Line quality analysis
Line Quality Measurement Using Contour-Based Straightness Ratio
Line quality is assessed by comparing the actual path length of a line’s contour to the ideal straight-line distance between its endpoints.
The measured path is obtained by tracing the contour from the top to the bottom of the line.
The straight-line reference is the direct Euclidean distance between the topmost and bottommost points.
- The line quality ratio is defined as:
Line Quality Ratio= Contour Length/Straight-Line Distance
- A perfectly straight line yields a ratio of 1.00.
Counterfeit lines often exhibit in- and outward bulges, increasing the contour length and thus the ratio (e.g., 1.40).
In practice, even genuine but circulated or soiled notes typically remain below 1.01, preserving high line fidelity.
This metric provides a robust, quantitative method for detecting deviations from expected line geometry in high-resolution banknote images.
Genuine
