Standardized Visual Defect Classification Methods for Greige Cloth Inspection
Standardized greige inspection combines calibrated D65 illumination and 4-point scoring to convert visual cloth defects into precise commercial deductions.
Backlit Transmitted Illumination
Optical Arrangement
Inspection methods for industrial fabrics utilize light sources positioned directly behind the material to reveal structural density. This setup generates backlit transmitted illumination to create high contrast between the solid linen yarns and the open spaces in the weave. By passing light directly through the woven sheet, the system exposes variations in yarn thickness and identifies missed picks.
It establishes a baseline where the solid mass of the flax fiber blocks the rays while empty voids allow maximum light passage.
Detection Efficiency
Woven defects such as slubs or thin spots alter the amount of light that penetrates the cloth. Automated cameras measure this light passage to map the consistency of the linen batch. If a thick knot is present, the transmitted energy drops, triggering a flag in the inspection log.
When a broken warp yarn creates a gap, the brightness surges, confirming a local failure. This variation in transmission operates as a primary metric for identifying irregular pick densities or missing threads. The measurement depends on the thickness of the fabric, the yarn count, the density of the weave and the specific color of the dyed linen.
Defect Isolation
Quality grading protocols in Chinese linen mills use this setup during the final finishing check. Placing the light behind the moving web ensures that internal variations become visible before the fabric is rolled and packed. This continuous monitoring prevents flawed yards from being dispatched to the buyer.
It isolates structural issues before the cloth undergoes subsequent dyeing or treatment.