Patent ID: 7982876

Claim:
Apparatus for automatically inspecting a stream of matter of varying composition, comprising: an emitting device serving to emit electromagnetic radiation of a substantially constant intensity, to an irradiated zone of said stream at which said electromagnetic radiation penetrates a surface of said matter, said irradiated zone extending continuously across substantially the width of said stream, said electromagnetic radiation penetrating said surface and being varied by said matter, a receiving device for receiving the varied electromagnetic radiation emanating from said matter at a detection zone substantially separate from said irradiated zone, a physical light stop serving to isolate said detection zone from said irradiated zone, said physical light stop being a screen comprising one or more adjustable sub-screens distributed across substantially the width of said stream, and a detecting device serving to generate detection data in dependence upon the varied electromagnetic radiation, said matter extends through both said irradiated zone and said detection zone, wherein said detecting device serves to detect the intensity of the electromagnetic radiation emanating from said detection zone of a plurality of selected wavelengths substantially simultaneously and at least the majority of the varied electromagnetic radiation received at said receiving device being that electromagnetic radiation which penetrates said matter and is then scattered by said matter as transflected electromagnetic radiation to be received at said receiving device substantially simultaneously with the emitting of said electromagnetic radiation.