1. Non-invasive method of identifying contours with complex structures having an error recognition rate tending towards zero, which method can be used to distinguish and identify features of a slaughtered animal body with respect to each other, said method being utilised on the basis of a characteristic piece to determine, by means of image processing, data in the form of measurement values of individual sections, partial sections, averaged sections and areas with reference to contour progressions for calculating the muscle-meat percentage, the trade classification and the associated trade value and market value, and also to rate the quality of slaughtered animal bodies with further characteristic image information, characterised in that during error recognition of contours of a slaughtered animal body which have complex structures and which are to be distinguished and identified, an operator at a workstation in the form of a PC interacts with the computer and provides sufficient indications relating to the unidentified or incorrectly identified contour to be sought, in that by employing an image reproduction device at least one support point is in each case set in the illustration of an image of the region of interest of the slaughtered animal body in one or several regions, in which data is to be determined from measurements.