Capture quality should be checked before interpretation
In GDV/EPI analysis, changes in contrast, sharpness, finger position, clipping or saturation can alter the geometry of the light pattern. If these technical changes are mistaken for a biological signal, apparent differences may simply reflect capture conditions. Quality control therefore belongs before morphology, sector interpretation or longitudinal trend analysis.
This demo uses only general properties of the image file. It estimates dynamic range, a basic sharpness proxy, saturated pixels, bright signal near the border and centroid offset. It does not know the GDV camera calibration, actual exposure, finger identity, skin condition or capture protocol. Its score is therefore a technical orientation, not a validated GDV index.
What to check before a retake
- whether the pattern is clipped by the image border;
- whether a large part of the image is saturated;
- whether the image is obviously blurred or off-centre;
- whether the technical anomaly repeats in the next capture.