Coins and Precious Metal Surfaces Anomaly Opto solino RTI sensor
Detecting micro defects and surface irregularities using BRDF computational imaging
Customer Task:
Coins, medals and precious metal products require extremely high surface quality standards. In minting processes and precious metal production, even very small surface defects can reduce the value, appearance and authenticity of the final product.
Manufacturers require reliable inspection methods for:
- minted coin surfaces
- engraved structures and micro-details
- reflective precious metal finishes
- security and authenticity features
- surface contamination or mechanical damage
The goal is to detect surface defects early in the production process and ensure consistent quality.
Inspection Challenges:
Inspecting coin surfaces and precious metal finishes presents several challenges for conventional machine vision systems.
Typical challenges include:
- highly reflective metal surfaces such as silver or gold
- complex engraved microstructures
- decorative surface textures and fine radial patterns
- small scratches, dents or contamination
- changing reflections depending on illumination direction
Standard camera systems rely on fixed lighting conditions and often fail to reveal subtle surface irregularities. Strong reflections can hide defects or make inspection results inconsistent.
As a result, many inspections still rely on manual visual inspection performed by trained operators.
Technology Principle
The solino RTI sensor uses BRDF-based computational imaging to reveal surface structures. Within milliseconds the system captures a series of images under different illumination angles and reconstructs the surface reflectance information computationally.
Key elements include:
- 64 multi-directional LED illumination
- photometric stereo image capture
- reflectance-based surface reconstruction
- computational defect enhancement
This approach creates a stable and repeatable inspection environment independent of external lighting conditions.
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Application
The solino 50×50 sensor can be used to inspect coins, medals and precious metal surfaces directly after minting or during final quality control.
Typical inspection targets include:
- coin engravings and relief structures
- fine radial surface textures
- lettering and microstructures
- reflective precious metal finishes
- surface contamination or handling damage
The system captures the surface under 64 illumination directions, even very small defects become visible.
Original RGB image vs. solino surface anomalyCPI Image
Original RGB image vs. solino contrast enhancement CPI Image
Technology Benefits
Using controlled multi-directional illumination, solino enhances the visibility of surface anomalies on reflective precious metal surfaces such as:
- micro scratches or dents on coins
- irregularities in engraved details
- surface contamination or particles
- wear or deformation of fine structures
The technology works particularly well on polished or reflective metal surfaces where traditional imaging often struggles due to uncontrolled reflections.
Original RGB image vs. solino surface texture CPI Image
Solution Architecture: Software & Hardware together in one solution
Item nummer: 100-SO-50-MAN-001 solino 50x50 - Viewer - Stand
The inspection system consists of:
- solino RTI sensor
- integrated dome illumination with 64 LEDs
- high-resolution 20MP industrial camera
- solinoStudio inspection software and batch acquisition and processing
The compact sensor design allows easy integration into production machines.
Inspection workflow:
- Component is positioned under the solino sensor
- The system captures a series of images
- Computational algorithms reconstruct the surface reflectance information
- solino studio allows image capturing and processing
Conclusion
The solino RTI sensor combines controlled illumination with computational imaging to reveal surface structures that are difficult to detect using traditional camera systems.
This enables reliable inspection of coins, engraved surfaces and precious metal products, helping manufacturers maintain the highest quality standards and protect the value.
Additional Image processing and AI available on request
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