7. Conclusion and outlook

This study demonstrates the feasibility of an automatic filter cleanliness measurement system based on digital image analysis. The innovative feature of the proposed system is that it uses standard, low-cost equipment: an office-type scanner connected to a PC. Compared with visual assessment, such a system offers a number of advantages: quantitative, precise and objective measurement, and excellent repeatability of the measurement, regardless of the analysis location. What's more, during the course of the project, the technicians became aware of other advantages offered by these digital techniques, such as simplified sample archiving (around 400 images can be stored on a CD-Rom), or other very useful options in production quality management, such as visualization of test history, monitoring and statistical analysis, etc. Last but not least, the solution adopted is very open-ended, and will...