Bosch
Automated optical inspection needs images covering many defect types, but Bosch’s manufacturing quality is high, so a new line cannot naturally accumulate enough defective parts. Waiting for real defects delays model and line commissioning; deliberately damaging parts is expensive and still may not cover the full defect space.
Bosch Research used images from an earlier product and only a double-digit number of real examples per defect class to perform domain transfer and generate roughly 15,000 synthetic defect images. Twelve 2D/3D camera views capture stator welds. A vision model trained on real and synthetic data classifies each part and automatically routes repairable defects back into production, while imaging experts review false positives and retrain the model.
The vision model performs high-speed screening and controls the rework route. Imaging engineers review false positives—for example, whether a weak weld is still acceptable—and update the OK/defect boundary through manual retraining. Non-repairable defects remain subject to the plant’s quality process.
- Define the six weld-defect classes and their repairability
- Inventory reusable legacy images and the limited new-product samples
- Use synthetic data to cover long-tail defects instead of waiting for failures
- Connect model output directly to the rework flow
- Have plant experts continuously recalibrate false positives and acceptance boundaries
- Synthetic data can address scarce defect examples in high-quality manufacturing
- Validate synthetic data together with real samples
- Map model decisions to concrete rework and scrap actions
- Domain experts must continue to own the production quality boundary
Bosch reports that approximately 15,000 synthetic images were produced from a double-digit number of real images per defect type. The plant expects the approach to shorten the project by six months and generate annual productivity gains in the six-figure euro range. These are projected benefits while the new line is still being trained and expanded.
- The six-month reduction and six-figure euro gain are Bosch projections; they are not stated as audited realized benefits.
- The public article does not provide train/test splits, false-positive rates, or out-of-sample evaluation.