation head having a light source and a product signal receiver arranged in the vicinity of the light source, the reflected light from the image points of the material to be tested being decomposed by means of various coloured filters of adjacent detection elements of a row of the receiver into a plurality of spectral regions and the material to be tested being sorted on the basis of the colour values (measured value of the intensity in the respective colour). According to the invention, to improve the detection rate, it is provided that in the case of material to be tested which is mixed with reject parts, in each case the colour values of the product are investigated in a plurality of selected subregions, in that in each subregion a classifier determines associated areas of image points having colour values falling into the respective subregion and carries out a classification according to predetermined criteria from the geometry and the size of these detection areas.