Difference Metric
Visual discrimination values represent the delta between a defect signal and the background noise of a fabric surface. A favorable optical contrast ratio allows for the automatic detection of small shade variances or oil spots during mill inspection. Higher values improve the reliability of sorting machines by making flaws clearly visible against the native texture of the weave.
Imaging Setup
Lighting placement relative to the camera lens determines how shadows and highlights reveal fiber irregularities. The optical contrast ratio must be high enough to trigger the detection algorithm without causing false alerts from the shadows of a heavy knit. Adjusting the strobe intensity or the angle of incidence optimizes the clarity of the image stream.
When colors are very dark, software enhancement is required to artificially boost the gap between common yarn and foreign particulates.
Algorithm Success
Effectiveness peaks when the sensor can distinguish between a deliberate slub and a contaminating speck. A low optical contrast ratio causes the quality control system to miss subtle defects that may later appear in the finished garment.
Verification Check
Testing the setup involves using calibrated targets with known reflectance levels to ensure sensor stability. Consistent optical contrast ratio levels keep the fabric grading consistent across different mill shifts.
