An arrangement for the optical evaluation of harvested crop in a harvesting machine includes a camera located for taking images of threshed out crop elements (grain and material other than grain) being conveyed within a channel of the machine. An electronic image processing system receives the images and identifies individual objects in the images, these objects being classified into predetermined object classes by way of comparing at least one of color, contour or texture features of the individual objects and corresponding characteristics of reference objects filed in a data bank. The processing system then determines the absolute or relative numbers or areas of the individual objects assigned to the respective object classes.