Verfahren zum optischen Sortieren von Schuettgut

The invention relates to a process for the optical sorting of bulk material in a colour sorting machine, by which bulk material is conveyed over a conveyor belt and travels past an observation head comprising a light source and a product signal receiver arranged in proximity to the light source, whereby the reflected light of the pixels of the test material is divided into several spectral ranges by various colour filters of adjacent detection elements of a row of the receiver and the test material is sorted according to the colour values (measured value of intensity in each colour). In order to improve the detection rate, the invention foresees that in a test material containing reject parts, the colour values of the product are analyzed in several subranges by determining in each subrange a classifier for connecting areas of pixels with colour values occurring in each subrange and by performing a classification according to specified criteria consisting of the geometry and the size o f said detection areas.