# Evaluation of an Optical Sorter Effectiveness in Separating Maize Seeds Intended for Sowing
## 1 Introduction
The complexity of the technological conditioning process is different from one station to another, which is determined by the degree of difficulty of cleaning certain seeds, as well as the requirements for their sowing [38]. The simplest processes are in the household-type stations, and the most complex in the corn drying and calibrating stations [39; 40; 41]. The density at sowing the hybridization lots was considered efficient in the past around the values of 65-70,000 plants\(\cdot\)ha\({}^{-1}\); however, the current market trends encourage a higher sowing density. This can lead to quality problems, which may imply the need for further separation [42; 43]. After harvesting, the seeds contain various impurities (minerals, organic residues, seeds of weeds and other cultivated plants, splinters, insects, etc.). The presence of these foreign bodies in the grain mass exerts a negative influence on the preservation of the products, diminishing the technical food value and the germinative properties of the seeds. In addition, some products contain toxic weed seeds or insects at different stages of development. In order to improve the purity of the products and create homogenous batches in terms of uniformity, the product mass has to be cleaned and sorted [44; 45]. There are several technical solutions for sorting operations, such as mechanical, pneumatic, aerodynamic, and optical separation. In current agricultural practices, mechanical cleaning and sorting solutions have the greatest weight [46; 47]. Cleaning represents the set of operations performed to remove impurities from the mass of products while sorting aims to separate the seed categories of size, shape, and color. That is why, in order to establish a technology for separating impurities, the physical-mechanical properties of both the basic product and the impurities were analyzed [48; 49; 50]. The most significant quality requirements regarding the purity and uniformity of the grains are met in the field of processing and obtaining seeds intended for sowing [51; 52; 53; 54]. This fact is due to the need to perpetuate and use the biological value of a species (to obtain high production, special nutritional properties, and higher resistance to stress factors and diseases), and to create optimal conditions for sowing and sprouting (when the seeds are uniform, their phytosanitary status and germination are good, the seeders have a safer and more precise operation, the sprouting is uniform, the plants start growing simultaneously, and the differences in the level of development are small). In addition, the time needed for harvesting the fields is longer, which can reduce natural and artificial losses [55; 56; 57; 58; 59; 60]. The aim of the current research was to determine the technological impact of an optical sorter on improving the quality of maize seeds destined for sowing. Therefore, the goal of the case study was to isolate the production flow's main challenges and implement the best corrective measures to minimize operating problems. The degree to which the contaminants may be reduced was determined using two different methods of testing. In this way, farmers will be able to select and effectively manage the technical elements of a grain-cleaning flow. The work approach described in this research, as well as the outcomes, may be of great interest for the implementation of separation technologies. The study also aims to address an issue that farmers typically do not anticipate, namely the possibility that a significant amount of high-quality seeds could be lost during the optical separation process.