The smaller the color gap between coating and substrate, the better the coating—yet the harder its edge defects are to see. DaoAI amplifies low contrast from the signal channel itself, not from harder contrast hardware.
This coating web plant applies functional coatings onto transparent or light substrates, where the color difference between coating and substrate is minimal. Coating edges, skips, shrinkage and unevenness are nearly invisible under conventional grayscale imaging. These low-contrast boundaries are the most critical quality metric of the coating process—and the hardest scene for machine vision.
The line previously used plain grayscale thresholds. The faint defect signal drowned in noise; raising the threshold caused misses, lowering it flooded false alarms, forcing constant operator intervention. With the web running at high speed, the human eye simply could not stably catch the subtle color shift at the edge.
The DaoAI AI-AOI Dominant-channel Enhancement Solution
DaoAI AI-AOI introduced dominant-channel enhancement: targeting the specific spectral difference between coating and substrate, it amplifies the low-contrast signal on the most sensitive color channel before handing it to the detection model. Compared with plain grayscale processing, the dominant channel turns a color difference the eye can barely resolve into a clearly judgeable feature, fundamentally raising the detectability of low-contrast boundaries.
- Automatically selects the most sensitive dominant channel per coating-substrate color gap, amplifying faint edge signals
- Recall on hidden defects—coating edges, skips, shrinkage, unevenness—lifted above 95%
- Suppresses background noise under low contrast, cutting false alarms and misses together
- No costly imaging hardware swap—upgrade runs on the existing cameras
Smaller color gap means better coating but harder-to-see defects—dominant-channel enhancement turns invisible low contrast into a judgeable feature.
After deployment, recall on low-contrast coating boundary defects stabilized above 95%. Early detection of skips and shrinkage rose markedly, coating parameter anomalies were flagged at the head of the web, and whole-roll scrap fell. Operators shifted from staring at screens tuning thresholds to handling confirmed defects, improving both efficiency and stability.