# The Influence of Filtration on the Results of Measurements Made with Optical Coordinate Systems
## 5 Conclusions  
The obtained measurement results allowed for a series of statistical analyses to be carried out, which confirmed the assumptions regarding the reliability of the results obtained using optical systems with variable-focal-length optics and a variable working distance. The optical sensor in the multisensory machine used for measurements showed  
Figure 10: Games–Howell multiple comparison test.  
Figure 9: Determination coefficient result.  
how significant an impact the use of inappropriate filter sizes can have. The use of a filter has a significant impact on the measurement results; therefore, before using a filter, the user should carefully consider to what extent they want to obtain reliable results reflecting the real image of the measured detail. A compromise must be found between the benefits and losses resulting from the use of an inappropriate filter.  
The conducted study confirmed that filtration is one of the elements that influences the distortion of reality. This fact means that the machine user should analyze the validity of using filtration or balance the benefits of its use. This does not mean that filtration is unnecessary. On the contrary, it is a very useful tool, allowing for measurements and the separation of noise generated in the manufacturing process. The plastic injection process is a complicated manufacturing process, much more difficult than the steel manufacturing process. This conclusion is boldly put, because plastics are more susceptible to the influence of temperature and shrinkage during the process. Post-production processing is also a difficulty, because it is not possible to carry out corrections by means of mechanical processing, unlike for parts manufactured from steel. The use of filtration should be based on experience and tests, so as not to improve too much the real level of quality obtained in the original process.  
The use of filtration with a value higher than \"0\" has an impact on the obtained results. In the conducted studies, it turned out that the use of filtration at the level of \"5\" or \"10\" allowed us to obtain results close to the real ones. In such a case, cutting off noise is a cosmetic procedure, because it does not interfere with the depth of the material but only corrects the measured edge. The use of filter values of \"20\" or more causes distortion of the real dimensions and thus negatively affects the adjustments and settings of machines in the process.  
In addition to confirming the thesis regarding the influence of filtration, the tests carried out in this study also influenced the planning of the next experiment. The authors intend to conduct another study using \"Dust\" filters for details that will be subjected to calibration. Determining the reference value will provide a real reference for the values obtained from measurements using filtration. This will allow us to obtain information on the extent to which the algorithm used affects the actual measurement result.  
Conceptualization, W.Z. and A.G.; methodology, W.Z.; investigation, W.Z. and W.H.; data curation, W.Z. and W.H.; writing--original draft preparation, W.Z. and A.G.; writing--review and editing, W.Z., A.G. and J.A.S.; visualization, W.Z.; supervision, J.A.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Polish Ministry of Education and Science, grant number DWD/4/25/2020.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
Author [PERSON] was employed by the company Lear Corporation Poland II, Sp.z o.o. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.