Perception-based Line Quality Measurement

It is well-known that many sub-attributes of line quality, such as edge raggedness, line waviness, etc., contribute to the perception of the overall line quality. But the relative importance of these sub-attributes is not clear, nor is there a method available for combining them into one representative number for overall line quality. To address these issues, we have designed and conducted a series of psychophysical experiments, which explore the shape of the human visual transfer functions (VTF) relevant to the perception of these sub-attributes. Based on this, we have proposed an approach to assess overall line quality. In our method, we first pre-process the line image acquired (for example from a scanner) and extract certain profiles relevant to line quality measurement. A set of corresponding VTF’s is then applied to these profiles to calculate the various sub-attributes. Finally, overall line quality is determined by the weighted combination of these individual sub-attributes. Our preliminary results show that this measurement correlates well with human perception of overall line quality, for the sub-attributes studied.