An optimization method improves article pickup and discharge reliability in a picking process using a robot. An article is picked-up from or out of a first load carrier and is placed in or on or dropped into or onto a second load carrier by a gripping unit on the robot head. In an image processing step, a gripping pose for the gripping unit is calculated for picking-up the article by determining at least one dimension from a captured image and by determining a range allocation by comparing with dimension ranges. Using a confidence value, a dimension value is determined, from stored article reference data or from a normalization value of the dimension range and allocated to the determined dimension. In a preparation step, a mathematical scattering measure function is applied for the determined dimension and dimension ranges, and normalization and confidence values of the dimension ranges are determined therefrom.