# Evaluation of an Optical Sorter Effectiveness in Separating Maize Seeds Intended for Sowing
## 4 Discussion  
The quality of the work performed by the optical sorter in the scenario under investigation can be assessed by comparing it with other sorters that operate according to other principles. In the case of aerodynamic or mechanical separation, for example, there are several options for controlling the operational processes to ensure that the primary product is not lost. The quality of the raw materials gained by calibration and gravitation in this instance allows for direct market sale of the seeds. That is why the expectations after the introduction of an optical sorter were very high. The farmers expected to increase the quality level without compromising the base material.  
Recent studies on optical separation technologies are focused less on the separation of impurities and more on the detection of certain illnesses, determining certain resistant breeding lines, and the development of seedlings for use in new industries, such as suspended greenhouses [61; 62; 63; 64]. A study that researched the optical removal of mycotoxin-contaminated kernels using a dual-wavelength high-speed commercial sorter [65] found that in the first pass through the sorter, aflatoxin was reduced by an average of 46%, and fumanisin was reduced by 57% while removing 4% to 9% of the corn. In the second pass of the accepted kernels, aflatoxin was reduced by 88% while removing approximately 13% of the corn. One study [66] obtained very good results for separating different corn varieties using optical sorting, showing that for this objective, optical separation could be the best technological solution. Other studies, which focused on the sorting of several types of wheat [67], showed separation results close to those found in the present research. For commercial sorters, more sorting indices have been developed as a result of the complexity of the sorting process and the development of various spectrum pretreatments, although many of them are not suitable for high-speed implementations.  
The optical sorter tested in our study cannot remove impurities without removing good grains along with them. This is proven by the fact that when there are higher impurities (6.83% compared to 2.82%) from the rate of good seeds entering the processing, the percentage of good grains that are lost to rejection is higher (4.50% compared to 1.34%). As a result, the loss of useful grains may be a typical operational characteristic of the optical sorting technology that users should be aware of and accept; otherwise, it might seem to be a technical issue. For each increase in an impurity by 1% of the mass of seeds entering the  
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Table 2: The quality of the products (direct method (DM), using “artificial impurity” method).  
optical sorter, there are 0.16% of extracted impurities, but 0.70% of good seeds are also lost as \"reject\".  
This situation shows that the processing efficiency of the optical sorter is low for raw materials with a relatively high-quality level. The overall performance of the equipment is negatively impacted by the loss of high-quality seeds. At the same time, it should be noted that the value of the good grains lost by sending them to \"refuse\" represents a financial loss, considering the expense incurred for the production of the respective grains. This results in an increase in production costs while income decreases. Under these conditions, the profit is reduced by the increase in expenses on the one hand, but there is also a decrease in income on the other hand.  
The goal of the current Romanian agricultural practice is to achieve an equilibrium where it is preferable to leave a small quantity of impurities unremoved rather than discard the useful product and incur financial losses. Moreover, in many cases, these impurities can be eliminated in the next stage of the technological flow.  
The optical sorter is useful in all cases when the value of the main product lost by elimination to \"refuse\" is lower than the value created by increasing the quality of the processed seeds.