Abstract: A sorting apparatus for sorting articles randomly disposed across a wide path is characterized by a plurality of side-by-side viewer elements each assigned a corresponding side-by-side sector of an illuminated viewed area through which the articles to be sorted pass. Electrical signals indicative of the instantaneous average value of light reflected from articles at two predetermined wavelengths as those articles pass through a sector of the viewed area are multiplexed and a classification signal functionally related to the ratio of the two signals is determined. The classification signal is compared to a reference signal indicative of an article having a predetermined physical characteristic, and a reject signal is generated if the compared signals differ by a predetermined amount. The reject signal is stored in an assigned memory location corresponding to the sector of the viewed area through which the article passed.