Denim AI Visual Inspection Equipment
Denim AI visual inspection equipment targets indigo-dyed denim fabric, performing inline inspection of skew, holes, color differences, weaving defects, slub interference, cat's whisker indentations and other defects, with OK/NG output and production line interlocking.
Materials Overview
Indigo surface reflection + slub texture create double interference with judgement
Denim AI visual inspection equipment images indigo-dyed denim fabric, and the algorithm identifies defects such as weft skew, holes, color difference, weaving defects, slub interference, and cat's-whisker indentation, outputs OK/NG results, and interlocks with the production line. It is suitable for roll and cut-piece formats.
Denim is usually indigo-dyed with slub yarns (irregular thick and thin sections) and has a certain amount of surface reflection. The slubs themselves are normal texture but resemble weaving defects such as weft breaks and thick warp, so they are easily confused; and the reflection from the indigo surface swallows scratch and relief detail. These two points are the typical interference in denim inspection.
Defects specific to denim include weft skew (skewed fabric surface), holes, color difference (indigo batch variation), weaving defects (broken warp or weft, float stitches), abnormal slubs, cat-whisker indentation (finishing creases), and oil stains. Among these, weft skew is a geometric problem and requires angle measurement for judgement.
Denim is mostly used in garments and bags and luggage, with high output and fast material feed. For inspection, AI treats slubs as normal background and then identifies real defects; weft skew is measured using the edge and texture direction angle. Changing dye lots mainly requires adjusting the color datum.
Applicable Type
Raw Denim
Unwashed, the focus is on weaving defects and weft skew
Washed Denim
Whisker creases are present; process effects must be distinguished from defects
Stretch Denim
Contains spandex; positioning prevents stretching
Denim Cut Pieces
Already cut, inspected piece by piece with defect locating
Denim Roll Stock
Continuous material feed, line-scan full-width inspection
Common defect
| Defect Types | Typical Manifestations | Inspection Focus Points |
|---|---|---|
| Weft skew | Fabric texture direction is skewed | Angle measurement judgement; a geometry issue |
| hole | Warp/weft breakage forming holes | Backlight Is the Most Direct |
| color difference | Indigo batch variation, shade variation | Stable Color Reference |
| Weaving Defects | Broken warp/weft, skipped yarn | Distinguish From Slubs |
| Slub Abnormality | Slub too thick or missing | Build a normal slub model |
| Whiskering / Indentation | Finishing Creases | Separate process marks from defects |
| oil stain | Oil Spots, Stains | Compared against indigo background |
| Foreign fibers | White Filaments, Off-color Yarn | High-contrast Features |
inspection Workflow
Complete chain from loading to judgment
- 01 Denim loading / roll unwinding or cut-piece feeding
- 02 Flattening and tension control
- 03 Triggered imaging (suppresses glare)
- 04 Texture orientation angle measurement (weft skew)
- 05 Slub background modeling
- 06 Defect segmentation and classification
- 07 Defect Grading
- 08 Synthesized OK / NG
- 09 Marking / rejection and image archiving
AI Inspection Principles
AI Visual Inspection Principles
Denim inspection has to deal with both "reflection" and "slub interference". The algorithm first builds a model of the normal slub texture and a color baseline, isolating true defects such as missing weft, holes and color difference; weft skew is measured geometrically using the texture direction angle. If indigo reflection is not suppressed adequately, scratch-type defects cannot be imaged.
For illumination, diffused light provides even lighting and suppresses indigo reflection; low-angle light exposes cat's whisker creases and surface relief; backlight is used for holes. On washed denim the cat's whisker effect is a process feature, so the acceptance criteria must state clearly whether it is rejected.
For judgement, we recommend modeling the slubs as normal background and treating weft skew as a separate geometric item. The specific threshold and angle tolerance must be confirmed by measurement with OK / NG samples and the acceptance specification.
Applicable Industry
Applicable equipment
Common Question
How Do You Distinguish Slubs from Weft Breaks?
Can Weft Skew Be Measured Automatically?
Are whisker creases on washed denim counted as defects?
Indigo Is Highly Reflective: Can Scratches Still Be Seen Clearly?
What is the inspection accuracy?
What samples are needed to develop a solution?
Can It Be Integrated Into an Existing Production Line?
Submit sample testing
Send us OK and NG samples of denim in different states such as raw and washed, and we will run slub modeling and weft skew measurements and provide illumination plan and judgement recommendations.
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We have received your sample testing request. A solution engineer will contact you within 1 business day via contact you.
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Send Us Your Material and We Will Show You the Measured Results
Provide several OK and NG samples of the material, and a solution engineer will run actual imaging and judgement tests on the equipment to give a workable inspection configuration recommendation, rather than reading the datasheet alone.